TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.100 PURPOSE
Section 370.100 Purpose
The purpose of this Part is to
establish criteria for the design and preparation of plans and specifications
for wastewater collection and treatment systems.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
 | TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.110 SCOPE AND APPLICABILITY
Section 370.110 Scope and
Applicability
a) These design criteria apply to conventional design concepts
for wastewater collection and treatment systems. Where non-conventional
concepts or approaches to collection and treatment, particularly for very small
systems, are being considered, the Agency should be contacted for any design
guidance that may be available.
b) In evaluating plans and specifications for new processes, the
Agency will consider the specific information submitted with the design in
accordance with the provisions of Section 370.520(b) for situations involving
new process evaluation.
c) These criteria are intended to establish limiting values for
those aspects of plans and specifications which the Agency evaluates and to
promote, as far as practicable, uniformity of practice throughout the State.
For projects with a design flow average of over 100 million gallons per day
(mgd), the application of specific design parameters in these criteria should
be evaluated on a unit-by-unit basis to insure optimum design performance and
cost effective construction. In applying these criteria, consideration must be
given to the characteristics (including current water quality) and uses of the
receiving stream in order to insure compliance with the applicable regulations
of the Illinois Pollution Control Board (hereinafter "IPCB"). Users
should also be cognizant of Federal requirements.
d) The word "shall" is used where practice is
sufficiently standardized to warrant compliance with specific requirements, or
where safeguarding the public health or protecting water quality justifies such
definite action. Words such as "should", "recommended" or
"preferred" indicate desirable procedures or methods with deviations
subject to individual project consideration.
e) Definitions of terms and their use are intended to be in
accordance with the GLOSSARY – WATER AND WASTEWATER CONTROL ENGINEERING,
jointly prepared by the American Public Health Association (APHA), American
Water Works Association (AWWA), American Society of Civil Engineers (ASCE), and
Water Environment Federation (WEF). The units of expression are in accordance
with the WEF Manual of Practice Number 6, Units of Expression for Wastewater
Treatment.
(Source: Added at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.115 INCOPORATIONS BY REFERENCE
Section 370.115
Incoporations by Reference
a) The following materials are incorporated by reference:
1) "Glossary: Water and Wastewater Control
Engineering", Joint Editorial Board of the American Public Health
Association, American Society of Civil Engineers, American Wasteworks
Association, American Pollution Control Federation (1969).
2) ASTM Standards – American Society for Testing and Materials,
100 Bar Harbor Drive, West Conshohoken PA:
ASTM C12-95 – "Standard Practice for Installing
Vitrified Clay Pipe Lines", Vol. 04.05, Chemical Resistant Materials,
Vitrified Clay, Concrete, Fiber-Cement Products; Mortars; Masonry (1996).
ASTM C969-94 – "Standard Practice for Infiltration and
Exfiltration Acceptance Testing of Installed Precast Concrete Pipe Sewer
Lines", Vol. 04.05, Chemical Resistant Materials, Vitrified Clay,
Concrete, Fiber-Cement Products; Mortars; Masonry (1996).
ASTM C124 – "Standard Test Method for Concrete Sewer
Manholes by the Negative Pressure (Vacuum) Test", Vol. 04.05, Chemical
Resistant Materials, Vitrified Clay, Concrete, Fiber-Cement Products; Mortars;
Masonry (1996).
ASTM D2321 – "Standard Practice for Underground
Installation of Themoplastic Pipe for Sewers and Other Gravity-Flow
Applications", Vol. 08.04, Plastic Pipe and Building Products (1996).
3) "AWWA Standard for Installation of Ductile-Iron Mains and
their Appurtenances", ANSI/AWWA C600-93 (1994) American Wasteworks
Association, 6666 Quincy Avenue, Denver CO 80235.
4) "National Electrical Code Handbook", 7th ed. (1996),
National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101,
Quincy MA 02269-9101.
5) "Standard Specifications for Water and Sewer Main
Construction in Illinois", 5th ed. (1996), Illinois Society of
Professional Engineers, Illinois Municipal League, the Association General
Contractors of Illinois, Underground Contractors Association.
6) "Standard Specifications for Road and Bridge
Construction" (1997), Illinois Department of Transportation.
7) Manuals of Practice, Joint Task Force of the Water Environment
Federation (WEF) (formerly Water Pollution Control Federation), 601 Wythe
Street, Alexandria VA 22314-1994 and the American Society of Civil Engineers
(ASCE), 345 East 47th Street, New York NY 10017-2398:
"Gravity Sanitary Sewer Design and Construction",
WPCF Manual of Practice (MOP) No. FD-5 (1982).
"Units of Expression for Wastewater Management",
WEF Manual of Practice (MOP) No. 6 (1982).
"Design of Municipal Wastewater Treatment Plants",
vol. 1, WEF Manual of Practice (MOP) No. 8 (1992).
b) The incorporations cited in this Section include no further
editions or amendments.
(Source: Added at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART B: ENGINEERING REPORTS, PLANS AND SPECIFICATIONS
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.200 GENERAL
Section 370.200 General
The criteria in this Subpart B
are intended to be the technical basis for the preparation of the engineering
reports and plans and specifications for waste collection and treatment works.
For project planning requirements, applicable State and Federal guidance,
regulations and statutes shall be consulted.
a) Grant Projects
For projects
that will be funded by Stateor Federal grants, applicable regulations, policy
and guidance documents will govern the non-technical requirements and shall be
used in the facility planning process.
b) Non Grant Projects
For those
projects which are not covered by applicable State or Federal project planning
requirements or for those other projects in which there is no project planning
guidance in the applicable State or Federal regulations or statutes, the
project planning guidance set forth in Section 370.112 shall be utilized.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.210 ENGINEERING REPORT
Section 370.210 Engineering
Report
a) General
1) The engineering report assembles basic information; presents
design criteria and assumptions; examines alternate projects including
preliminary layouts and cost estimates; describes financing methods, user
charges and operation and maintenance costs; reviews organizational and
staffing requirements; offers a conclusion with a proposed project for client
consideration; and outlines official actions and procedures to implement the
project.
2) The concept, factual data and controlling assumptions and
considerations for the functional planning of sewerage facilities are presented
for each process unit and for the whole system. These data form the continuing
technical basis for the detailed design and preparation of construction plans
and specifications.
3) Architectural, structural, mechanical and electrical designs
are usually excluded. Sketches may be used to aid in presentation of a
project. Outline specifications of process units, special equipment, etc., may
be included.
4) Engineering reports are not required for sewer extensions or
sewer connections, but shall be required for the following projects:
A) New treatment plants.
B) Expansion or major modification of existing plants.
C) New collection systems.
D) Major upgrading of existing collection systems.
b) Content
The
engineering report shall:
1) Prescribe design period and projected population.
2) Describe the specific service area for immediate consideration
and indicate possible extensions and ultimate use.
3) Present data and information on anticipated quantities of flow
and wastewater constituents. Data from comparable existing installations may
be used to develop the design basis of the proposed facilities if data for the
project under design cannot be obtained in accordance with procedures set forth
in Subparts C, D and E of these standards.
4) Specify the scope and nature of collection system including
pump stations and force mains for immediate and ultimate service areas.
5) Discuss various treatment alternatives with reference to
optimum treatability and other relevant factors.
6) Develop a detailed basis of design for the recommended
treatment process.
7) Indicate compliance with applicable effluent limitations and
discuss the impact of the project on receiving waters.
8) Indicate compliance with the requirements of the Illinois
Groundwater Protection Act [415 ILCS 55].
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.211 DESIGN FLOWS
Section 370.211 Design Flows
The following flows shall be
identified in the basis of design for sewers, lift stations, sewage treatment
plants, treatment units and other wastewater handling facilities.
a) Design Average Flow
The design
average flow is the average of the daily volumes to be received for a
continuous 12-month period of the design year, expressed as a volume per unit
of time.
b) Design Maximum Flow
The design
maximum flow is the largest volume of flow to be received during a continuous
24-hour period, expressed as a volume per unit of time.
c) Design Peak Hourly Flow
The design
peak hourly flow is the largest volume of flow to be received during a one hour
period, expressed as a volume per unit of time.
d) Design Peak Flow
The design
peak flow is the instantaneous maximum flowrate to be received.
(Source: Added at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.220 DETAILED ENGINEERING PLAN DRAWINGS FORMAT
Section 370.220 Detailed
Engineering Plan Drawings Format
a) General
Detail plans shall contain as necessary, the following:
1) Plan views.
2) Elevations.
3) Sections and supplementary views which, together with the
specifications and general layouts, facilitate construction of the works.
4) Dimensions and relative elevations of structures.
5) Location and outline form of equipment.
6) Location and sizing of piping.
7) Water levels.
8) Ground elevations.
9) Location and identification of all private and public water
supply wells (refer to Section 370.210(b)(8)), structures and facilities (refer
to Section 370.350(b)(1)(A)).
10) Descriptive notations as necessary for clarity.
b) Plans of Sewers
1) General Plan
Except as provided in subsection (b)(1)(C) below, a
comprehensive plan of the existing and proposed sewers shall be submitted for
projects involving new sewer systems or substantial additions to existing
systems. This plan shall show the following:
A) Geographical Features
i) Topography and elevations: Existing or proposed streets and
all streams or water surfaces shall be clearly shown. Contour lines at suitable
intervals should be included.
ii) Streams: The direction of flow in all streams, and high and
low water elevations of all water surfaces at sewer outlets and overflows shall
be shown.
iii) Boundaries: The boundary lines of the municipality and the sewer
district or area to be sewered shall be shown.
B) Sewers
The plan shall show the location, size and direction of flow
of all existing and proposed sanitary and combined sewers draining to the
treatment works concerned.
C) Sewer Atlas
The comprehensive plan of the existing sewers described above
need not be submitted in each case if the system owner has furnished the Agency
a copy of its sewer atlas showing the information required by subsection
(b)(1). The project submittal, however, must include all the proposed work,
and must be accompanied by a location map showing the proposed project and the
route of the outlet sewer to the receiving plant, where necessary.
2) Detail Plans
Detail plans shall be submitted. Profiles should have a
horizontal scale of not more than 100 feet to the inch and a vertical scale of
not more than 10 feet to the inch. Plan views should be drawn to a
corresponding horizontal scale. Plans and profiles shall show:
A) Location of streets and sewers.
B) Line of ground surface, size, material and type of pipe, length
between manholes, invert and surface elevation at each manhole, and grade of
sewer between each two adjacent manholes. All manholes shall be numbered on
the plan and correspondingly numbered on the profile.
C) Except where overhead sewers are required by local ordinance,
if there is any question of the sewer being sufficiently deep to serve any
residence, the elevation and location of the basement floor shall be plotted on
the profile of the sewer which is to serve the house in question. The engineer
shall state that all sewers are sufficiently deep to serve adjacent basements
except where otherwise noted on the plans.
D) Locations of all special features such as inverted siphons,
concrete encasements, elevated sewers, etc.
E) All known existing structures both above and below ground which
might interfere with the proposed construction, particularly water mains, gas
mains, storm drains, etc.
F) Special detail drawings, made to a scale to clearly show the
nature of the design, shall be furnished to show the following particulars:
i) All stream crossings and sewer outlets, with elevations of
the stream bed and of normal and extreme high and low water levels.
ii) Cross sections and details of all special or non standard
joints.
iii) Details of all sewer appurtenances such as manholes,
lampholes, inspection chambers, inverted siphons, regulators, tide gates and
elevated sewers.
c) Plans of Sewage Pumping Stations
1) Location Plan
A plan shall be submitted for projects involving construction
or revision of pumping stations. This plan shall show the following:
A) The location and extent of the tributary area.
B) Any municipal boundaries within the tributary area.
C) The location of the pumping station and force main.
2) Detail Plan
Detail plans shall be submitted showing the following where
applicable:
A) Grading plan of the station site.
B) Location of existing pumping station.
C) Proposed pumping station, including provisions for installation
of future pumps or ejectors.
D) Elevation of high flood water at the site, and maximum
elevation of sewage in the collection system upon occasion of power failure,
and the pumping station elevations.
E) Test borings and groundwater elevations.
F) Force main routing and profile.
d) Plans of Sewage Treatment Plants
1) Location Plan
A) A plan shall be submitted showing the sewage treatment plant in
relation to the remainder of the system.
B) Sufficient topographic features shall be included to indicate
its location with relation to streams and the point of discharge of treated
effluent.
C) All residences within one-half mile of the site shall be shown.
2) General Layout
Layouts of the proposed sewage treatment plant shall be
submitted, showing:
A) Topography of the site.
B) Size and location of plant structures.
C) Schematic flow diagram showing the flow through various plant
units.
D) Piping, including any arrangements for by-passing individual
units. Materials handled and direction of flow through pipes shall be shown.
E) Test borings and expected range of ground water elevations.
3) Detail Plans
Detail plans shall show the following:
A) Location, dimensions and elevations of all existing and
proposed plant facilities, including flood protection structures where
applicable.
B) Elevations of high and low water levels of the body of water to
which the plant effluent is to be discharged.
C) Type, size, pertinent features, and manufacturer's rated
capacity of all pumps, blowers, motors and other mechanical devices.
D) Hydraulic profiles of the treatment plant at design peak flow
including recirculated flows at the 25-year flood elevation in the receiving
watercourse. To ensure their proper functioning, the hydraulic profile at
measuring devices at minimum flow shall be shown.
E) Hydraulic profiles shall be shown for supernatant liquor lines,
recirculating flow piping and sludge transfer lines at the design peak flows
carried by each system.
F) Adequate description of any features not otherwise covered by
specifications or engineer's report.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.230 SPECIFICATIONS TO ACCOMPANY DETAILED ENGINEERING PLAN DRAWINGS
Section 370.230
Specifications to Accompany Detailed Engineering Plan Drawings
a) Complete technical specifications for the construction of
sewers, sewage pumping stations, sewage treatment plants, and all
appurtenances, shall accompany the plans.
b) The specifications accompanying construction drawings shall
include, but not be limited to, the following:
1) All construction information, not shown on the drawings, which
is necessary to inform the builder in detail of the design requirements as to
the quality of materials and workmanship and fabrication of the project.
2) The type, size, strength, operating characteristics and rating
of equipment.
3) Allowable infiltration.
4) The complete requirements for all mechanical and electrical
equipment, including machinery, valves, piping and jointing of pipe.
5) Electrical apparatus, wiring and meters.
6) Laboratory fixtures and equipment.
7) Operating tools.
8) Construction materials.
9) Special filter materials such as stone, sand, gravel or slag.
10) Chemicals when used.
11) Miscellaneous appurtenances.
12) Instruction for testing materials and equipment as necessary.
13) Availability of soil boring information.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.240 REVISIONS TO APPROVED PLANS AND SPECIFICATIONS
Section 370.240 Revisions to
Approved Plans and Specifications
a) Any deviations from approved plans or specifications for
structural configuration, appurtenances or manufactured equipment, affecting
capacity, flow, operation of units or operational safety, and for substitution
of the manufactured equipment specified and depicted in the plan documents
shall be approved in writing by the Agency before such installation of
equipment or construction changes are made.
b) Plans and specifications requiring Agency approval under
subsection (a) should be submitted well in advance of the ordering and delivery
of equipment or any construction work which will be affected by such changes,
to allow sufficient time for review and approval. Record drawings of the
project as completed shall be submitted to the Agency.
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.250 OPERATION DURING CONSTRUCTION
Section 370.250 Operation
During Construction
Specifications shall contain a
time schedule describing the plant and collection system operational modes
during construction. Where units essential to effluent quality are involved,
temporary measures, such as wet hauling, sludge storage lagoons and portable
pumping facilities shall be included in the specifications so as to ensure
continuity of operation as required and approved by the Agency.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.260 ENGINEERS SEAL
Section 370.260 Engineers
Seal
Plans and specifications,
prepared by an Illinois Registered Professional Engineer when required by
Section 14 of the Illinois Professional Engineering Act [225 ILCS 325/14],
fully describing the design, nature, function and interrelationship of each individual
component of the facility or source, shall be submitted, except that the Agency
may waive this requirement for plans and specifications when the application is
for a routine renewal.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART C: DESIGN OF SEWERS
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.300 GENERAL CONSIDERATIONS
Section 370.300 General
Considerations
a) Type of Sewers
The Agency
will approve plans for new sewer systems and extensions only when designed as
the separate sanitary type in which precipitation runoff and ground water from
foundation drains are excluded. The Agency will not approve the installation
of new combined sewers, except as provided in 35 Ill. Adm. Code 306.302.
b) Design Period
Sewer systems
should be designed for the estimated ultimate tributary population, except in
considering parts of the systems that can be readily increased in capacity.
Similarly, consideration should be given to the maximum anticipated capacity of
institutions, industrial parks, etc.
c) Design Factors
In determining
the required capacities of sanitary sewers, the following factors should be
considered:
1) Design peak flow.
2) Additional design peak flow from industrial plants.
3) Ground water infiltration.
4) Topography of area.
5) Location of waste treatment plant.
6) Depth of excavation.
7) Pumping requirements.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.310 DESIGN BASIS
Section 370.310 Design Basis
a) Per Capita Flow
1) New Sewers for Undeveloped Areas
New sewer
systems to serve currently undeveloped areas shall be designed on the basis of
a design average flow of not less than 100 gallons per capita per day which is
assumed to cover normal infiltration, but an additional allowance should be
made where conditions are unfavorable.
2) New Sewers for Existing Developed Areas
For new sewers
designed to serve existing developed areas, the design average flow per capita
(100 gpd) shall be appropriately increased to allow for inflow/infiltration
contributions from the existing buildings other than roof and foundation drains
which shall be excluded in accordance with Section 370.121(a).
b) Design Peak Flow
1) The design peak flow for sanitary sewers shall be selected
based on one of the following methods:
A) The ratio of peak to average daily flow as determined from
Appendix D, Figure No. 1.
B) Values established from an infiltration/inflow study acceptable
to the Agency.
2) Use of other values for the design peak flow will be
considered if justified on the basis of extensive documentation.
3) Combined Sewer Interceptors
Intercepting
sewers, in the case of combined sewer systems, should fulfill the above
requirements for sewers and have sufficient additional capacity to transport
the increment of combined sewage required by the IPCB Regulations.
c) Alternate Methods
When
deviations from subsections (a) and (b) are proposed, a description of the
procedure used for sewer design shall be included in the submission of plan
documents.
d) Basis of Design and Calculations
The basis of
design for all sewer projects shall accompany the plan documents. Calculations
shall be submitted to show that sewers will have sufficient hydraulic capacity
to transport the design peak flows.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.320 DETAILS OF DESIGN AND CONSTRUCTION
Section 370.320 Details of
Design and Construction
a) Minimum Size
No public
gravity sewer conveying raw sewage shall be less than 8 inches in diameter.
b) Depth
Sewers shall
be sufficiently deep to prevent freezing. Sewers should be sufficiently deep
to serve basements except where overhead sewers are required by local
ordinances or will be provided.
1) Minimum Cover
The minimum
cover of sewers shall be no less than 3 feet unless special structural
protection is provided.
2) Buoyancy
Where high
ground water conditions are anticipated, buoyancy of sewers shall be considered
and, if necessary, adequate provisions should be made for protection.
c) Slope
1) All sewers shall be designed and constructed to give mean
velocities, when flowing full, of not less than 2.0 feet per second, based on
Manning's formula using an "n" value of 0.013. The following minimum
slopes shall be provided; however, slopes greater than these are desirable:
|
Slope in Feet
|
|
|
|
|
|
|
|
Sewer Size
|
Per 100 Feet
|
Flow (mgd)
|
|
|
|
|
|
8 inch
|
0.40
|
0.49
|
|
10 inch
|
0.28
|
0.75
|
|
12 inch
|
0.22
|
1.07
|
|
14 inch
|
0.17
|
1.43
|
|
15 inch
|
0.15
|
1.61
|
|
16 inch
|
0.14
|
1.85
|
|
18 inch
|
0.12
|
2.35
|
|
21 inch
|
0.10
|
3.23
|
|
24 inch
|
0.08
|
4.13
|
|
27 inch
|
0.067
|
5.17
|
|
30 inch
|
0.058
|
6.37
|
|
33 inch
|
0.050
|
7.66
|
|
36 inch
|
0.046
|
9.23
|
|
42 inch
|
0.036
|
12.41
|
2) Under special conditions, if detailed justifiable reasons are
given, slopes slightly less than those required for the 2.0 feet per second
velocity when flowing full may be permitted. Such decreased slopes will only
be considered where the depth of flow will be 0.3 of the diameter or greater
for design average flow. Whenever such decreased slopes are selected, the
design engineer must furnish with his report his computations of the depths of
flow in such pipes at minimum, design average, and design peak rates of flow.
It must be recognized that decreased slopes may cause additional sewer
maintenance expense and special linings or materials should be considered for
corrosion protection.
3) Uniform Slope
Sewers shall be laid with uniform slope between manholes.
4) Steep Slope Protection
Sewers on 20 percent slope or greater shall be anchored
securely with concrete anchors or equal, spaced as follows:
A) Not over 36 feet center to center on grades 20 percent and up
to 35 percent.
B) Not over 24 feet center to center on grades 35 percent and up
to 50 percent.
C) Not over 16 feet center to center on grades 50 percent and
over.
d) Alignments
1) Straight Alignments
Except as noted in subsection (d)(2), all sewers shall be
laid with straight alignments between manholes.
2) Curvilinear Alignments
Curvilinear sewers are permitted in special cases provided
the following minimum requirements are met:
A) Curvilinear Sewers 24 Inches in Diameter and Smaller
i) Location: Curvilinear alignments should follow the general
alignment of streets.
ii) Type Curve: Only simple curve design is acceptable.
iii) Radius of Curvature: The minimum allowable radius of
curvature is 300 feet.
iv) Manholes: Manholes are required at the beginning and end of
all curves.
v) Joints: Compression joints are required. The ASTM or AWWA
maximum allowable deflection of the pipe joints shall not be exceeded.
vi) Velocity: In order to maintain a minimum velocity of 2 feet
per second in curvilinear sewers, hydraulics of the curvilinear alignment shall
be taken into account and the minimum slopes indicated in subsection (c)(1)
must be increased accordingly.
B) Curvilinear Sewers 24 Inches Through 48 Inches in Diameter
Curvilinear sewers larger than 24 inches in diameter up to 48
inches in diameter constructed with pressure pipe meeting AWWA standards may be
used. Other curvilinear sewers larger than 24 inches in diameter up to 48
inches in diameter shall meet the requirements of subsection (d)(2)(A) except
that the joints must be manufactured so that they fit together squarely without
deflection at the design curvature and the radius of curvature may be less than
300 feet.
C) Curvilinear Sewers Larger Than 48 Inches in Diameter
Curvilinear sewers larger than 48 inches in diameter shall be
provided with square fitting compression joints and shall meet the requirements
of subsection (d)(2)(A)(vi). The remaining design requirements under
subsection (d)(2)(A) for these sewers will be reviewed by the Agency on a case
by case basis.
e) Increasing Size
When a smaller sewer joins a larger one, the invert of the
larger sewer should be sufficiently lower to maintain the energy gradient. An
approximate method for securing these results is to place the 0.8 depth point
of both sewers at the same elevation.
f) High Velocity Protection
Where velocities greater than 15 feet per second are
attained, the special provisions described in subsection (c)(4) shall be made
to protect against displacement by erosion and shock.
g) Materials and Installation
1) Materials
A) Any generally accepted material for sewers will be given
consideration, but the material selected should be suitable for local
conditions, such as character of industrial wastes, possibility of septicity,
soil characteristics, exceptionally heavy external loadings, abrasion,
structural considerations and similar problems.
B) All sewers shall be designed and installed to prevent damage
from superimposed loads. Proper allowance for loads on the sewer shall be made
because of the width and depth of trench. When the bearing strength of the
pipe is not adequate to withstand the superimposed loading, other pipe
material, special handling, concrete cradle or special construction shall be
used.
C) For new pipe materials for which ASTM standards have not been established
(see subsection (g)(2)), the designing engineer shall provide complete
installation specifications developed on the basis of criteria adequately
documented and certified in writing by the pipe manufacturer to be satisfactory
for the design conditions for the specific project. Such documentation and
manufacturers' certification shall be submitted as a part of the project plan
documents.
2) Installation
A) Standards
i) Installation specifications shall contain appropriate
requirements based on the criteria, standards and requirements established by
ASTM. Requirements shall be set forth in the specifications for the pipe and
methods of bedding and backfilling thereof so as not to damage the pipe or its
joints, impede cleaning operations and future tapping, nor create excessive
side fill pressures or ovalation of the pipe, nor seriously impair flow
capacity.
ii) For new pipe material, the installation specifications shall
meet the provisions of subsection (g)(1).
B) Trenching
i) The width of the trench shall be ample to allow the pipe to
be laid and jointed properly and to allow the backfill to be placed and
compacted as needed. The trench sides shall be kept as nearly vertical as
possible. When wider trenches are dug, appropriate bedding class and pipe
strength shall be used.
ii) Ledge rock, boulders, and large stones shall be removed to
provide a minimum clearance of 4 inches below and on each side of all pipe and
joints.
C) Bedding
i) Bedding classes A, B, or C, as described in ASTM Cl2-95,
"Standard Practice for Installing Vitrified Clay Pipe Lines" (1996)
or "Standard Specifications for Water and Sewer Main Construction in
Illinois", 5th ed. (1996) (no later additions or amendments) or WPCF
Manual of Practice (MOP) No. FD-5 (1982) (no later additions or amendments)
shall be used for all rigid pipe provided the proper strength pipe is used with
the specified bedding to support the anticipated load.
ii) Bedding class I, II, or III, as described in ASTM D2321-89,
"Standard Practice for Underground Installation of Thermoplastic Pipe for
Sewers and Other Gravity-Flow Applications" (1996) (no later editions or
amendments) or Standard Specifications for Water and Sewer Main Construction in
Illinois, 5th ed. (1996) (no later additions or amendments), or WPCF MOP No.
FD-5 (1982)(no later additions or amendments) shall be used for all flexible
pipe provided the proper strength pipe is used with the specified bedding to
support the anticipated load.
D) Backfill
i) Backfill shall be of a suitable material removed from
excavation except where other material is specified. Debris, frozen material,
large clods or stones, organic matter, or other unstable materials shall not be
used for backfill within 2 feet of the top of the pipe.
ii) Backfill shall be placed in such a manner as not to disturb
the alignment of the pipe.
iii) For flexible pipe, as a minimum, backfill material shall be
placed and carefully compacted in accordance with ASTM D2321-89 (1996) to
provide the necessary support for the pipe.
3) Deflection Testing of Flexible Pipe.
A) The design specifications shall provide that the first 1200
feet of sewer and at least 10% of the remainder of the sewer project shall be
deflection tested. The entire length of a sewer of less than 1200 feet shall
be deflection tested.
B) If the deflection test is to be run using a rigid ball or
mandrel, it shall have a diameter equal to 95% of the inside or base diameter
of the pipe as established in the ASTM standard to which the pipe is
manufactured. The test shall be performed without mechanical pulling devices.
C) The individual lines to be tested shall be tested for final
acceptance no sooner than 30 days after they have been installed.
D) Whenever possible and practical, the testing shall initiate at
the downstream lines and proceed towards the upstream lines.
E) No pipe shall exceed a deflection of 5%.
F) In the event that the deflection exceeds the 5% limit in 10%
or more of the manhole intervals tested, the total sewer project shall be
tested.
h) Joints and Infiltration
1) Joints
The type and method of making joints and the materials used
shall be included in the specifications and also shall be shown on the plans.
Sewer joints shall be specified to minimize infiltration and to prevent the
entrance of roots. Joint material shall conform to ASTM standards. Cement
grout joints shall not be used for pipe to pipe joints.
2) Leakage Testing
Leakage tests shall be specified.
A) Test Sections
The design specifications shall provide that the first 1200
feet and at least 10% of the remainder of the sewer project shall be tested for
leakage. The entire length of a sewer of less than 1200 feet shall be tested
for leakage. In the event that 10% or more of the manhole intervals tested do
not pass the leakage test, the entire sewer project shall be tested.
B) Testing Methods
Testing methods may include appropriate water or low pressure
air testing. The use of television cameras or other visual methods for
inspection prior to placing the sewer in service and prior to acceptance is
recommended.
C) Water Testing
i) The leakage outward or inward (exfiltration or infiltration)
shall not exceed the following limits in gallons per inch of pipe diameter per
mile per day for any section of the system:
Exfiltration: 240
Infiltration: 200
ii) An exfiltration or infiltration test shall be performed with
a minimum positive head of 2 feet.
D) Air Testing
If used, the air test shall, as a minimum, conform to the
test procedure described in Section 31-1.11B of Standard Specifications for
Water and Sewer Main Construction in Illinois, 5th ed. (1996)(no later
additions or amendments). The specifications shall require that the time
required for a pressure drop from 3.5 to 2.5 PSIG not be less than the time
specified in the Air Test Table in Appendix C. The testing methods selected
should take into consideration the range in groundwater elevations projected
and the situation during the test.
i) Service Connections
Sewer service connections shall meet the same criteria as
public sanitary sewers described elsewhere in this Subpart C except as noted in
this subsection (i). Roof and foundation drain connections to the sewer service
connection are prohibited except as provided for in 35 Ill. Adm. Code 306.302.
The service connection tap into the public sewer shall be watertight and shall
not protrude into the public sewer. If a saddle type connection is used, it
shall be a commercially available device designed to join with the types of
pipe that are to be connected. All materials used to make service connections
shall be compatible with one another and with the pipe materials to be joined,
and shall be corrosion-proof.
1) Size
Service sewers and fittings shall be a minimum of 4 inches in
diameter, but shall not be less than the diameter of the plumbing pipe from the
building.
2) Slope
Service sewers shall have a minimum slope of 1%.
3) Alignment
When straight line alignment is not maintained on service
connections, cleanouts or manholes shall be provided at points of changes in
alignment.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.330 MANHOLES
Section 370.330 Manholes
a) Location
Except as noted in Section 370.123(d)(2), manholes shall be
installed at the end of each line; at all changes in grade, size or alignment;
at all sewer intersections; and at distances not greater than 400 feet for
sewers 15 inches or less, and 500 feet for sewers 18 inches through 30 inches.
Distances up to 600 feet may be approved in cases where adequate modern
cleaning equipment for such spacing is provided. Greater spacing may be
permitted in larger sewers and in those carrying a settled effluent. Lampholes
may be used only for special conditions and shall not be substituted for
manholes nor installed at the end of laterals greater than 150 feet in length.
b) Type
1) Drop Type
A pipe shall be provided for a sewer entering a manhole where
its invert elevation is more than 24 inches above the manhole invert. If an
inside drop pipe is used, the manhole diameter shall be large enough to provide
a minimum clearance of 48 inches between the pipe and the opposite side of the
manhole. Inside drip pipes shall be anchored to the manhole wall with
corrosion-proof fasteners and bands. For sewers 36 inches in diameter or
greater, the requirements for a drop pipe do not apply if the spring line of
the incoming pipe is at or below the spring line of the main sewer. As a
minimum, the diameter of the drop pipe shall be at least 2/3 as large as the
diameter of the sewer tributary to the drop pipe.
2) Non Drop Type
Where the difference in elevation between the incoming sewer
invert and the manhole invert is less than 24 inches, the manhole invert should
be filleted to prevent solids deposition.
c) Diameter
1) For sewers 36 inches in diameter and smaller, the minimum
diameter of manholes shall be 48 inches. For sewers larger than 36 inches in
diameter, the manhole diameter at the invert shall be sufficiently large to
accommodate the incoming pipes; and the riser barrel diameter shall be a
minimum of 48 inches.
2) A minimum access lid diameter of 24 inches shall be provided.
d) Flow Channel
The flow channel through manholes should be made to conform
in shape and slope to that of the sewers. A bench shall be provided which
should have a minimum slope of 2 inches per foot.
e) Watertightness
1) Construction Requirements
Watertight manhole covers shall be used wherever the manhole
tops may be flooded by surface runoff or high water or are below cover.
Pickholes shall not be larger than 1 inch in diameter or shall be of the
concealed type. Construction lifting holes on manhole rings shall be plugged
from the outside and the exterior and joints of the manhole elements shall be
waterproofed. Precast inlet and outlet connections fitted with "0"
rings or other equally watertight connections shall be provided.
2) Inspection
The specifications shall include a requirement for inspection
and leakage testing of all manholes for watertightness in accordance with ASTM
C969-94 – "Standard Practice for Infiltration and Exfiltration Acceptance
Testing of Installed Precast Concrete Pipe Sewer Lines", Vol. 04.05,
Chemical Resistant Materials, Vitrified Clay, Concrete, Fiber-Cement Products;
Mortars; Masonry (1996) (no later editions or amendments) or ASTM C1244-93
"Standard Test Method for Concrete Sewer Manholes by the Negative Pressure
(Vacuum) Test", Vol. 04.05, Chemical Resistant Materials, Vitrified Clay,
Concrete, Fiber-Cement Products; Mortars; Masonry (1996) (no later editions or
amendments) prior to placing into service.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.340 SEWERS IN RELATION TO STREAMS
Section 370.340 Sewers in
Relation to Streams
a) Location of Sewers on Streams
1) Cover Depth
A) The top of all sewers entering or crossing streams shall be at
a sufficient depth below the natural bottom of the stream bed to protect the
sewer line. In general the following cover requirements must be met:
i) One foot of cover is required where the sewer is located in
rock.
ii) Three feet of cover is required in other material. In major
streams, more than three feet of cover may be required.
iii) In paved stream channels, the top of the sewer line should be
placed below the bottom of the channel pavement.
B) Less cover will be approved only if the proposed sewer crossing
will not interfere with the future improvements to the stream channel. Reasons
for requesting less cover should be given in the project proposal.
2) Horizontal Location
Sewers located along streams shall be located outside of the
stream bed and sufficiently removed therefrom to provide for future possible
stream widening and to prevent pollution by siltation during construction.
3) Structures
The sewer outfalls, headwalls, manholes, gate boxes, or other
structures shall be located so they do not interfere with the free discharge of
flood flows of the stream.
4) Alignment
Sewers crossing streams should be designed to cross the
stream as nearly perpendicular to the stream flow as possible and shall be
designed without change in grade. Sewer systems shall be designed to minimize
the number of stream crossings.
b) Construction
1) Materials and Backfill
A) Sewers entering or crossing streams shall be constructed of
cast or ductile iron pipe with mechanical joints and shall be capable of
absorbing pipe movement and joint-deflection while remaining intact and
watertight.
B) The backfill used in the trench shall be coarse aggregate,
gravel, or other materials which will not cause siltation, pipe damage during
placement or chemical corrosion in place.
2) Siltation and Erosion
Construction methods that will minimize siltation and erosion
shall be employed. The design engineer shall include in the project
specifications the methods to be employed in the construction of sewers in or
near streams to provide adequate control of siltation and erosion.
Specifications shall require that cleanup, grading, seeding, and planting or
restoration of all work areas shall begin immediately. Exposed areas shall not
remain unprotected for more than seven days.
c) Aerial Crossings
1) Structural Support
Support shall be provided for all joints in pipes utilized
for aerial crossings. The supports shall be designed to prevent frost heave,
overturning and settlement.
2) Freeze and Expansion Protection
Protection against freezing shall be provided. This may be
accomplished through the use of insulation and increased slope. Expansion
jointing shall be provided between the aerial and buried sections of the sewer
line.
3) Flood Clearance
For aerial stream crossings, the impact of flood waters and
debris shall be considered. The bottom of the pipe should be placed no lower
than the elevation of the 50 year flood.
d) Inverted Siphons
Inverted siphons shall have not less than 2 barrels, with a
minimum pipe size of 6 inches and shall be provided with necessary
appurtenances for convenient flushing and maintenance. Long radius fittings
should be used. The inlet and outlet structures shall have adequate clearances
for rodding; and in general, sufficient head shall be provided and pipe sizes
selected to secure velocities of at least 3.0 feet per second for design
average flows. The inlet and outlet structures shall be designed so that the
design average flow is diverted to 1 barrel, and so that either barrel may be
cut out of service for cleaning.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.350 PROTECTION OF WATER SUPPLIES
Section 370.350 Protection
of Water Supplies
a) Water Supply Interconnections
There shall be no physical connections between a public or
private potable water supply system and a sewer, or appurtenance thereto, which
would permit the passage of any sewage or polluted water into the potable
supply.
b) Location Relative to Water Works Structures
1) Location and Soil Condition
A) The engineering plan documents shall show the location of all
existing water works structures (basins, wells, other treatment units, etc.)
that are within 200 feet of the proposed sewer.
B) Soil conditions in the vicinity of the water works structures
shall be investigated and depicted on the plans.
2) Minimum Distances
The following minimum distances apply to clay and loan soils
and, as a minimum, shall be doubled for sand. In areas where creviced
limestone or gravel may be encountered, the Agency shall be contacted for a
determination as to what minimum separation distances and special construction
will be required.
A) Non-watertight sewers and sewer appurtenances such as manholes
and wetwells shall not be located closer than 50 feet from water works
structures.
B) Sewers located closer than 50 feet to water works structures
shall be constructed with water main quality pipe and joints that comply with
35 Ill. Adm. Code 653.119. All such pipe shall be pressure tested in
accordance with "AWWA Standard for Installation of Ductile-Iron Water
Mains and their Appurtenances," ANSI/AWWA C600-93 (1994), (no later
editions or amendments) for a working pressure equal to or greater than the
maximum possible surcharge head to assure watertightness prior to backfilling.
No sewer shall be located closer than 10 feet from water works structures.
c) Relation to Water Mains
1) Horizontal and Vertical Separation
A) Whenever possible, a sewer must be at least ten feet
horizontally from any existing or proposed water main.
B) Should local conditions exist which would prevent a lateral
separation of ten feet, a sewer may be closer than ten feet to a water main
provided that the water main invert is at least eighteen inches above the crown
of the sewer, and is either in a separate trench or in the same trench on an
undisturbed earth shelf located to one side of the sewer.
C) If it is impossible to obtain proper horizontal and vertical
separation as described above, both the water main and sewer must be
constructed with water main quality pipe and joints that comply with 35 Ill.
Adm. Code 653.119 and shall be pressure tested in accordance with "AWWA
Standard for Installation of Ductile-Iron Water Mains and their
Appurtenances," ANSI/AWWA C600-93 (1994) (no later editions or amendments)
for a working pressure equal to or greater than the maximum possible surcharge
head to assure watertightness before backfilling.
2) Water-Sewer Line Crossings
A) Whenever possible, sewers crossing water mains shall be laid
with the sewer below the water main with the crown of the sewer a minimum of 18
inches below the invert of the water main. The vertical separation shall be
maintained on each side of the crossing until the perpendicular distance from
the water main to the sewer is at least 10 feet. The crossing shall be
arranged so that the sewer joints will be equidistant and as far as possible
from the water main joints. Adequate support shall be provided for the water
mains to prevent damage due to settling of the sewer trench. Refer to Appendix
H, Drawing No. 1.
B) Where a sewer crosses under a water main and it is not possible
to provide an 18-inch vertical separation, the following special construction
methods shall be specified (refer to Appendix H, Drawing No. 2):
i) The sewer shall either be constructed with water main pipe
and joints that comply with 35 Ill. Adm. Code 653.119 and shall be pressure
tested in accordance with "AWWA Standard for Installation of Ductile-Iron
Water Mains and their Appurtenances," ANSI/AWWA C600-93 (1994) (no later
editions or amendments) for a working pressure equal to or greater than the
maximum possible surcharge head or shall be encased in a carrier pipe with the
ends sealed, that, along with the joints, complies with 35 Ill. Adm. Code
653.119.
ii) The water main quality sewer or carrier pipe shall extend on
each side of the crossing to a point where the perpendicular distance from the
water main to the sewer is at least 10 feet.
iii) For the required length of the water main quality sewer or
carrier pipe, omit the select granular cradle and granular backfill to one
foot over the crown of the sewer and use selected excavated material (Class IV)
and compact to 95% of Standard Proctor maximum density.
iv) Point loads between the sewer or sewer casing and the water
main are prohibited.
v) Adequate support shall be provided for the water main to
prevent damage due to settling of the sewer trench.
C) Where it is not possible for a proposed sewer to cross under an
existing water main, the specifications shall require the construction methods
set out in subsection (c)(2)(B) above and shall require that any select
granular backfill above the crown of the water main be removed within the width
of the proposed sewer trench and be replaced with select excavated material
(Class IV) compacted to 95% of Standard Proctor maximum density. Where a
proposed sewer must cross over a proposed water main, an 18-inch vertical
separation shall be maintained. Refer to Appendix H, Drawing No. 3.
3) Sewer Manhole Separation From Water Main
No water pipe shall pass through or come into contact with
any part of a sewer manhole.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART D: SEWAGE PUMPING STATIONS
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.400 GENERAL
Section 370.400 General
a) Flooding
Sewage pumping station structures and electrical and
mechanical equipment shall be protected from physical damage by the 100 year
flood. Sewage pumping stations should remain fully operational and accessible
during the 25 year flood. Regulations of State and Federal agencies regarding
flood plain obstructions shall be considered.
b) Accessibility
The pumping station shall be readily accessible by
maintenance vehicles during all weather conditions. The facility should be
located off the traffic way of streets and alleys.
c) Grit
Where it is necessary to pump sewage prior to grit removal,
the design of the wet well and pump station piping shall receive special
consideration to avoid operational problems from the accumulation of grit.
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.410 DESIGN
Section 370.410 Design
The following items should be
given consideration in the design of sewage pumping stations:
a) Type
Sewage pumping stations in general use fall into three
types: wet well/dry well, submersible, and suction lift.
b) Structures
1) Separation
Dry wells, including their superstructure, shall be
completely separated from the wet well. Common walls must be gastight.
2) Pump Removal
Provision shall be made to facilitate removing pumps and
motors.
3) Access
A) Suitable and safe means of access shall be provided to dry
wells and to wet wells. Access to wet wells containing either bar screens or
mechanical equipment requiring inspection or maintenance shall conform to
Section 370.600(a)(2)(C).
B) For built-in-place pump stations, a stairway to the dry well
with rest landings shall be provided at vertical intervals not to exceed 12
feet. For factory-built pump stations over 15 feet deep, a rigidly fixed
landing shall be provided at vertical intervals not to exceed 10 feet. Where a
landing is used, a suitable and rigidly fixed barrier shall be provided to
prevent an individual from falling past the intermediate landing to a lower
level. A manlift or elevator may be used in lieu of landings in a
factory-built station, provided emergency access is included in the design.
4) Buoyancy
Where high ground water conditions are anticipated, buoyancy
of the sewage pumping station structures shall be considered and, if necessary,
adequate provisions shall be made for protection.
c) Pumps and Pneumatic Ejectors
1) Multiple Units
Multiple pumps or ejector units shall be provided. Where
only two units are provided, they shall be of the same size. Units shall have
capacity such that, with any unit out of service, the remaining units will have
capacity to handle the design peak flows. A single pump equipped with an
audio-visual alarm system to warn of failure may be used when serving only one
single-family dwelling.
2) Protection Against Clogging
A) Pumps handling combined sewage shall be preceded by readily
accessible bar racks to protect the pumps from clogging or damage. Bar racks
should have clear openings not exceeding 1 inch. Where a bar rack is provided,
a mechanical hoist shall also be provided. Where the size of the installation
warrants, mechanically cleaned and/or duplicate bar racks shall be provided.
B) Pumps handling separate sanitary sewage from 30 inch or larger
diameter sewers shall be protected by bar racks meeting the above
requirements. Appropriate protection from clogging shall also be considered
for small pumping stations.
3) Pump Openings
Pumps handling raw sewage shall be capable of passing spheres
of at least 3 inches in diameter. Pump suction and discharge openings shall be
at least 4 inches in diameter. Grinder pumps that do not meet these
requirements may be used solely for lift stations with a capacity of 70 gpm or
less with the largest unit out of service.
4) Priming
The pump shall be so placed that under normal operating
conditions it will operate under a positive suction head, except as specified
in Section 370.133.
5) Electrical Equipment
Electrical systems and components (e.g., motors, lights,
cables, conduits, switchboxes, control circuits, etc.) in raw sewage wet wells,
or in enclosed or partially enclosed spaces where hazardous concentrations of
flammable gases or vapors may be present, shall comply with the National
Electrical Code requirements for Class 1 Group D, Division 1 locations. In
addition, equipment located in the wet well shall be suitable for use under
corrosive conditions. Each flexible cable shall be provided with water-tight
seal and separate strain relief. A fused disconnect switch located above ground
shall be provided for all pumping stations. When such equipment is exposed to
weather, it shall meet the requirements of weatherproof equipment (National
Electric Manufacturers Association (NEMA) 3R or 4).
6) Intake
Each pump shall have an individual intake. Wet well and
intake design should be such as to avoid turbulence near the intake and to
prevent vortex formation.
7) Dry Well Dewatering
Duplicate sump pumps equipped with dual check valves for each
pump shall be provided in the dry well to remove leakage or drainage with
discharge above the maximum high water level of the wet well. Water ejectors
connected to a potable water supply will not be approved. All floor and
walkway surfaces should have an adequate slope to a point of drainage. Pump
seal leakage shall be piped or channeled directly to the sump. The sump pumps
shall be sized to remove the maximum pump seal water discharge which would
occur in the event of a pump seal failure.
8) Pumping Rates
The pumps and controls of main pumping stations, and
especially pumping stations operated as part of treatment works, should be
selected to operate at varying delivery rates. The stations shall be designed
to deliver as uniform flow as practicable in order to minimize hydraulic
surges. The peak design flow of the station shall be determined in accordance
with Sections 370.300(c), 370.310(b) and 370.520(c) and should be adequate to
maintain a minimum velocity of 2 feet per second in the force main. Refer to
Section 370.470(f).
d) Controls
Control float tubes and bubbler lines should be so located as
not to be unduly affected by turbulent flows entering the well or by the
turbulent suction of the pumps. Provision shall be made to automatically
alternate the pumps in use.
e) Valves
Shutoff valves shall be placed on suction and discharge lines
of each pump. A check valve shall be placed on each discharge line, between
the shutoff valve and the pump. Check valves shall not be located on a
vertical rise unless they are specifically designed for such usage.
f) Wet Wells
1) Divided Wells
Where continuity of pumping station operation is critical,
consideration should be given to dividing the wet well into two sections,
properly interconnected, to facilitate repairs and cleaning.
2) Size
The design fill time and minimum pump cycle time shall be
taken into account in sizing the wet well. The effective volume of the wet
well shall be based on design average flow and a filling time not to exceed 30
minutes unless the facility is designed to provide flow equalization. The pump
manufacturer's duty cycle recommendations shall be used in selecting the
minimum cycle time. When the anticipated initial flow tributary to the pumping
station is less than the ultimate average design flow, provisions should be
made so that the holding time indicated is not exceeded for initial flows. When
the wet well is designed for flow equalization as part of a treatment plant,
provisions should be made to prevent septicity.
3) Floor Slope
The wet well floor shall have a minimum slope of 1 to 1 to
the hopper bottom. The horizontal area of the hopper bottom shall be no
greater than necessary for proper installation and function of the inlet.
4) Air Displacement
Covered wet walls shall provide for air displacement open to
the atmosphere, such as by an inverted "j" tube or similar means.
g) Ventilation
1) General
Adequate ventilation shall be provided for all pump
stations. Where the dry well is below the ground surface, mechanical
ventilation is required. If screens or mechanical equipment requiring
maintenance or inspection is located in the wet well, permanently installed
ventiliation is required. There shall be no interconnection between the wet
well and dry well ventilation systems.
2) Air Inlets and Outlets
In dry wells over 15 feet deep, multiple inlets and outlets
should be used. Dampers should not be used on exhaust or fresh air ducts and
fine screens or other obstructions in air ducts should be avoided to prevent
clogging.
3) Electrical Controls
Switches for operation of ventilation equipment should be
marked and located conveniently. All intermittently operated ventilation
equipment shall be interconnected with the respective pit lighting system.
Consideration should be given also to automatic controls where intermittent
operation is used. The manual lighting ventilation switch shall override the
automatic controls.
4) Fans, Heating and Dehumidification
The fan wheel shall be fabricated from non-sparking
material. Automatic heating and dehumidification equipment shall be provided
in all dry wells. The electrical equipment and components shall meet the
requirements of subsection (c)(5) above.
5) Wet Wells
Wet well ventilation may be either continuous or
intermittent. Ventilation, if continuous, should provide at least 12 complete
air changes per hour; if intermittent, at least 30 complete air changes per
hour. Air shall be forced into the wet well by mechanical means rather than
exhausted from the wet well. Portable ventilation equipment shall be provided
for use at submersible pump stations and at wet wells with no permanently
installed ventilation equipment.
6) Dry Wells
Dry well ventilation may be either continuous or
intermittent. Ventilation, if continuous, should provide at least 6 complete
air changes per hour; if intermittent, at least 30 complete air changes per
hour. A system of two-speed ventilation with an initial ventilation rate of 30
changes per hour for 10 minutes and an automatic switch-over to 6 changes per
hour may be used to conserve heat.
h) Flow Measurement
Suitable devices for measuring sewage flow shall be provided
at all pumping stations. Indicating, totalizing and recording flow
measurement shall be provided at pumping stations with a 1200 gpm or greater
design peak flow. Elapsed time meters used in conjunction with pumping rate
tests may be used for pump stations with a design peak flow of up to 1200 gpm.
i) Water Supply
There shall be no physical connection between any potable
water supply and a sewage pumping station which under any conditions might
cause contamination of the potable water supply. If a potable water supply is
brought to the station, it should comply with conditions stipulated under
Section 370.146(b)(3). In-line backflow preventors shall not be used.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.420 SUCTION-LIFT PUMP STATIONS
Section 370.420 Suction-Lift
Pump Stations
a) Pump Priming and Lift Requirements
Suction lift pumps shall be of the self-priming or
vacuum-priming type and shall meet the applicable requirements of Section
370.132. Suction lift pump stations using dynamic suction lifts exceeding the
limits outlined in the following sections may be approved upon submission of
factory certification of pump performance and detail calculations indicating
satisfactory performance under the proposed operating conditions. Such
detailed calculations must include static suction lift as measured from
"lead pump off" elevation to center line of pump suction, friction
and other hydraulic losses of the suction piping, vapor pressure of the liquid,
altitude correction, required net positive suction head, and a safety factor of
at least 6 feet.
1) Self-priming Pumps
Self-priming pumps shall be capable of rapid priming and
repriming at the "lead pump on" elevation. Such self-priming and
repriming shall be accomplished automatically under design operating
conditions. Suction piping should not exceed the size of the pump suction and
shall not exceed 25 feet in total length. Priming lift at the "lead pump
on" elevation shall include a safety factor of at least 4 feet from the
maximum allowable priming lift for the specific equipment at design operating conditions.
The combined total of dynamic suction lift at the "pump off"
elevation and required net positive suction head at design operating conditions
shall not exceed 22 feet.
2) Vacuum-priming Pumps.
Vacuum-priming pump stations shall be equipped with dual vacuum
pumps capable of automatically and completely removing air from the suction
lift pump. The vacuum pumps shall be adequately protected from damage due to
sewage. The combined total of dynamic suction lift at the "pump off"
elevation and required net positive suction head at design operating conditions
shall not exceed 22 feet.
b) Equipment, Wet Well Access and Valve Location
The pump equipment compartment shall be above grade or offset
and shall be effectively isolated from the wet well to prevent the humid and
corrosive sewer atmosphere from entering the equipment compartment. Wet well
access shall not be through the equipment compartment. Wet well access may not
be through the equipment compartment and shall be at least 24 inches in diameter.
Gasketed replacements shall be provided to cover the opening to the wet well
for pump units removed for servicing. Valves shall not be located in the wet
well.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.430 SUBMERSIBLE PUMP STATIONS - SPECIAL CONSIDERATIONS
Section 370.430 Submersible
Pump Stations - Special Considerations
Submersible pump stations shall
meet the applicable requirements under Section 370.132, except as modified in
this Section.
a) Construction
Submersible pumps and motors shall be designed specifically
for raw sewage use, including totally submerged operation during a portion of
each pumping cycle, and shall meet the requirements of the National Electrical
Code (1996). An effective method to detect shaft seal failure or potential
seal failure shall be provided.
b) Pump Removal
Submersible pumps shall be readily removable and replaceable
without dewatering the wet well or disconnecting any piping in the wet well.
c) Electrical
1) Power Supply and Control
Electrical supply, control and alarm circuits shall be
designed to provide strain relief and to allow disconnection from outside the
wet well. Terminals and connectors shall be protected from corrosion by
location outside the wet well or through use of watertight seals. If located
outside, weatherproof equipment shall be used.
2) Controls
The motor control center shall be located outside the wet
well, readily accessible, and be protected by conduit seal or other appropriate
measures meeting the requirements of the National Electrical Code, to prevent
the atmosphere of the wet well from gaining access to the control center. The
seal shall be so located that the motor may be removed and electrically
disconnected without disturbing the seal.
3) Power Cord
Pump motor power cords shall be designed for flexibility and
serviceability under conditions of extra hard usage and shall meet the
requirements of the National Electric Code (1996) for flexible cords in sewage
pump stations. Ground fault interruption protection shall be used to
de-energize the circuit in the event of any failure in the electrical integrity
of the cable. Power cord terminal fittings shall be corrosion-resistant and
constructed in a manner to prevent the entry of moisture into the cable, shall
be provided with strain relief appurtenances, and shall be designed to
facilitate field connecting.
d) Valves
Valves required under Section 370.132(e) shall be located in
a separate valve pit. Provision shall be made to remove accumulated water from
the valve pit. Accumulated water in valve pits deeper than 4 feet shall be
pumped to the wet well or gravity drained to the ground surface. Valve pits 4
feet deep or less may be gravity drained to the wet well through a trapped and
vented drain that meets the applicable requirements found in 77 Ill. Adm. Code
890, "Illinois Plumbing Code". Such pits shall have entrances that
fully expose the pit to the atmosphere. Check valves that are integral to the
pump need not be located in a separate valve pit provided that the valve can be
removed from the wet well in accordance with subsection (b) above. Provision
shall be made for the use of portable ventiliation equipment during periods of
maintenance.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.440 ALARM SYSTEMS
Section 370.440 Alarm
Systems
Alarm systems shall be provided
for pumping stations. The alarm shall be activated in cases of power failure,
pump failure, unauthorized entry, or any cause of pump station malfunction.
Pumping station alarms shall be telemetered to a municipal facility that is
manned 24 hours a day. If such a facility is not available and a 24-hour
holding capacity is not provided, the alarm shall be telemetered to city
offices during normal working hours and to the home of the person(s) in
responsible charge of the lift station during off-duty hours. Audio-visual
alarm systems with a self-contained power supply may be acceptable in some
cases in lieu of the telemetering system outlined above, depending upon
location, station holding capacity and inspection frequency.
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.450 EMERGENCY OPERATION
Section 370.450 Emergency
Operation
a) Objective
The objective of emergency operation is to prevent the
discharge of raw or partially treated sewage to any waters and to protect
public health by preventing back-up of sewage and subsequent discharge to
basements, streets, and other public and private property.
b) Emergency Pumping Capability
Provision of emergency pumping capability is mandatory and
may be accomplished by connection of the station to at least two independent
utility substations, or by provision of portable or in-place internal combustion
engine equipment which will generate electrical or mechanical energy, or by the
provision of portable pumping equipment. Emergency standby systems shall have
sufficient capacity to start up and maintain the total rated running capacity
of the station. Regardless of the type of emergency standby system provided, a
riser from the force main with rapid connection capabilities and appropriate
valving shall be provided for all lift stations to hook up portable pumps.
c) Emergency High Level Overflows
For use during possible periods of extensive power outages,
mandatory power reductions, or uncontrollable emergency conditions,
consideration should be given to providing a controlled, high-level wet well
overflow to supplement alarm systems and emergency power generation in order to
prevent backup of sewage into basements, or other discharges which may cause
severe adverse impacts on public interests, including public health and
property damage. Where a high level overflow is utilized, consideration shall
also be given to the installation of storage/detention tanks, or basins, which
shall be made to drain to the station wet well. Where such overflows affect
public water supplies or waters used for culinary or food processing purposes,
a storage detention basin, or tank, shall be provided having 2-hour detention
capacity at the anticipated overflow rate.
d) Equipment Requirements
1) General
The following general requirements shall apply to all
internal combustion engines used to drive auxiliary pumps, service pumps
through special drives, or electrical generating equipment:
A) Engine Protection
The engine must be protected from operating conditions that
would result in damage to equipment. Unless continuous manual supervision is
planned, protective equipment shall be capable of shutting down the engine and
activating an alarm on site and as provided in Section 370.135. Protective
equipment shall monitor for conditions of low oil pressure and overheating,
except that oil pressure monitoring will not be required for engines with
splash lubrication.
B) Size
The engine shall have adequate rated power to start and
continuously operate all connected loads.
C) Fuel Type
Reliability and ease of starting, especially during cold
weather conditions, should be considered in the selection of the type of fuel.
D) Engine Ventilation
The engine shall be located above grade with adequate
ventilation of fuel vapors and exhaust gases.
E) Routine Start-up
All emergency equipment shall be provided with instructions
indicating the need for regular starting and running of such units at full
loads.
F) Protection of Equipment
Emergency equipment shall be protected from damage at the
restoration of regular electrical power.
2) Engine - Drive Pumping Equipment
Where permanently-installed or portable engine-driven pumps
are used, the following requirements in addition to general requirements shall
apply:
A) Pumping Capacity
Engine-drive pumps shall meet the design pumping requirements
unless storage capacity is available for flows in excess of pump capacity.
Pumps shall be designed for anticipated operating conditions, including suction
lift if applicable.
B) Operation
The engine and pump shall be equipped to provide automatic
start-up and operation of pumping equipment unless manual start-up and
operation is justified. Provisions shall also be made for manual start-up.
Where manual start-up and operation is justified, storage capacity and alarm
system must meet the requirements of subsection (d)(2)(C).
C) Portable Pumping Equipment
Where part or all of the engine-driven pumping equipment is
portable, sufficient storage capacity shall be provided to allow time for
detection of pump station failure and transportation and hookup of the portable
equipment.
3) Engine-Driven Generating Equipment
Where permanently-installed or portable engine-driven
generating equipment is used, the following requirements shall apply in
addition to general requirements of subsection (d)(1):
A) Generating Capacity
i) Generating unit size shall be adequate to provide power for
pump motor starting current and for lighting, ventilation, and other auxiliary
equipment necessary for safety and proper operation of the lift station.
ii) The operation of only one pump during periods of auxiliary
power supply must be justified. Such justification may be made on the basis of
the design peak flows relative to single-pump capacity, anticipated length of
power outage, and storage capacity.
iii) Special sequencing controls shall be provided to start pump
motors unless the generating equipment has capacity to start all pumps
simultaneously with auxiliary equipment operating.
B) Operation
Provisions shall be made for automatic and manual start-up
and load transfer unless only manual start-up and operation is justified. The
generator must be protected from operating conditions that would result in
damage to equipment. Provisions should be considered to allow the engine to
start and stabilize at operating speed before assuming the load. Where manual
start-up and transfer is justified, storage capacity and alarm system must meet
the requirements of subsection (d)(3)(C).
C) Portable Generating Equipment
Where portable generating equipment or manual transfer is
provided, sufficient storage capacity shall be provided to allow time for
detection of pump station failure and transportation and connection of
generating equipment. The use of special electrical connections and double
throw switches are recommended for connecting portable generating equipment.
4) Independent Utility Substations
Where independent substations are used for emergency power,
each separate substation and its associated transmission lines must be capable
of starting and operating the pump station at its rated capacity.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.460 INSTRUCTIONS AND EQUIPMENT
Section 370.460 Instructions
and Equipment
Sewage pumping stations and
portable equipment shall be supplied with a complete set of operational
instructions, including emergency procedures, maintenance schedules, tools and
such spare parts as may be necessary.
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.470 FORCE MAINS
Section 370.470 Force Mains
a) Velocity and Diameter
At design pumping rates, a cleansing velocity of at least 2
feet per second should be maintained. Lower velocities may be permitted for
very small installations. The minimum force main diameter for raw sewage shall
be 4 inches except for grinder pump lift stations as allowed under Section
370.410(c)(3).
b) Air and Vacuum Relief Valve
An air relief valve shall be placed at high points in the
force main to prevent air locking. Vacuum relief valves may be necessary to
relieve negative pressure on force mains. Force main configuration and head
conditions shall be evaluated as to the need for and placement of vacuum relief
valves.
c) Termination
Force mains should enter the gravity sewer system at a point
not more than 2 feet above the flow line of the receiving manhole.
d) Design Pressure
The force mains and fittings, including reaction blocking,
shall be designed to withstand normal pressure and pressure surges (water
hammer). The need for surge protection chambers shall be evaluated.
e) Special Construction
Force main construction near streams or water works
structures and at water main crossings shall meet applicable provisions of
Sections 370.125 and 370.126.
f) Design Friction Losses
1) Friction losses through force mains shall be based on the
Hazen and Williams formula or other acceptable methods. When the Hazen and
Williams formula is used, the value for "C" shall be 100 for unlined
iron or steel pipe for design. For other smooth pipe materials such as
polyvinyl chloride, polyethylene or lined ductile iron, a higher "C"
value not to exceed 120 may be allowed for design.
2) When initially installed, force mains will have a
significantly higher "C" factor. The effect of the higher
"C" factor should be considered in calculating maximum power
requirements and duty cycle time to prevent damage to the motor.
g) Identification
Where force mains are constructed of material which might
cause the force main to be confused with potable water mains, the force main
shall be appropriately identified.
h) Flexible Pipe Force Main Embedment
Embedment bedding (haunching and initial backfill as depicted
in ASTM D2321-89, Figure (1)) shall be in accordance with Section 20-2.21 A and
20.2.21 B of Standard Specifications for Water and Sewer Main Construction in
Illinois, 5th ed. (1996)(no later editions or amendments).
i) Leakage Testing
Leakage testing shall be specified, including testing methods
and leakage limits.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART E: SEWAGE TREATMENT WORKS
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.500 PLANT LOCATION
Section 370.500 Plant
Location
a) General
The following items shall be considered when selecting a
plant site:
1) Proximity to residential areas.
2) Direction of prevailing winds.
3) Necessary routing to provide accessibility by all weather
roads.
4) Area available for expansion.
5) Local zoning requirements.
6) Local soil characteristics, geology, and topography available
to minimize pumping.
7) Access to receiving stream.
8) Compatibility of treatment process with the present and
planned future land use, including noise, potential odors, air quality, and
anticipated sludge processing and disposal techniques.
9) The requirements of the Illinois Groundwater Protection Act [415
ILCS 55].
b) Critical Sites
Where a site must be used which is critical with respect to
the items in subsection (a), appropriate measures shall be taken to minimize
adverse impacts.
c) Flood Protection
The treatment works structures, electrical and mechanical
equipment shall be protected from physical damage by the maximum 100 year
flood. Treatment works shall remain fully operational during the 25 year
flood. This requirement applies to new construction and to existing facilities
undergoing major modification. Flood plain regulations of State and Federal
agencies shall be considered.
d) Plant Accessibility
All plant facilities shall be accessible by an all weather
road.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.510 QUALITY OF EFFLUENT
Section 370.510 Quality of
Effluent
The required degree of
wastewater treatment shall be established by reference to applicable effluent
and water quality standards contained in 35 Ill. Adm. Code Subtitle C, Chapter
I unless more stringent limitations have been established.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.520 DESIGN
Section 370.520 Design
a) Type of Treatment
1) As a minimum, the following items shall be considered in the
selection of the type of treatment:
A) Present and future effluent requirements.
B) Location and local topography of the plant site.
C) The effects of industrial wastes likely to be encountered.
D) Ultimate disposal of sludge.
E) System capital costs.
F) System operating and maintenance costs and basic energy
requirements.
G) Existing unit process performance and capacity.
H) Process complexity governing operating personnel requirements.
I) Environmental impact on present and future adjacent land use.
2) The plant design shall provide the necessary flexibility to
perform satisfactorily within the expected range of waste characteristics and
volumes.
b) Required Engineering Data for New Process Evaluation
1) The policy of the Agency is to encourage rather than obstruct
the development of any methods or equipment for treatment of wastewaters. The
lack of inclusion in these standards of some types of wastewater treatment
processes or equipment should not be construed as precluding their use. The
Agency may approve other types of wastewater treatment processes and equipment
under the condition that the operational reliability and effectiveness of the
process or device shall have been demonstrated with a suitably-sized prototype
unit operating at its design load conditions, to the extent required.
2) To determine that such new processes and equipment have a
reasonable and substantial chance of success, the Agency will require the
following:
A) Monitoring observations, including test results and engineering
evaluations, demonstrating the efficiency of such processes.
B) Detailed description of the test methods.
C) Testing, including appropriately-composited samples, under
various ranges of strength and flow rates (including diurnal variations) and
waste temperatures over a sufficient length of time to demonstrate performance
under climatic and other conditions which may be encountered in the area of the
proposed installations.
D) Other appropriate information.
3) The Agency will require that appropriate testing be conducted
and evaluations be made under the supervision of a competent process engineer
other than those employed by the manufacturer or developer.
c) Design Loads
1) Hydraulic Design
A) New Systems
Plans for sewage treatment plants to serve new sewer systems
for municipalities or sewer districts shall be based upon a design average
daily flow of at least 100 gallons per capita, to which must be added
industrial waste volumes. The design also shall include appropriate allowance
for flow conditions determined under Section 370.122.
B) Existing Systems
Where there is an existing sewer system, the volume and rates
of the existing sewage flows shall be determined. The determination shall
include both dry weather and wet weather flows. At least one year's flow data
should be used to determine the design flows that are defined in Section
370.220.
C) Treatment Plant Design Capacity
The treatment plant capacity shall be rated on the design
average flow, selected after any sewer system rehabilitation, plus appropriate
future growth. The design of treatment units that are not subject to peak flow
requirements shall be based on the design average flow. For plants subject to
high wet weather flows or overflow detention pumpback flows, the design maximum
flow that the plant is to treat on a sustained basis must be specified.
2) Organic Design
A) New Systems Minimum Design
i) Domestic waste treatment design shall be on the basis of at
least 0.17 pounds of biochemical oxygen demand (BOD5) per capita per day and
0.20 pounds of suspended solids per capita per day.
ii) When garbage grinders are used in areas tributary to a
domestic treatment plant, the design basis should be increased to 0.22 pounds
of BOD5 and 0.25 pounds of suspended solids per capita per day.
iii) Domestic waste treatment plants that will receive industrial
wastewater flows shall be designed to include these industrial waste loads.
B) Existing Systems
When an existing treatment works is to be upgraded or
expanded, organic design shall be based upon the actual strength of the
wastewater as determined from measurements taken in accordance with subsection
(c)(1)(B), with an appropriate increment for growth as determined under the
provisions of subsection (c)(2)(A).
3) Shock Effects
Domestic waste treatment designs shall consider and take into
account the shock effect of high concentrations and diurnal peaks for short
periods on the treatment process, particularly for small waste treatment plants
serving institutions, restaurants, schools, etc.
4) Design by Analogy
Data from similar existing systems may be utilized in the
case of new systems; however, thorough investigation and adequate documentation
shall be made to establish the reliability and applicability of such data.
d) Conduits
1) All piping and channels shall be designed to carry the maximum
expected flows. The incoming sewer shall be designed for unrestricted flow.
Bottom corners of the channels must be filleted. Conduits shall be designed to
avoid creation of pockets and corners where solids can accumulate.
2) Suitable gates should be placed in channels to seal off unused
sections which might accumulate solids. The use of shear gates is permitted
where they can be used in place of gate valves or sluice gates. Non-corrodible
materials shall be used for these control gates.
e) Arrangement of Units
Component parts of the plant should be arranged for greatest
operating convenience, flexibility, economy, continuity of maximum effluent
quality, and so as to facilitate installation of future units.
f) Flow Division Control
Flow division control facilities shall be provided as
necessary to insure organic and hydraulic loading control to plant process
units and shall be designed for easy operator access, change, observation, and
maintenance. The use of head boxes equipped with sharp-crested weirs or
similar devices are recommended. The use of valves for flow splitting is not
acceptable. Appropriate flow measurement shall be incorporated in the flow
division control design.
g) Load Equalization and Attenuation
1) Equalization of hydraulic and organic loads to downstream
treatment units is recommended where the peak hourly load exceeds 300% of the
design average load. Particular attention shall be given to equalization of
pumped flows to limit hydraulic surges on downstream units.
2) Plants proposed to receive sewage wastes from only
institutions (motels, schools, hospitals, nursing homes, etc.) or industries
which discharge substantially the total flow in 12 hours or less, shall be
designed to include flow equalization. Where flow equalization facilities are
provided, the design shall include adequate aeration and mixing equipment to
prevent septicity.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.530 PLANT DETAILS
Section 370.530 Plant
Details
a) Installation of Mechanical Equipment
The specifications shall be so written that the installation
and initial operation of major items of mechanical equipment will be inspected
and approved by a representative of the manufacturer.
b) Bypasses
Properly located and arranged bypass structures and piping
shall be provided so that each unit of the plant can be removed from service
independently. The bypass design shall facilitate plant operation during unit
maintenance and emergency repair so as to minimize deterioration of effluent
quality and insure rapid process recovery upon return to normal operational
mode.
c) Unit Bypass and Wastewater Pumpage During Construction
Final plans and specifications for upgrading or expanding
existing treatment plants shall include construction scheduling of any unit
bypassing, and appropriate temporary wastewater pumpage acceptable to the
Agency to minimize temporary water quality degradation. Refer to Section
370.260.
d) Drains and Buoyancy Protection
1) Means shall be provided to dewater each unit. Pipes subject
to clogging shall be provided with means for mechanical cleaning or flushing.
2) Due consideration should be given to the possible need for
hydrostatic pressure relief devices to prevent flotation of structures.
e) Construction Materials
Due consideration should be given to the selection of
materials which are to be used in sewage treatment works because of the
possible presence of hydrogen sulfide and other corrosive gases, greases, oils,
and similar constituents frequently present in sewage. This is particularly
important in the selection of metals and paints. Dissimilar metals should be
avoided to minimize galvanic action.
f) Painting
The use of paints containing mercury should be avoided. In
order to facilitate identification of piping, particularly in the large plants,
it is suggested that the different lines be color coded. The following color
scheme is recommended for purposes of standardization:
1) Sludge line – brown
2) Gas line – orange
3) Potable water line – blue
4) Non-potable water line - blue with 3 inch yellow band spaced
30 inches apart
5) Chlorine line – yellow
6) Sewage line – gray
7) Compressed air line – green
8) Water lines for heating digesters or buildings – blue with a
6-inch red band spaced 30 inches apart
9) Sulfur dioxide line – yellow with red bands.
10) The contents shall be stenciled on the piping, labeling the
contents in a contrasting color.
g) Operating Equipment
A complete outfit of tools, accessories (such as portable
pump and ventilation blowers, etc.), and spare parts necessary for the plant
operators use shall be provided. Readily accessible storage space and work
bench facilities shall be provided. Consideration shall be given to provision
of a garage storage area for large equipment storage, maintenance, and repair.
h) Erosion Control During Construction
Effective site erosion control shall be provided during
construction.
i) Grading and Landscaping
Upon completion of the plant, the ground should be graded and
seeded. Concrete or gravel walkways should be provided for access to all
units. Where possible, steep slopes should be avoided to prevent erosion.
Surface water shall not be permitted to drain into any unit. Particular care
shall be taken to protect trickling filter beds, sludge beds, and intermittent
sand filters from storm water runoff. Landscaping shall be provided when a
plant must be located near residential areas.
j) Confined Spaces
The number of confined spaces should be minimized for safety
purposes.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.540 PLANT OUTFALLS
Section 370.540 Plant
Outfalls
a) Discharge Impact Control
The outfall sewer shall be designed to discharge to the
receiving stream in a manner acceptable to the Agency. Consideration should be
given in each case to the following:
1) Preference for free fall or submerged discharge at the site
selected.
2) Utilization of cascade aeration of effluent discharge to
increase dissolved oxygen.
3) Limited or complete across-stream dispersion as needed to
protect aquatic life movement and growth in the immediate reaches of the
receiving stream.
b) Design and Construction
The outfall sewer shall be so constructed and protected
against the effects of flood water, waves, ice, or other hazards as to
reasonably insure its structural stability and freedom from stoppage. A
manhole should be provided at the shore end of all gravity sewers extending
into the receiving waters. Hazards to navigation shall be considered in
designing outfall sewers.
c) Sampling Provisions
All outfalls shall be designed so that a sample of the
effluent can be readily obtained at a point after the final treatment process
and before discharge to or mixing with the receiving waters.
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.550 ESSENTIAL FACILITIES
Section 370.550 Essential
Facilities
a) Emergency Power or Pumping Facilities
1) All plants shall be provided with an alternate source of
electric power or pumping capability to allow continuity of operation during
power failures. Methods of providing power or pumping capability include:
A) The connection to at least 2 independent public utility sources
such as substations. A power line from each substation into the treatment
plant with capability for switchover to the second power source by plant
operating personnel will be required.
B) Portable or in place internal combustion engine equipment which
will generate electrical or mechanical energy. Refer to Section 370.136(d).
C) Portable pumping equipment when only emergency pumping is
required. Refer to Section 370.136(d).
2) Standby Generating Capacity Requirements
Standby generating capacity normally is not required for
aeration equipment used in the activated sludge process. In cases where a
history of long term (4 hours or more) power outages have occurred, auxiliary
power for minimum aeration of the activated sludge will be required.
3) Degree of Treatment Required
No reduction in degree of treatment due to power outages will
be allowed when the wastewater is to be treated by installations using
trickling filters, waste stabilization ponds and/or other low energy usage
treatment devices.
4) Continuity of Disinfection
The design shall provide for continuous disinfection during
all power outages, if required due to critical outfall locations and receiving
waters.
5) Continuity of Dechlorination
For facilities using dechlorination equipment, the design
shall provide for continuous dechlorination during all power outages, if
required due to critical outfall locations and receiving waters.
b) Water Supply
1) General
An adequate supply of potable water under pressure should be
provided for use in the laboratory and general cleanliness around the plant.
No piping or other connections shall exist in any part of the treatment works
which, under any conditions, might cause the contamination of a potable water
supply.
2) Direct Connections
A) Potable water from a municipal or separate supply may be used
directly at points above grade for the following hot and cold supplies:
i) Lavatory
sink
ii) Water
closet
iii) Laboratory
sink (with vacuum breaker)
iv) Shower
v) Drinking
fountain
vi) Eye
wash fountain
vii) Safety
shower
viii) Fire
protection sprinklers
B) Hot water for any of the above units shall not be taken
directly from a boiler used for supplying hot water to a sludge heat exchanger
or digester heating unit.
3) Indirect Connections
A) Where a potable water supply is to be used for any purpose in a
plant other than those listed in subsection (b)(2)(A), a break tank, pressure
pump and pressure tank shall be provided. Water shall be discharged to the
break tank through an air-gap at least 6 inches above the maximum flood line or
the spill line of the tank, whichever is higher. A sketch of an acceptable
break tank is contained in Appendix G, Figure No. 4. In-line backflow
preventers are not acceptable.
B) A sign shall be permanently posted at every hose bib, faucet,
or sill cock located on the water system beyond the break tank to indicate that
the water is not safe for drinking.
4) Separate Potable Water Supply
Where it is not possible to provide potable water from a
public water supply, a separate well may be provided. Location and construction
of the well should comply with requirements of the governing State and local
regulations. Requirements governing the use of the supply are those contained
in subsections (b)(2) and (b)(3).
5) Separate Non-Potable Water Supply
Where a separate non-potable water supply is to be provided,
a break tank will not be necessary, but all sill cocks and hose bibs shall be
posted with a permanent sign indicating the water is not safe for drinking.
c) Sanitary Facilities
Toilet, shower, and lavatory should be provided in sufficient
numbers and at convenient locations to serve the expected plant personnel.
d) Floor Slope
Floor surfaces shall be sloped adequately to a point of
drainage.
e) Stairways
Stairways shall be installed in lieu of ladders for access to
those units requiring inspection and maintenance, including but not limited to
trickling filters, digesters, aeration tanks, clarifiers and tertiary filters.
Spiral or winding stairs are permitted only for secondary access where dual
means of egress are provided. Stairways shall have slopes between 30 and 40
degrees from the horizontal to facilitate carrying samples, tools, etc. Each
tread and riser shall be of uniform dimension in each flight. Minimum tread run
shall not be less than 9 inches. The sum of the tread run and riser shall not
be less than 17 nor more than 18 inches. A flight of stairs shall consist of
not more than a 12 foot continuous rise without a platform.
f) Flow Measurement
1) Flow measurement facilities shall be provided so as to measure
the following flows:
A) Plant effluent flow.
B) Plant influent flow, if significantly different from plant
effluent flow, such as for lagoons and plants with excess flow storage or flow
equalization.
C) Excess flow treatment facility discharges.
D) Other flows required to be monitored under the provisions of an
NPDES discharge permit.
E) Flows required for plant operational control, including but not
limited to return activated sludge flow, waste activated sludge flow,
recirculation flow and recycle flows.
2) Indicating, totalizing and recording flow measurement devices
shall be provided for all mechanical plants for all flows except those
specified in subsection (f)(1)(E) above. Flow measurement equipment for lagoon
systems shall consist of, at a minimum, elapsed time meters used in conjunction
with pumping rate test or calibrated weirs. All flow measurement equipment
must be sized to function effectively in the full range of flows expected and
shall be protected against freezing.
3) Flow measurement equipment including entrance and discharge
conduit configuration and critical control elevations shall be designed to
ensure that the required hydraulic conditions necessary for accurate
measurement are provided. Conditions that must be avoided include turbulence,
eddy currents, air entrainment, etc., that upset the normal hydraulic
conditions that are necessary.
g) Sampling Equipment
Effluent composite sampling equipment shall be provided at
all mechanical plants and at other facilities where necessary to meet discharge
permit monitoring requirements.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.560 SAFETY
Section 370.560 Safety
a) Adequate provision shall be made to effectively protect the
operator and visitors from hazards. The following shall be provided to fulfill
the particular needs of each plant:
1) Enclosure of the plant site with a fence designed to
discourage the entrance of unauthorized persons and animals.
2) Installation of hand rails and guards around all tanks, pits,
stairwells, and other hazardous structures.
3) Provision of first aid equipment at marked locations.
4) Posting of "No Smoking" signs in hazardous areas.
5) Protective clothing and equipment such as air packs, goggles,
gloves, hard hats, safety harnesses and hearing protection.
6) Provision of portable blower and sufficient hose.
7) Portable lighting equipment that complies with the National Electrical
Code.
8) Appropriately placed warning signs for slippery areas,
non-potable water fixtures, low head clearance areas, open service manhole,
hazardous chemical storage areas, flammable fuel storage areas, etc.
9) Smoke and fire detectors, fire extinguishers, and appropriate
waste receptacles.
10) Provisions for confined space entry in accordance with the
requirements of the Occupational Safety and Health Act and any other applicable
regulatory requirements.
b) Hazardous Chemical Handling
1) Containment Materials
The materials utilized for storage, piping, valves, pumping,
metering, splash guards, etc., shall be specially selected considering the
physical and chemical characteristics of each hazardous or corrosive chemical.
2) Secondary Containment and Storage
A) Wet and Dry Chemicals
Chemical storage areas shall be enclosed in dikes or curbs
which will contain the stored volume until it can be safely transferred to
alternate storage or released to the wastewater at controlled rates which will
not damage facilities, inhibit the treatment processes, or contribute to stream
pollution. Liquid polymer should be similarly contained to reduce areas with
slippery floors, especially to protect travelways. Non-slip floor surfaces are
desirable in polymer handling areas.
B) Liquified Gas Chemicals
Chlorine and sulfur dioxide cylinder and container storage
shall meet the requirements of Sections 370.1020 and 370.1040. Ammonia gas
cylinder isolation shall be provided. Gas cylinder storage facilities shall be
equipped with appropriate alarm system and emergency repair equipment and
control system.
3) Eye Wash Fountains and Safety Showers
A) Eye wash fountains and safety showers utilizing potable water
shall be provided in the laboratory and on each floor level or work location
involving hazardous or corrosive chemical storage, mixing (or slaking),
pumping, metering, or transportation unloading. These facilities are to be as
close as practical to possible chemical exposure sites and are to be fully
useful during all weather conditions. The eye wash fountains shall be supplied
with water of moderate temperature (50º – 90º Fahrenheit (F)), separate from
the hot water supply, suitable to provide 15 minutes to 30 minutes of
continuous irrigation of the eyes.
B) The emergency showers shall be capable of discharging 30 to 50
gallons per minute (gpm) of water at moderate (50º – 90º F) temperature at
pressures of 20 to 50 pounds per square inch (psi). The eye wash fountains and
showers shall be no more than 25 feet from points of caustic exposure.
4) Splash Guards
All pumps or feeders for hazardous or corrosive chemicals
shall have guards which will effectively prevent spray of chemicals into space
occupied by personnel. The splash guards are in addition to guards to prevent
injury from moving or rotating machinery parts.
5) Piping, Labeling, Coupling Guards, Location
A) All piping containing or transporting corrosive or hazardous
chemicals shall be identified with labels every ten feet and with at least two
labels in each room, closet, or pipe chase. Color coding may also be used, but
is not an adequate substitute for labeling.
B) All connections (flanged or other type), except adjacent to
storage or feeder areas, shall have guards which will direct any leakage away
from space occupied by personnel. Pipes containing hazardous or corrosive
chemicals should not be located above shoulder level except where continuous
drip collection trays and coupling guards will eliminate chemical spray or
dripping onto personnel.
6) Protective Clothing and Equipment
The following items of protective clothing or equipment shall
be available and utilized for all operations or procedures where their use will
minimize injury hazard to personnel:
A) Air pack breathing apparatus for protection against chlorine
and other toxic gases.
B) Chemical workers' goggles or other suitable goggles. (Safety
glasses are insufficient.)
C) Face masks or shields for use over goggles.
D) Dust masks to protect the lungs in dry chemical areas.
E) Rubber gloves.
F) Rubber aprons with leg straps.
G) Rubber boots (leather and wool clothing should be avoided near
caustics).
H) Safety harness and line.
7) Warning Systems and Signs
A) Facilities shall be provided for automatic shutdown of pumps
and sounding of alarms when failure occurs in a pressurized chemical discharge
line.
B) Warning signs requiring use of goggles and dust masks shall be
located near chemical unloading stations, pumps, and other points of frequent
hazard.
8) Dust Collection
Dust collection equipment shall be provided where dry
chemicals are stored or used to protect personnel from dusts injurious to the
lungs or skin and to prevent polymer dust from settling on walkways which
become slick when wet.
9) Container Identification
The identification and hazard warning data included on
shipping containers, when received, shall appear on all containers (regardless
of size or type) used to store, carry, or use a hazardous substance. Sewage
and sludge sample containers should be adequately labeled. Below is a suitable
label to identify a sewage sample as a hazardous substance:
Raw Sewage
Sample Point No. _____
Contains Harmful Bacteria.
May contain hazardous or
toxic material.
Do not drink or swallow.
Avoid contact with openings
or breaks in the skin.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.570 LABORATORY
Section 370.570 Laboratory
a) All treatment works shall include a laboratory for making the
necessary analytical determinations and operating control tests, except for
those plants utilizing only processes not requiring laboratory testing for
plant control and satisfactory off-site laboratory provisions are made to meet
the permit monitoring requirements. For plants where a fully equipped
laboratory is not required, the requirements for utilities and equipment such
as fume hoods may be reduced or omitted.
b) The laboratory shall have sufficient size, bench space,
equipment and supplies to perform all self-monitoring analytical work required
by discharge permits, and to perform the process control tests necessary for
good management of each treatment process included in the design.
c) The facilities and supplies necessary to perform analytical
work to support industrial waste control programs will normally be included in
the same laboratory. The laboratory size and arrangement must be sufficiently
flexible and adaptable to accomplish these assignments. The layout should
consider future needs for expansion in the event that more analytical work is
needed.
d) Location and Space
1) The laboratory should be located on ground level, easily
accessible to all sampling points, with environmental control as an important
consideration. It shall be located in a separate room or building away from
vibrating machinery or equipment which might have adverse effects on the
performance of laboratory instruments or the analyst, or shall be designed to
prevent structural transmission of machine vibration. The floor and wall
construction shall be designed to keep out machine noise (blowers, pumps,
etc.). The following minimum conditions shall be met:
A) Blowers, pumps, etc., must be located on a separate floor pad.
B) Common walls between machinery rooms must be double-walled with
sound insulation between the walls. Connecting doors or windows to machinery
rooms are not acceptable.
C) Common attic space shall be blocked off and effective sound
proof material provided in the ceiling.
2) A minimum of 400 square feet of floor space should be
allocated for the laboratory. Less space may be allowed if the sampling and
analysis program, approved by the Agency, does not require a full-time laboratory
chemist. If more than two persons normally will be working in the laboratory
at any given time, 100 square feet of additional space should be provided for
each additional person. Bench-top working surface should occupy at least 35
percent of the total floor space.
3) Minimum ceiling height should be 8 feet 6 inches. If
possible, this height should be increased to provide for the installation of
wall-mounted water stills, distillation racks, and other equipment with
extended height requirements.
4) Additional floor and bench space should be provided to
facilitate performance of analysis of industrial wastes, as required by the
discharge permit and the utilities industrial waste pretreatment program. The
above minimum space does not provide office or administration space.
e) Materials
1) Ceilings
Acoustical tile should be used for ceilings except in high
humidity areas where they should be constructed of cement plaster. Materials
containing asbestos shall not be used.
2) Walls
For ease of maintenance and a pleasant working environment,
light-colored ceramic tile should be used from floor to ceiling for all
interior walls.
3) Floors
Floor surface materials shall be fire resistant and highly
resistant to acids, alkalies, solvents, and salts.
4) Doors
A) Two exit doors should be located to permit a straight egress
from the laboratory, preferably at least one to outside the building. Panic
hardware should be used. They should have large glass windows for easy
visibility of approaching or departing personnel.
B) Automatic door closers should be installed; swinging doors
should not be used.
C) Flush hardware should be provided on doors if cart traffic is
anticipated. Kick plates are also recommended.
f) Cabinets and Bench Tops
1) Cabinets
A) Wall-hung cabinets are useful for dust-free storage of
instruments and glassware.
B) Units with sliding glass doors are preferable. They should be
hung so the top shelf is easily accessible to the analyst. Thirty inches from
the bench top is recommended.
C) One or more cupboard-style base cabinets should be provided for
storing large items; however, drawer units are preferred for the remaining
cabinets. Drawers should slide out so that entire contents are easily visible.
They should be provided with rubber bumpers and with stops which prevent
accidental removal. Drawers should be supported on ball bearings or nylon
rollers which pull easily in adjustable steel channels. All metal drawer
fronts should be double-wall construction. All cabinet shelving should be acid
resistant and adjustable from inside the cabinet.
2) Bench Tops
Generally, bench-top height should be 36 inches. However,
areas to be used exclusively for sit-down type operations should be 30 inches
high and include kneehole space. One-inch overhangs and drip grooves should be
provided to keep liquid spills from running along the face of the cabinet.
Tops should be furnished in large sections, 1¼ inches thick. They should be
field joined into a continuous surface with acid, alkali, and solvent-resistant
cements which are at least as strong as the material of which the top is made.
3) Utility Accessories
Water, gas, air, and vacuum service fixtures; traps,
strainers, overflows, plugs and tailpieces; and all electrical service fixtures
shall be supplied with the laboratory furniture.
g) Hoods
Fume hoods to promote safety and canopy hoods over
heat-releasing equipment shall be installed.
1) Fume Hoods
A) Location
i) Fume hoods should be located where air disturbance at the
face of the hood is minimal. Air disturbance may be created by persons walking
past the hood; by heating, ventilating or air-conditioning systems; by drafts
from opening or closing a door; etc.
ii) Safety factors should be considered in locating a hood. If a
hood is situated near a doorway, a secondary means of egress must be provided.
Bench surfaces should be available next to the hood so that chemicals need not
be carried long distances.
B) Design and Materials
i) The selection of fume hoods, their design and materials of
construction, must be made by considering the variety of analytical work to be
performed and the characteristics of the fumes, chemicals, gases, or vapors
that will or may be released. Special design and construction is necessary if
perchloric acid use is anticipated. Consideration should be given for providing
more than one fume hood to minimize potential hazardous conditions throughout
the laboratory.
ii) Fume hoods are not appropriate for operation of
heat-releasing equipment that does not contribute to hazards, unless they are
provided in addition to those needed to perform hazardous tasks.
C) Fixtures
i) One
cup sink should be provided inside each fume hood.
ii) All switches, electrical outlets, and utility and baffle
adjustment handles should be located outside the hood. Light fixtures should
be explosion-proof.
D) Exhaust
Continuous duty exhaust capability should be provided.
Exhaust fans should be explosion-proof. Exhaust velocities should be checked
when fume hoods are installed.
E) Alarms
A buzzer for indicating exhaust fan failure and a static
pressure gauge should be placed in the exhaust duct. A high temperature
sensing device located inside the hood should be connected to the buzzer.
2) Canopy Hoods
Canopy hoods should be installed over the bench-top areas
where hot plate, steam bath, or other heating equipment or heat-releasing
instruments are used. The canopy should be constructed of steel, plastic, or
equivalent material, and finished with enamel to blend with other laboratory
furnishings.
h) Sinks
1) The laboratory should have a minimum of 3 sinks (not including
cup sinks). At least 2 of them should be double-well with drainboards.
Additional sinks should be provided in separate work areas as needed, and
identified for the use intended.
2) Waste openings should be located toward the back so that a
standing overflow will not interfere. All water fixtures on which hoses may be
used should be provided with reduced zone pressure backflow preventers to
prevent contamination of water lines.
3) The sinks should be constructed of material highly resistant
to acids, alkalies, solvents, and salts, and should be abrasion and heat
resistant, non-absorbent, light in weight and have all appropriate characteristics
for laboratory applications. Traps should be made of glass, plastic, or lead
and easily accessible for cleaning.
i) Ventilation and Lighting
1) Laboratories shall be separately air conditioned and
dehumidification shall be provided where laboratory control tests procedures
will be affected by high humidity conditions. Separate exhaust ventilation
outlet locations (fume and heat hoods, room air, etc.) shall be provided remote
from ventilation intakes.
2) Adequate lighting, free from shadows, shall be provided to
permit reading of laboratory instrument dials, glassware calibrations, etc.
j) Gas and Vacuum
1) Natural or bottled gas should be supplied to the laboratory.
Digester gas should not be used.
2) An adequately-sized line source of vacuum should be provided
with outlets available throughout the laboratory.
k) Balance and Table
An analytical balance of the automatic, digital readout,
single pan, 0.1 milligram sensitivity type shall be provided. A heavy
special-design balance table which will minimize vibration of the balance shall
be provided. It shall be located as far as practical from windows, doors, or
other sources of drafts or air movements, so as to minimize undesirable impacts
from these sources upon the balance.
l) Equipment, Supplies and Reagents
The laboratory shall be provided with all of the equipment,
supplies, and reagents that are needed to carry out all of the facility's
analytical testing requirements. Discharge permit, process control, and
industrial waste monitoring requirements must be considered when specifying
equipment needs. References such as Standard Methods and the USEPA Analytical
Procedures Manual should be consulted prior to specifying equipment items.
m) Power Supply Regulation
1) To eliminate voltage fluctuation, electrical lines supplying
the laboratory should be controlled with a constant voltage, harmonic
neutralized type of transformer. This transformer should contain less than 3%
total root mean square (rms) harmonic content in the output, should regulate to
+¿1% for an input range of +¿15% of nominal voltage, with an
output of 118 volts. For higher voltage requirements, the 240-volt lines
should be similarly regulated.
2) Electrical devices in the laboratory not requiring a regulated
supply (i.e., ordinary resistance heating devices) that are non-portable may be
wired to an unregulated supply.
n) Laboratory Grade Water Source
A laboratory grade water source, with at least one gallon per
hour capacity, shall be installed complete with all utility connections. The
type of treatment used to produce laboratory grade water shall be based on the
quality of water required for the tests to be performed at the plant.
Laboratory water treatment devices shall be constructed of materials that are
compatible with the water to be treated and produced.
o) Laboratory Safety Equipment
Laboratory safety equipment shall be provided in accordance
with the requirements of Section 370.560(a)(3), (a)(9), (b)(3) and (b)(6).
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART F: PRELIMINARY TREATMENT
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.600 GENERAL CONSIDERATIONS
Section 370.600 General
Considerations
a) Safety
Safety Features Relative to Location
1) Railings and Gratings
A) Manually cleaned channels shall be protected by guard railings
and deck gratings, with adequate provisions for removal or opening to
facilitate raking.
B) Mechanically cleaned channels shall be protected by guard
railings and deck gratings. Consideration should also be given to temporary
access arrangements to facilitate maintenance and repair.
2) Mechanical Devices
A) Mechanical screening equipment shall have adequate removable
enclosures to protect personnel against accidental contact with moving parts
and to prevent dripping in multi-level installations.
B) A positive means of locking out each mechanical device shall be
provided.
3) Units and Equipment in Deep Pits
Manually cleaned screens located in pits deeper than 4 feet
shall be provided with stairway access, adequate lighting and ventiliation, and
convenient and adequate means for removing screenings. Access ladders may be
used instead of steps in pits less than 4 feet deep. Hoisting or lifting
equipment shall be used where necessitated by the depth of the pit or the
amount of material to be removed.
4) In Buildings
Units and equipment installed in buildings where other
equipment or offices are located shall be isolated from the rest of the
building, and shall be provided with separate outside entrances and separate
and independent means of ventilation.
5) Ventilation
A) Adequate ventilation shall be provided for installations
described in subsections (a)(3) and (4). Ventilation may either be continuous
or intermittent. If continuous, ventilation shall provide at least 12 complete
air changes per hour; if intermittent, ventilation shall provide at least 30
complete air changes per hour.
B) Where the pit is deeper than 4 feet mechanical ventilation is
required, and the air shall be forced into the screen pit area rather than
exhausted from the screen pit. The maximum distance from the fresh air
discharge and the working deck floor shall be 24 inches. Dampers should not be
used on fresh air ducts. Obstructions in air ducts should be avoided to
prevent clogging. Air intake screens (bird and insect) shall be located so as
to be easily accessible for cleaning.
C) Switches for operation of ventilation equipment should be
marked and located at the entrance to the screen pit area. All intermittently
operated ventilating equipment shall be interconnected with the respective
lighting system. Consideration should be given to automatic controls where
intermittent operation is used. The manual lighting-ventilation switch shall
override the automatic controls.
D) The fan wheel shall be fabricated from non-sparking material.
Refer to Section 370.610(a)(3)(C) for motor and electrical requirements.
6) Electrical Fixtures
Electrical fixtures and controls in enclosed places where gas
may accumulate shall comply with Section 370.610(a)(3)(C).
b) Communition
Communition or other in-stream shredding of sewage solids
shall be followed by primary settling or fine screening devices to remove the
shredded stringy materials prior to the activated sludge process to minimize
operational problems associated with reaglomeration of stringy materials.
c) Channels
Channels shall be equipped with the necessary gates to divert
flow from any one unit. Provisions must also be made for dewatering each
unit. Channels preceding and following screens shall be shaped and filleted as
necessary to eliminate settling of solids.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.610 SCREENING DEVICES
Section 370.610 Screening
Devices
a) Bar Racks and Screens
1) Where Required
Screening of raw sewage shall be provided at all mechanical
treatment works. For lift station applications, see Subpart D.
2) Design and Installation
A) Manually Cleaned Screens
Clear openings for manually cleaned screens between bars
should be from 1 to 1 3/4 inches. Design and installation shall be such that
they can be conveniently cleaned. An accessible platform shall be provided on
which the operator may rake screenings easily and safely. Suitable drainage
facilities with return flow to process shall be provided for the platform.
B) Mechanical Screens
Clear openings for mechanically cleaned screens may be as
small as practical to assure the proper operation and maintenance of treatment
facilities. Mechanical screens shall be located so as to be protected from
freezing and to facilitate maintenance.
C) Velocities Through Screens
For manually or mechanically raked bar screens the maximum
velocities during peak flow periods should not exceed 2.5 feet per second. The
velocity shall be calculated from a vertical projection of the screen openings
on the cross-sectional area between the invert of the channel and the flow
line. Excessive head loss through the screen, which may affect upstream flow
measurement or bypassing, shall be taken into account.
D) Invert
The screen channel invert shall be at least 3 inches below
the invert of the incoming sewers. To prevent jetting action, the length
and/or construction of the screen channel shall be adequate to reestablish
hydraulic flow pattern following the drop in elevation.
E) Slope
Manually cleaned screens should be placed on a slope of 30 to
45 degrees with the horizontal.
3) Control Systems
A) Timing Devices
All mechanical units which are operated by timing devices
should be provided with auxiliary controls which will set the cleaning
mechanism in operation at predetermined high water marks.
B) Manual Override
Automatic controls shall be supplemented by a manual
override.
C) Electrical Fixtures and Controls
Electrical fixtures and controls in enclosed places where gas
may accumulate shall comply with the National Electrical Code requirements for
Class I, Group D, Division I locations.
4) Disposal of Screenings
A) Amply-sized, vector-proof facilities shall be provided for
removal, handling and storage of screenings in a sanitary manner. Suitable
drainage facilities shall be provided for the storage areas with drainage
returned to process. The return of ground screenings to the sewage flow is
unacceptable.
B) Disposal shall be in accordance with 35 Ill. Adm. Code 700 and
shall be discussed in the plan documents.
b) Auxiliary Screens
Where mechanically operated screening is used, auxiliary
manually cleaned screens shall be provided. Design shall include provisions
for automatic diversion of the entire sewage flow through the auxiliary screens
should the regular units fail. Refer to subsection (a)(2).
c) Fine Screens
Fine screens may be used in lieu of primary sedimentation
providing that subsequent treatment units are designed on the basis of
anticipated screen performance. Fine screens should not be considered
equivalent to primary sedimentation. Where fine screens are used, additional
removal of floatable oils and greases shall be provided if they will adversely
affect the function of downstream treatment units.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.620 GRIT REMOVAL FACILITIES
Section 370.620 Grit Removal
Facilities
a) Where Required
Grit removal facilities should be provided for all sewage
treatment plants and are required for plants receiving sewage from combined
sewers or from sewer systems receiving substantial amounts of grit. If a plant
serving a separate sewer system is designed without grit removal facilities,
the design shall include provision for future installation. Consideration
shall be given to possible damaging effects on pumps, and other preceding
equipment, and the need for additional storage capacity in treatment units
where grit is likely to accumulate.
b) Location
Grit removal facilities should be located ahead of pumps. In
such cases, coarse bar racks should be placed ahead of mechanically cleaned
grit removal facilities. Comminution equipment, when used, shall be located
downstream of the grit facility in order to reduce the operation and
maintenance problems associated with grit.
c) Type and number of units
1) The selection of the type of grit removal shall be based on
necessary flexibility of velocity control to remove the selected size grit
particulates through the range of expected plant flows, the volume of grit
expected, and available area and hydraulic gradient limits at the site. Aerated
or area type grit removal units equipped with adequate controls for operational
flexibility are recommended where flow rates and grit characteristics and
volume are expected to vary widely.
2) Plants treating wastes from combined sewers shall have at
least one, preferably two or more, mechanically cleaned grit removal units,
with provision for unit bypassing. A single manually cleaned or mechanically
cleaned grit chamber with unit bypass is acceptable for small sewage treatment
plants serving separate sanitary sewer systems. Minimum facilities for larger
plants serving separate sanitary sewers shall be at least one mechanically
cleaned unit with a unit bypass.
d) Design Factors
1) Channel Type Units
A) Turbulence Control
The equipment and inlet and outlet structures shall be
designed to minimize turbulance throughout the channel.
B) Velocity and Detention
Channel-type chambers shall be designed to provide controlled
velocities as close as possible to 1 foot per second. The detention period
shall be based on the size of particle to be removed.
2) Aerated Units
A) Inlet
The inlet shall be located and arranged to prevent short
circuiting to the outlet and oriented to the unit flow pattern so as to provide
for adequate scouring segregation of organic and grit materials prior to
discharge.
B) Detention
A detention time of at least 3 minutes at design peak flow
should be provided.
C) Air Supply
Air should be supplied at 5 cubic feet per minute (cfm) per
foot of tank length. The rate of air supplied shall be widely variable so as
to maximize unit process effectiveness.
3) Grit Washing and Freeze Protection
All facilities not provided with positive velocity control
should include means for grit washing to further separate organic and inorganic
materials. Grit elevator and washing facilities shall be housed to prevent
freezing. Provision for adequate heating and ventilation shall be provided to
prevent corrosion.
4) Drains
Provisions should be made for dewatering each unit.
5) Water
An adequate supply of water under pressure shall be provided
for clean up.
e) Grit Removal
Grit removal facilities located in pits shall be provided
with mechanical equipment for pumping or hoisting grit to ground level. Pits
deeper than 4 feet shall be provided with stairway access. An approved-type
elevator or manlift may be desirable in some locations. Adequate ventilation,
as described in Section 370.600(a)(5), and lighting shall be provided for pits
that are deeper than 4 feet or are within an enclosed area.
f) Grit Handling
Impervious, non-slip, working surfaces with drains back to process
shall be provided for grit handling areas. Safety handrails shall be provided
around the working platform areas. If grit is to be transported, the conveying
equipment shall be designed to avoid loss of material and protection from
freezing. Grit disposal methods shall be in compliance with 35 Ill. Adm. Code
700 and shall be described in the plan documents.
g) Electrical
All electrical fixtures and controls in enclosed or below
grade grit removal areas where hazardous gases may accumulate shall meet the
requirements of the National Electrical Code (1996) for Class 1, Group D,
Division 1 locations.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.630 PRE-AERATION
Section 370.630 Pre-Aeration
Pre-aeration of sewage to reduce
septicity may be required in special cases.
(Source: Added at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART G: SETTLING
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.700 GENERAL CONSIDERATIONS
Section 370.700 General
Considerations
a) Number of Units
Multiple units capable of independent operation are desirable
and shall be provided in all plants where design average flows exceed 100,000
gallons per day. Plants not having multiple units shall include other
provisions to assure continuity of treatment.
b) Arrangement
Settling tanks shall be arranged in accordance with Sections
370.520(e) and 370.710(g).
c) Flow Distribution
Effective flow splitting devices and control appurtenances
shall be provided to insure proper organic and hydraulic proportion of flow to
each unit. Refer to Section 370.520(f).
d) Tank Configuration
Consideration should be given to the probable flow pattern in
the selection of tank size and shape, and inlet and outlet type and location.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.710 DESIGN CONSIDERATIONS
Section 370.710 Design
Considerations
a) Dimensions
The minimum length of flow from inlet to outlet should be 10
feet unless special provisions are made to prevent short circuiting. The
sidewater depth for primary clarifiers shall be as shallow as practicable, but
not less than 7 feet. Clarifiers following the activated sludge process shall
have sidewater depths of at least 12 feet to provide adequate separation zone
between the sludge blanket and the overflow weirs. Clarifiers following fixed
film reactors shall have sidewater depth of at least 7 feet.
b) Surface Settling Rates (Overflow Rates)
The hydraulic design of settling tanks shall be based on the
anticipated peak hourly flow.
1) Primary and Bypass Settling Tanks
A) Primary Settling
Some indication of BOD removals may be obtained by reference
to Appendix E, Figure No. 2. The figure should not be used to design units
which receive wastewaters which have BOD and total suspended solids
concentrations which are substantially different from normal domestic sewage.
The operating characteristics of such units should be established by
appropriate field and laboratory tests. If activated sludge is wasted to the
primary settling unit, then the design surface settling rate shall not exceed
1,000 gallons per day per square foot based on design peak hourly flow,
including all flows to the unit. Refer to subsection (b)(3) and Section
370.820.
B) Combined Sewer Overflow and Bypass Settling
The maximum surface settling rate shall not exceed 1,800
gallons per day per square foot based on peak hourly flow. Minimum liquid
depth shall not be less than 10 feet. Minimum detention shall not be less than
one hour. The minimum length of flow from inlet baffle to outlet should be 10
feet, unless special provisions are made to prevent short-circuiting.
2) Intermediate Settling Tanks
Surface settling rates for intermediate settling tanks
following series units of fixed film reactor processes should not exceed 1500
gallons per day per square foot based on design peak hourly flow. Surface
settling rates for intermediate settling tanks following the activated sludge
process shall not exceed 1000 gallons per day per square foot based on design
peak hourly flow.
3) Final Settling Tanks
Settling tests should be conducted wherever a pilot study of
biological treatment is warranted by unusual waste characteristics or treatment
requirements. Testing shall be done where proposed loadings go beyond the
limits set forth in subsections (b)(3)(A) and (b)(3)(B).
A) Final Settling Tanks - Fixed Film Biological Reactors
Surface settling rates for settling tanks following trickling
filters or rotating biological contactors shall not exceed 1000 gallons per day
per square foot based on design peak hourly flow.
B) Final Settling Tanks - Activated Sludge
i) Multiple units capable of independent operation shall be
provided at all plants. To perform properly while producing a concentrated
return flow, activated sludge settling tanks must be designed to meet
thickening as well as solids separation requirements.
ii) Since the rate of recirculation of return sludge is quite
high in activated sludge processes, surface settling rate and weir overflow
rate should be adjusted for the various processes to minimize the problems with
sludge loadings, density currents, inlet hydraulic turbulence, and occasional
poor sludge settleability.
iii) The hydraulic loadings shall not exceed 1000 gallons per day
per square foot based on design peak hourly flow, and 800 gallons per day per
square foot based on peak hourly flow for separate activated sludge
nitrification stage. Refer to Section 370.1210(c)(4).
iv) The solids loading shall not exceed 50 pounds solids per day
per square foot at the design peak hourly rate.
v) Flow equalization is recommended where the peak hourly load
exceeds 300% of the design average load.
C) Rectangular Units
Rectangular final settling tanks following the activated
sludge process frequently exhibit poor solids separation characteristics and
should therefore be avoided. If land availability or other local conditions
mandate the use of rectangular final clarifiers following the activated sludge
process, the following design modifications shall be made:
i) Within practicable limits, length shall be approximately
equal to the width.
ii) Excess
weir length shall be provided.
iii) Baffles shall be provided to interrupt longitudinal density
currents.
iv) Weir placement shall be adjustable, so as to allow
optimization of the upflow takeoff points.
c) Inlet Structures
Inlets and inlet baffling should be designed to dissipate the
inlet velocity, to distribute the flow equally both horizontally and vertically
and to prevent short circuiting. Channels should be designed to maintain a
velocity of at least one foot per second at one-half the design flow. Corner
pockets and dead ends should be eliminated and corner fillets or channeling
used where necessary. Provisions shall be made for prevention or removal of
floating materials in inlet structures.
d) Weirs
1) General
Overflow weirs shall be readily adjustable over the life of
the structure to correct for differential settlement of the tank.
2) Location
Overflow weirs shall be located to optimize actual hydraulic
detention time, and minimize short circuiting.
3) Design Rates
Weir loadings shall not exceed 20,000 gallons per day per
lineal foot based on design peak hourly flows for plants having design average
flows of 1.0 mgd or less. Overflow rates shall not exceed 30,000 gallons per
day per lineal foot based on design peak hourly flow for plants having design
average flow of greater than 1.0 mgd. Higher weir overflow rates may be
allowed for bypass settling tanks. If pumping is required, weir loadings
should be related to pump delivery rates to avoid short circuiting. Refer to
Section 370.410(c)(8).
4) Weir Troughs
Weir troughs shall be designed to prevent submergence at
maximum design flow, and to maintain a velocity of at least one foot per second
at one-half design average flow.
e) Submerged Surfaces
The tops of troughs, beams, and similar submerged construction
elements shall have a minimum slope of 1.4 vertical to 1 horizontal; the
underside of such elements should have a slope of 1 to 1 to prevent the
accumulation of scum and solids.
f) Unit Dewatering
Unit dewatering featuring shall conform to the provisions
outlined in Section 370.530. The bypass design should also provide for
redistribution of the plant flow to the remaining units.
g) Freeboard
Walls of settling tanks shall extend at least 6 inches above
the surrounding ground surface and shall provide not less than 12 inches
freeboard. Additional freeboard or the use of wind screens is recommended
where larger settling tanks are subject to high velocity wind currents that
would cause tank surface waves and inhibit effective scum removal.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.720 SLUDGE AND SCUM REMOVAL
Section 370.720 Sludge and
Scum Removal
a) Scum Removal
Full surface mechanical scum collection and removal
facilities, including baffling, shall be provided for all settling tanks,
except for Imhoff tanks. The unusual characteristics of scum which may
adversely affect pumping, piping, sludge handling and disposal, should be
recognized in design. Provisions may be made for the discharge of scum with
the sludge; however, other special provisions for disposal may be necessary.
Refer to Section 370.710(g).
b) Sludge Removal
Mechanical sludge collection and withdrawal facilities shall
be designed to assure an effective and controlled rate of removal of the
sludge. Suction withdrawal is encouraged.
1) Sludge Hopper
The minimum slope of the side walls shall be 1.7 vertical to
1 horizontal. Hopper wall surfaces should be made smooth with rounded corners
to aid in sludge removal. Hopper bottoms shall have a maximum dimension of 2
feet. Extra depth sludge hoppers for sludge thickening are not acceptable.
2) Cross-Collectors
Cross-collectors serving one or more settling tanks may be
useful in place of multiple sludge hoppers.
3) Sludge Removal Piping
Each hopper shall have an individually valved sludge
withdrawal line at least 6 inches in diameter. The static head available for
withdrawal of sludge shall be 30 inches or greater, as necessary to maintain a
3 feet per second velocity in the withdrawal pipe. Clearance between the end
of the withdrawal line and the hopper walls shall be sufficient to prevent
"bridging" of the sludge. Adequate provisions shall be made for
rodding or back-flushing individual pipe runs. Piping shall also be provided
to return waste sludge from secondary and tertiary processes to primary
clarifiers where they are used. Refer to Section 370.820.
4) Sludge Removal Control
Sludge wells equipped with telescoping valves or swing pipes
are recommended for primary sludge and fixed film sludges where periodic
withdrawal is proposed. Air lift type of sludge removal will not be approved
for removal of primary sludges.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.730 PROTECTION AND SERVICE FACILITIES
Section 370.730 Protection
and Service Facilities
a) Operator Protection
All settling tanks shall be equipped to enhance safety for
operators. Such features shall appropriately include machinery covers, life
lines, stairways, walkways, handrails and slip-resistant surfaces. If
sidewalls are extended more than three feet above the liquid level or four feet
above ground level, convenient walkways must be provided to facilitate
housekeeping and maintenance.
b) Mechanical Maintenance Access
The design shall provide for convenient and safe access to
routine maintenance items such as gear boxes, scum removal mechanisms, baffles,
weirs, inlet stilling baffle area, and effluent channels.
c) Electrical Fixtures and Controls
Electrical fixtures and controls in enclosed settling basins
shall meet the requirements of the National Electric Code for Class I, Group D,
Division 1 locations. The fixtures and controls shall be located so as to
provide convenient and safe access for operation and maintenance. Adequate
area lighting shall be provided.
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.740 IMHOFF TANKS
Section 370.740 Imhoff Tanks
a) General
Imhoff tanks may be used for the sedimentation of settleable
solids and for the unheated anaerobic digestion of these solids.
b) Settling Compartment Design
1) Settling Rate
Surface settling rate shall not exceed 1000 gallons per day
per square foot based upon design peak hourly flow.
2) Detention Period
A detention period of not less than 1 hour based upon design
peak hourly flow shall be provided.
3) Dimensions
The minimum length of flow between inlet and outlet should be
10 feet and at least 6 feet of settling depth should be provided.
4) Freeboard
The freeboard shall be 18 inches or more.
5) Hopper Slope
The bottom of the settling chamber of the conventional tank
shall have a slope of at least 1.4 vertical to 1.0 horizontal. The slot at the
bottom of the settling chamber allowing solids passage shall have a minimum
opening and a minimum overlap of 6 inches.
6) Inlets and Outlets
Inlet and outlet arrangements should be designed so that the
direction of flow may be reversed to allow for a more even distribution of
solids in the digestion compartment. Adequate scum baffles shall be provided at
the ends of the flow-through chamber.
7) Weirs
Weir design and overflow rates shall be in accordance with
Section 370.710(d).
8) Walkway
A walkway along the length of the tank shall be provided.
c) Sludge Digestion Compartment Design
1) Digestion Chamber Capacity
The digestion chamber shall provide 4 cubic feet of volume
per capita for primary treatment and should provide 6 cubic feet of volume per
capita if secondary process sludge is also to be digested. The capacity shall
be measured below a horizontal plane 18 inches below the settling chamber slot.
2) Vent Area
A surface area equal to 20% of the total tank surface area
shall be provided for venting the digestion compartment.
3) Hopper Slope
The bottom of the digestion chamber should be a hopper type
structure with minimum side slopes of 1.75 vertical to 1.0 horizontal. Sludge
draw-off from the digestion chamber is usually accomplished by utilizing the
hydrostatic head with a minimum differential of 6 feet being required. Eight
inch diameter sludge draw-off piping or larger shall be used.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.750 SEPTIC TANK - TILE SYSTEM
Section 370.750 Septic Tank
- Tile System
a) General
Septic tank tile systems shall be used only for domestic or
similar organic waste, where soil conditions are suitable and sewers tributary
to treatment works are not available.
b) Design Standards
Specific design information is contained in the document
titled "Private Sewage Disposal Licensing Act & Code", which can
be obtained from:
State of Illinois
Department of Public Health
Springfield, Illinois 62706.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART H: SLUDGE PROCESSING AND DISPOSAL
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.800 GENERAL
Section 370.800 General
Facilities for processing sludge
shall be provided at all mechanical sewage treatment plants. Handling
equipment shall be capable of processing sludge to a form suitable for ultimate
disposal.
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.810 PROCESS SELECTION
Section 370.810 Process
Selection
The selection of sludge handling
unit processes should be based upon at least the following considerations:
a) Local land use.
b) System energy requirements.
c) Cost effectiveness of sludge thickening and dewatering.
d) Equipment complexity and staffing requirements.
e) Adverse effects of heavy metals and other sludge components
upon the unit processes.
f) Sludge digestion or stabilization requirements.
g) Side stream or return flow treatment requirements (e.g.,
digester or sludge storage facilities supernatant, dewatering unit filtrate,
wet oxidation return flows).
h) Sludge storage requirements.
i) Methods of ultimate disposal.
j) Back-up techniques of sludge handling and disposal.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.820 SLUDGE THICKENING
Section 370.820 Sludge
Thickening
a) Sludge thickeners to reduce the volume of sludge should be
considered. The design of thickeners (gravity tank, gravity belt, dissolved-air
flotation, centrifuge, and others) should take into account the type and
concentration of sludge, the sludge stabilization processes, storage
requirements, the method of ultimate sludge disposal, chemical needs, and the
cost of operation. The use of gravity thickening tanks for unstabilized
sludges is not recommended because of problems due to septicity unless provisions
are made for adequate control of process operational problems as well as
problems of odors at the gravity thickener and any following unit processes.
Particular attention should be given to the pumping and piping of the
concentrated sludge and possible onset of anaerobic conditions.
b) Process selection and unit process design parameters should be
based on prototype studies. The Agency will require such studies where the
sizing of other plant units is dependent on performance of the thickeners.
Refer to Section 370.520(b) for any new process determination.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.830 ANAEROBIC SLUDGE DIGESTION
Section 370.830 Anaerobic
Sludge Digestion
a) General
1) Multiple Units
Multiple units or alternate methods of sludge processing
shall be provided. Facilities for sludge storage and supernatant separation in
an additional unit may be required, depending on raw sludge concentration and
disposal methods for sludge and supernatant.
2) Depth
If process design provides for supernatant withdrawal, the
proportion of depth to diameter should be such as to allow for the formation of
a reasonable depth of supernatant liquor. A minimum side water depth of 20
feet is recommended.
3) Design Maintenance Provisions
To facilitate emptying, cleaning, and maintenance the
following features are desirable:
A) Slope
The tank bottom shall slope to drain toward the withdrawal
pipe. For tanks equipped with a suction mechanism for sludge withdrawal, a
bottom slope not less than 1 to 12 is recommended. Where the sludge is to be
removed by gravity alone, 1 to 4 slope is recommended.
B) Access Manholes
At least 2 access manholes should be provided in the top of
the tank in addition to the gas dome. There should be stairways to reach the
access manholes. A separate side wall manhole shall be provided that is large
enough to permit the use of mechanical equipment to remove grit and sand. The
side wall access manhole should be low enough to facilitate heavy equipment
handling and may be buried in the earthen bank insulation.
C) Safety
Non-sparking tools, rubber-soled shoes, safety harness, gas
detectors for inflammable and toxic gases, and at least two self-contained
breathing units shall be provided for emergency use.
4) Toxic Materials
If the anaerobic digestion process is proposed, the basis of
design shall be supported by wastewater analyses to determine the presence of
undesirable materials, such as high concentrations of sulfates and inhibitory
concentrations of heavy metals.
b) Sludge Inlets and Outlets, Recirculation and High Level
Overflows
1) Multiple sludge inlets and draw-offs and, where used, multiple
recirculation suction and discharge points to facilitate flexible operation and
effective mixing of the digester contents shall be provided unless adequate
mixing facilities are provided within the digester.
2) One inlet should discharge above the liquid level and be
located at approximately the center of the tank to assist in scum breakup. The
second inlet should be opposite to the suction line at approximately the 2/3
diameter point across the digester.
3) Raw sludge inlet discharge points should be so located as to
minimize short circuiting to the digested sludge or supernatant draw-offs.
4) Sludge withdrawal to disposal should be from the bottom of the
tank. The bottom withdrawal pipe should be interconnected with the necessary
valving to the recirculation pipe, to increase versatility in mixing the tank
contents.
5) An unvalved vented overflow shall be provided to prevent
damage to the digestion tank and cover in case of accidental overfilling. This
emergency overflow shall be piped to a point and at a rate in the treatment
process or sidestream treatment facilities so as to minimize the impact on
process units.
c) Tank Capacity
1) Rational Design
The total digestion tank capacity shall be determined by
rational calculations based upon such factors as volume of sludge added, its
percent solids, and character, the temperature to be maintained in the
digesters, the degree or extent of mixing to be obtained, the degree of
volatile solids reduction required, method of sludge disposal, and the size of
the installation with appropriate allowances for gas, scum, supernatant and
digested sludge storage. Secondary digesters of two-stage series digestion
systems that are used for digested sludge storage and concentration shall not
be credited in the calculations for volumes required for sludge digestion.
Calculations should be submitted to justify the basis of design.
2) Empirical Design
When such calculations are not submitted to justify the
design based on the above factors, the minimum combined digestion tank capacity
outlined below will be required. Such requirements assume that the raw sludge
is derived from ordinary domestic wastewater, a digestion temperature is to be
maintained in the range of 85~ to 95~ F (29~ to 35~ C), 40 to 50 percent
volatile matter in the digested sludge, and that the digested sludge will be
removed frequently from the process. (See also subsection (a)(1) above and
Section 370.860(a)(1).)
A) Completely Mixed Systems
For digestion systems providing for intimate and effective
mixing of the digester contents, the system may be loaded up to 80 pounds of
volatile solids per 1000 cubic feet of volume per day in the active digestion
units.
B) Moderately Mixed Systems
For digestion systems where mixing is accomplished only by
circulating sludge through an external heat exchanger, the system may be loaded
up to 40 pounds of volatile solids per 1000 cubic feet of volume per day in the
active digestion units. This loading may be modified upward or downward
depending upon the degree of mixing provided.
C) Digester Mixing
Facilities for mixing the digester contents shall be provided
where required for proper digestion by reason of loading rates or other
features of the system. Where sludge recirculation pumps are used for mixing,
they shall be provided in accordance with the applicable requirements of
Section 370.850(a).
d) Gas Collection, Piping, and Appurtenances
1) General
All portions of the gas system including the space above the
tank liquor, storage facilities and piping shall be so designed that under all
normal operating conditions, including sludge withdrawal, the gas will be
maintained under pressure. All enclosed areas where any gas leakage might
occur shall be adequately ventilated.
2) Safety Equipment
All necessary safety facilities shall be included where gas
is produced. Pressure and vacuum relief valves and flame traps together with
automatic safety shut off valves shall be provided and protected from
freezing. Water seal equipment shall not be installed. Safety equipment and
gas compressors should be housed in a separate room with an exterior door.
3) Gas Piping and Condensate
Gas piping shall have a minimum diameter of 4 inches, except
that a smaller diameter pipe may be used at the gas production meter. Gas
piping shall slope to condensation traps at low points. The use of
float-controlled condensate traps is not permitted. Condensation traps shall
be protected from freezing. Tightly fitted self-closing doors should be
provided at connecting passageways and tunnels which connect digestion
facilities to other facilities to minimize the spread of gas. Piping galleries
shall be ventilated in accordance with subsection (d)(7).
4) Gas Utilization Equipment
Gas burning boilers, engines, etc., shall be located in well
ventilated rooms. Such rooms would not ordinarily be classified as a hazardous
location if isolated from the digestion gallery or ventilated in accordance
with subsection (d)(7). Gas lines to these units shall be provided with
suitable flame traps.
5) Electrical Fixtures
Electrical fixtures and controls, in places enclosing
anaerobic digestion appurtenances, where hazardous gases are normally contained
in the tanks and piping, shall comply with the National Electric Code for Class
1, Group D, Division 2 locations. Refer to subsection (d)(7).
6) Waste Gas
A) Waste gas burners shall be readily accessible and should be
located at least 50 feet away from any plant structure if placed at ground
level, or may be located on the roof of the control building if sufficiently
removed from the tank. Waste gas burners shall be of sufficient height to
prevent injury to personnel due to wind or downdraft conditions.
B) All waste gas burners shall be equipped with automatic ignition
such as a pilot light or a device using a photoelectric cell sensor.
Consideration should be given to the use of natural or propane gas to insure
reliability of the pilot.
C) Gas piping shall be sloped at a minimum of 2 percent up to the
waste gas burner with a condensate trap provided in a location not subject to
freezing.
7) Ventilation
Any underground enclosures connecting with digestion tanks or
containing sludge or gas piping or equipment shall be provided with forced
ventilation in accordance with Section 370.410(g)(1-4) and (6).
8) Meter
A gas meter with bypass shall be provided to meter total gas
production for each active digestion unit. Total gas production for two-stage
digestion systems operated in series may be measured by a single gas meter with
proper interconnected gas piping. Where multiple primary digestion units are
used with a single secondary digestion unit, a gas meter shall be provided for
each primary digestion unit. The secondary digestion unit may be
interconnected with the gas measurement unit of one of the primary units.
Interconnected gas piping shall be properly valved with gastight gate valves to
allow measurement of gas production from, or maintenance of, either digestion
unit. Gas meters may be of the orifice plate, turbine or vortex type. Positive
displacement meters are not recommended. The meter used must be specifically
designed for contact with corrosive and dirty gases.
e) Digestion Tank Heating
1) Insulation
Wherever possible digestion tanks should be constructed above
ground-water level and shall be suitably insulated to minimize heat loss.
Maximum utilization of earthen bank insulation should be used.
2) Heating Facilities
Sludge may be heated by circulating the sludge through
external heaters or by units located inside the digestion tank. Refer to
subsection (e)(2)(B).
A) External Heating
Piping shall be designed to provide for the preheating of
feed sludge before introduction into the digesters. Provisions shall be made
in the lay-out of the piping and valving to facilitate heater exchanger tube
removal and cleaning of the lines. Heat exchanger sludge piping should be
sized for peak heat transfer requirements. Heat exchangers should have a
heating capacity of 130 percent of the calculated peak heating requirement to
account for sludge tube fouling.
B) Other Heating Methods
i) The use of hot water heating coils affixed to the walls of
the digester, or other types of internal heating equipment that require
emptying the digester contents for repair, are not acceptable.
ii) Other systems and devices have been developed recently to
provide both mixing and heating of anaerobic digester contents. These systems
will be reviewed on their own merits. Operating data detailing their
reliability, operation and maintenance characteristics will be required.
3) Heating Capacity
A) Sufficient heating capacity shall be provided to consistently
maintain the design sludge temperature considering the insulation provided and
ambient cold weather conditions. Where digestion tank gas is used for other
purposes, an auxiliary fuel may be required.
B) The provision of standby heating capacity or the use of
multiple units sized to provide the heating requirements shall be considered
unless acceptable alternative means of handling raw sludge are provided.
4) Hot Water Internal Heating Controls
A) Mixing Valves
A suitable automatic mixing valve shall be provided to temper
the boiler water with return water so that the inlet water to the removable
heat jacket or coil in the digester can be held below a temperature at which
caking will be accentuated. Manual control should also be provided by suitable
bypass valves.
B) Boiler Controls
The boiler should be provided with suitable automatic
controls to maintain the boiler temperature at approximately 180~ F (82~ C) to
minimize corrosion and to shut off the main gas supply in the event of pilot
burner or electrical failure, low boiler water level, low gas pressure,
excessive boiler water temperature or pressure.
C) Boiler Water Pumps
Boiler water pumps shall be sealed and sized to meet the
operating conditions of temperature, operating head and flow rate. Duplicate
units shall be provided.
D) Thermometers
Thermometers shall be provided to show inlet and outlet
temperatures of the sludge, hot water feed, hot water return and boiler water.
E) Water Supply
The chemical quality of the water supply shall be suitable
for use as boiler water. Refer to Section 370.550(b) for additional water
supply considerations.
5) External Heater Operating Controls
All controls necessary to insure effective and safe operation
are required. Provision for duplicate units in critical elements should be
considered.
f) Supernatant Withdrawal
Where supernatant separation is to be used to concentrate
sludge in the digester units and increase digester solids retention time, the
design shall provide for ease of operation and positive control of supernatant
quality.
1) Piping Size
Supernatant piping should not be less than 6 inches in
diameter.
2) Withdrawal Arrangements
A) Withdrawal Levels
Piping should be arranged so that withdrawal can be made from
3 or more levels in the tank. An unvalved vented overflow shall be provided.
The emergency overflow shall be piped to a point and at a rate in the treatment
process or sidestream treatment facilities so as to minimize the impact on
process units.
B) Withdrawal Selection
On fixed cover tanks the supernatant withdrawal level should
preferably be selected by means of interchangeable extensions at the discharge
end of the piping.
C) Supernatant Selector
A fixed screen supernatant selector or similar device may
only be used in an unmixed secondary digestion unit. If such a supernatant
selector is provided, provisions shall be made for at least one other draw-off
level located in the supernatant zone of the tank, in addition to the unvalved
emergency supernatant draw-off pipe. High pressure back-wash facilities shall
be provided.
3) Sampling
Provision shall be made for sampling at each supernatant
draw-off level. Sampling pipes should be at least 1 1/2 inches in diameter and
should terminate at a suitably sized sampling sink or basin.
4) Supernatant Disposal
Supernatant return and disposal facilities shall be designed
to prevent adverse hydraulic and organic effects on plant operations. If
nutrient removal (e.g., phosphorus, ammonia) must be accomplished at a plant,
then a separate supernatant side stream treatment system should be considered.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.840 AEROBIC SLUDGE DIGESTION
Section 370.840 Aerobic
Sludge Digestion
a) General
The aerobic sludge digestion system shall include provisions
for digestion, supernatant separation, sludge concentration and any necessary
sludge storage. These may be accomplished with separate tanks or processes or
in digestion tanks.
b) Multiple Units
Multiple digestion units capable of independent operation are
recommended for all plants and shall be provided in those plants where the
design average flow exceeds 100,000 gallons per day. Plants without multiple
units shall provide alternate sludge handling and disposal methods.
c) Tank Capacity
1) The following digestion tank capacities are based on a solids
concentration of 2 percent with supernatant separation performed in a separate
tank. If supernatant separation is performed in the digestion tank, a minimum
of 25 percent additional volume is required. These capacities shall be
provided unless sludge thickening facilities (refer to Section 370.820) are
utilized to thicken the feed solids concentration to greater than 2 percent.
If such. thickening is provided, the digestion volumes may be decreased
proportionally.
|
(ft.(3)/Population
|
|
|
Sludge Source
|
Equivalent (P.E.))
|
|
|
|
|
Waste activated sludge-no
primary settling
|
|
|
4.5*
|
|
|
|
|
|
Primary plus waste activated
sludge
|
|
|
|
.0*
|
|
|
|
|
Waste activated sludge
exclusive of primary sludge
|
|
|
|
.0*
|
|
|
|
|
Extended aeration activated
sludge
|
|
|
|
.0
|
|
|
|
|
Primary plus fixed film
reactor sludges
|
|
|
|
.0
|
*These volumes apply to waste activated sludge from single
stage nitrification facilities with less than 24 hours detention time based on
design average flow.
2) These volumes are based on digester temperatures of 59~ F
(15~ C) and a solids retention time of 27 days. Aerobic digesters shall be
covered to minimize heat loss or these volumes shall be increased for colder
temperature applications. Refer to subsection (g) below for necessary sludge
storage. Additional volume may be required if the land application disposal
method is used in order to meet applicable Federal regulations.
d) Mixing
Aerobic digesters shall be equipped with devices which can
maintain solids in suspension and which provide complete mixing of the digester
contents.
e) Air Requirements
Sufficient air shall be provided to keep the solids in
suspension and maintain dissolved oxygen between 1 and 2 milligrams per liter
(mg/l). For minimum mixing and oxygen requirements, an air supply of 30 cfm
per 1000 cubic feet of tank volume shall be provided with the largest blower
out of service. If diffusers are used, the nonclog type is recommended, and
they should be designed to permit continuity of service. If mechanical turbine
aerators are utilized, at least two turbine aerators per tank shall be provided
to permit continuity of service. Mechanical aerators are not acceptable for use
in aerobic digesters due to freezing conditions experienced throughout
Illinois.
f) Supernatant Separation and Scum and Grease Removal
1) Supernatant Separation
Facilities shall be provided for effective separation or
decanting of supernatant. Separate facilities are recommended; however,
supernatant separation may be accomplished in the digestion tank if additional
volume is provided, in accordance with subsection (c) above. The supernatant
drawoff unit shall be designed to prevent the recycle of scum and grease back
to plant process units. Provision should be made to withdraw supernatant from
multiple levels of the supernatant withdrawl zone.
2) Scum and Grease Removal
Facilities shall be provided for the effective collection of
scum and grease for final disposal and to prevent recycle back to plant process
units and prevent long term accumulation and potential for discharge of scum
and grease in the effluent.
g) High Level Emergency Overflow
An unvalved high level overflow and any necessary piping
shall be provided to return digester overflow back to the head of the plant or
to the aeration process in case of accidental overfilling. The design of the
overflow shall take into account the length of time and rate at which sludge is
wasted during periods when the treatment plant is unattended, potential effects
of overflow on plant process units, location of the discharge from the emergency
overflow, and the potential for discharge of suspended solids in the plant
effluent.
h) Digested Sludge Storage Volume
1) Sludge storage must be provided in accordance with Section
370.870 to accommodate daily sludge production volumes and as an operational
buffer for unit outage and adverse weather conditions. Designs utilizing
increased sludge age in the activated sludge system as a means of storage are
not acceptable.
2) Liquid sludge storage capacity shall be based on the following
values unless digested sludge thickening facilities are utilized (refer to
Section 370.173) to provide solids concentrations to greater than 2 percent.
|
Sludge Source
|
Volume (ft.(3)/P.E./day)
|
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.845 HIGH PH STABILIZATION
Section 370.845 High pH
Stabilization
a) General
Alkaline material may be added to liquid primary or secondary
sludges for sludge stabilization in lieu of digestion facilities, to supplement
existing digestion facilities, or for interim sludge handling. Inasmuch as the
high pH stabilization process does not reduce organic matter but rather
increases the mass of dry sludge solids, so that additional volumes of sludge
will be generated in the absence of supplemental dewatering, the design shall
account for the increased sludge quantities for storage and handling,
transportation and disposal methods and associated costs. Alkaline material
may be added to dewatered sludges for stabilization pursuant to Section
370.520(b).
b) Operational Criteria
Sufficient alkaline material shall be added to liquid sludge
in order to produce a homogeneous mixture with a minimum pH of 12 after 2 hours
of vigorous mixing. Facilities for adding supplemental alkaline material shall
be provided to maintain the pH of the sludge during interim sludge storage
periods.
c) Odor Control and Ventilation
Odor control facilities shall be provided for sludge mixing
and treated sludge storage tanks that are located within ½ mile of residential
or commercial areas. Indoor sludge mixing, storage and processing facilities
shall have ventilation that meets the ventilation requirements contained in
Section 370.410(g)(1-4) and (6) and shall comply with the safety precautions
contained in Section 370.560. Adequate facilities shall be provided to
condition the exhaust air to meet the applicable substantive and permitting
requirements of 35 Ill. Adm. Code Subtitle B: Air Pollution.
d) Mixing Tanks and Equipment
1) Tanks
Mixing tanks may be designed to operate as either a batch or
continuous flow process. A minimum of two tanks of adequate size to provide a
minimum of 2 hours of contact time in each tank shall be provided. The
following factors shall also be taken into account in determining the number
and size of tanks:
A) Peak sludge flow rates;
B) Storage between batches;
C) Dewatering or thickening performed in tanks;
D) Repeating sludge treatment due to pH decay of stored sludge;
E) Sludge thickening prior to sludge treatment;
F) Type of mixing device used and associated maintenance and
repair requirements.
2) Equipment
Mixing equipment shall be designed to provide vigorous
agitation within the mixing tank, to maintain solids in suspension and to
provide for a homogenous mixture of the sludge solids and alkaline material.
Mixing may be accomplished by either diffused aeration or mechanical mixing.
For diffused aeration, an air supply of 30 cfm per 1000 cubic feet of mixing
tank volume with the largest blower out of service shall be provided.
Nonclogging diffusers designed to permit continuity of service should be used.
Mechanical mixers shall be designed to assure continuity of service during
freezing weather conditions and shall be equipped with impellers designed to
minimize fouling from debris in the sludge.
e) Chemical Feed and Storage Equipment
1) General
Equipment used for handling or storing alkaline shall be
designed to provide operator protection from eye and tissue damage. Refer to
Section 370.560 for proper safety precautions. Material storage, slaking and
feed equipment shall be sealed as airtight as practicable to prevent contact of
alkaline material with atmospheric carbon dioxide and water vapor and to
prevent the escape of dust material. All equipment and associated transfer
lines and piping shall be accessible for cleaning.
2) Feed and Slaking Equipment
The design of the feeding equipment shall be determined by
the treatment plant size, type of alkaline material used, slaking required and
operator requirements. Automated or batch equipment may be used. Automated
feeders may be volumetric or gravimetric, based on accuracy, reliability and
maintenance requirements. Manually operated batch slaking of quicklime (CaO)
should be avoided unless protective clothing and equipment are provided. At
small plants, for safety reasons the use of hydrated lime (Ca(OH)[2]) over
quicklime is recommended. Feed and slaking equipment shall be sized to handle
a minimum of 150% of the peak sludge flow rate, including sludge that may need
to be retreated due to pH decay. Duplicate units shall be provided.
3) Chemical Storage Facilities
Alkaline materials may be received in either bag or bulk
form. Materials delivered in bags must be stored indoors and elevated above
floor level. Bags should be multi-walled and moisture-proof. Dry bulk storage
containers must be as airtight as practicable and shall contain a mechanical
agitation mechanism. Storage facilities shall be sized to provide a minimum
30-day supply of alkaline materials. Adequate provisions shall be made to meet
the applicable substantive and permitting requirements of 35 Ill. Adm. Code
Subtitle B: Air Pollution.
f) Sludge Storage
Refer to Section 370.870 for general design considerations
for sludge storage facilities. The design shall incorporate the following
considerations for the storage of high pH stabilized sludge:
1) Liquid Sludge
Liquid high pH stabilized sludge shall be stored in a tank or
vessel equipped with rapid sludge withdrawl mechanisms for sludge disposal or
retreatment and may not be stored in a lagoon. Provision shall be made for
adding alkaline material in the storage tank. Mixing equipment meeting the
requirements of subsection (d)(2) above shall be provided in all storage tanks.
2) Dewatered Sludge
On-site storage of dewatered high pH stabilized sludge shall
be limited to 30 days. Provisions shall be made for rapid retreatment or
disposal of dewatered sludge stored on site in case of sludge pH decay.
3) Off-Site Storage
There shall be no off-site storage of high pH stabilized
sludge unless the Agency has issued a permit for off-site storage.
g) Disposal
Methods and options for immediate sludge disposal should be
used in order to reduce the on-site sludge inventory and the amount of sludge
that must be retreated to reduce odors when sludge pH decay occurs. Where land
application is used, the sludge must be incorporated into the soil within 24
hours after application.
(Source: Added at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.850 SLUDGE PUMPS AND PIPING
Section 370.850 Sludge Pumps
and Piping
a) Sludge Pumps
1) Capacity
Pump capacities shall be adequate but not excessive.
Provision for varying pump capacity is desirable. A rational basis of design
shall be provided with the plan documents.
2) Duplicate Units
Duplicate units shall be provided at all installations.
3) Type
Plunger pumps, screw feed pumps or other types of pumps with
demonstrated solids handling capability shall be provided for handling raw
sludge. Where centrifugal pumps are used, a parallel positive displacement
pump shall be provided as an alternate to pump heavy sludge concentrations,
such as primary or thickened sludges, that may exceed the pumping head of the
centrifugal pump.
4) Minimum Head
A minimum positive head of 24 inches shall be provided at the
suction side of centrifugal type pumps and is desirable for all types of sludge
pumps. Maximum suction lifts should not exceed 10 feet for plunger pumps.
5) Sampling Facilities
Unless sludge sampling facilities are otherwise provided,
quick closing sampling valves shall be installed at the sludge pumps. The size
of valve and piping should be at least 1½ inches and terminate at a suitably
sized sampling sink or floor drain.
b) Sludge Piping
1) Size and Head
Digested sludge withdrawal piping should have a minimum
diameter of 8 inches for gravity withdrawal and 6 inches for pump suction and
discharge lines. Where withdrawal is by gravity, the available head on the
discharge pipe should be at least 4 feet and preferably more. Undigested
sludge withdrawl piping shall be sized in accordance with Section
370.720(b)(3).
2) Slope and Flushing Requirements
Gravity piping should be laid on uniform grade and
alignment. Slope on gravity discharge piping should not be less than 3 percent
for primary sludges and all sludges thickened to greater than 2 percent
solids. The slope on gravity discharge piping should not be less than 2
percent for aerobicly digested sludge or waste activated sludge with less than
2 percent solids. Cleanouts shall be provided for all gravity sludge piping.
Provisions shall be made for draining and flushing discharge lines. All sludge
pipe shall be suitably located or otherwise adequately protected to prevent
freezing.
3) Supports
Special consideration shall be given to the corrosion
resistance and permanence of supporting systems for piping located inside the
digestion tank.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.860 SLUDGE DEWATERING
Section 370.860 Sludge
Dewatering
a) General
On-site sludge dewatering facilities shall be provided for
all plants, although the following requirements may be reduced or omitted, if
justified, with on-site liquid sludge storage facilities or approved off-site
sludge disposal.
1) Anaerobic Digestion Sludge Production
For purposes of calculating sludge handling and disposal
needs, sludge production values from a two-stage anaerobic digestion process
shall be based on a maximum solids concentration of 5% without additional
thickening. The solids production values, calculated on a dry weight basis,
shall be based on the following values for the listed processes:
A) Primary plus waste activated sludge – at least 0.12
lbs/P.E./day;
B) Primary plus fixed film reactor sludge – at least 0.09
lbs/P.E./day.
2) Aerobic Digestion Sludge Production
For purposes of calculating sludge handling and disposal
needs, sludge production values from an aerobic digester shall be based on a
maximum solids concentration of 2% without additional thickening. The solids
production values, calculated on a dry weight basis, shall be based on the
following values for the listed processes:
A) Primary plus waste activated sludge – at least 0.16
lbs/P.E./day;
B) Primary plus fixed film reactor sludge--at least 0.12 lbs/P.E./day.
3) Production from Other Sludge Treatment Processes
For purposes of calculating sludge handling and disposal
needs, sludge production values from other sludge treatment processes shall be
determined by rational calculations in the basis of design. Refer to Section
370.520(b) for any new process determinations.
b) Sludge Drying Beds
1) Applicability
Sludge drying beds may be used for dewatering well digested
sludge from either the anaerobic or aerobic process. Due to the large volume
of sludge produced by the aerobic digestion process, consideration should be
given to using a combination of dewatering systems or other means of ultimate
sludge disposal.
2) Unit Sizing
Sludge drying bed area shall be calculated on a rational
basis with the following items taken into account:
A) The volume of wet sludge produced by existing and proposed
processes.
B) Depth of wet sludge drawn to the drying beds. For design
calculations purposes a maximum depth of 8 inches shall be utilized. For
operational purposes, the depth of sludge placed on the drying bed may vary
from the design depth based on the solids content and the type of digestion
used.
C) Total digester volume and other wet sludge storage facilities.
D) Degree of sludge thickening provided after digestion.
E) The maximum drawing depth of sludge which can be removed from
the digester or other sludge storage facilities without causing process or
structural problems.
F) The time required on the bed to produce a removable cake.
Adequate provision shall be made for sludge dewatering and/or sludge disposal
facilities for those periods of time during which outside drying of sludge on
beds is hindered by weather. For Illinois that season is considered to extend
from early November through at least April.
G) Capacities of auxiliary dewatering facilities.
3) Percolation Type Bed Components
A) Gravel
The lower course of gravel around the underdrains should be
properly graded and should be 12 inches in depth, extending at least 6 inches
above the top of the underdrains. It is desirable to place this in 2 or more
layers. The top layer of at least 3 inches should consist of gravel ⅛
inch to ¼ inch in size.
B) Sand
The top course should consist of at least 6 to 9 inches of
clean, washed, coarse sand. The effective size of the sand should be in the
range of 0.8 to 1.5 millimeters. The finished sand surface should be level.
C) Underdrains
Underdrains should be at least 4 inches in diameter laid with
open joints. Perforated pipe may also be used. Underdrains should be spaced not
more than 20 feet apart. Various pipe materials may be used, so long as they
are sufficiently strong and are corrosion resistant.
D) Additional Dewatering Provisions
Consideration shall be given to providing a means of
decanting the supernatant of sludge placed on the sludge drying beds. More
effective decanting of supernatant may be accomplished with polymer treatment
of the sludge.
4) Walls
Walls should be water-tight and extend 18 inches above and at
least 6 inches below the surface of the bed. Outer walls should be curbed or
extended at least 4 inches above the outside grade elevation to prevent soil
from washing on to the beds.
5) Sludge Removal
Each bed shall be constructed so as to be readily and
completely accessible to mechanical cleaning equipment. Concrete runways spaced
to accommodate mechanical equipment shall be provided. Special attention
should be given to assure adequate access to the areas adjacent to the
sidewalls. Entrance ramps down to the level of the sand bed shall be
provided. These ramps shall be high enough to eliminate the need for an
entrance end wall for the sludge bed.
c) Sludge Lagoons for Dewatering
1) General
Lagoons as a means of dewatering digested sludge will be
permitted only upon proof that the character of the digested sludge and the
design mode of operation are such that offensive odors will not result. Where
sludge lagoons are permitted, adequate provisions shall be made for other
sludge dewatering facilities or sludge disposal in the event of upset or
failure of the sludge digestion process.
2) Location
Sludge lagoons shall be located as far as practicable from
inhabited areas or areas likely to be inhabited during the lifetime of the
structures.
3) Seal
Adequate provisions shall be made to seal the lagoon bottoms
and embankments to prevent leaching into adjacent soils or groundwater. Refer
to Section 370.930(d)(1)(A), (d)(2)(C) and (d)(2)(D).
4) Access
Provisions shall be made for sludge pumping or heavy
equipment access for sludge removal from the lagoon.
d) Mechanical Dewatering Facilities
1) General
Provision shall be made to maintain sufficient continuity of
service so that sludge may be dewatered without accumulation beyond storage
capacity. The number of vacuum filters, centrifuges, filter presses, belt
filters, or other mechanical dewatering facilities should be sufficient to
dewater the sludge produced with the largest unit out of service. Unless other
standby wet sludge facilities are available, adequate storage facilities of at
least 4 days production volume shall be provided. Documentation must be
submitted justifying the basis of design of mechanical dewatering facilities.
2) Water Supply Protection
The water supply for mechanical dewatering facilities shall
meet the requirements of Section 370.550(b).
3) Auxiliary Facilities for Vacuum Filters
Back-up vacuum and filtrate pumps shall be provided. It is
permissible to have uninstalled back-up vacuum and filtrate pumps for every
three or less vacuum filters, provided that the installed units can easily be
removed and replaced. At least one filter media replacement unit shall be
provided.
4) Ventilation
Adequate facilities shall be provided for ventilation of the
dewatering area. The exhaust air should be properly conditioned to avoid odor
nuisance. Ventilation shall be provided in accordance with Section
370.410(g)(6).
5) Chemical Handling Enclosures
Lime-mixing facilities should be completely enclosed to
prevent the escape of lime dust. Chemical handling equipment should be
automated to eliminate the manual lifting requirement. Refer to Section
370.560.
e) Drainage and Filtrate Disposal
Drainage from beds or filtrate dewatering units shall be
returned to the sewage treatment process at appropriate points and rates.
f) Other Dewatering Facilities
If it is proposed to dewater sludge by other methods, a
detailed description of the process and design data shall accompany the plans.
Refer to Section 370.520(b) for any new process determinations.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.870 SLUDGE STORAGE AND DISPOSAL
Section 370.870 Sludge
Storage and Disposal
a) Storage
1) General
Sludge storage facilities shall be provided at all mechanical
treatment plants, and may consist of any combination of drying beds, lagoons,
separate tanks, additional volume in stabilization units, pad areas or other
means to store either liquid or dried sludge. Drainage of supernatant from
sludge storage facilities shall be returned to the sewage treatment process at
appropriate points and rates. Refer to Section 370.860(b) and (c) for drying
bed and lagoon design criteria, respectively.
2) Volume
Rational calculations justifying the number of days of
storage based on the total sludge handling and disposal system shall be
submitted. Refer to Sections 370.840(g) and 370.860(a) for anaerobicly and
aerobicly digested sludge production values; values for other stabilization
processes shall be justified on the basis of design. If land application is
the only means of sludge disposal used at a treatment plant, a minimum of 150
days storage shall be provided, in order to account for inclement weather and cropping
practices.
b) Disposal
1) Landfilling
Sludge and sludge residues may be disposed of in Agency
approved municipal solid waste landfill units under the terms and conditions of
permits issued by the Agency's Bureau of Land. On-site landfilling shall be
conducted in conformance with the design recommendations of the Bureau of Land
and must be approved by the Agency's Bureau of Water.
2) Land Application
Specific design criteria for land application of sludge are
set out in Design Criteria for Sludge Application on Land, 35 Ill. Adm. Code
391. Additional operating criteria may be obtained from applicable Federal
regulations. In order to assure compliance with the facility's effluent
standards, alternative sludge disposal options to account for inclement weather
and cropping practices are recommended.
3) Sludge Lagoons
The use of lagoons for ultimate disposal of sludge is not
recommended because of odor potential, area and volume required and possible
long term problems from groundwater contamination. If a lagoon is proposed, a
hydrogeologic survey must be performed to demonstrate the appropriateness of a
disposal lagoon at the particular site. A groundwater monitoring program must
be included in any sludge lagoon design. Refer to Section 370.860(c) for
lagoon design criteria.
4) Other Disposal Methods
A detailed description of the technique and design data shall
accompany the plans of any proposal to dispose of sludge by methods other than
those specified in this Section. Refer to Section 370.520(b) for any new
process determinations.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART I: BIOLOGICAL TREATMENT
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.900 TRICKLING FILTERS
Section 370.900 Trickling
Filters
a) General
1) Applicability
Trickling filters may be used for treatment of sewage
amenable to treatment by aerobic biologic processes. Trickling filters shall be
preceded by settling tanks equipped with scum and grease collecting devices, or
other suitable pretreatment facilities.
2) Design Basis
Filters shall be designed so as to provide the required
reduction in biochemical oxygen demand, ammonia nitrogen, or to properly
condition the sewage for subsequent treatment processes.
3) Multiple Units
Multiple trickling filter units capable of independent
operation are recommended for all plants and must be provided for those plants
where the design average flow exceeds 100,000 gallons per day. Plants not
having multiple units shall include other provisions to assure continuity of treatment.
b) Dosing Equipment
1) Distribution
A) All hydraulic factors involving proper distribution of sewage
on the filter should be carefully calculated and submitted with the basis of
design.
B) The sewage may be distributed over the filter by rotary
distributors or other suitable devices which will permit reasonably uniform
distribution to the surface area. At design average flow, the deviation from
calculated uniformly distributed volume per square foot of the filter surface
shall not exceed plus or minus 10 percent at any point.
2) Dosing and Recirculation
A) Sewage may be applied to the filters by siphons, pumps or by
gravity discharge from preceding treatment units when suitable flow
characteristics have been developed. Application of the sewage should be
continuous except for low rate filters. A hydraulic system for recirculation
shall be provided for new facilities and should be considered where existing
trickling filter units are included in treatment plant upgrading.
B) The piping system, including dosing equipment and distributor,
shall be designed to provide capacity for the peak hourly flow rate including
recirculation rates determined under subsection (h).
3) Distributor Head Requirements
For reaction type distributors, a minimum head of 24 inches
between low water level in siphon chamber and center of arms is required.
Similar allowances shall be made in design for added pumping head requirements
where pumping to the reaction type distributor is used. The design shall
include the head required at the center column for the full range of flows, taking
into account all head losses from the center column back to the dosing facility
at all water levels. Calculations shall be submitted to justify the basis of
design.
4) Clearance
A minimum clearance of 6 inches between media and distributor
arms shall be provided. Refer to subsection (e)(4).
c) Media
1) Quality
The media may be crushed rock, slag or specially manufactured
material. The media shall be durable, resistant to spalling or flaking, and be
relatively insoluble in sewage. The top 18 inches shall have a loss by the
20-cycle, sodium sulfate soundness test of not more than 10 percent, as
prescribed by ASCE Manual of Engineering Practice, Number 13, the balance to
pass a 10-cycle test using the same criteria. Slag media shall be free from
iron. Manufactured media shall be resistant to ultraviolet degradation,
disintegration, erosion, aging, all common acid and alkalies, organic
compounds, and fungus and other biological attack. Such media shall be
structurally capable of supporting a man's weight or a suitable access walkway
shall be provided to allow for distributor maintenance.
2) Depth
The filter media shall have a minimum depth of 6 feet above
the underdrains. For rock media filters (subsection (c)(3)(A)), only the top 7
feet of the volume of the filter shall be considered in BOD removal credit
computations. For manufactured media filters see subsection (c)(3)(B).
3) Size and Grading of Media
A) Rock, Slag and Similar Media
i) Rock, slag and similar media shall not contain more than 5
percent by weight of pieces whose longest dimension is 3 times the least
dimension.
ii) Media shall be free from thin elongated and flat pieces,
dust, clay, sand, or fine material and shall conform to the following size and
grading when mechanically graded over vibrating screen with square openings:
Passing 4 1/2 inch screen – 100% by weight
Retained on 3 inch screen – 95-100% by weight
Passing 2 inch screen – 0-2% by weight
Passing 1 inch screen – 0-1% by weight
B) Manufactured Media
Suitability of size, space, media configuration and depth
will be evaluated on the basis of experience with installations handling
similar wastes and loadings. To ensure sufficient void clearance, media with a
specific surface area of no more than 30 square feet per cubic foot may be used
for filters employed for carbonaceous reduction, and media with a specific
surface area of no more than 45 square feet per cubic foot may be used for
second stage ammonia reduction. See subsection (c)(1) for quality
requirements.
4) Handling and Placing of Media
A) Material delivered to the filter site shall be stored on wood
planks or other approved clean hard surfaced areas.
B) All material shall be rehandled at the filter site and no
material shall be dumped directly into the filter. Crushed rock, slag and
similar media shall be rescreened or forked at the filter site to remove all
fines.
C) The material shall be placed by hand to a depth of 12 inches
above the tile underdrains and all material shall be carefully placed so as not
to damage the underdrains. The remainder of the material may be placed by
means of belt conveyors or equally effective methods approved by the engineer.
D) Manufactured media shall be handled and placed as recommended
by the manufacturer and approved by the engineer.
E) Trucks, tractors, or other heavy equipment shall not be driven
over the filter during or after construction.
d) Underdrainage System
1) Arrangement
Underdrains with semi-circular inverts or equivalent should
be provided and the underdrainage system shall cover the entire floor of the
filter. Inlet openings into the underdrains shall have an unsubmerged gross
combined area equal to at least 15 percent of the surface area of the filter.
2) Slope
The underdrains shall have a minimum slope of 1 percent.
Effluent channels shall be designed to produce a minimum velocity of 2 feet per
second at design average flow of application to the filter and shall have
adequate capacity for the peak hourly flow rate including the required
recirculation flows.
3) Flushing
Provision should be made for flushing the underdrains. In
small filters, use of a peripheral head channel with vertical vents is
acceptable for flushing purposes. Inspection facilities should be provided.
4) Ventilation Requirements for Underdrains
The underdrainage system, effluent channels, and effluent
pipe should be designed to permit free passage of air. The size of drains,
channels, and pipe should be such that not more than 50 percent of their
cross-sectional area will be submerged under the design hydraulic loading.
Consideration should be given in the design of the effluent channels to the
possibility of increased hydraulic loading.
e) Special Features
1) Flooding
Provision shall be made in the design of conventional rock
filter structures so that the media may be flooded.
2) Maintenance
All distribution devices, underdrains, channels and pipes
shall be designed so that they may be properly maintained, flushed or drained.
3) Flow Measurement
Devices shall be provided to permit measurement of flow to
the filter, and of recirculated flows.
4) Protection From Freezing
Trickling filters shall be covered to protect from freezing,
and to maintain operation and treatment efficiencies. The filter cover shall
be constructed of appropriate corrosion resistant materials and designed to
allow operator access for maintenance, repair and replacement of the filter
dosing equipment.
5) Ventilation of Covered Filters
Forced ventilation shall be provided for covered trickling
filters to insure adequate oxygen for process requirements. Windows or simple
louvered mechanisms so arranged to insure air distribution throughout the
enclosure shall be provided. The ventilation facilities shall be designed to
allow operator control of air flow in accordance with outside temperature.
Design computations showing the adequacy of air flow to satisfy process oxygen
requirements shall be submitted.
f) Two-Stage Filters
The foregoing standards also apply to second stage filters.
g) Special Applications
1) Roughing Filters
In some instances it is desirable to partially reduce the
organic strength of wastewaters. In such cases trickling filters may be used
for roughing treatment. Design parameters and contaminant removal efficiencies
will be approved on a case-by-case basis. Refer to subsections (h)(2) and
(h)(3).
2) Nitrifying Filters
Trickling filters may, under favorable conditions, be used as
nitrification devices. Design parameters and contaminant removal efficiencies
will be approved on a case-by-case basis. Refer to Section 370.1210(d).
h) Efficiency
1) Single Stage, Settling Tank – No Recirculation
Expected reduction of BOD of settled normal domestic
wastewater by a single stage filter, packed with crushed rock, slag or similar
material and with subsequent settling, shall be determined from Appendix F,
Figure No. 3. In developing this curve, loading due to recirculated sewage has
not been considered.
2) Single or Multi-Stage, Settling Tank – Recirculation
Expected BOD removal efficiencies may also be determined by
theoretical and empirical formula if accompanied by detailed explanation,
particularly for roughing filters and for filters with recirculation. (Refer
to WEF Manual of Practice (MOP) No. 8, "Design of Municipal Wastewater
Treatment Plants", vol. 1 (1992).)
3) Single or Multi-Stage, No Settling Tank – Recirculation
Filters not followed by a settling tank and discharging into a subsequent
treatment process shall not be credited with BOD removal efficiencies as in
subsections (h)(1) and (h)(2) above. Expected performance in such cases, including
filters packed with manufactured media, shall be determined from prototype
testing and full-scale plant experience.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.910 ROTATING BIOLOGICAL CONTACTORS (REPEALED)
Section 370.910 Rotating
Biological Contactors (Repealed)
(Source: Repealed at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.915 ROTATING BIOLOGICAL CONTACTORS
Section 370.915 Rotating
Biological Contactors
a) General
Wastewater treatment facilities that propose to use rotating
biological contactors (RBCs) shall submit to the Agency for review field
experience and operational data that demonstrates that observed problems with
the process have been solved at similar full scale installations. The Agency
will review the claimed field experience against known field conditions and the
operational history of observed problems at similar facilities.
b) Mechanical Reliability and Structural Integrity
1) The mechanical and structural reliability of the shafts and
media subjected to cyclic stress reversals must be demonstrated relative to the
design life of the plant and the known weight of the machines based on field
experience.
2) The design must show that film thickness will be effectively
controlled throughout all parts of the media pack to prevent excessive film
weight and water pickup weight due to plugging restrictions. The equipment
design must include load cells to warn of the need for film thickness control
and to demonstrate the effectiveness of the proposed film thickness control
practices.
c) Process Reliability
1) Process reliability must be demonstrated, including proven
operational control procedures relative to design organic loadings for the unit
media area or volume, which satisfactorily insure that the applicable effluent
standards are met. The process design shall also include proven operational
control procedures that will prevent process functional deficiencies and media
plugging that cause the weight to exceed shaft and media structural
capabilities during the design life of the plant.
2) The design must show that adequate void clearance (as
distinguished from void ratio) is provided to insure that the biological film,
including any grease and fats that may accumulate, will not interefere with the
flow of liquid and air in the media pack. The Agency will compare the RBC
designs under review to past experience with designs used for plastic trickling
filter media to accomplish adequate void clearance.
3) The design shall provide for maintaining a minimum of 2.0 mg/l
dissolved oxygen in the basin liquor. The effectiveness of the proposed method
for maintaining adequate dissolved oxygen will be evaluated based on field
experience at similar full scale installations.
4) If pilot testing is proposed, the size of the RBC pilot plant
unit and the scope and duration of the testing program on the specific waste
that will be treated must be thoroughly documented. The proposed pilot testing
program should be submitted to the Agency for comment prior to the initiation
of testing. The RBC pilot units must be of prototype scale. Because of
differential seasonal weight and plugging field problems, the test period must
cover the four seasons, to allow the Agency to evaluate the proposed design
against the experience of existing full scale plants.
5) The process design must include provisions for meeting
applicable effluent limits with some units out of service for unit repair,
biofilm thickness control, out-of-balance correction and other operational
problems. Added units for standby credit will be required to insure compliance
with effluent limitations and to prevent mechanical or structural failures
during periods of unit outage for maintenance, repair, or process control
purposes.
(Source: Added at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.920 ACTIVATED SLUDGE
Section 370.920 Activated
Sludge
a) General
1) Applicability
A) Biodegradable Wastes
The activated
sludge process, and its various modifications, may be used to treat wastewater
which is amenable to biological treatment. Approval of new activated sludge
plants shall be limited to those plants where the design average flow capacity
exceeds 0.25 mgd.
B) Operation Control Requirements
The activated sludge process requires close attention and
competent operating supervision. Facilities and appurtenances for routine
control and control tests shall be provided at all activated sludge plants.
These requirements shall be considered when proposing this type of treatment.
C) Energy Requirements
This process requires major energy usage to meet aeration
demands. Energy costs and potential mandatory emergency public power reduction
events, in relation to critical water quality conditions, must be carefully
evaluated. Capability of energy usage phasedown while still maintaining
process viability, both under normal and emergency energy availability
conditions, must be included in the activated sludge design.
2) Specific Process Selection
The activated sludge process and its several modifications
may be employed to accomplish varied degrees of removal of suspended solids and
reduction of 5-day BOD and nitrogenous oxygen demand. Choice of the process
most applicable will be influenced by the proposed plant size, type of waste to
be treated, treatability of waste, degree and consistency of treatment required
and local factors. All designs shall provide for flexibility in operation.
All plants shall be designed to operate in at least two modes.
3) Winter Protection
Units shall be protected against freezing. Maximum
utilization of earthen bank insulation shall be considered.
4) Process Efficiency
The activated sludge process designed within the organic and
hydraulic loading limits of these standards, treating normal domestic
wastewaters unaffected by surge loadings, long term peak flows, or industrial
wastes, may be expected to meet an effluent standard of 20 mg/l CBOD5
or BOD5 and 25 mg/l suspended solids when computed on a 30-day
monthly average basis. Those installations which are anticipated to be subject
to surge loadings, long term peak flows or industrial wastes shall have
appropriate design modifications in order to assure consistent effluent
quality.
b) Preliminary Treatment
Effective removal of grit, debris, excessive oil and grease
and screening of solids shall be accomplished prior to the activated sludge
process. Where primary settling does not precede the activated sludge process,
screening with ½ inch or smaller clear opening is recommended in order to
prevent plugging of return sludge piping and pumps.
c) Primary Treatment Bypass
When primary settling is used, provision shall also be made
for discharging raw sewage directly to the aeration tanks following preliminary
treatment.
d) Process Organic Loadings
The aeration tank capacities and permissible loadings for the
several adaptations of the processes shown in the table shall be used.
Permissible Organic Loading
For The Activated Sludge Processes
For Normal Domestic Sewage*
|
Process Mode
|
Plant Design Average Flow
|
Aeration Tank Organic Loading,
lbs BOD5/day/1000 cu. ft.
|
|
Conventional, Complete Mix, Contact Stabilization,** Step Aeration,
Tapered Aeration
|
Less than 1 mgd
|
35
|
|
1 mgd or greater
|
50
|
|
Extended Aeration Single Stage Nitrification
|
|
15***
|
* Where significant industrial wastes will be tributary to the
process, design modification shall be made as required by subsection (a)(4), to
assure compliance with effluent standards.
** Total aeration capacity includes both contact and reaeration
capacities.
*** Detention time at Design Average Flow for extended aeration
shall be 24 hours. This requirement may govern tank capacity. Detention time
for single stage activated sludge for nitrification is governed by Section
370.1210(c)(3)(B).
e) Aeration Tanks
1) Multiple Units
Multiple tanks shall be provided. Tanks shall be designed so
that each tank may be dewatered and operated independently.
2) Tank Geometry
The dimensions
of each independent mixed liquor aeration tank or return sludge reaeration tank
shall be such as to maintain effective mixing and utilization of air. Liquid
depths should not be less than 10 feet. The shape of the tank, the location of
the inlet and outlet and the installation of aeration equipment shall provide for
positive control of short-circuiting through the tank.
3) Freeboard
All aeration
tanks shall have a freeboard of not less than 18 inches. Greater heights are
desirable. Suitable water spray systems or other approved means of froth and
foam control shall be provided if foaming is anticipated.
4) Inlet and Outlet Control
Inlets and
outlets for each aeration tank unit shall be suitably equipped with valves,
gates, stop plates, weirs, or other devices to permit balancing, proportioning,
and measuring the flow to and from any unit and to maintain reasonably constant
liquid level. The hydraulic elements of the system shall permit the design
peak flow to be carried with any single aeration tank out of service.
5) Conduits
Channels and
pipes carrying liquids with solids in suspension shall be designed to maintain
self-cleansing velocities or shall be agitated to keep such solids in
suspension at all design rates of flow. Adequate provisions should be made to
drain segments of channels which are not being used due to alternate flow
patterns.
f) Aeration Equipment
1) General
A) Aeration requirements depend upon mixing energy, BOD loading,
degree of treatment, oxygen uptake rate, mixed liquor suspended solids
concentration and sludge age. Aeration equipment shall be capable of
maintaining a dissolved oxygen concentration of 2.0 mg/1 in the aeration tanks
under all design loads. Energy transfer shall be sufficient to maintain the
mixed liquor solids in suspension.
B) In the case of nitrification, the oxygen requirement for
oxidizing ammonia must be added to the above requirement for carbonaceous BOD
removal. The nitrogen oxygen demand (NOD) shall be taken as 4.6 times the
diurnal peak ammonia (as nitrogen) content of the influent. In addition, the
oxygen demands due to recycle flows such as sludge processing, return from excess
flow first flush storage and other similar flows, must be taken into account
due to the high concentrations of BOD and ammonia associated with such flows.
C) Careful consideration should be given to maximizing oxygen
utilization per unit power input. Unless flow equalization is provided, the
aeration system should be designed to match the diurnal organic load variation
while economizing on power input.
2) Diffused Air Systems
A) Except as noted in subsection (f)(2)(B) below, normal aeration
tank air requirements shall be based upon a design figure of 1,500 cu. ft. of
air supplied/lb. of BOD5 applied to the aeration tanks. This design
figure assumes that the equipment is capable of transferring 1.0 lb. of oxygen
to the aeration tank contents/lb. of BOD5 applied to the aeration
tank. For the extended aeration process, air requirements shall be based on a
design figure of 2250 cu. ft. of air supplied per lb. of BOD5 applied
to the aeration tanks to account for oxygen demand for endogenous respiration
and ammonia (as nitrogen) for normal strength waste. Refer to Section
370.1210(c) for nitrification requirements.
B) Air requirements may be determined based upon transferring 1.0
lb. oxygen/lb. of applied oxygen demand, as determined by subsection (f)(1) above,
using standard equations incorporating the factors listed below. When using
this design technique, the field oxygen transfer efficiency of the equipment
shall be included in the specifications, and the detailed design computations
shall be contained in the basis of design:
i) Tank depth;
ii) Alpha factor of the waste;
iii) Beta factor of the waste;
iv) Documented aeration device transfer efficiency;
v) Minimum aeration tank dissolved oxygen concentrations;
vi) Critical wastewater temperature;
vii) Plant altitude.
C) In the absence of experimentally determined alpha and beta
factors for the design described in subsection (f)(2)(B) above, wastewater transfer
efficiency shall be assumed to be no more than 50% of clean water efficiency
for plants treating primarily (90% or greater) domestic sewage. Treatment
plants whose waste contains higher percentages of industrial wastes shall use a
correspondingly lower percentage of clean water efficiency and shall submit
calculations to justify such a percentage. The design wastewater oxygen
transfer efficiency of the equipment shall be included in the specifications.
D) The specified capacity of blowers or air compressors,
particularly centrifugal blowers, should take into account that the air intake
temperature may reach 115° F or higher and the pressure may be less than
normal. The specified capacity of the motor drive should also take into
account that the intake air may be -20° F or less and may require oversizing of
the motor or a means of reducing the rate of air delivery to prevent
overheating or damage to the motor.
E) The blowers shall be provided in multiple units, so arranged
and in such capacities as to meet the maximum total air demand with the single
largest unit out of service. The design shall also provide for varying the
volume of air delivered in proportion to the load demand of the plant.
F) The air diffusion piping shall be capable of delivering 200
percent of the design air requirements. Air piping systems should be designed
such that the friction head loss from the blower outlet (or silencer outlet
where used) to the diffuser inlet does not exceed 0.5 psi at 100 percent of
design air requirements at average operating conditions for temperature and
pressure.
G) The spacing of diffusers should be in accordance with the
oxygenation requirements through the length of the channel or tank, and should
be designed to facilitate adjustments of their spacing without major revision
to air header piping. Diffusers in any single assembly shall have
substantially uniform pressure loss.
H) Individual assembly units of diffusers shall be equipped with
control valves, preferably with indicator markings for throttling and for
complete shut off. The arrangement of diffusers shall also permit their
removal for inspection, maintenance and replacement without dewatering the tank
and without shutting off the air supply in the tank, unless the dewatered aeration
basins are no more than 25% of the total aeration basin capacity. Total
aeration basin capacity shall include the basins in both stages of a two-stage
activated sludge process.
I) Air filters shall be provided in numbers, arrangement, and
capacities to furnish at all times an air supply sufficiently free from dust to
prevent clogging of the diffuser system used.
3) Mechanical Aeration Systems
A) Oxygen requirements shall be determined in accordance with
subsections (f)(2)(B) and (f)(2)(C) above.
B) The mechanism and drive unit shall be designed for the expected
conditions in the aeration tank in terms of the power performance. Certified
testing shall verify mechanical aerator performance. The design field oxygen
transfer efficiency of the equipment shall be included in the specifications,
and the detailed design computations shall be contained in the basis of design.
C) The mechanical aerators shall be provided in multiple units, so
arranged and in such capacities as to maintain all biological solids in
suspension, meet maximum oxygen demand and maintain process performance with
the largest unit out of service. Provision shall be made for varying the amount
of oxygen transferred in proportion to the load demand on the plant.
D) Due to high heat loss, the mechanism as well as subsequent
treatment units shall be protected from freezing.
E) Motors, gear housing, bearings and grease fittings shall be
easily accessible and protected from inundation and spray as necessary for
proper functioning of the unit.
g) Return Sludge Equipment
1) Return Sludge Rate
The rate of sludge return, expressed as a percentage of
design average flow of sewage, shall be variable between limits of 15 and 100
percent.
2) Return Sludge Pumps
A) If motor driven return sludge pumps are used, the maximum
return sludge capacity shall be obtained with the largest pump out of service.
The rate of sludge return shall be varied by such means as variable speed
motors or drives, multiple constant speed pumps, or telescoping valves. A
positive head should be provided on pump suctions. Pumps shall be capable of
passing spheres of at least 3 inches in diameter. Pump suction and discharge
openings shall be at least 4 inches in diameter.
B) If air lift pumps are used for returning sludge from each
settling tank, no standby unit shall be required provided that the design of
the air lifts is such as to facilitate their rapid and easy cleaning. Air
lifts should be at least 3 inches in diameter and provided with adjustable air
valving to permit flow control in accordance with subsection (g)(1) above.
3) Return Sludge Piping
Suction and discharge piping should be at least 4 inches in
diameter and should be designed to maintain a velocity of not less than 2 feet
per second when return sludge facilities are operating at normal return sludge
rates. Suitable devices for observing, measuring, sampling and controlling
return activated sludge flow from each settling tank shall be provided.
4) Waste Sludge Control
Waste sludge control facilities should have a maximum
capacity of not less than 25 percent of the average rate of sewage flow and
function satisfactorily at rates of 0.5 percent of average sewage flow. Means
for observing, measuring, sampling and controlling waste activated sludge flow
shall be provided. Waste sludge may be discharged to the primary settling
tank, concentrator or thickening tank, sludge digestion tank, vacuum filters,
or any practical combination of these units. Refer to Sections 370.820 and
370.710(b)(1)(A).
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.930 WASTE STABILIZATION PONDS AND AERATED LAGOONS
Section 370.930 Waste
Stabilization Ponds and Aerated Lagoons
a) Supplement To Engineer's Report
1) The engineer's report shall contain pertinent information on
location, geology, soil conditions, area for expansion, and any other factors
that will affect the feasibility and acceptability of the proposed treatment.
2) Supplementary Field Survey Data
The following information must be submitted in addition to
that required in Section 370.111:
A) The location and direction of all residences, commercial
development, and water supplies within ½ mile of the proposed pond.
B) Soil borings to determine surface and subsurface soil
characteristics of the immediate area and their effect on the construction and
operation of a pond located on the site.
C) Data demonstrating anticipated percolation rates at the
elevation of the proposed pond bottom.
D) A description, including maps showing elevations and contours
of the site and adjacent area suitable for expansion.
E) Sulfate content of the water supply.
F) Identification of the location, depth and discharge point of
any field tile in the immediate area of the proposed site.
b) Location
1) Distance From Habitation
A pond site should be as far as practicable from habitation
or any area which may be built up within a reasonable future period.
2) Prevailing Winds
If practicable, ponds should be located so that local
prevailing winds will be in the direction of uninhabited areas. Preference
should be given sites which will permit an unobstructed wind sweep across the
ponds, especially in the direction of the local prevailing winds.
3) Surface Runoff
Adequate provisions shall be made to divert storm water
around the ponds and otherwise protect pond embankments.
4) Ground Water Contamination
The requirements of the Illinois Groundwater Protection Act
[415 ILCS 55] shall be taken into account in the siting of ponds. Ponds should
not be located proximate to water supplies and other facilities subject to
contamination or located in areas of porous soils and fissured rock
formations. If conditions dictate using such a site, then the potential for
and the means necessary to combat groundwater contamination shall be critically
evaluated in the engineer's report. In such locations, the Agency will require
groundwater monitoring wells.
5) Geology
Ponds shall not be located in areas subject to sink holes and
mine subsidence. Soil borings and tests to determine the characteristics of
surface soil and subsoil shall be made a part of preliminary pond site
selection surveys. Gravel and limestone areas should be avoided; however,
where conditions dictate locating ponds in such areas and the minimum
separation between the pond bottom and gravel or limestone will be less than 10
feet, the Agency shall be contacted about the necessary precautions.
c) Basis Of Design
1) Organic Loading
A) Waste Stabilization Ponds
The organic loading on each cell shall not exceed the
loadings listed below. If more accurate design information for the particular
type waste is not submitted and supported by the engineer, subsequent cells
shall be sized for an organic loading of 25% of each preceding cell.
i) North of Illinois Highway 116 (Pontiac) 22 lbs. BOD per acre
per day.
ii) Between Illinois Highway 116 and U.S. Highway 50, 26 lbs. BOD
per acre per day.
iii) South of U.S. Highway 50 (Salem-Carlyle) 30 lbs. BOD per acre
per day.
B) Aerated Lagoons
The organic loading for aerated lagoons shall not exceed 0.5
lb. BOD[5] day per 1,000 cu. ft. first cell nor 0.3 lb. BOD[5] day per 1,000
cu. ft. on any subsequent cells. If more accurate design information for the
particular type waste is not submitted and supported by the engineer, the
second and third cells shall be sized for an organic loading of 25% of each
preceding cell.
2) Depth
A) Waste Stabilization Ponds
The minimum operating liquid depth for waste stabilization
ponds should be 2 feet. The maximum operating liquid depth shall be based on
design storage requirements and shall not be less than 5 feet.
B) Aerated Lagoons
The design water depth for aerated lagoons should be 10 to 15
feet. This depth limitation may be altered depending on the aeration equipment,
waste strength, climatic and geological conditions.
3) Aeration Requirements For Aerated Lagoons
A) Aeration systems shall be designed to provide, with the largest
unit out of service, a minimum of 1,500 cu. ft. of air/lb. of BOD5
in the raw waste (1.5 lbs. of oxygen/lb. of BOD5 plus oxygen
required to oxidize the ammonia present in the raw waste). The aeration
equipment shall be located to ensure proper mixing and distribution of oxygen
in proportion to oxygen demand in multiple cells. Splash type aerators with
motors above the water surface may not be used.
B) Where hose type diffusers are used, the holes shall be of
sufficient size to prevent plugging by dissolved solids incrustation.
4) Multiple Cells
A minimum of two cells to be operated in series or parallel
should be provided for all waste stabilization ponds when they are utilized as
a part of the primary and secondary treatment process. The number of cells
required for aerated lagoons are dependent upon the degree of treatment
required. Refer to subsection (c)(6).
5) Pond Shape
The shape of all primary cells should be such that there are
no narrow or elongated portions. Round, square, or rectangular ponds with a
length not exceeding 3 times the width are considered most desirable. No
islands, peninsulas, or coves should be permitted. Dikes should be rounded at
corners to minimize accumulations of floating materials.
6) Solids Removal
All lagoon systems shall include effective solids removal
facilities. Design criteria for acceptable solids removal facilities are
contained in Subpart K. Other solids removal facilities may be approved in
accordance with Section 370.520(b).
d) Construction Details
1) Embankments and Dikes
A) Material
Embankments and dikes shall be constructed of relatively
impervious materials and compacted to at least 90% Standard Proctor density to
form a stable structure. Vegetation and other unsuitable material shall be
removed from the area upon which the embankment is to be placed.
B) Top Width
The minimum embankment top width should be 8 feet to permit
access of maintenance vehicles. Lesser top widths will be considered for very
small installations.
C) Maximum Embankment Slopes
i) Inner
Slopes:
3 horizontal to 1 vertical.
ii) Outer
Slopes:
3 horizontal to 1 vertical.
D) Minimum Embankment Slopes
i) Inner
Slopes:
4 horizontal
to 1 vertical. Flatter slopes are sometimes specified for larger installations
because of wave action but have the disadvantage of added shallow areas
conducive to emergent vegetation.
ii) Outer
Slopes:
Outer slopes
shall be sufficient to prevent surface runoff from entering the ponds.
E) Freeboard
Minimum freeboard shall be 3 feet except for very small
installations 2 feet may be acceptable.
F) Erosion Control Requirements
For effective erosion control on the lagoon embankments, both
seeding and riprap (or acceptable alternate) are required.
i) Seeding
Embankments
shall be seeded from the outside toe to 1 foot above the high water line on the
dikes, measured on the slope. Perennial type, low growing, spreading grasses
that withstand erosion and can be kept mowed are most satisfactory for seeding
of embankments. In general, alfalfa and other long rooted crops should not be
used in seeding, since the roots of this type plant are apt to impair the water
holding efficiency of the dikes. The County Agricultural Extension Agent can
usually advise as to hardy, locally suited permanent grasses which would be
satisfactory for embankment seeding.
ii) Riprap
Riprap (or
acceptable alternate) shall be placed on the inner slope of the embankments
from 1 foot above the high water mark to 1 foot below the low water level.
Riprap shall be comprised of a two-layer system consisting of a minimum 4-inch
layer of coarse aggregate that meets the Illinois Department of Transportation
(IDOT) Standard Specification for Road and Bridge Construction adopted January
1, 1997 for the gradations in the range of CA-6 through CA-10 and a minimum
12-inch layer of stone. The rock layer shall consist of evenly graded material
with a maximum weight of 150 pounds per piece and shall meet the IDOT
gradations for rock of either Grade No. 3 or 4.
2) Pond Bottom
A) Uniformity
Finished elevations shall not be more than 3 inches from the
average elevation of the bottom. Shallow or feathering fringe areas usually
result in locally unsatisfactory conditions.
B) Vegetation
The bottom shall be cleared of vegetation and debris. Organic
material thus removed shall not be used in the dike core construction.
However, suitable topsoil relatively free of debris may be used as cover
material on the outer slopes of the embankment.
C) Soil
Soil used in constructing the pond bottom (not including the
seal) shall be relatively incompressible and tight. Porous topsoil shall be
removed. Porous areas, such as gravel or sandy pockets, shall be removed and
replaced with well compacted clay. The entire bottom shall be compacted at or
up to 4% above the optimum water content to at least 90% Standard Proctor
density.
D) Seal
The pond bottom and embankments shall be sealed such that
seepage loss through the seal is as low as possible. Seals consisting of
soils, bentonite or synthetic liners may be used, provided that the
permeability, durability and integrity of the proposed material is demonstrated
for anticipated conditions. The results of a testing program that
substantiates the adequacy of the proposed seal shall be incorporated into or
accompany the engineering report. Standard ASTM procedures or similar accepted
testing methods shall be used for all tests.
i) A seal consisting of soil materials shall have a thickness of
at least 24 inches and a permeability of less than 1x10-7 cm per
second. Provision shall be made in the specifications for demonstrating the
permeability of the seal after completion of construction and prior to filling
the pond.
ii) For a seal that consists of a synthetic liner, seepage loss
through the liner shall not exceed a quantity equivalent to seepage loss through
a soil seal as described above.
E) Prefilling
Prefilling the pond after completion of testing is
recommended in order to protect the seal from weed growth, to prevent drying
and cracking and to reduce odor during initial operation. The pond dikes must
be completely prepared as described in subsection (d)(1)(F). Synthetic liners
shall be protected from damage during installation and filling.
3) Influent Lines
A) Material
Any generally accepted material for underground sewer
construction will be given consideration for the influent line to the pond.
The material selected should be adapted to local conditions. Special
consideration must be given to the character of the wastes, possibility of
septicity, exceptionally heavy external loadings, abrasion, the necessity of
reducing the number of joints, soft foundations, and similar problems.
B) Manholes
A readily accessible manhole shall be installed at the
terminus of the trunk sewer or the force main, unless the force main discharges
directly to the lagoon as described in subsection (d)(3)(H). The manhole shall
be located as close to the dike as topography permits and its invert should be
at least 6 inches above the maximum operating level of the pond to provide
sufficient hydraulic head without surcharging the manhole. Surcharging of the
sewer upstream from the inlet manhole is not permitted.
C) Grade
i) Influent line can be placed at zero grade and should be
located along the bottom of the pond so that the top of the pipe is just below
the average elevation of the pond bottom. The pipe shall have adequate seal
below it.
ii) The laying of the influent pipe on the surface of the pond
bottom is prohibited.
D) Point of Discharge
Influent lines to the primary cell should terminate at
approximately the third point farthest from the outlet structure. For
interconnecting piping to secondary cells refer to subsection (d)(4)(B).
E) Flow Distribution
Flow distribution structures shall be designed to effectively
split hydraulic and organic loads proportionally to primary cells. Refer to
Section 370.520(f).
F) Submerged Inlets
Submerged inlet lines shall discharge horizontally into a
shallow, saucer-shaped depression which should extend below the pond bottom not
more than the diameter of the influent pipe plus 1 foot.
G) Discharge Apron
The end of the discharge line should rest on a suitable
concrete apron with a minimum size of 2 feet square.
H) Force Mains
Force mains discharging directly to lagoons are permitted if
the force main has a freefall discharge into the lagoon and is not turned
upward at the point of discharge. The point of discharge shall be at
approximately the third point farthest from the outlet structure and the pipe
shall be sloped for drainage into the lagoon to avoid freezing.
I) Anti-Seep Collars
Anti-seep collars shall be used on all piping passing through
or under the lagoon embankments.
4) Outlet Structures and Interconnecting Piping
A) Outlet Structure
i) Outlet structures shall be designed to allow the operating
level of the pond to be adjusted to permit operation at depths of 2 feet to the
maximum depth. The design shall also allow effluent to be drawn from various
depths below all operating levels. All structures and devices such as weirs,
gates and valves shall be watertight and capable of being easily adjusted by
the operator without the need of additional mechanical equipment. Wooden
stop-planks are not acceptable for level control.
ii) Drawoff lines should not be located any lower than 12 inches
off the bottom to control eroding velocities and avoid pickup of bottom
deposits.
iii) A locking device should be provided to prevent unauthorized
access to the level control facilities.
iv) When possible, the outlet structure should be located on the
windward side to prevent short circuiting. The outlet structure shall be
properly baffled to prevent the discharge of floating material.
v) Consideration must be given in the design of all structures to
protect against freezing or ice damage under winter conditions.
B) Interconnecting Piping and Unit Bypass
i) Interconnecting piping and overflows should be constructed of
materials that will withstand damage during construction and operation, giving
special consideration to damage that may occur during compaction of embankments
and damage to shallow piping. Piping shall be sized to allow transfer of
maximum flows without raising the lagoon water level by more than 6 inches in
the upstream cell. In no case shall interconnecting pipe be less than 8 inches
in diameter. Interconnecting piping between cells should be valved or provided
with other arrangements to regulate flow between structures and permit flexible
depth control.
ii) The interconnecting pipe to the secondary cell should
discharge horizontally near the lagoon bottom to minimize need for erosion
control measures and should be located as near the dividing dike as
construction permits.
iii) Piping and valves shall be provided so that each cell can be
operated independently of any other cell. Provision shall be made for
independent cell dewatering.
C) Anti-Seep Collars
Anti-seep collars shall be used on all interconnecting and outlet
piping passing through or under the lagoon embankments.
5) Miscellaneous
A) Fencing
The pond area shall be enclosed with a suitable fence to
preclude livestock and discourage trespassing. A vehicle access gate of
sufficient width to accommodate mowing equipment shall be provided. All access
gates shall be provided with locks.
B) Warning Signs
Appropriate signs should be provided along the fence around
the pond to designate the nature of the facility and advise against
trespassing.
C) Flow Measurement, Sampling and Level Gauge
Provisions for flow measurement and sampling shall be
provided on the inlet and outlet. Pond level gauges shall be provided. The
NPDES permit monitoring requirements for the facility shall be taken into
account. Elapsed time meters on pumps or calibrated weirs may be used as flow
measurement devices for lagoons.
D) Sludge Removal
When an existing lagoon is to be
upgraded, the project design shall provide for removal of any sludge
accumulation in the existing lagoon. The sludge removed shall be disposed of
in accordance with IPCB regulations.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.940 INTERMITTENT SAND FILTRATION FOR SECONDARY TREATMENT
Section 370.940 Intermittent
Sand Filtration for Secondary Treatment
a) Applicability
Use of the intermittent sand filter for secondary treatment
is generally limited to weak to normal strength wastewaters which are amenable
to biological treatment. Cold weather operational problems may preclude the use
of this process unless the influent temperature to the filter is adequate to
allow efficient filter operation necessary to meet the applicable effluent
standards.
b) Pretreatment Requirements
Wastewaters applied to intermittent sand filters must be
substantially free of grit, debris, oil and grease, floating and suspended
materials, and components which inhibit biological processes and cause rapid
clogging of the filter. Special consideration shall be given to the design of
preceding treatment units, including dosing facilities, to limit heat loss
during winter operation.
c) Multiple Units
Intermittent sand filters shall be provided in multiple
units, designed for independent operation and maintenance.
d) Location
Intermittent sand filters treating septic tank or primary
effluent should be restricted to relatively isolated locations or otherwise
modified in order to minimize odor nuisances.
e) Recirculation
Recirculation of filter effluent may be practiced in order to
attenuate and equalize organic and hydraulic loads to the filter, and improve
unit process efficiency, control odors, and improve day-to-day reliability.
1) Rate
A recirculation rate of up to 300% of the settled sewage load
to the filter may be provided.
2) Variability
The capability of varying the recirculation rate allows
greater process control and optimization of process efficiency. This feature
shall be included where recirculation is provided.
f) Dosing
1) Dosing Volumes
The dosing facilities shall be designed for a capacity of
2,500 gallons per 1,000 sq. ft. of filter bed to be dosed at any given time.
2) Dosing Rates for Siphons or Pumps
Siphons (at minimum head) or pumps shall have a discharge
capacity at least 100% in excess of the maximum rate of inflow to the dosing
tank, including recirculation, and at average head, at least 90 gallons per
minute per 1,000 square feet.
3) Discharge Line Capacity
The discharge lines to the beds shall have sufficient
capacity to permit the full rated discharge of the siphons or pumps.
g) Construction Details
1) Earth Base
The earth base of the filters shall be sloped to the
underdrains.
2) Underdrains
The sand filter shall be provided with open-joint or
perforated pipe underdrains. They should be sloped to the outlet and spaced
not to exceed 10 foot centers. Vertical riser vents shall be provided at both
ends of each underdrain pipe and shall be located as not to be overtopped at
maximum dosing depth.
3) Media
A) Gravel Base
Clean graded gravel, preferably placed in at least three
layers, should be placed around the underdrains and to a depth of at least 6
inches over the top of the underdrains. Crushed stone may not be used in lieu
of gravel. Suggested gradings for the three layers are:
1½" to ¾", ¾" to ¼", ¼" to ⅛".
B) Sand
At least 24 inches of clean washed sand shall be provided.
Sand shall be durable and relatively insoluble in sewage. Clay content shall
be less than 1% by weight. The effective size shall be 0.3 to 1.0 millimeter
(mm). The uniformity coefficient shall not be greater than 3.5.
4) Splash Slabs
Splash slabs shall be provided at each point of discharge to
the filter. A means of dissipating the energy of the discharge velocity shall
be provided around the periphery of the splash slab.
5) Curbs
Provision shall be made to prevent soil and surface runoff
from entering the filter area. Curbs should be high enough to hold the maximum
dose and provide adequate freeboard.
6) Distribution System
A) Arrangement
Provision shall be made for even distribution of the flow on
the filter surface. If troughs or piping are used, they shall be so located
that the maximum lateral travel of the flow on the media surface is not more
than 20 feet.
B) Drains
Troughs, discharge piping or other distribution equipment
shall be sloped to drain to prevent freezing.
h) Loading Rates
The loading rates shall be based on the raw sewage flow and
organic strength. The following loading rates shall not be exceeded:
|
Raw Waste Strength
(Bod5
mg/l)
|
|
Dose
Rate
(gals./ft.2/day
|
|
100 to 200
|
|
3
|
|
200 to 300
|
|
2
|
|
above 300
|
|
1
|
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART J: DISINFECTION
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1000 GENERAL
Section 370.1000 General
Where needed to meet applicable
standards, disinfection of the effluent shall be provided. The design shall
provide for meeting both the bacterial standards and any disinfectant residual
limits applicable to the effluent.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1010 DISINFECTION PROCESS SELECTION
Section 370.1010
Disinfection Process Selection
a) The disinfection process should be selected after due
consideration of waste characteristics, type of treatment processes provided
prior to disinfection, waste flow rates, waste pH, disinfectant demand rates,
current technology application, cost of equipment, chemical availability, power
costs and maintenance requirements. Areawide public safety shall be considered
where large liquid chlorine or sulfur dioxide containers are to be handled.
b) Chlorine may be used in the form of liquid chlorine or calcium
or sodium hypochlorite. Dechlorination will be required where necessary to
meet applicable chlorine residual effluent limitations.
c) An ultra-violet radiation system may be used as an alternative
disinfection process.
d) Other alternative means of disinfection will be evaluated
according to the provisions of Section 370.520(b).
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1020 CHLORINE DISINFECTION
Section 370.1020 Chlorine
Disinfection
a) Type of Feed Equipment
The types of chlorine feed equipment include:
1) Vacuum solution feed by gas;
2) Direct gas feed;
3) Hypochlorite solution positive displacement pump feed;
4) Hypochlorite tablet feed.
b) Selection of Feed Equipment
The selection of the type of chlorine feed equipment shall
take into account operator safety and overall public safety relative to the
proximity of the sewage treatment plant to populated areas and to the security
of the gas cylinder or container storage.
c) Output Capacity of Gas Chlorine Cylinders
|
Delivery
Rates (lbs of chlorine/day)
|
|
Ambient
Temp.
°F
|
100
pound Cylinder
|
150
pound Cylinder
|
1
Ton Container
|
|
40
|
6
|
9
|
100
|
|
50
|
14
|
21
|
240
|
|
60
|
23.7
|
35.5
|
385
|
|
70
|
32
|
47.5
|
536
|
|
80
|
41.2
|
62
|
700
|
Some types of vacuum chlorinators can deliver chlorine at rates greater
than those listed above under the same conditions. When designs include rates
in excess of those indicated above, manufacturer's specifications and test
results shall be provided.
d) Standby Equipment and Spare Parts
Standby equipment of sufficient capacity should be available
to replace the largest unit during shutdowns. Spare parts shall be available
for all chlorinators to replace parts which are subject to wear and breakage.
e) Potable Water Supply Protection
An ample supply of water shall be available for operating the
chlorinator. Where a booster pump is required, duplicate equipment should be
provided and, when necessary, also standby power (refer to Section 370.550(a)(4)).
Protection of a potable water supply shall conform to the requirements of
Section 370.550(b)(3). In-line backflow preventers are not acceptable.
f) Chlorine Gas Supply
1) Cylinders
The use of 1-ton containers should be considered where the
average daily chlorine gas consumption is over 150 pounds. All upright
chlorine cylinders shall be strapped securely to prevent tipping.
2) Tank Cars
A) At large installations the use of tank cars, generally
accompanied by evaporators, may be considered. Areawide public safety shall be
evaluated as a part of the considerations. Provision shall be made for a
chlorine supply during tank car switching.
B) The tank car being used for the chlorine supply shall be
located on a dead end, level track that is a dedicated siding. The tank car
shall be protected from accidental bumping by other railway cars by a locked
de-rail device, a closed lock switch, or both. The area shall be clearly
posted "DANGER CHLORINE." The tank car shall be secured by adequate
fencing with locked gates for personnel and rail access.
C) The tank car site shall be provided with an operating platform
at the unloading point that allows for easy access to the protective housing on
the tank car for flexible feed line connection and valve operation. Area
lighting adequate for night time operation and maintenance shall be provided.
3) Scales
A) Scales shall be provided for weighing cylinders and containers
at all plants using chlorine gas.
B) At large plants, indicating and recording scales are
recommended. At a minimum, a platform scale shall be provided. Scales shall
be made of corrosion-resistant material. Scales should be recessed unless
hoisting equipment is provided or the scales are low enough to allow the
cylinders to be rolled onto them.
4) Evaporators
Where manifolding of several cylinders or containers will be
required to evaporate sufficient chlorine, consideration should be given to
liquid drawoff and installation of an evaporator.
5) Leak Detection and Controls
A bottle of ammonium hydroxide solution should be available
for detecting chlorine leaks. Consideration should also be given to the
provision of caustic soda solution reaction tanks for absorbing the contents of
leaking 1-ton containers where such containers are in use. Also, when
cylinders, containers or tank cars are used, a leak repair kit approved by the
Chlorine Institute shall be provided. At installations using over 150 pounds
of chlorine gas per day consideration should be given to the installation of
automatic gas detection and related alarm equipment.
g) Piping and Connections
1) Piping systems should be as simple as possible, and shall be
specially selected and manufactured to be suitable for chlorine service, with a
minimum number of joints. Piping should be well supported and protected
against temperature extremes.
2) The chlorine system piping shall be color coded and labeled to
distinguish it from sulfur dioxide and other plant piping. Where sulfur
dioxide is used, the piping and fittings for chlorine and sulfur dioxide
systems shall be designed so that interconnection between the two systems
cannot occur.
h) Housing
1) Container and Equipment Location
Containers and feed equipment should be located indoors, in a
suitable fire-resistant building. Gas cylinders should be protected from
direct sunlight if not located indoors.
A) Separation
If gas chlorination equipment and chlorine cylinders or
containers are to be housed in a building used for other purposes, the chlorine
cylinders or containers and equipment shall be located in an isolated room.
This room shall not contain any sulfonation equipment, sulfur dioxide cylinders
or other equipment unrelated to chlorination. Common walls to other areas of
the building shall be gastight. Doors to this room shall open only to the
outside of the building and shall be equipped with panic hardware. Rooms shall
be at ground level and shall permit easy access to all equipment. Storage
areas should be separated from the feed area.
B) Inspection Window
A clear gastight window shall be installed in the chlorinator
room to permit the units to be viewed and gauges to be read without entering
the room.
C) Heat
Chlorinator housing facilities shall be provided with a means
of heating so that a temperature of at least 60° F can be maintained. Where
chlorine gas is to be withdrawn from cylinders or containers, the cylinders or
containers shall be maintained at essentially room temperature. The room shall
be protected from excessive heat. If liquid chlorine is to be withdrawn from
the cylinders or containers to an evaporator unit, the feed cylinders or
containers may be located in an unheated area.
3) Ventilation For Gas Chlorination Systems
A) Forced, mechanical ventilation shall be installed which will
provide 1 complete air change per minute. The entrance to the air exhaust duct
from the room shall be within 12 inches of the floor and the point of discharge
shall be so located as not to contaminate the air in the immediate vicinity of
the entrance door to the chlorinator room or ventilation inlet or window or
entrance door to any buildings or inhabited areas. Where the public may be
subjected to extensive exposure to chlorine in case of chlorine leaks,
scrubbers may be required on the ventilation discharge.
B) The chlorination room air inlets shall be so located as to provide
cross ventilation with air and at such temperature that will not adversely
affect the chlorination equipment. The vent hose from the chlorinator shall
discharge to the outside atmosphere above grade.
4) Electrical Controls
The controls for the fans and lights shall be provided at
those locations where it is necessary to enter the chlorination room and shall
automatically operate when the door is opened and continue to operate when the
operator enters the room and the door is closed. Provision shall be made for
manual operation of controls from the outside of the room without opening the
door.
5) Outdoor Cabinet Housing
Outdoor shallow cabinet-type units, with wide opening doors,
that are shallow enough not to need or require operator entry, may be used to
house the containers and feed equipment. Use of such cabinets shall be limited
to small plants that provide seasonal disinfection or use less than 10 pounds
of chlorine per day. Only two chlorine gas cylinders of 150 pounds or less on
line may be housed in the cabinets. The following items shall be provided for
in the design:
A) The cabinet structure shall be located on and securely anchored
to a concrete slab sized to allow for safe transport and handling of the cylinders.
The structure and slab shall be capable of withstanding expected wind loadings
on the cabinet. The design of the cabinet support slab shall take into account
the effects of frost and settling due to soil stability. Flexible piping
connections should be considered for lines connected to the cabinet.
B) The cabinet shall be protected from direct sunlight to prevent
overheating of the chlorine cylinders.
C) The cabinet doors shall extend the full width of the long side
of the cabinet structure so that the full interior of the cabinet is exposed
with the door open. Provision shall be made to secure the open doors while the
operator is changing cylinders and maintaining the feed equipment.
D) The cabinet depth shall not exceed 24 inches. The feed
equipment shall be positioned to allow easy access for maintenance and to allow
observation of the gauges and meters.
E) Provision shall be made for chains, wall mounted fastener hooks
or similar means for anchoring the chlorine cylinders to prevent tipping.
F) The cabinet structure shall be corrosion resistant to chlorine
gas.
G) Where electrical power is available, the cabinet should be
placed in a well-lighted area.
i) Respiratory Protection Equipment
Respiratory protection equipment meeting the requirements of
the National Institute for Occupational Safety and Health (NIOSH) shall be
available at all installations where chlorine gas is handled and shall be
stored in a convenient location outside of any room where chlorine is used or
stored. The respiratory protection units shall use compressed air, have at
least a 30-minute capacity, and be compatible with or exactly the same as
NIOSH-approved units used by the local fire department. Instructions for
using, testing, and replacing mask parts shall be posted. At large
installations, consideration should be given to providing acid suits and fire
suits.
j) Application of Chlorine
1) Contact Period
After thorough mixing, a minimum contact period of 15 minutes
at design peak hourly flow or maximum rate of pumpage shall be provided.
2) Chlorinator Dosing Rate Capacity
Chlorinators shall be designed to have a capacity adequate to
produce an effluent that will meet the applicable bacterial limits. Where
necessary to meet the operating ranges, multiple units shall be provided for
adequate peak capacity and for a sufficiently low feed rate on turn down to allow
proper chlorine residual. The chlorination system shall be designed on a
rational basis and calculations justifying the equipment sizing and number of
units shall be submitted for the whole operating range of flow rates, including
the minimum turn down capacity for the type of control to be used. System
design considerations shall include the controlling sewage flow meter
(sensitivity and location), telemetering equipment and chlorinator controls.
For treated normal domestic sewage the following dosing capacity, based on
design average flow, is suggested (see Section 370.520(c)(1)):
|
Type
of Treatment
|
|
Dosage
(mg/l)
|
|
Primary Settled Sewerage
|
|
20
|
|
Lagoon Effluent (unfiltered)
|
|
20
|
|
Trickling Filter Plant Effluent
|
|
10
|
|
Lagoon Effluent (filtered)
|
|
10
|
|
Activated Sludge Plant Effluent
|
|
6
|
|
Activated Sludge Plants with Chemical Addition
|
|
4
|
|
Filtered Effluent Following Mechanical Biological Treatment
|
|
4
|
k) Contact Tank
1) Mechanical means of sludge removal is recommended and should
be provided unless multiple chlorine tanks are provided. Portable deck-level
vacuum cleaning equipment may be used for small treatment plants. Provisions
for draining contact tanks not equipped with mechanical sludge removal
equipment shall be provided, with the drain flow returned to process for
treatment.
2) Exception to the requirement of duplicate contact tanks may be
granted if the contact tank follows a sand filter or if the main treatment
works is a waste stabilization pond, with provisions for storing the sewage
flow for several days while the contact tank is being cleaned.
3) Adequate mixing during the chlorine contact period shall be
insured by the installation of adequate baffling, air or other mixing
equipment. Facilities for the retention and removal of floating scum shall be
provided.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1021 DECHLORINATION
Section 370.1021
Dechlorination
a) General
Dechlorination of sewage plant effluents may be required to
reduce toxicity due to chlorine residuals.
b) Feed Equipment
1) Type
The common types of dechlorination feed equipment using
sulfur compounds include:
A) Vacuum solution feed of sulfur dioxide gas.
B) Positive displacement pump feed or aqueous solutions of sulfite
or bisulfite products.
2) Selection of Feed Equipment
The selection of the type of feed equipment using sulfur
compounds shall include consideration of operator safety and overall public
safety relative to the proximity of the sewage treatment plant to populated
areas and the security of the gas cylinder storage. The selection and design
of sulfur dioxide feeding equipment shall take into account the fact that the
gas reliquifies very easily.
c) Output Capacity of Sulfur Dioxide Cylinders
The number of feed cylinders or containers necessary to meet
the design delivery rates shall be based on the physical, thermodynamic and
chemical properties for sulfur dioxide. Refer to the Compressed Gas
Association publication CGA G-3-1988 "Sulfur Dioxide" or other
standard reference sources for information on sulfur dioxide properties.
d) Standby Equipment and Spare Parts
Standby equipment should be available of sufficient capacity
to replace the largest unit during shutdown. Spare parts to replace parts that
are subject to wear and breakage shall be available for all sulfonators.
e) Potable Water Supply
An ample supply of water shall be available for operating the
sulfonator. Where a booster pump is required duplicate equipment should be
provided and, when necessary, standby power. (Refer to Section
370.550(a)(4).) Protection of the potable water supply shall conform to the
requirements of Section 370.550(b)(6). In-line back flow preventers may not be
used.
f) Sulfur Dioxide Gas Supply
1) Cylinders
The use of 1-ton containers should be considered where the
average daily sulfur dioxide consumption is over 150 pounds. All upright
sulfur dioxide cylinders shall be strapped securely to prevent tipping.
2) Tank Cars
A) The use of tank cars, generally accompanied by evaporators, may
be considered for large installations. Areawide public safety shall be
evaluated as part of the considerations. Continuity of sulfur dioxide supply
shall be maintained during tank car switching.
B) The tank car being used for the sulfur dioxide supply shall be
located on a dead end, level track that is a dedicated siding. The tank car
shall be protected from accidental bumping by other railway cars by a locked
de-rail device, a closed lock switch, or both. The area shall be clearly
posted "DANGER SULFUR DIOXIDE." The tank car shall be secured by
adequate fencing with locked gates for personnel and rail access.
C) The tank car site shall be provided with an operating platform
at the unloading point that allows for easy access to the protective housing on
the tank car for flexible feed line connection and valve operation. Area lighting
adequate for night time operation and maintenance shall be provided.
3) Scales
A) Scales shall be provided for weighing cylinders or containers
at all plants using sulfur dioxide gas.
B) At large plants indicating and recording scales are
recommended. At a minimum, a platform scale shall be provided. Scales shall
be made of corrosion resistant material. Scales should be recessed unless
hoisting equipment is provided or the scales are low enough to allow the
cylinders to be rolled onto them.
4) Evaporator
Where the manifolding of several cylinders or containers will
be required to evaporate sufficient sulfur dioxide, consideration should be
given to liquid drawoff and installation of an evaporator. A liquid nitrogen
gas padding system to enhance the liquid sulfur dioxide delivery rate should be
considered.
5) Leak Detection and Controls
Sulfur dioxide leak detection equipment shall be provided
which has a sensitivity level equal to that of ambient air pollution monitoring
equipment. Where cylinders, one-ton containers and tank cars are used, a leak
repair kit that is compatible for use with sulfur dioxide gas shall be
provided. Leak repair kits used for chlorine gas (Section 370.1020(f)(5))
equipped with gasket materials suitable for service with sulfur dioxide may be
used. (See paragraphs 10.4 and 13.2 of "Sulfur Dioxide," Compressed
Gas Association, Inc., Publication CGA G-3-1988 for a discussion of suitable
materials.) Refer to Section 370.560.
g) Piping and Connections
1) Piping systems should be as simple as possible, with a minimum
number of joints, and shall be suitable for sulfur dioxide service. Piping
should be well supported and protected against temperature extremes.
2) The piping for the sulfur dioxide system shall be color-coded
and labeled to distinguish it from chlorine piping, and the system shall be
designed so that interconnections with chlorine piping cannot occur.
h) Housing
1) Container and Equipment Location
Containers and feed equipment should be located inside a fire
resistant building. Gas cylinders and containers should be protected from
direct sunlight.
A) Isolation
If gas sulfonation equipment and sulfur dioxide cylinders
will be located in a building also used for other purposes, the sulfur dioxide
equipment and containers shall be located in an isolated room that shall not
contain any chlorination equipment, chlorine containers or any other equipment
unrelated to sulfonation. Common walls to other areas of the building shall be
gastight. Doors to the room shall open only to the outside and shall be
equipped with panic hardware. Rooms shall be at ground level and shall allow
easy access to all equipment. Storage areas should be separated from feed
areas; sulfur dioxide and chlorine cylinders shall be stored in separate areas.
B) Inspection Window
A clear gastight window shall be installed in the sulfonate
room to permits the units to be viewed and gauges to be read without entering
the room.
2) Heat
Sulfonator housing facilities shall be provided with a means
of heating so that cylinder temperatures can be maintained in the range of 90
to 100° F when sulfur dioxide is to be withdrawn from the cylinder. The
sulfonator room shall be protected from excessive heat.
3) Ventilation for Sulfur Dioxide Systems
A) Forced, mechanical ventilation that will provide one complete
air change per minute shall be installed in the sulfonator room. The entrance
to the exhaust duct from the room shall be within 12 inches from the floor and
the point of discharge shall be located so as not to contaminate the air in the
immediate vicinity of the door to the sulfonator room or ventilation inlet to
any buildings or inhabited areas.
B) The air inlets to the sulfator room shall be located so as to
provide cross ventilation with air and at temperatures that will not adversely
affect the sulfonation equipment. The vent hose from the sulfonator shall
discharge to the outside atmosphere above grade.
4) Electrical Controls
Controls for fans and lights shall be located at the
entrances to the sulfonation room and shall automatically operate when the door
is opened and continue in operation when the operator enters the room and the
door is closed. Provision shall be made for operation of the fans and lights
from the outside without opening the door.
i) Respiratory Protection Equipment
Respiratory protection equipment meeting the requirements of
NIOSH shall be available at all installations where sulfur dioxide gas is
handled and shall be stored in a convenient location outside of any room where
sulfur dioxide is used or stored. The units shall use compressed air, shall
have at least a 30-minute capacity and shall be the same as or compatible with
NIOSH-approved units used by the local fire department. Instructions for
using, testing and replacing mask parts shall be posted. At large
installations, providing acid suits and fire suits should be considered.
j) Application of Sulfonation Chemicals
1) Contact Period and Reaeration
A minimum contact period of 30 seconds, including mixing
time, at design peak hourly flow or maximum pumpage rate shall be provided.
Mechanical mixers are required unless the mixing facility will provide the
necessary hydraulic turbulence to assure thorough mixing. A means of
reaeration shall be provided to insure maintenance of the required dissolved
oxygen concentration in the effluent and the receiving stream after
sulfonation. When choosing a reaeration method the fact that excess sulfur
dioxide, formed when the dechlorinating chemicals are dissolved in water, may
be expected to consume 1 mg of dissolved oxygen for every 4 mg of sulfur
dioxide should be taken into account.
2) Sulfonation Dosing Rate Capacity
A) Capacity
Sulfonators shall be designed to have a capacity adequate to
produce an effluent that meets the applicable chlorine residual effluent
limits. Where necessary to meet the operating ranges, multiple units shall be
provided for adequate peak capacity and to provide a sufficiently low feed rate
on turn down to avoid depletion of the dissolved oxygen concentrations in the
receiving waters. The sulfonator system shall be designed on a rational basis
and calculations justifying the equipment sizing and number of units shall be
submitted for the entire operating range, including the minimum turn down
capability for the type of control to be used. System considerations shall
include the sensitivity and location of the controlling sewage flow meter, the
telemetering equipment and sulfonator controls.
B) Dosing Rates
The design dosage rate of the sulfonation equipment shall be
based on the particular dechlorinating chemical used and the applicable
residual chlorine limits. The following theoretical amounts of the commonly
used dechlorinating chemicals may be used for initial approximations to size
feed equipment.
|
|
Theoretical
mg/l required to neutralize 1 mg/l Cl2
|
|
Sulfur dioxide (gas)
|
0.90
|
|
Sodium meta bisulfite
(solution)
|
1.34
|
|
Sodium bisulfite (solution)
|
1.46
|
The design
shall take into account the fact that under good mixing conditions
approximately 10% more dechlorinating chemical than theoretical value is
required for satisfactory results.
C) Liquid Solution Tanks
Mixing and dilution tanks for dechlorinating feed solutions
shall be provided as necessary to mix dry compounds and to dilute liquid
compounds to provide for proper dosage. Solution tanks should be covered to
minimize evaporation. The mixing and dilution tanks should be sized to provide
sufficient feed solution for several days of operation. The tanks shall be
made of materials that will withstand the corrosive nature of the solutions.
Refer to Section 370.560.
(Source: Added at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1022 ULTRAVIOLET DISINFECTION
Section 370.1022 Ultraviolet
Disinfection
Because operating data and
experience with this process is not well established, expected performance of
the ultraviolet disinfection units shall be based upon either experience at
similar full scale installations or thoroughly documented prototype testing
with the particular wastewater. Use of this process should be limited to high
quality effluent having at least 65% ultraviolet radiation transmittance at 254
nanometers wave length and BOD and suspended solids concentrations no greater
than 30 mg/l at any time. Projects will be evaluated by the Agency on the
basis of the factors set out in Section 370.530(b).
(Source: Added at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1030 CHLORINE GAS SUPPLY (REPEALED)
Section 370.1030 Chlorine
Gas Supply (Repealed)
(Source: Repealed at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1040 PIPING AND CONNECTIONS (REPEALED)
Section 370.1040 Piping and
Connections (Repealed)
(Source: Repealed at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1050 HOUSING (REPEALED)
Section 370.1050 Housing
(Repealed)
(Source: Repealed at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1060 RESPIRATORY PROTECTION EQUIPMENT (REPEALED)
Section 370.1060 Respiratory
Protection Equipment (Repealed)
(Source: Repealed at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1070 APPLICATION OF CHLORINE (REPEALED)
Section 370.1070 Application
of Chlorine (Repealed)
(Source: Repealed at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1080 SAMPLING AND TESTING
Section 370.1080 Sampling
and Testing
a) Facilities shall be included for collecting samples, as
monitoring requirements warrant, of the disinfected effluent.
b) Where chlorine disinfection is used, equipment shall be
provided for measuring chlorine residual using accepted test procedures.
c) Where required by the Agency, equipment shall also be provided
for measuring fecal coliform using accepted test procedures.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART K: TERTIARY FILTRATION
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1100 APPLICABILITY
Section 370.1100
Applicability
Various types of tertiary
filters may be used to polish effluents of secondary treatment plants.
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1110 TYPE
Section 370.1110 Type
a) Granular media filtration is considered to include the
following type units:
1) High rate single, dual and multi-media of either the pressure
or gravity type with facilities for backwashing.
2) Low rate sand filters dosed intermittently or periodically.
b) Low rate filtration is generally limited in use to small
installations.
c) For miscellaneous considerations, refer to Section 370.203(j).
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1120 HIGH RATE FILTRATION
Section 370.1120 High Rate
Filtration
a) Design Considerations
Care should be given in the selection of pumping equipment
ahead of filter units to minimize shearing of flow particles. Consideration
should be given in the plant design to providing flow-equalization facilities
to moderate filter influent quality and quantity.
b) Pretreatment
A positive method shall be provided to control the suspended
solids loading to the filters. Equipment for the feeding of chemical coagulant
aids prior to secondary settling shall be provided unless other equally
effective means of suspended solids control are used.
c) Multiple Units
Multiple units shall be provided. At least three units
should be provided. Units shall be capable of independent operation and
maintenance.
d) Filtration Rates
The peak hourly flow rate applied to the filter shall not
exceed 5 gpm/sq. ft. of filter area, computed with one unit out of service.
1) Rate Controls
Controls shall be provided which allow adjustment and control
of the rate of flow to each filter unit.
2) Flow Measurement
The flow to each filter shall be monitored by indicating
equipment.
e) Accessibility and Maintenance
Each filter unit shall be designed and installed so that
there is ready and convenient access to all components and the media surface
for inspection and maintenance without taking other units out of service.
f) Housing
Housing of filter units shall be provided. The housing shall
be constructed of suitable corrosion-resistant materials. All controls shall
be enclosed, and the structure housing the filter, controls and equipment shall
be provided with heating and ventilation adequate to minimize problems with
excess humidity.
g) Construction Details
1) Underdrains
The underdrain system shall be designed for uniform
distribution of flow of backwash water (and air, if provided) without danger of
clogging from solids in the backwash water. A positive means of pressure
relief shall be provided for the underdrain system to prevent structural damage
by excessive backwash pressures. The selection of the underdrain system shall
be based on demonstrated satisfactory field experience under similar
conditions.
2) Media
The selection of proper media sizes and types depends upon
the filtration rate selected, the type of treatment provided the influent to
the filter, filter configuration, and effluent quality objectives. In dual or
multi-media filters, media size and type selection must consider compatibility
among media. Media shall be selected and provided to meet specific conditions
and treatment requirements relative to the project under consideration. The
selection and sizing of the media shall be based on demonstrated satisfactory
field experience under similar conditions. All media shall have a uniformity
coefficient of 1.7 or less. The uniformity coefficient, effective size, depth
and type of media shall be set forth in the specification.
3) Appurtenances
The design of the filter appurtenances shall be based on
demonstrated satisfactory field experience under similar conditions. The
filters shall be equipped with the following:
A) Wash water troughs.
B) Surface wash, air scouring equipment or mechanical agitation
designed to adequately remove entrapped solids from the media.
C) Equipment for measuring filter head loss.
D) Filter influent and effluent sampling points.
Also refer to subsections (h)(2), (h)(4) and (i) below.
h) Backwash
1) Rate and Duration
The backwash rate shall be adequate to fluidize and expand
each media layer a minimum of 20 percent based on the media selected. Minimum
and maximum backwash rates shall be based on demonstrated satisfactory field
experience under similar conditions. The design shall provide for a minimum
backwash period of 10 minutes. Excessive backwash rates may cause washout of
the filter media.
2) Control and Flow Measurement
A positive means of shutting off flow to a filter shall be
provided. Controls shall be provided which permit adjustment of both the
backwash rate and the backwash period. Flow measurement of the backwash flow
rate shall be provided. A staff gauge or wall mounted scale to allow use of
the rise rate for flow measurement may be used.
3) Clearwell
A clearwell or other plant tankage isolated from unfiltered
flows shall be provided as a source of backwash water. Filtered plant effluent
shall be used as backwash water. The volume of storage provided shall be
sufficient to allow sequential backwashing of at least 2 filter units at the
design backwash rate.
4) Chlorination of Filter Backwash
Provision shall be made for periodic chlorination of filter
backwash water (or filter influent) to control slime growths. The flows from
the cleaning of the filters shall be returned to the head of the plant. Refer
to subsection (h)(6)(A) below.
5) Backwash Pumps
Where used, backwash pumps shall be provided in multiple
units, designed for independent operation and maintenance. Pumps shall be sized
in accordance with subsection (h)(1) above to provide the required backwash
rate with one unit out of service and should be of equal size. The total
dynamic head of the pump shall be limited to that needed for the application so
that undue stress of the underdrain system will not occur. Refer to subsection
(g)(1) above.
6) Mudwell
A mudwell or other plant tankage shall be provided to hold
backwash water from the filters. The volume provided shall be sufficient to
hold the water generated by the backwashing of two filter units including the
water in and above the filter media prior to filtration. Refer to subsection
(h)(1) above. Filter backwash shall be returned to process or otherwise
treated to insure compliance with applicable standards.
A) Return Rate
The rate of return of filter backwash to the treatment units
shall not exceed 15 percent of the design average flow to the treatment units.
Refer to subsection (j)(1) below and Section 370.520(g).
B) Mudwell Return Pumps
Backwash return pumps, where used, shall be provided in
multiple units designed for independent operation and maintenance. The units
shall be sized to provide the required pumping rate with the largest unit out
of service. Refer to subsection (h)(6)(A) above.
i) Control Panel
Automatic controls shall be provided, with a manual override
on the control panel for operating equipment, including each individual valve
essential to the filter operation.
j) Miscellaneous Considerations
1) Return Backwash Loadings
The return of backwash water and solids will result in
increases in the hydraulic and suspended solids loads to the preceding
treatment units. Design of these units shall take into account the increased
loads.
2) Oil and Grease
Filters at treatment plants treating wastewaters containing
above normal concentrations of greases or similar materials should be of the
gravity type. Facilities should be considered for the periodic addition of
chemicals to remove greases in such cases.
3) Proprietary Equipment
Proprietary equipment not conforming to the requirements of
this section will be evaluated on a case-by-case basis in accordance with
Section 370.520(b).
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1130 LOW RATE INTERMITTENT OR PERIODICALLY DOSED SAND FILTERS
Section 370.1130 Low Rate
Intermittent or Periodically Dosed Sand Filters
a) Applicability
1) Intermittent sand filters may be used to polish secondary
effluents. The process removes residual suspended solids and soluble
biochemical oxygen demand and converts ammonia to nitrate. (See Section
370.1210(b).)
2) Cold weather operational problems may preclude the use of this
process unless the influent temperature to the filter is adequate to allow
efficient filter operation necessary to meet the applicable effluent standards.
3) Because of manual labor necessary to clean, maintain and
replace sand on the filters, the application is usually limited to small waste
treatment plants.
b) Design Criteria
The criteria of Section 370.940(b), (c), and (f)(3), are
generally applicable to intermittent sand filters used as tertiary filtration
units.
1) Dosing Volumes
The dosing facilities shall be sized to provide for a 12-hour
dosing cycle for each bed.
2) Siphon or Pump Capacity
Siphons (at minimum head) or pumps shall have a discharge
capacity at least 100 percent in excess of the maximum rate of inflow to the
dosing tank, including recirculation, and at average head, at least 90 gallons
per minute per 1,000 square feet being dosed.
3) Recirculation
Provision for recirculation of filter effluent may be
included to improve process flexibility.
A) Rate
A recirculation rate of up to 100% of design average flow to
the filter may be provided.
B) Variability
Capability for varying the recirculation rate shall be
provided.
4) Loading Rates
The hydraulic load of secondary wastewater applied to
supplemental intermittent sand filters shall not exceed 15 gallons per day
(gpd)/sq. ft. More conservative application rates should be provided for low
quality filter influents. Refer to subsection (d)(3) below.
c) Construction Details
The criteria of Section 370.940(g) are generally applicable
to tertiary intermittent sand filters. Also, refer to subsection (d).
d) Special Design Considerations in Lagoon Systems
1) General
Low rate sand filter systems that are intermittently or
periodically dosed may be used to reduce suspended solids from multicell
aerated or nonaerated sewage lagoon treatment plants.
2) Cold Weather Design
Lagoons which have sand filters shall be designed to provide
storage of flows received during cold weather when the filter is expected to be
inoperable.
3) Hydraulic Loading
A) The filter area design considerations must include the
following:
i) The total annual flow volume to be treated (Section
370.520(c)(1)) including wet weather flows if the lagoons are to be used for
wet weather storage.
ii) The effective net days annually for filter operation
excluding cold weather shut-down and filter maintenance time.
iii) Lagoon
effluent quality.
iv) Extent
and reliability of flow data from the sewer system.
B) Where sewer system conditions are not favorable or industrial
waste loadings are expected to increase algae blooms, the loading rate should
be limited to 10 gal./ft.(2)/day.
4) Dosing Considerations
A) Methods of Operation
The design should include allowance for periodic dosing of
varied volumes onto the filter while the filter discharge is shut off, then to
be followed by a filtration period to completely empty the filter at a
controlled rate.
B) Depth
The filter shall be designed for flexibility of dosing depth
from 6 inches to 2 feet.
C) Valving, Piping, Flow Measurement
i) The filter shall be provided with valving to allow shutting
off and controlling rate of flow both onto and from the filter. A flow
measurement weir or flume shall be provided both on the inlet and outlet of the
filter for operator control of the dosing and filtration rates under the
falling head conditions.
ii) The outlet valving, piping and flow measurement shall be
designed to allow complete drainage of the filter underdrains at the end of the
filter cycle to insure aerobic conditions in the filter during the rest period.
D) Dosing Inlet Structures
The dosing inlet structures shall be designed to dissipate
inlet velocity and prevent sand scouring during the dosing period at the high
dose rates. The inlet structures should be arranged to not interfere with
maintenance of the sand surface.
5) Filter Containment Structure
The filter containment may be of vertical concrete walls on
three sides (refer to subsection (d)(6) below) or sloped earthen berms with
impervious lining, constructed to insure that no ground surface runoff or silts
get onto the sand surface. A freeboard of 1 foot above the maximum design
dosing depth should be provided.
6) Access Ramps
The filter should be designed with a ramp on one end sloped
and surfaced for access to the edge of the bed by wheeled vehicle to facilitate
removing and replacement of sand. For larger filters, concrete tracks at the
level of the sand surface may be desirable to reduce distance sand must be
handled.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
SUBPART L: NUTRIENT REMOVAL
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1200 PHOSPHORUS REMOVAL BY CHEMICAL TREATMENT
Section 370.1200 Phosphorus
Removal by Chemical Treatment
a) General
1) Method
Addition of lime or the salts of aluminum or iron may be used
for the chemical removal of soluble phosphorus. The phosphorus reacts with the
calcium, aluminum or iron ions to form insoluble compounds. These insoluble
compounds may be flocculated with or without the addition of a coagulant aid
such as a polyelectrolyte to facilitate separation by sedimentation.
2) Design Basis
A) Preliminary Testing
Laboratory, pilot or full-scale trial of various chemical
feed systems and treatment processes are recommended to determine the
achievable performance level, cost-effective design criteria, and ranges of
required chemical dosages.
B) System Flexibility
Systems shall be designed with sufficient flexibility to
allow for several operational adjustments in chemical feed location, chemical
feed rates, and for feeding alternate chemical compounds.
b) Process Requirements
1) Dosage
The required chemical dosage shall include the amount needed
to react with the phosphorus in the wastewater, the amount required to drive
the chemical reaction to the desired state of completion, and the amount
required due to inefficiencies in mixing or dispersion. Excessive chemical
dosage should be avoided.
2) Chemical Selection
A) The choice of lime or the salts of aluminum or iron should be
based on the wastewater characteristics and the economics of the total system.
B) When lime is used it may be necessary to neutralize the high pH
prior to subsequent treatment in secondary biological systems or prior to
discharge in those flow schemes where lime treatment is the final step in the
treatment process.
3) Chemical Feed Points
Selection of chemical feed points shall include consideration
of the chemicals used in the process, necessary reaction times between chemical
and polyelectrolyte additions, and the wastewater treatment processes and
components utilized. Considerable flexibility in feed location should be
provided, and multiple feed points are recommended.
4) Flash Mixing
Each chemical must be mixed rapidly and uniformly with the
flow stream. Where separate mixing basins are provided, they should be
equipped with mechanical mixing devices. The detention period should be at
least 30 seconds.
5) Flocculation
The particle size of the precipitate formed by chemical
treatment may be very small. Consideration should be given in the process
design to the addition of synthetic polyelectrolytes to aid settling. The
flocculation equipment should be adjustable in order to obtain optimum floc
growth, control deposition of solids, and prevent floc destruction.
6) Liquid - Solids Separation
A) The velocity through pipes or conduits from flocculation basins
to settling basins should not exceed 1,5 feet per second in order to minimize
floc destruction. Entrance works to settling basins should also be designed to
minimize floc shear.
B) Settling basin design shall be accordance with criteria
outlined in Subpart G. For design of the sludge handling system, special
consideration should be given to the type and volume of sludge generated in the
phosphorus removal process.
7) Filtration
Effluent filtration shall be considered where effluent
phosphorus concentrations of less than 1 mg/1 must be achieved.
c) Feed Systems
1) Location
A) All liquid chemical mixing and feed installations should be
installed on corrosion-resistant pedestals and elevated above the highest
liquid level anticipated during emergency conditions. Refer to Section
370.147(b)(2)(A).
B) Lime feed equipment should be located so as to minimize the
length of slurry conduits. All slurry conduits shall be accessible for
cleaning.
2) Liquid Chemical Feed Pumps
A) Liquid chemical feed pumps should be of the positive
displacement type with variable feed rate. Pumps shall be selected to feed the
full range of chemical quantities required for the phosphorus mass loading
conditions anticipated with the largest unit out of service.
B) Screens and valves shall be provided on the chemical feed pump
suction lines.
C) An air break or anti-siphon device shall be provided where the
chemical solution stream discharges to the transport water stream to prevent an
induction effect resulting in overfeed.
D) Consideration shall be given to providing pacing equipment to
optimize chemical feed rates.
3) Dry Chemical Feed System
A) Each dry chemical feeder shall be equipped with a dissolver
which is capable of providing a minimum 5-minute retention at the maximum feed
rate.
B) Polyelectrolyte feed installations should be equipped with two
solution vessels and transfer piping for solution make-up and daily operation.
C) Make-up tanks shall be provided with an eductor funnel or other
appropriate arrangement for wetting the polymer during the preparation of the
stock feed solution. Adequate mixing should be provided by a large-diameter
low-speed mixer.
d) Storage Facilities
1) Size
Storage facilities shall be sufficient to insure that an
adequate supply of the chemical is available at all times. Exact size required
will depend on size of shipment, length of delivery time, and process
requirements. Storage for a minimum of a 10-day supply should be provided.
2) Location
A) The liquid chemical storage tanks and tank fill connections
shall be located within a containment structure having a capacity exceeding the
total volume of all storage vessels. Valves on discharge lines shall be
located adjacent to the storage tank and within the containment structure.
B) Auxiliary facilities, including pumps and controls, within the
containment area shall be located above the highest anticipated liquid level.
Containment areas shall be sloped to a sump area and shall not contain floor
drains.
C) Bag storage should be located near the solution make-up point
to avoid unnecessary transportation and housekeeping problems.
3) Accessories
A) Platforms, stairways, and railings should be provided as
necessary to afford convenient and safe access to all filling connections,
storage tank entries, and measuring devices.
B) Storage tanks shall have reasonable access provided to
facilitate cleaning.
e) Other Requirements
1) Materials All chemical feed equipment and storage facilities
shall be constructed of materials resistant to chemical attack by all chemicals
normally used for phosphorus treatment.
2) Temperature, Humidity and Dust Control
Precautions shall be taken to prevent chemical storage tanks
and feed lines from reaching temperatures likely to result in freezing or
chemical crystallization at the concentrations employed. Enclosure heating or
insulation may be required. Consideration must be given to temperature,
humidity and dust control in all chemical feed room areas.
3) Cleaning
Consideration shall be given to the accessibility of piping.
Piping should be installed with plugged wyes, tees or crosses at changes in
direction to facilitate cleaning.
4) Drains and Drawoff
Above-bottom drawoff from chemical storage or feed tanks
shall be provided to avoid withdrawal of settled solids into the feed system.
A bottom drain shall also be installed for periodic removal of accumulated
settled solids.
f) Hazardous Chemical Handling
The requirements of Section 370.147(b), Hazardous Chemical
Handling, shall be met.
g) Sludge Handling
1) General
Consideration shall be given to the type and additional
capacity of the sludge handling facilities needed when chemicals are added.
2) Dewatering
Design of dewatering systems should be based, where possible,
on an analysis of the characteristics of the sludge to be handled.
Consideration should be given to the ease of operation, effect of recycle
streams generated, production rate, moisture content, dewaterability, final
disposal, and operating cost.
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.1210 AMMONIA CONTROL
Section 370.1210 Ammonia
Control
a) General
Ammonia control can be accomplished by physical, chemical,
biological and ion-exchange techniques. These criteria contain design
standards for a limited number of biological types and configurations of
ammonia control systems. Other types and configuration of systems will be
evaluated in accordance with Section 370.520(b).
1) Process Selection
A) Biological systems, normally used to accomplish secondary
levels of treatment, may be adapted to function as nitrification systems. In
applications of the fixed growth processes staged biological treatment is
normally provided. The single stage activated sludge process has been found to
be reliable for nitrification and is more commonly used than the two-stage
activated sludge process.
B) Because operating data and experience for the fixed growth
processes for nitrification are not well established, expected performance in
all cases shall be based upon experience at similar full scale installations or
thoroughly documented prototype testing with the particular wastewater. The
design shall provide the necessary flexibility to perform satisfactorily within
the range of expected waste characteristics and temperatures.
2) Alkalinity and pH Control
Biological utilization of ammonia to produce nitrates is consumptive
of available alkalinity in the ratio of 7.14 pounds alkalinity (as CaCO3)
per pound of ammonia nitrogen (as N) oxidized. The determination of the need
for added alkalinity must be calculated and included in the basis of design to
be submitted with the plan documents for Agency approval. The following
factors shall be taken into account in determining the amount of alkalinity to
be added:
A) The available alkalinity in the raw wastewater and any
sidestreams;
B) The total ammonia load (including sidestreams such as flows
from digesters and sludge handling facilities) imposed on the process;
C) The alkalinity needed to maintain pH levels in the range of 7.2
to 8.4.
3) Load Equalization
Load equalization shall be considered to limit peak loadings
of ammonia from plant sidestreams or slug sources on the sewer system. For the
fixed growth biological nitrification processes, the ammonia loading peaks
shall be limited to 150% of the design average ammonia loading value.
b) Intermittent Sand Filters
Intermittent sand filters, used in conjunction with various
primary and secondary treatment systems, may be considered for use as a
biological process to convert ammonia to nitrate.
1) Construction Details
The construction details are generally as described in
Section 370.940(g).
2) Loading Criteria
A) Following Primary Treatment
The design loading criteria following primary treatment is
described in Section 370.940(e), (f) and (h) except that reduced organic
loadings should be considered to insure meeting effluent ammonia limitations.
B) Following Secondary Treatment
The design loading criteria following secondary treatment is
described in Section 370.1130(b)(4) and (d)(3).
c) Suspended Growth Systems
1) Applicability
Suspended growth nitrifying systems may be designed as a
single stage process with combined carboneous BOD removal and nitrogenous
oxygen demand reductions or as the second stage of a two-stage process
following a first stage activated sludge process or other types of biological
treatment such as trickling filters.
2) Design Requirements
A) Aeration and Mixing
For nitrification, the oxygen requirement for oxidizing
ammonia must be added to the requirement for carbonaceous BOD removal. The
nitrogen oxygen demand shall be taken as 4.6 times the peak hourly ammonia (as
N) content of the influent. In addition, the oxygen demands due to sidestream
flows (digestion and sludge handling facilities and the like) must be
considered due to the high concentrations of BOD and ammonia associated with
such flows. Sufficient aeration and mixing capability shall be provided to maintain
a sludge age of up to 20 days and a dissolved oxygen concentration in the
aeration tank of at least 2 mg/l.
B) Power
Careful consideration should be given to maximizing oxygen
utilization per unit of power input. Unless flow equalization is provided, the
aeration system should be designed to match the peak hourly load variation
while economizing on power input.
C) Temperature
Careful consideration shall be given in the design and
selection of aeration and mixing equipment to minimize heat losses and to
maintain sewage temperatures of at least 50º F in cold weather.
D) Chemical Feed
Where the ratio of ammonia to available alkalinity in the
wastewater requires its use, chemical feed equipment shall be provided to
maintain adequate alkalinity and a pH level between 7.2 and 8.4.
3) Single Stage Activated Sludge
In addition to the requirements of Section 370.920, the
following criteria shall govern the design:
A) Organic Loading Organic loading shall not exceed 15 lbs/day of
BOD5 per 1,000 cu.ft. of available tank volume.
B) Detention Time
The hydraulic detention time shall be a minimum of 8 hours
based on the plant design average flow as determined by Section 370.520(c).
4) Activated Sludge Nitrifying Stage Following Secondary Treatment
The following subsections set out criteria in addition to the
requirements of Section 370.920 for the activated sludge nitrifying stage
following a first stage activated sludge or fixed growth process used for
carbonaceous BOD removal.
A) Organic Loading
BOD5 concentration shall be limited to 20-50 mg/1.
B) Detention Time
The hydraulic detention time shall be a minimum of 6 hours
based on the plant design average flow as determined by Section 370.520(c).
C) Special Design Requirement
The following requirements in addition to subsection (c)(3)
above, shall be provided:
i) Bypass around the first stage process to allow discharge of
raw or primary settled sewage to the second stage aeration tank as needed as a
carbon source for control of the nitrification process.
ii) Careful consideration shall be given in the design and
selection of covers and ventilation or aeration and mixing equipment to
minimize heat losses in the first stage process and maintain sewage
temperatures of at least 50º F in cold weather.
d) Fixed Growth Systems
1) Applicability
Nitrifying fixed growth systems may be used following
activated sludge and fixed growth systems used for carbonaceous BOD removal.
2) Design Requirements
A) Peak Loadings
In addition to the requirements of Section 370.900, the
design of fixed growth systems shall take into account the peak hourly ammonia
content of the influent. The design shall provide for ammonia load
equalization in accordance with subsection (a)(3) above.
B) Temperature
Adequate cover or housing of the nitrification units shall be
provided and preceding systems shall be designed or upgraded to minimize heat
losses to maintain sewage temperatures of at least 50º F in cold weather.
C) Ventilation for Process Air Requirements
Adequate ventilation shall be provided to satisfy the oxygen
demand of the process. Refer to Section 370.900(e)(5).
D) Chemical Feed
Chemical feed equipment shall be provided to maintain
adequate alkalinity concentrations and a pH level between 7.2 and 8.4 where the
ratio of ammonia to available alkalinity in the wastewater requires its use.
E) Post-Process Settling
Settling tanks following nitrifying fixed growth systems
shall be provided and designed in accordance with Subpart G. A single unit
will be allowed if the applicable BOD and suspended solids effluent limitations
can be met and other serious operational problems will not occur when the
clarifier is temporarily out of service.
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
Section 370.APPENDIX A Table No. 1 – Resident Occupancy Criteria
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.APPENDIX B TABLE NO. 2 COMMONLY USED QUANTITIES OF SEWAGE FLOWS FROM MISCELLANEOUS TYPE FACILITIES
Section 370.APPENDIX B Table
No. 2 – Commonly Used Quantities of Sewage Flows From Miscellaneous Type
Facilities
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Type of Establishment
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Gallons
Per Person Per Day (Unless otherwise noted)
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Airports (per passenger)
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5
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Bathhouses and swimming pools
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10
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Camps:
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|
|
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Campground
with central comfort stations
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35
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With flush
toilets, no showers
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25
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Construction
camps (semi-permanent)
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50
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Day camps
(no meals served)
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15
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Resort camps (night and day) with limited plumbing
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50
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Luxury
camps
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100
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Cottages and small dwellings with seasonal occupancy
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75
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Country clubs (per resident member)
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100
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Country clubs (per non-resident member present)
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25
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|
Dwellings:
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|
|
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Boarding
houses
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50
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(additional
for non-resident boarders)
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10
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Rooming
houses
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40
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Factories (gallons per person, per shift, exclusive of industrial
wastes)
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35
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Hospitals (per bed space)
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250
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Hotels with laundry (2 persons per room) per room
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150
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Institutions other than hospitals including Nursing Homes (per bed
space)
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125
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Laundries-self service (gallons per wash)
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30
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Motels (per bed space) with laundry
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50
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Picnic parks (toilet wastes only per park user)
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5
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Picnic parks with bathouses, showers and flush toilets (per park user)
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10
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Restaurants (toilet and kitchen wastes per patron)
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10
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Restaurants (kitchen wastes per meal served)
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3
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Restaurants (additional for bars and cocktail lounges)
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2
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Schools:
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Boarding
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100
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Day, without gyms, cafeterias or showers
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15
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Day, with gyms, cafeterias and showers
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25
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Day, with cafeterias, but without gyms or showers
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20
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Service stations (per vehicle served)
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5
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Swimming pools and bathouses
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10
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Theaters:
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Movie (per auditorium seat)
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5
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Drive-in (per car space)
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10
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Travel trailer parks without individual water and sewer hook-ups (per
space)
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50
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Travel trailer parks with individual water and sewer hook-ups (per
space)
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100
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Workers:
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Offices, schools and business establishments (per shift)
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15
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(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.APPENDIX C TABLE NO. 3 AIR TEST TABLE FOR SANITARY SEWER LEAKAGE TESTING*
Section 370.APPENDIX C Table
No. 3 – Air Test Table for Sanitary Sewer Leakage Testing*
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SPECIFICATION
TIME (MIN:SEC) REQUIRED FOR PRESSURE DROP
FROM
3½ TO 2½ PSIG WHEN TESTING ONE PIPE DIAMETER ONLY
|
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Length of Sewer Pipe In
Feet
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PIPE
DIAMETER, INCHES
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4
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6
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8
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10
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12
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15
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18
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21
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24
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25
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0:04
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0:10
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0:28
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0:28
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0:40
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1:02
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1:29
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2:01
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2:38
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50
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0:09
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0:20
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0:35
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0:55
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1:19
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2:04
|
2:58
|
4:03
|
5:17
|
|
75
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0:13
|
0:30
|
0:53
|
1:23
|
1:59
|
3:06
|
4:27
|
6:04
|
7:55
|
|
100
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0:18
|
0:40
|
1:10
|
1:50
|
2:38
|
4:08
|
5:56
|
8:05
|
10:34
|
|
125
|
0:22
|
0:50
|
1:28
|
2:18
|
3:18
|
5:09
|
7:26
|
9:55
|
11:20
|
|
150
|
0:26
|
0:59
|
1:46
|
2:45
|
3:58
|
6:11
|
8:30
|
|
|
|
175
|
0:31
|
1:09
|
2:03
|
3:13
|
4:37
|
7:05
|
|
|
|
|
200
|
0:35
|
1:19
|
2:21
|
3:40
|
5:17
|
|
|
|
12:06
|
|
225
|
0:40
|
1:29
|
2:38
|
4:08
|
5:40
|
|
|
10:25
|
13:36
|
|
250
|
0:44
|
1:39
|
2:56
|
4:35
|
|
|
8:31
|
11:35
|
15:07
|
|
275
|
0:48
|
1:49
|
3:14
|
4:43
|
|
|
9:21
|
12:44
|
16:38
|
|
300
|
0:53
|
1:59
|
3:31
|
|
|
|
10:12
|
13:53
|
18:09
|
|
350
|
1:02
|
2:19
|
3:47
|
|
|
8:16
|
11:54
|
16:12
|
21.10
|
|
400
|
1:10
|
2:38
|
|
|
6:03
|
9:27
|
13:36
|
18:31
|
24:12
|
|
450
|
1:19
|
2:50
|
|
|
6:48
|
10:38
|
15:19
|
20:50
|
27:13
|
|
500
|
1:28
|
|
|
5:14
|
7:34
|
11:49
|
17:01
|
23:09
|
30:14
|
*From Standard Specifications
for Water and Sewer Main Construction in Illinois, Fourth Edition, May, 1986.
(Copies may be obtained from Illinois Society of Professional Engineers,
Springfield, Illinois 62704.)
(Source: Amended at 21 Ill. Reg. 12444, effective August 28, 1997)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.APPENDIX D FIGURE NO. 1 - DESIGN OF SEWERS RATIO OF PEAK FLOW TO DAILY AVERAGE FLOW
Section 370.APPENDIX D Figure
No. 1 - Design of Sewers – Ratio of Peak Flow to Daily Average Flow
(REFER
TO 35 ILL. ADM. CODE 372.310(b)
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.APPENDIX E FIGURE NO. 2 PRIMARY SETTLING
Section 370.APPENDIX E Figure
No. 2 – Primary Settling
(REFER
TO 35 ILL. ADM. CODE 70.710(b)(1)(A))
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.APPENDIX F FIGURE NO. 3 B.O.D. REMOVAL SINGLE STAGE TRICKLING FILTER UNITS INCLUDING POST SETTLING NO RECIRCULATION INCLUDED
Section 370.APPENDIX F Figure
No. 3 – B.O.D. Removal Single Stage Trickling Filter Units Including Post
Settling – No Recirculation Included
(REFER
TO 35 ILL. ADM. CODE 370.900(h)(1))
| TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE C: WATER POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 370
ILLINOIS RECOMMENDED STANDARDS FOR SEWAGE WORKS
SECTION 370.APPENDIX G FIGURE NO. 4 BREAK TANK SKETCH FOR POTABLE WATER SUPPLY PROTECTION
Section 370.APPENDIX G Figure
No. 4 – Break Tank Sketch for Potable Water Supply Protection
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