SUBTITLE F: PUBLIC WATER SUPPLIES
CHAPTER I: POLLUTION CONTROL BOARD
PART 611 PRIMARY DRINKING WATER STANDARDS
SECTION 611.312 MAXIMUM CONTAMINANT LEVELS (MCLS) FOR DISINFECTION BYPRODUCTS (DBPS)
Section 611.312 Maximum Contaminant Levels (MCLs) for Disinfection Byproducts (DBPs)
a) Bromate and Chlorite. MCLs for bromate and chlorite apply to CWS and NTNCWS suppliers:
|
Disinfection Byproduct |
MCL (mg/L) |
|
Bromate |
0.010 |
|
Chlorite |
1.0 |
1) A Subpart B system supplier must comply with this subsection (a).
2) USEPA identifies best available technology, treatment techniques, or other means available for achieving compliance with the MCLs for bromate and chlorite:
|
Disinfection Byproduct
|
Best Available Technology
|
|
Bromate |
Controlling the ozone treatment process to reduce bromate production. |
|
Chlorite |
Controlling the treatment processes to reduce disinfectant demand and controlling the disinfection treatment processes to reduce disinfectant levels. |
b) TTHM and HAA5
1) A supplier must comply with the Subpart Y MCLs for TTHM and HAA5 as a locational running annual average at each monitoring location, as Section 611.970(c) requires.
|
Disinfection Byproduct |
MCL (mg/L)
|
|
Total trihalomethanes (TTHM) |
0.080 |
|
Haloacetic acids (five) (HAA5) |
0.060 |
2) USEPA identifies the best available technology, treatment techniques, or other means available for complying with the MCLs for TTHM and HAA5 for any supplier disinfecting its source water:
|
Disinfection Byproduct |
Best Available Technology
|
|
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5) |
Enhanced coagulation or enhanced softening, plus GAC10; or nanofiltration with a molecular weight cutoff ≤ 1000 Daltons; or GAC20 |
3) USEPA identifies the best available technology, treatment techniques, or other means available for achieving compliance with the MCLs TTHM and HAA5 for consecutive systems, which only apply to the disinfected water that a consecutive system buys or otherwise receives from a wholesale system:
|
Disinfection Byproduct |
Best Available Technology |
|
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5) |
Any system serving 10,000 or more persons: Improved distribution system and storage tank management to reduce residence time, plus using chloramines for disinfectant residual maintenance; or Any system serving fewer than 10,000 persons: Improved distribution system and storage tank management to reduce residence time. |
BOARD NOTE: This Section derives from 40 CFR 141.64.
(Source: Amended at 47 Ill. Reg. 16486, effective November 2, 2023)