Ill. Admin. Code tit. 35 § 611.312

Current through Register Vol. 48, No. 50, December 13, 2024

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 [LESS THAN OR EQUAL TO] 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.

Ill. Admin. Code tit. 35, § 611.312

Amended at 31 Ill. Reg. 11757, effective July 27, 2007

Amended at 42 Ill. Reg. 1140, effective 1/4/2018

Amended at 44 Ill. Reg. 6996, effective 4/17/2020

Amended at 47 Ill. Reg. 16486, effective 11/2/2023

BOARD NOTE: This Section derives from 40 CFR 141.64.