(a) Bromate and chlorite. The maximum contaminant levels (MCLs) for bromate and chlorite are as follows: ------------------------------------------------------------------------
Disinfection byproduct MCL (mg/L)------------------------------------------------------------------------Bromate.................................................... 0.010Chlorite................................................... 1.0------------------------------------------------------------------------
(1) Compliance dates for CWSs and NTNCWSs. Subpart H systems serving 10,000 or more persons must comply with this paragraph (a) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this paragraph (a) beginning January 1, 2004.
(2) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for bromate and chlorite identified in this paragraph (a): ------------------------------------------------------------------------
Disinfection byproduct Best available technology------------------------------------------------------------------------Bromate................................ Control of ozone treatment
process to reduce production
of bromateChlorite............................... Control of treatment processes
to reduce disinfectant demand
and control of disinfection
treatment processes to reduce
disinfectant levels------------------------------------------------------------------------
(b) TTHM and HAA5. (1) Subpart L--RAA compliance. (i) Compliance dates. Subpart H systems serving 10,000 or more persons must comply with this paragraph (b)(1) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this paragraph (b)(1) beginning January 1, 2004. All systems must comply with these MCLs until the date specified for subpart V compliance in Sec. 141.620(c). ------------------------------------------------------------------------
Disinfection byproduct MCL (mg/L)------------------------------------------------------------------------Total trihalomethanes (TTHM)............................... 0.080Haloacetic acids (five) (HAA5)............................. 0.060------------------------------------------------------------------------
(ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(1): ------------------------------------------------------------------------
Disinfection byproduct Best available technology------------------------------------------------------------------------Total trihalomethanes (TTHM) and Enhanced coagulation or
Haloacetic acids (five) (HAA5). enhanced softening or
GAC10, with chlorine as the
primary and residual
disinfectant------------------------------------------------------------------------
(2) Subpart V--LRAA compliance. (i) Compliance dates. The subpart V MCLs for TTHM and HAA5 must be complied with as a locational running annual average at each monitoring location beginning the date specified for subpart V compliance in Sec. 141.620(c). ------------------------------------------------------------------------
Disinfection byproduct MCL (mg/L)------------------------------------------------------------------------Total trihalomethanes (TTHM)............................... 0.080Haloacetic acids (five) (HAA5)............................. 0.060------------------------------------------------------------------------
(ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(2) for all systems that disinfect their source water: ------------------------------------------------------------------------
Disinfection byproduct Best available technology------------------------------------------------------------------------Total trihalomethanes (TTHM) and Enhanced coagulation or
Haloacetic acids (five) (HAA5). enhanced softening, plus
GAC10; or nanofiltration with
a molecular weight cutoff
<=1000 Daltons; or GAC20------------------------------------------------------------------------
(iii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(2) for consecutive systems and applies only to the disinfected water that consecutive systems buy or otherwise receive: ------------------------------------------------------------------------
Disinfection byproduct Best available technology------------------------------------------------------------------------Total trihalomethanes (TTHM) and Systems serving =10,000: Improved
distribution system and
storage tank management to
reduce residence time, plus
the use of chloramines for
disinfectant residual
maintenance
Systems serving <10,000:
Improved distribution system
and storage tank management to
reduce residence time------------------------------------------------------------------------ [71 FR 478, Jan. 4, 2006]