§141.64 Maximum contaminant levels for disinfection byproducts.

(a) The maximum contaminant levels (MCLs) for disinfection byproducts are as follows:

 
------------------------------------------------------------------------
                                                                MCL (mg/
                    Disinfection byproduct                         L)
------------------------------------------------------------------------
Total trihalomethanes (TTHM)..................................     0.080
Haloacetic acids (five) (HAA5)................................     0.060
Bromate.......................................................     0.010
Chlorite......................................................     1.0
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(b) Compliance dates. (1) CWSs and NTNCWSs. Subpart H systems serving 10,000 or more persons must comply with this section 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 section beginning January 1, 2004.

(2) A system that is installing GAC or membrane technology to comply with this section may apply to the State for an extension of up to 24 months past the dates in paragraphs (b)(1) of this section, but not beyond December 31, 2003. In granting the extension, States must set a schedule for compliance and may specify any interim measures that the system must take. Failure to meet the schedule or interim treatment requirements constitutes a violation of a National Primary Drinking Water Regulation.

(c) 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 disinfection byproducts identified in paragraph (a) of this section:

 
------------------------------------------------------------------------
         Disinfection byproduct             Best available technology
------------------------------------------------------------------------
TTHM...................................  Enhanced coagulation or
                                          enhanced softening or GAC10,
                                          with chlorine as the primary
                                          and residual disinfectant
HAA5...................................  Enhanced coagulation or
                                          enhanced softening or GAC10,
                                          with chlorine as the primary
                                          and residual disinfectant.
Bromate................................  Control of ozone treatment
                                          process to reduce production
                                          of bromate.
Chlorite...............................  Control of treatment processes
                                          to reduce disinfectant demand
                                          and control of disinfection
                                          treatment processes to reduce
                                          disinfectant levels.
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[63 FR 69465, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001]