[Code of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR142.60]

[Page 663-664]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 142_NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION--Table of 
 
  Subpart G_Identification of Best Technology, Treatment Techniques or 
 
Sec. 142.60  Variances from the maximum contaminant level for total 

                     Other Means Generally Available


trihalomethanes.

    (a) The Administrator, pursuant to section 1415(a)(1)(A) of the Act, 
hereby identifies the following as the best technology, treatment 
techiques or other means generally available for achieving compliance 
with the maximum contaminant level for total trihalomethanes (Sec. 
141.12(c)):
    (1) Use of chloramines as an alternate or supplemental disinfectant 
or oxidant.
    (2) Use of chlorine dioxide as an alternate or supplemental 
disinfectant or oxidant.
    (3) Improved existing clarification for THM precursor reduction.
    (4) Moving the point of chlorination to reduce TTHM formation and, 
where necessary, substituting for the use of chlorine as a pre-oxidant 
chloramines, chlorine dioxide or potassium permanganate.
    (5) Use of powdered activated carbon for THM precursor or TTHM 
reduction

[[Page 664]]

seasonally or intermittently at dosages not to exceed 10 mg/L on an 
annual average basis.
    (b) The Administrator in a state that does not have primary 
enforcement responsibility or a state with primary enforcement 
responsibility (primacy state) that issues variances shall require a 
community water system to install and/or use any treatment method 
identified in Sec. 142.60(a) as a condition for granting a variance 
unless the Administrator or primacy state determines that such treatment 
method identified in Sec. 142.60(a) is not available and effective for 
TTHM control for the system. A treatment method shall not be considered 
to be ``available and effective'' for an individual system if the 
treatment method would not be technically appropriate and technically 
feasible for that system or would only result in a marginal reduction in 
TTHM for the system. If, upon application by a system for a variance, 
the Administrator or primacy state that issues variances determines that 
none of the treatment methods identified in Sec. 142.60(a) is available 
and effective for the system, that system shall be entitled to a 
variance under the provisions of section 1415(a)(1)(A) of the Act. The 
Administrator's or primacy state's determination as to the availability 
and effectiveness of such treatment methods shall be based upon studies 
by the system and other relevant information. If a system submits 
information intending to demonstrate that a treatment method is not 
available and effective for TTHM control for that system, the 
Administrator or primacy state shall make a finding whether this 
information supports a decision that such treatment method is not 
available and effective for that system before requiring installation 
and/or use of such treatment method.
    (c) Pursuant to Sec. 142.43 (c) through (g) or corresponding state 
regulations, the Administrator or primacy state that issues variances 
shall issue a schedule of compliance that may require the system being 
granted the variance to examine the following treatment methods (1) to 
determine the probability that any of these methods will significantly 
reduce the level of TTHM for that system, and (2) if such probability 
exists, to determine whether any of these methods are technically 
feasible and economically reasonable, and that the TTHM reductions 
obtained will be commensurate with the costs incurred with the 
installation and use of such treatment methods for that system:

    Introduction of off-line water storage for THM precursor reduction.
    Aeration for TTHM reduction, where geographically and 
environmentally appropriate.
    Introduction of clarification where not currently practiced.
    Consideration of alternative sources of raw water.
    Use of ozone as an alternate or supplemental disinfectant or 
oxidant.

    (d) If the Administrator or primacy state that issues variances 
determines that a treatment method identified in Sec. 142.60(c) is 
technically feasible, economically reasonable and will achieve TTHM 
reductions commensurate with the costs incurred with the installation 
and/or use of such treatment method for the system, the Administrator or 
primacy state shall require the system to install and/or use that 
treatment method in connection with a compliance schedule issued under 
the provisions of section 1415(a)(1)(A) of the Act. The Administrator's 
or primacy state's determination shall be based upon studies by the 
system and other relevant information. In no event shall the 
Administrator require a system to install and/or use a treatment method 
not described in Sec. 142.60 (a) or (c) to obtain or maintain a 
variance from the TTHM Rule or in connection with any variance 
compliance schedule.

[48 FR 8414, Feb. 28, 1983]