[Code of Federal Regulations]

[Title 40, Volume 21]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 40CFR125.62]



[Page 320-322]

 

                   TITLE 40--PROTECTION OF ENVIRONMENT

 

         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

 

PART 125_CRITERIA AND STANDARDS FOR THE NATIONAL POLLUTANT DISCHARGE 

ELIMINATION SYSTEM--Table of Contents

 

 Subpart G_Criteria for Modifying the Secondary Treatment Requirements 

               Under Section 301(h) of the Clean Water Act

 

Sec.  125.62  Attainment or maintenance of water quality which assures 



protection of public water supplies; assures the protection and propagation 

of a balanced indigenous population of shellfish, fish, and wildlife; and 

allows recreational activities.



    (a) Physical characteristics of discharge. (1) At the time the 

301(h) modification becomes effective, the applicant's outfall and 

diffuser must be located and designed to provide adequate initial 

dilution, dispersion, and transport of wastewater such that the 

discharge does not exceed at and beyond the zone of initial dilution:

    (i) All applicable water quality standards; and

    (ii) All applicable EPA water quality criteria for pollutants for 

which there is no applicable EPA-approved water quality standard that 

directly corresponds to the EPA water quality criterion for the 

pollutant.

    (iii) For purposes of paragraph (a)(1)(ii) of this section, a State 

water quality standard ``directly corresponds'' to an EPA water quality 

criterion only if:

    (A) The State water quality standard addresses the same pollutant as 

the EPA water quality criterion and

    (B) The State water quality standard specifies a numeric criterion 

for that pollutant or State objective methodology for deriving such a 

numeric criterion.

    (iv) The evaluation of compliance with paragraphs (a)(1) (i) and 

(ii) of this section shall be based upon conditions reflecting periods 

of maximum stratification and during other periods when discharge 

characteristics, water quality, biological seasons, or oceanographic 

conditions indicate more critical situations may exist.

    (2) The evaluation under paragraph (a)(1)(ii) of this section as to 

compliance with applicable section 304(a)(1) water quality criteria 

shall be based on the following:

    (i) For aquatic life criteria: The pollutant concentrations that 

must not be exceeded are the numeric ambient values, if any, specified 

in the EPA section 304(a)(1) water quality criteria documents as the 

concentrations at which acute and chronic toxicity to aquatic life 

occurs or that are otherwise identified as the criteria to protect 

aquatic life.

    (ii) For human health criteria for carcinogens: (A) For a known or 

suspected carcinogen, the Administrator shall determine the pollutant 

concentration that shall not be exceeded. To make this determination, 

the Administrator shall first determine a level of risk associated with 

the pollutant that is acceptable for purposes of this section. The 

Administrator shall then use the information in the section 304(a)(1) 

water quality criterion document, supplemented by all other relevant 

information, to determine the specific pollutant concentration that 

corresponds to the identified risk level.

    (B) For purposes of paragraph (a)(2)(ii)(A) of this section, an 

acceptable risk level will be a single level



[[Page 321]]



that has been consistently used, as determined by the Administrator, as 

the basis of the State's EPA-approved water quality standards for 

carcinogenic pollutants. Alternatively, the Administrator may consider a 

State's recommendation to use a risk level that has been otherwise 

adopted or formally proposed by the State. The State recommendation must 

demonstrate, to the satisfaction of the Administrator, that the 

recommended level is sufficiently protective of human health in light of 

the exposure and uncertainty factors associated with the estimate of the 

actual risk posed by the applicant's discharge. The State must include 

with its demonstration a showing that the risk level selected is based 

on the best information available and that the State has held a public 

hearing to review the selection of the risk level, in accordance with 

provisions of State law and public participation requirements of 40 CFR 

part 25. If the Administrator neither determines that there is a 

consistently used single risk level nor accepts a risk level recommended 

by the State, then the Administrator shall otherwise determine an 

acceptable risk level based on all relevant information.

    (iii) For human health criteria for noncarcinogens: For 

noncarcinogenic pollutants, the pollutant concentrations that must not 

be exceeded are the numeric ambient values, if any, specified in the EPA 

section 304(a)(1) water quality criteria documents as protective against 

the potential toxicity of the contaminant through ingestion of 

contaminated aquatic organisms.

    (3) The requirements of paragraphs (a)(1) and (a)(2) of this section 

apply in addition to, and do not waive or substitute for, the 

requirements of Sec.  125.61.

    (b) Impact of discharge on public water supplies. (1) The 

applicant's modified discharge must allow for the attainment or 

maintenance of water quality which assures protection of public water 

supplies.

    (2) The applicant's modified discharge must not:

    (i) Prevent a planned or existing public water supply from being 

used, or from continuing to be used, as a public water supply; or

    (ii) Have the effect of requiring treatment over and above that 

which would be necessary in the absence of such discharge in order to 

comply with local and EPA drinking water standards.

    (c) Biological impact of discharge. (1) The applicant's modified 

discharge must allow for the attainment or maintenance of water quality 

which assures protection and propagation of a balanced indigenous 

population of shellfish, fish, and wildlife.

    (2) A balanced indigenous population of shellfish, fish, and 

wildlife must exist:

    (i) Immediately beyond the zone of initial dilution of the 

applicant's modified discharge; and

    (ii) In all other areas beyond the zone of initial dilution where 

marine life is actually or potentially affected by the applicant's 

modified discharge.

    (3) Conditions within the zone of initial dilution must not 

contribute to extreme adverse biological impacts, including, but not 

limited to, the destruction of distinctive habitats of limited 

distribution, the presence of disease epicenter, or the stimulation of 

phytoplankton blooms which have adverse effects beyond the zone of 

initial dilution.

    (4) In addition, for modified discharges into saline estuarine 

water:

    (i) Benthic populations within the zone of initial dilution must not 

differ substantially from the balanced indigenous populations which 

exist immediately beyond the boundary of the zone of initial dilution;

    (ii) The discharge must not interfere with estuarine migratory 

pathways within the zone of initial dilution; and

    (iii) The discharge must not result in the accumulation of toxic 

pollutants or pesticides at levels which exert adverse effects on the 

biota within the zone of initial dilution.

    (d) Impact of discharge on recreational activities. (1) The 

applicant's modified discharge must allow for the attainment or 

maintenance of water quality which allows for recreational activities 

beyond the zone of initial dilution, including, without limitation, 

swimming, diving, boating, fishing, and picnicking, and sports 

activities along shorelines and beaches.



[[Page 322]]



    (2) There must be no Federal, State, or local restrictions on 

recreational activities within the vicinity of the applicant's modified 

outfall unless such restrictions are routinely imposed around sewage 

outfalls. This exception shall not apply where the restriction would be 

lifted or modified, in whole or in part, if the applicant were 

discharging a secondary treatment effluent.

    (e) Additional requirements for applications based on improved or 

altered discharges. An application for a section 301(h) modified permit 

on the basis of an improved or altered discharge must include:

    (1) A demonstration that such improvements or alterations have been 

thoroughly planned and studied and can be completed or implemented 

expeditiously;

    (2) Detailed analyses projecting changes in average and maximum 

monthly flow rates and composition of the applicant's discharge which 

are expected to result from proposed improvements or alterations;

    (3) The assessments required by paragraphs (a) through (d) of this 

section based on its current discharge; and

    (4) A detailed analysis of how the applicant's planned improvements 

or alterations will comply with the requirements of paragraphs (a) 

through (d) of this section.

    (f) Stressed waters. An applicant must demonstrate compliance with 

paragraphs (a) through (e) of this section not only on the basis of the 

applicant's own modified discharge, but also taking into account the 

applicant's modified discharge in combination with pollutants from other 

sources. However, if an applicant which discharges into ocean waters 

believes that its failure to meet the requirements of paragraphs (a) 

through (e) of this section is entirely attributable to conditions 

resulting from human perturbations other than its modified discharge 

(including, without limitation, other municipal or industrial 

discharges, nonpoint source runoff, and the applicant's previous 

discharges), the applicant need not demonstrate compliance with those 

requirements if it demonstrates, to the satisfaction of the 

Administrator, that its modified discharge does not or will not:

    (1) Contribute to, increase, or perpetuate such stressed conditions;

    (2) Contribute to further degradation of the biota or water quality 

if the level of human perturbation from other sources increases; and

    (3) Retard the recovery of the biota or water quality if the level 

of human perturbation from other sources decreases.