Indiana Administrative Code
Title 327 - WATER POLLUTION CONTROL DIVISION
Article 5 - INDUSTRIAL WASTEWATER PRETREATMENT PROGRAMS AND NPDES
Rule 2 - Basic NPDES Requirements
Section 2-11.1 - Establishment of water quality-based effluent limitations for dischargers not discharging to waters within the Great Lakes system

Universal Citation: 327 IN Admin Code 2-11.1

Current through September 18, 2024

Authority: IC 13-14-8; IC 13-14-9; IC 13-15-1-2; IC 13-15-2-1; IC 13-18-3

Affected: IC 13-11-2; IC 13-18-4

Sec. 11.1.

(a) The water quality standards established through the criteria set forth in 327 IAC 2-1-6 and 327 IAC 2-1-8.9 or under the procedures described in 327 IAC 2-1-8.2 through 327 IAC 2-1-8.6 and 327 IAC 2-1-8.9 shall:

(1) be the basis for water quality-based effluent limitations (WQBELs) applicable to point source dischargers, not discharging to waters within the Great Lakes system, through NPDES permits (except for instances where a variance has been approved under 327 IAC 2-1-8.8 and 327 IAC 5-3-4.1); and

(2) not be enforceable against point source dischargers until translated into effluent limitations that are incorporated in NPDES permits in accordance with this article.

(b) This subsection describes how the surface water quality criteria in 327 IAC 2-1-6(a) and 327 IAC 2-1-8.9(g) or those criteria derived using the procedures in 327 IAC 2-1-8.2 through 327 IAC 2-1-8.6 and 327 IAC 2-1-8.9 will be applied in determining appropriate WQBELs to NPDES permits as follows:

(1) The final acute value (FAV = 2(AAC)) will be applied directly to the undiluted discharge, or, if dilution by discharge induced mixing is allowed, the AAC will be applied outside the discharge induced mixing zone. If the AAC for a metal is expressed in the form of dissolved metal, the AAC shall be set equal to Cinstream determined for the AAC in accordance with subdivision (8).

(2) The CAC and the TLSC will be applied outside of the mixing zone. In the absence of site-specific mixing zone data, the allowable mixing zone dilution shall be determined by applying the guideline in 327 IAC 2-1-4 to the Q7,10 low flow of the receiving stream. If the CAC for a metal is expressed in the form of dissolved metal, the CAC shall be set equal to Cinstream determined for the CAC in accordance with subdivision (8).

(3) The HLSC shall be applied outside of the mixing zone, if based on the consumption of organisms and incidental water intake. If based on consumption of organisms and drinking water, the HLSC shall apply at the point of the public water system intake, if this does not cause the HLSC based on consumption of organisms and incidental water intake to be exceeded outside of the mixing zone. Allowable mixing zone dilution shall be determined by applying the guideline of 327 IAC 2-1-4 to the Q7,10 low flow of the receiving stream if the HLSC is based on consumption of organisms and incidental water intake and the Q7,10 flow at the point of the public water system intake (provided the effluent has had time to fully mix with the receiving water) shall be allowed for dilution if the HLSC is based on consumption of organisms and drinking water.

(4) The criterion to provide an acceptable degree of protection to public health for cancer effects shall apply outside of the mixing zone if the criterion is based on consumption of organisms and incidental water intake and at the point of the public water system intake if based on the consumption of organisms and drinking water, if this would not cause the criterion based on the consumption of organisms and incidental water intake to be exceeded outside of the mixing zone. For calculation of allowable dilution, one-fourth (1/4) of the fiftieth percentile flow of the receiving stream shall be used if the criterion is based on consumption of organisms and incidental water intake, and the fiftieth percentile flow of the receiving stream at the point of the public water system intake can be used if the criterion is based on the consumption of organisms and drinking water.

(5) As used in this rule, "FAV", "AAC", "CAC", "TLSC", and "HLSC" have the meanings set forth in 327 IAC 2-1-9.

(6) For a new discharge of a BCC, the water quality standard for a BCC shall be applied directly to the undiluted discharge. Beginning January 1, 2004, the water quality criteria for a BCC shall be applied directly to the undiluted discharge for all discharges of a BCC. As used in this subdivision, "new discharge" means a discharge of a BCC that is initiated after the effective date of this subdivision.

(7) For intermittent or controlled discharges, the mixing zone dilution may be determined using stream flows other than those specified in this subsection if these alternate stream flows will ensure compliance with water quality criteria.

(8) The following procedures shall be used to calculate Cinstream, the total recoverable metal concentration outside the mixing zone that equates to an AAC or CAC expressed in the form of dissolved metal:

(A) For an AAC expressed in the form of dissolved metal, Cinstream shall be calculated by dividing the AAC by the acute translator found in clause (D).

(B) For a CAC expressed in the form of dissolved metal, Cinstream shall be calculated by dividing the CAC by the chronic translator found in clause (D).

(C) If all approved analytical methods for the metal inherently measure only its dissolved form, such as hexavalent chromium, Cinstream shall not be calculated and the AAC and CAC expressed in the form of dissolved metal shall be applied in determining appropriate WQBELs.

(D) Unless a site-specific translator is determined in accordance with clause (E), the following translators shall be used:

Table 11.1-1

Metals Translators Dissolved to Total Recoverable
Substances	Acute Translators	Chronic Translators
Arsenic (III)	1.000	1.000
Cadmium	1.136672-[(ln hardness)(0.041838)]	1.101672-[(ln hardness)(0.041838)]
Chromium (III)	0.316	0.860
Copper	0.960	0.960
Lead	1.46203-[(ln hardness)(0.145712)]	1.46203-[(ln hardness)(0.145712)]
Nickel	0.998	0.997
Silver	0.85
Zinc	0.978	0.986

(E) A discharger or proposed discharger may request the use of an alternate translator by using site-specific data. The discharger must conduct a site-specific study to identify the ratio of the dissolved fraction to the total recoverable fraction for a metal in the receiving waterbody outside the mixing zone. If the discharger provides an acceptable study and other provisions of 327 IAC 2-1 and this article are satisfied (such as antibacksliding and antidegradation), the commissioner shall use the site-specific translator. A translator derived for one (1) discharge into a waterbody segment may be applied to other discharges on the same waterbody segment if the translator would adequately represent the site-specific conditions applicable to the other discharges.

(c) In a case where a variance has been granted from a water quality standard under 327 IAC 2-1-8.8 and 327 IAC 5-3-4.1, WQBELs for the pollutant that is the subject of the variance shall be calculated under subsection (b) on the basis of the variance rather than the water quality standard.

(d) WQBELs in an NPDES permit for a metal calculated from a water quality criterion expressed in the form of dissolved metal that is:

(1) contained in 327 IAC 2-1; or

(2) subsequently developed under the procedures contained in 327 IAC 2-1; shall be expressed in the permit as total recoverable metal unless all approved analytical methods for the metal inherently measure only its dissolved form, such as hexavalent chromium.

(e) WQBELs for cyanide, calculated from a criterion for free cyanide contained in 327 IAC 2-1, shall be limited in the permit as free cyanide and monitored in the effluent using the "Cyanides Amenable to Chlorination" (CATC) method ( 40 CFR 136, Method 4500-CN G) or another method approved by the commissioner. The commissioner may include additional monitoring, limitations, or other requirements in a permit, on a case-by-case basis, if the additional requirements are necessary to ensure that water quality standards will be attained.

(f) When the WQBEL for any substance is less than the limit of quantitation normally achievable and determined by the commissioner to be appropriate for that substance in the effluent, the permit shall contain the following provisions:

(1) The permittee shall be required to use an approved analytical methodology for the substance in the effluent to produce the LOD and LOQ achievable in the effluent. This analytical method, and the LOD and LOQ associated with this method, shall be specified in the permit in addition to the following requirements:

(A) The permit shall include conditions that state that effluent concentrations less than the limit of quantitation are in compliance with the effluent limitations.

(B) In addition, the permit shall require the permittee to implement one (1) or more of the following requirements:

(i) Develop a more sensitive analytical procedure.

(ii) Use an existing, more sensitive, analytical procedure that has not been approved by EPA.

(iii) Conduct studies to determine the bioaccumulative or bioconcentrative properties of the substance in aquatic species through caged-biota studies or fish tissue analyses of resident species.

(iv) Conduct effluent bioconcentration evaluations.

(v) Conduct whole effluent toxicity testing.

(vi) Other requirements, as appropriate, such as engineering assessments or sediment analyses. For substances defined as BCCs, at a minimum, either item (iii) or (iv) shall be included in the permit.

(2) If the measured effluent concentrations for a substance are above the WQBELs and above the LOD specified by the permit in any three (3) consecutive analyses or any five (5) out of nine (9) analyses, or if any of the additional analyses required under subdivision (1)(B) indicate that the substance is present in the effluent at concentrations exceeding the WQBELs, the permit shall contain provisions that require the discharger to:

(A) determine the source of this substance through evaluation of sampling techniques, analytical/laboratory procedures, and industrial processes and wastestreams; and

(B) increase the frequency of sampling and testing for the substance.

(3) The permit shall contain provisions allowing the permit to be reopened, in accordance with section 16 of this rule, to include additional requirements or limitations if the information gathered under subdivisions (1) and (2) indicates that such additional requirements or limitations are necessary.

(g) The department shall use the representative ambient upstream concentration of a substance in determining the WQBELs for that substance. This upstream concentration shall be determined by the department on a case-by-case basis, using existing, acceptable data for the receiving water. Where limited or no acceptable data exists, the permittee shall be required to supply the necessary data. Whenever the representative ambient upstream concentration for a substance in the receiving water is determined to be greater than any applicable water quality criterion for that substance, the following conditions apply:

(1) If the source of the wastewater is not the receiving water, the permit limitations shall be calculated using the applicable water quality criterion and a value of zero (0) for the upstream dilution flow. Except for substances defined as BCCs, the department may establish limitations greater than the applicable water quality criterion for the substance as required in this subdivision, in a range up to, but not greater than, the lesser of the representative ambient upstream concentration of the substance in the receiving water or the representative ambient concentration of the substance in the body of water at the point of intake. The limitation shall only be increased above the criterion if it is demonstrated to the department that the concentration of the substance in the body of water at the point of intake exceeds the applicable criterion for that substance and that reasonable, practical, or otherwise required methods are implemented to minimize the addition of the substance to the wastewater.

(2) If the source of the wastewater is the receiving water, the effluent limitation for that substance shall equal the representative ambient upstream concentration of that substance in the receiving water as determined by the department. Where circumstances allow, such as the discharge of once through noncontact cooling water, this will be implemented through the use of net limitations, with a net limitation of zero (0) being applied to the effluent. The representative ambient upstream concentration applicable to this subdivision shall be established at the upper ninety-ninth percentile of the available acceptable upstream data or otherwise appropriately determined as the reasonably expected upstream concentration for that substance.

(h) In addition to the requirements of 40 CFR 122.43(a), NPDES permits shall include limitations more stringent than promulgated effluent limitations guidelines from Sections 301, 306, 307, 318, and 405 of the CWA where necessary to achieve water quality standards established under Section 303 of the CWA, including narrative criteria for water quality as follows:

(1) Limitations must control all pollutants or pollutant parameters (either conventional, nonconventional, or toxic pollutants) that the commissioner determines are, or may be, discharged at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above any narrative or numeric water quality criterion promulgated under 327 IAC 2-1-6.

(2) When determining whether a discharge causes, has the reasonable potential to cause, or contributes to an instream excursion above a narrative or numeric criterion within an Indiana water quality standard, the commissioner shall use procedures that account for:

(A) existing controls on point and nonpoint sources of pollution;

(B) the variability of the pollutant or pollutant parameter in the effluent;

(D) where appropriate, the dilution of the effluent in the receiving water.

(3) When the commissioner determines, using the procedures in subdivision (2), that a discharge causes, has the reasonable potential to cause, or contributes to an instream excursion above the allowable ambient concentration of a numeric criterion from 327 IAC 2-1-6 for an individual pollutant, the permit must contain effluent limitations for that pollutant.

(4) When the commissioner determines, using the procedures in subdivision (2), that a discharge causes, has the reasonable potential to cause, or contributes to an instream excursion above the numeric criterion for whole effluent toxicity, the permit must contain effluent limits for whole effluent toxicity.

(5) Except as provided in this subdivision, when the commissioner determines, using the procedures in subdivision (2), toxicity testing data, or other information, that a discharge causes, has the reasonable potential to cause, or contributes to an instream excursion above a narrative criterion from 327 IAC 2-1-6, the permit must contain effluent limitations for whole effluent toxicity. Limitations on whole effluent toxicity are not necessary where the commissioner demonstrates in the fact sheet or briefing memo of the NPDES permit, using the procedures in subdivision (2), that chemical-specific limits for the effluent are sufficient to attain and maintain applicable numeric and narrative water quality criteria.

(6) Where a water quality criterion has not been established for a specific chemical pollutant that is present in an effluent at a concentration that causes, has the reasonable potential to cause, or contributes to an excursion above a narrative criterion from 327 IAC 2-1-6, the commissioner must establish effluent limits using one (1) or more of the following options:

(A) Establish effluent limits using a calculated numeric water quality criterion for the pollutant that the commissioner demonstrates will attain and maintain applicable narrative water quality criteria and will fully protect the designated use. Such a criterion may be derived using a proposed state criterion, or an explicit policy or rule interpreting the narrative water quality criterion, supplemented with other relevant information that may include:

(i) EPA's Water Quality Standards Handbook, Second Edition-Revised (1994);

(ii) risk assessment data;

(iii) exposure data;

(iv) information about the pollutant from the Food and Drug Administration; and

(v) current EPA criteria documents.

(B) Establish effluent limits on a case-by-case basis, using EPA's water quality criteria, published under Section 304(a) of the CWA, supplemented where necessary by other relevant information.

(i) The permit identifies which pollutants are intended to be controlled by the use of the effluent limitation.

(ii) The fact sheet required by 327 IAC 5-3-8 sets forth the basis for the limit, including a finding that compliance with the effluent limit on the indicator parameter will result in controls on the pollutant of concern that are sufficient to attain and maintain applicable water quality standards.

(iii) The permit requires all effluent and ambient monitoring necessary to show that during the term of the permit the limit on the indicator parameter continues to attain and maintain applicable water quality standards.

(iv) The permit contains a reopening clause allowing the permitting authority to modify or revoke and reissue the permit if the limits on the indicator parameter no longer attain and maintain applicable water quality standards.

(7) When developing WQBELs under this subsection, the commissioner shall ensure the following:

(A) The level of water quality to be achieved by limits on point sources established under this subsection is derived from, and complies with, all applicable water quality standards.

(B) Effluent limits developed to protect a narrative water quality criterion or a numeric water quality criterion, or both, are consistent with the assumptions and requirements of any available WLA for the discharge prepared by the commissioner and approved by EPA under 40 CFR 130.7.

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