(a) Scope and applicability. (1) The requirements of this section apply to each POTW serving a population of 50,000 or more that has one or more toxic pollutants introduced into the POTW by one or more industrial dischargers and that seeks a section 301(h) modification.

(2) The requirements of this section apply in addition to any applicable requirements of 40 CFR part 403, and do not waive or substitute for the part 403 requirements in any way.

(b) Toxic pollutant control. (1) As to each toxic pollutant introduced by an industrial discharger, each POTW subject to the requirements of this section shall demonstrate that it either:

(i) Has an applicable pretreatment requirement in effect in accordance with paragraph (c) of this section; or

(ii) Has in effect a program that achieves secondary removal equivalency in accordance with paragraph (d) of this section.

(2) Each applicant shall demonstrate that industrial sources introducing waste into the applicant's treatment works are in compliance with all applicable pretreatment requirements, including numerical standards set by local limits, and that it will enforce those requirements.

(c) Applicable pretreatment requirement. (1) An applicable pretreatment requirement under paragraph (b)(1)(i) of this section with respect to a toxic pollutant shall consist of the following:

(i) As to a toxic pollutant introduced into the applicant's treatment works by an industrial discharger for which there is no applicable categorical pretreatment standard for the toxic pollutant, a local limit or limits on the toxic pollutant as necessary to satisfy the requirements of 40 CFR part 403; and

(ii) As to a toxic pollutant introduced into the applicant's treatment works by an industrial discharger that is subject to a categorical pretreatment standard for the toxic pollutant, the categorical standard and a local limit or limits as necessary to satisfy the requirements of 40 CFR part 403;

(iii) As to a toxic pollutant introduced into the applicant's treatment works by an industrial discharger for which there is no applicable categorical pretreatment standard for the toxic pollutant, and the 40 CFR part 403 analysis on the toxic pollutant shows that no local limit is necessary, the applicant shall demonstrate to EPA on an annual basis during the term of the permit through continued monitoring and appropriate technical review that a local limit is not necessary, and, where appropriate, require industrial management practices plans and other pollution prevention activities to reduce or control the discharge of each such pollutant by industrial dischargers to the POTW. If such monitoring and technical review of data indicate that a local limit is needed, the POTW shall establish and implement a local limit.

(2) Any local limits developed to meet the requirements of paragraphs (b)(1)(i) and (c)(1) of this section shall be:

(i) Consistent with all applicable requirements of 40 CFR part 403 and

(ii) Subject to approval by the Administrator as part of the 301(h) application review. The Administrator may require such local limits to be revised as necessary to meet the requirements of this section or 40 CFR part 403.

(d) Secondary removal equivalency. An applicant shall demonstrate that it achieves secondary removal equivalency through the use of a secondary treatment pilot (demonstration) plant at the applicant's facility which provides an empirical determination of the amount of a toxic pollutant removed by the application of secondary treatment to the applicant's influent where the applicant's influent has not been pretreated. Alternatively, an applicant may make this determination using influent that has received industrial pretreatment, notwithstanding the definition of secondary removal equivalency in § 125.58(w). The NPDES permit shall include effluent limits based on the data from the secondary equivalency demonstration when those limits are more stringent than effluent limits based on State water quality standards or water quality criteria, if applicable, or are otherwise required to assure that all applicable environmental protection criteria are met. Once such effluent limits are established in the NPDES permit, the POTW may either establish local limits or perform additional treatment at the POTW or a combination of the two to achieve the permit limit.