S.C. Code Regs. § § 61-9.133.103

Current through Register Vol. 48, 12, December 27, 2024

Section 61-9.133.103 - Special considerations

(a) Combined sewers. Treatment works subject to this part may not be capable of meeting the percentage removal requirements established under section133.102(a)(3)(a)(3) and section133.102(b)(3)(b)(3), or section133.105(a)(3)(a)(3) and section133.105(b)(3)(b)(3) during wet weather where the treatment works receive flows from combined sewers (i.e., sewers which are designed to transport both storm water and sanitary sewage). For such treatment works, the decisions must be made on a case-by-case basis as to whether any attainable percentage removal level can be defined, and if so, what the level should be.

(b) Industrial wastes. For certain industrial categories, the discharge to waters of the State of BOD₅ and TSS permitted under sections301(b)(1)(A)(i), (b)(2)(E)(b)(1)(A)(i), (b)(2)(E) or 306 of the CWA may be less stringent than the values given in section133.102(a)(1)(a)(1), section133.102(a)(4)(i)(a)(4)(i), section133.102(b)(1)(b)(1), section133.105(a)(1)(a)(1), section133.105(b)(1)(b)(1) and section133.105(e)(1)(i)(e)(1)(i). In cases when wastes would be introduced from such an industrial category into a publicly owned treatment works, the values for BOD₅ and TSS in section133.102(a)(1)(a)(1), section133.102(a)(4)(i)(a)(4)(i), section133.102(b)(1)(b)(1), section133.105(a)(1)(a)(1), section133.105(b)(1)(b)(1), and section133.105(e)(1)(i)(e)(1)(i) may be adjusted upwards provided that:

(1) The permitted discharge of such pollutants, attributable to the industrial category, would not be greater than that which would be permitted under sections301(b)(1)(A)(i)(b)(1)(A)(i), 301(b)(2)(E) or 306 of the CWA if such industrial category were to discharge directly into the waters of the State, and

(2) The flow or loading of such pollutants introduced by the industrial category exceeds 10 percent of the design flow or loading of the publicly owned treatment works. When such an adjustment is made, the values for BOD₅ or TSS in section133.102(a)(2)(a)(2), section133.102(a)(4)(ii)(a)(4)(ii), section133.102(b)(2)(b)(2), section133.105(a)(2)(a)(2), section133.105(b)(2)(b)(2), and section133.105(e)(1)(ii)(e)(1)(ii) shall be adjusted proportionately.

(c) Waste stabilization ponds.

(1) The Department, is authorized to adjust the minimum level of effluent quality set forth in section133.105(b)(1), (b)(2), and (b)(3)(b)(1), (b)(2), and (b)(3) for treatment works subject to this part, to conform to the suspended solids concentrations achievable with waste stabilization ponds, provided that:

(A) Waste stabilization ponds including aerated lagoon systems are the principal process used for secondary treatment; and

(B) Operation and maintenance data indicate that the TSS values specified in section133.105(b)(1), (b)(2), and (b)(3)(b)(1), (b)(2), and (b)(3) cannot be achieved.

(2)

(A) The term "TSS concentrations achievable with waste stabilization ponds" means a TSS value, determined by the Regional Administrator or the Department, subject to EPA approval, which is equal to the effluent concentration achieved 90 percent of the time within a State or appropriate contiguous geographical area by waste stabilization ponds that are achieving the levels of effluent quality for BOD₅ specified in section133.105(a)(1)(a)(1).

(B) Allowable limits:

(i) The 30-day average shall not exceed 90 mg/l.

(ii) The 7-day average shall not exceed 135 mg/l.

(d) Less concentrated influent wastewater for separate sewers. The Department may substitute either a lower percent removal requirement or a mass loading limit for the percent removal requirements set forth in section133.102(a)(3)(a)(3), section133.102(a)(4)(iii)(a)(4)(iii), section133.102(b)(3)(b)(3), section133.105(a)(3)(a)(3), section133.105(b)(3)(b)(3) and section133.105(e)(1)(iii)(e)(1)(iii) provided that the permittee satisfactorily demonstrates that:

(1) The treatment works is consistently meeting, or will consistently meet, its permit effluent concentration limits but its percent removal requirements cannot be met due to less concentrated influent wastewater,

(2) To meet the percent removal requirements, the treatment works would have to achieve significantly more stringent limitations than would otherwise be required by the concentration-based standard, and

(3) The less concentrated influent wastewater is not the result of excessive I/I. The determination of whether the less concentrated wastewater is the result of excessive I/I will use the definition of excessive I/I in 40 CFR 35.2005(b)(16) plus the additional criterion that inflow is non-excessive if the total flow to the POTW (i.e., wastewater plus inflow plus infiltration) is less than 275 gallons per capita per day.

(e) Less concentrated influent wastewater for combined sewers during dry weather. The Department, subject to EPA approval, is authorized to substitute either a lower percent removal requirement or a mass loading limit for the percent removal requirements set forth in section133.102(a)(3)(a)(3), section133.102(a)(a)(4(iii), section133.102(b)(3)(b)(3), section133.105(a)(3)(a)(3), section133.105(b)(3)(b)(3) and section133.105(e)(1)(iii)(e)(1)(iii) provided that the permittee satisfactorily demonstrates that:

(1) The treatment works is consistently meeting, or will consistently meet, its permit effluent concentration limits, but the percent removal requirements cannot be met due to less concentrated influent wastewater;

(2) To meet the percent removal requirements, the treatment works would have to achieve significantly more stringent effluent concentrations than would otherwise be required by the concentration-based standards; and

(3) The less concentrated influent wastewater does not result from either excessive infiltration or clear water industrial discharges during dry weather periods. If the less concentrated influent wastewater is the result of clear water industrial discharges, then the treatment works must control such discharges pursuant to R.61-9.403.

S.C. Code Regs. § 61-9.133.103