Code of Maine Rules › 06 - DEPARTMENT OF ENVIRONMENTAL PROTECTION › 096 - DEPARTMENT OF ENVIRONMENTAL PROTECTION - GENERAL › Chapter 525 - EFFLUENT GUIDELINES AND STANDARDS › Sec2 096-525-3 - Secondary Treatment [see 40 CFR 133] › Subsection 096-525-3-IV - Special considerations [see 40 CFR 133.103]

Current through 2024-29, July 17, 2024
(a) Combined sewers. Treatment works subject
				  to this Chapter may not be capable of meeting the percentage removal
				  requirements established under Subsection III(a)(3) and Subsection III(b)(3),
				  or Subsections VI(a)(3) and Subsection VI(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 decision 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 navigable waters of BOD-5
				  and SS permitted under sections 301(b)(1)(A)(i), (b)(2)(E) or 306 of the Act
				  may be less stringent than the values given in Subsection III(a)(1), Subsection
				  III(a)(4)(i), Subsection III(b)(1), Subsection VI(a)(1), Subsection VI(b)(1)
				  and Subsection VI(e)(1)(i). In cases when wastes would be introduced from such
				  an industrial category into a publicly owned treatment works, the values for
				  BOD-5 and SS in Subsection III(a)(1), Subsection III(a)(4)(i), Subsection
				  III(b)(1), Subsection VI(a)(1), Subsection VI(b)(1), and Subsection VI(e)(1)(i)
				  maybe 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 sections 301(b)(1)(A)(i), 301(b)(2)(E) or
				  306 of the Act if such industrial category were to discharge directly into the
				  navigable waters, 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
				  BOD-5 or SS in Subsection III(a)(2), Subsection III(a)(4)(ii), Subsection
				  III(b)(2), Subsection VI(a)(2), Subsection VI(b)(2), and Subsection
				  VI(e)(1)(ii) should be adjusted proportionately.
(c) Waste stabilization ponds. The
				  Department, subject to EPA approval, is authorized to adjust the minimum levels
				  of effluent quality set forth in Subsections VI(b)(1), (b)(2), and (b)(3) for
				  treatment works subject to this Chapter, to conform to the SS concentrations
				  achievable with waste stabilization ponds, provided that: (1) Waste
				  stabilization ponds are the principal process used for secondary treatment; and
				  (2) operation and maintenance data indicate that the SS values specified in
				  Subsections VI(b)(1),(b)(2), and (b)(3) cannot be achieved. The term ``SS
				  concentrations achievable with waste stabilization ponds'' means a SS value,
				  determined by 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 BOD-5 specified in Subsection
				  VI(a)(1).
(d) Less concentrated
				  influent wastewater for separate sewers. The Department is authorized to
				  substitute either a lower percent removal requirement or a mass loading limit
				  for the percent removal requirements set forth in Subsection III(a)(3),
				  Subsection III(a)(4)(iii), Subsection III(b)(3), Subsection VI(a)(3),
				  Subsection VI(b)(3) and Subsection VI(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 standards, 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 is authorized to substitute either a lower percent removal
				  requirement or a mass loading limit for the percent removal requirements set
				  forth in Subsection III(a)(3), Subsection III(a)(4)(iii), Subsection III(b)(3),
				  Subsection VI(a)(3), Subsection VI(b)(3) and Subsection VI(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. The determination of whether
				  the less concentrated wastewater results from excessive infiltration is
				  discussed in
				  40
				  CFR 35.2005(b)(28), plus the
				  additional criterion that either 40 gallons pre capita per day (gpcd) or 1500
				  gallons per inch diameter per mile of sewer (gpdim) may be used as the
				  threshold value for that portion of the dry weather base flow attributed to
				  infiltration. If the less concentrated influent wastewater is the result of
				  clear water industrial discharges, then the treatment works must control such
				  discharges pursuant to Chapter 528.