Title 119 - Nebraska Department of Environmental Quality
Chapter 21 - SECONDARY TREATMENT
001 Effluent limitations based on secondary treatment, pursuant to Section 304(d)(1) of the Clean Water Act for publicly owned treatment works shall be achieved from date of permit issuance. The conditions and requirements of 40 CFR part 133 pertaining to Secondary Treatment Regulations are hereby adopted and incorporated by reference.
002 Secondary Treatment. The following describe the maximum level of effluent pollutants allowed for secondary treatment facilities in terms of the parameters BOD, TSS and pH. All requirements for each parameter shall be achieved except as provided in subsections 003, 004 and 005 of this chapter, by all publicly owned treatment works and other discharges of domestic wastewater to waters of the State no later than July 1, 1988.
002.01A The 30-day average shall not exceed 30 mg/l.
002.01B The 7-day average shall not exceed 45 mg/l.
02.01C The 30-day average percent removal shall not be less than 85 percent.
002.01D Where the Department determines sufficient data exists, it may, in lieu of the parameter BOD and the levels of the effluent quality specified in 002.01, substitute the parameter CBOD with the following levels of the CBOD effluent quality provided:
002.01D1. The 30-day average shall not exceed 25 mg/l.
002.01D2. The 7-day average shall not exceed 40 mg/l.
002.01D3. The 30-day average percent removal shall not be less than 85 percent.
002.02 TSS -- For all Mechanical Facilities.
002.02A The 30-day average shall not exceed 30 mg/l.
002.02B The 7-day average shall not exceed 45 mg/l.
002.02C The 30-day average percent removal shall not be less than 85 percent.
02.03 SS -- For Lagoon Facilities.
002.03A The 30-day average shall not exceed 80 mg/l.
002.03B The maximum for any one day of discharge shall not exceed 120 mg/l.
003 Treatment Equivalent to Secondary Treatment.
This section describes the maximum level of effluent pollutants allowed for trickling filters (TF) facilities in terms of the parameters BOD, SS and pH.
003.01 BOD
003.01A The 30-day average shall not exceed 45 mg/l.
003.01B The 7-day average shall not exceed 65 mg/l.
003.01C The 30-day average percent removal shall not be less than 65 percent.
003.01D Where the Department determines sufficient data exists, it may, in lieu of the parameter BOD and the levels of the effluent quality specified in 003.01, substitute the parameter CBOD with the following levels of the CBOD effluent quality provided:
003.01D1. The 30-day average shall not exceed 40 mg/l.
003.01D2. The 7-day average shall not exceed 60 mg/l.
003.01D3. The 30-day average percent removal shall not be less than 65 percent.
003.02 TSS
003.02A The 30-day average shall not exceed 45 mg/l.
003.02B The 7-day average shall not exceed 65 mg/l.
003.02C The 30-day average percent removal shall not be less than 65 percent.
003.04 Permit Adjustments
003.04A. The Department may require more stringent limitations when adjusting permits if:
003.04A1. For existing facilities the Department determines that the 30-day average and 7-day average BOD and SS effluent values that could be achievable through proper operation and maintenance of the treatment works, based on an analysis of the past performance of the treatment works, would enable the treatment works to achieve more stringent limitations; or
003.04A2. For new facilities, the Department determines that the 30-day average and 7-day average BOD and SS effluent values that could be achievable through proper operation and maintenance of the treatment works, considering the design capability of the treatment process and geographical and climatic conditions, would enable the treatment works to achieve more stringent limitations.
004 Combined Sewers
Secondary treatment may not be capable of meeting the percentage removal requirements of subsections 002.01C, 002.01D3, 002.02C, 003.01C, 003.01D3, and 003.02C above during wet weather in treatment works which receive flows from combined sewers (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 that level should be.
005 Industrial Wastes.
For certain industrial categories, the discharge to waters of the State of biochemical oxygen demand and suspended solids permitted by any effluent limitation in an issued NPDES Permit may be less stringent than the values in subsections 002.01, 002.02, 002.03, 003.01 and 003.02 of this chapter. In cases when wastes would be introduced from such an industrial category into a publicly owned treatment works, the values for biochemical oxygen demand and suspended solids in subsections 002.01, 002.02, 002.03, 003.01, and 003.02 of this chapter may be adjusted proportionately.
006 Sampling and Test Procedures.
006.01 Sampling and test procedures for pollutants listed in subsection 001 above shall be in accordance with 40 CFR part 136 incorporated by reference.
006.02 Chemical oxygen demand (COD) or total organic carbon (TOC) may be substituted for biochemical oxygen demand (BOD) when a long term BOD:COD or BOD:TOC correlation has been demonstrated.
Enabling Legislation: Neb. Rev. Stat. §81-1505
Legal Citation: Title 119, Chapter 21, Nebraska Department of Environmental Quality
Nebraska Department of Environmental Quality
1200 "N" Street, Suite 400
P.O. Box 98922
Lincoln, Nebraska 68509
(402) 471-2186