648 Fermentation and Biochemical Engineering Handbook NPDES permits are available from the EPA or from a state authorized toissue NPDES permits. Upon authorization of a state NPDES program, the state is primarily responsible for issuing permits and administrating the NPDES permit program. State NPDES programs must be consistent with minimum federal requirements Under the Federal Clean Water Act's National Pollutant Discharge Elimination System(NPDES) permitting program, two approaches exist for controlling pollutant discharges from individual and municipal waste treatment facilities: the technology-based approach and the water-quality based approach Technology-based controls consist of uniform EPA established stan dards of treatment that apply to direct industrial dischargers and publicly owned waste water treatment works. These uniform standards known as effluent limitations, generally are in the heart of npdeS permits and place numeric limits on the amount of effluent pollutant concentrations permitted at the point of discharge(end-of-pipe Industrial effluent limitations are derived from technologies that are available for treating the effluent and removing pollutants, and also are based on considerations of cost and economic achievability. The water quality based approach is used to develop stricter effluent limitations where technol ogy based controls will not be stringent enough to ensure that waters can support their intended uses 3. 2 Effluent Limitations EPa and the states issue waste water discharge permits to individual factories, power plants, refineries, and other private companies, based on nationaleffluent limitation guidelines. These are based on chemical, physical and biological characteristics of effluent that industry may dump into water ways. An effluent limitation guideline sets the degree of reduction of a pollutant that can be achieved through the application of various levels of technology, Aneffluent limitation is a restriction on the amount of a pollutant that can be released from a point source into a water body. The discharge of waste water containing metals has effluent limitations, standards, or prohi bitions, expressed in terms of the total metal, that is, the sum of the dissolved and suspended fractions of the metal648 Fermentation and Biochemical Engineering Handbook NPDES permits are available from the EPA or from a state authorized to issueNPDES permits. Upon authorization of a state NPDES program, the state is primarily responsible for issuing permits and administrating the NPDES permit program. State NPDES programs must be consistent with minimum federal requirements. Under the Federal Clean Water Act’s National Pollutant Discharge Elimination System (NPDES) permitting program, two approaches exist for controlling pollutant discharges from individual and municipal waste water treatment facilities: the technology-based approach and the water-quality based approach Technology-based controls consist of uniform EPA established stan￾dards of treatment that apply to direct industrial dischargers and publicly owned waste water treatment works. These uniform standards, known as effluent limitations, generally are in the heart of NPDES permits and place numeric limits on the amount of effluent pollutant concentrations permitted at the point of discharge (end-of-pipe). Industrial effluent limitations are derived from technologies that are available for treating the effluent and removing pollutants, and also are based on considerations of cost and economic achievability. The water quality based approach is used to develop stricter effluent limitations where technol￾ogy based controls will not be stringent enough to ensure that waters can support their intended uses. 3.2 Emuent Limitations EPA and the states issue waste water discharge permits to individual factories, power plants, refineries, and other private companies, based on national effluent limitation guidelines. These are based on chemical, physical and biological characteristics of effluent that industry may dump into water ways. An effluent limitation guideline sets the degree of reduction of a pollutant that can be achieved through the application of various levels of technology. An effluent limitation is a restriction on the amount of a pollutant that can be released from a point source into a water body. The discharge of waste water containing metals has effluent limitations, standards, or prohi￾bitions, expressed in terms of the total metal, that is, the sum of the dissolved and suspended fractions of the metal