Effluent guidelines

Effluent Guidelines (also referred to as Effluent Limitation Guidelines (ELGs)) are U.S. national standards for wastewater discharges to surface waters and publicly owned treatment works (POTW) (also called municipal sewage treatment plants). The United States Environmental Protection Agency (EPA) issues Effluent Guideline regulations for categories of industrial sources of water pollution under Title III of the Clean Water Act (CWA). The standards are technology-based, i.e. they are based on the performance of treatment and control technologies (e.g., Best Available Technology). Effluent Guidelines are not based on risk or impacts of pollutants upon receiving waters. Since the mid-1970s, EPA has promulgated ELGs for 59 industrial categories, with over 450 subcategories. Effluent Guidelines currently control pollution at approximately 40,000 facilities that discharge directly to the nation's waters, 129,000 facilities that discharge to POTWs, and construction sites. Effluent Guidelines are implemented in water discharge permits issued to facilities through the National Pollutant Discharge Elimination System (NPDES). Regulated pollutants vary by industry category, with effluent limitations typically expressed as mass loadings or concentrations. The regulations cover pollutants for which there are approved analytical testing methods. EPA has published many methods in its regulations, and has approved the use of other methods published by peer-reviewed sources, such as Standard Methods. Although the effluent limitations are based on the performance of control and treatment technologies (and not the impacts to receiving waters), the regulations do not require discharging facilities to use specific technologies. The facilities may choose any technologies to meet the numerical limitations. In the 1972 CWA Congress specified an initial list of categorical regulations that EPA was required to promulgate. The 1977 CWA amendments provided a list of pollutant and pollutant groups to be considered by the agency in developing regulations.