National pollutant discharge elimination system

The National Pollutant Discharge Elimination System (NPDES) seeks to end the discharge of all types of industrial, municipal, and agricultural waste from point sources into American waters. These point sources include industrial facilities and publicly owned treatment works (POTWs), as well as runoff from urban areas.

The NPDES was established by the Federal Water Pollution Control Act Amendments of 1972 and was expanded under the Water Quality Act of 1987. Most NPDES programs are administered by the states, under the direction of the Office of Wastewater Management of the U. S. Environmental Protection Agency (EPA).

Nationwide more than 400,000 facilities are required to obtain NPDES permits. NPDES permits usually license a facility to discharge a given amount of a pollutant under specific conditions, although permits also are granted for other types of waste disposal. Permits are required only for facilities that discharge directly into bodies of water. The NPDES National Pretreatment Program regulates indirect discharges, such as discharges to POTWs. Although the NPDES encompasses all of the nation's surface waters, including wetlands and seasonal streams, discharges into ground water that is not connected to surface water are not regulated unless required by the state. Individual permits are issued to a single facility for a maximum of five years. General permits license multiple facilities that have similar types of discharge within a specific geographical area. Most agricultural facilities, with the exception of concentrated-animalfeeding facilities, are exempt from NPDES regulations.

NPDES permits require that discharges be treated using the best technology available. If these technology-based standards do not protect the water, water-qualitybased standards must be met instead. Permits may contain both technology-based limits, such as a nationwide limit on total suspended solids in a discharge, and water-qualitybased limits, such as ammonia limitations based on aquatic toxicity. Permits issued by the EPA must meet state water-quality standards and local discharge limits. Permits include monitoring and reporting requirements and draft permits are open for public comment.

The NPDES initially focused on controlling the discharge of conventional pollutants such as suspended solids, oil and grease, and disease-causing organisms. By 1989 facilities were required to meet "Best Conventional Pollutant Control Technology" (BCT) limits, as well as "Best Available Technology Economically Achievable" (BAT) limits for the discharge of toxic and non-conventional pollutants. Toxic and priority pollutants include 126 metals, organic substances, and pollutant classes. Non-conventional pollutants include nitrogen , phosphorus , chlorine , and ammonia, as well as parameters such as whole effluent toxicity. BAT standards require facilities to utilize the best control and treatment methods that are achievable. Unlike earlier NPDES standards, the benefits do not have to be weighed against the costs of control and treatment.

NPDES permits typically require POTWs to provide physical separation and settling of wastes, biological treatment, and disinfection. The NPDES also regulates sludge from POTWs, as well as municipal separate storm sewer systems and combined sewer overflow systems. The latter discharge untreated effluent during storms. Polluted storm water discharges include runoff from land, streets, parking lots, and building roofs. Industrial storm-water discharges must meet both water-quality-based standards and the storm-water equivalents of BCT and BAT standards. By March 2003 NPDES storm water permits will be required for construction sites of at least one acre, as well as some smaller sites.

The NPDES has significantly reduced the discharge of pollutants into American waterways and has brought about major improvements in the quality of the nation's water resources . In 1972 only one-third of these waters were safe for swimming and fishing compared with two-thirds in 2001. Wetlands loss has been reduced from 460,000 acres annually to 70–90,000 acres per year. Soil erosion from agricultural runoff has been reduced by one billion tons annually. Nitrogen and phosphorous levels in waterways have decreased. Modern wastewater treatment facilities now serve 173 million people, compared to only 85 million in 1972. As of 2001, more than 50 categories of industry and hundreds of thousands of businesses, as well as more than 16,000 municipal sewage treatment systems, were in compliance with the NPDES standards.

However the remaining sources of water pollution are more difficult to regulate. The EPA estimates that over 20,000 river sections, lakes, and estuaries, including about 300,000 miles of shoreline, are polluted. The vast majority of the American population lives within 10 miles of these waters. The millions of smaller sources of pollution are varied and less amenable to available technological solutions. These include hundreds of thousands of storm-water sources and about 450,000 animal-feeding operations. Therefore the NPDES is focusing more on the pollution problems of individual watersheds, developing total maximum daily loads, or pollution budgets, for up to 40,000 bodies of water and rivers segments.

[Margaret Alic Ph.D. ]

RESOURCES

PERIODICALS

Treadway, Elizabeth, Andrew Reese, and Douglas Noel. "EPA Finalizes Phase II Regs." The American City and County 115, no. 4 (March 2000): 44–9.

OTHER

Office of Wastewater Management. Water Permitting 101. U.S. Environmental Protection Agency. [cited May 25, 2002]. <www.epa.gov/npdes/pubs/101pape.htm>.

Office of Water. Wastewater Primer. U.S. Environmental Protection Agency. [cited May 26, 2002]. <www.epa.gov/npdes/pubs/primer.pdf>.

Water Permits Division, Office of Water. Protecting the Nation's Waters Through Effective NPDES Permits: A Strategic Plan, FY 2001 and Beyond. U. S. Environmental Protection Agency. June 2001 [cited May 25, 2002]. <www.epa.gov/npdes/pubs/strategicplan.pdf>.

ORGANIZATIONS

Friends of the Earth, 1025 Vermont Avenue, NW, Washington, DC, USA 20005, (202) 783-7400, Fax: (202) 783-0444 , Toll Free: (877) 843-8687, Email: [email protected], <www.foe.org>

Office of Wastewater Management, U.S. Environmental Protection Agency, Mail Code 4201, 401 M Street, SW, Washington, DC, USA 20460, (202) 260-5922, Fax: (202) 260-6257, <www.epa.gov/npdes>