Defining Wastewater & Wastewater Treatment

Wastewater treatment refers to the physical, chemical, and biological processes used to remove pollutants from wastewater before discharging it into a body of water. Since the Clean Water Act was issued in 1972, there are now more than 16,000 publicly-owned wastewater treatment plants (POWTs) in operation in the United States.

Approximately 255,000 million gallons per day (mgd) of industrial wastewater—treated by chemical, physical, and biological processes—is discharged daily into U.S. waterways. Industries commonly reuse wastewater and process water as water availability becomes scarce, and they are challenged to provide environmentally sustainable wastewater treatment while reducing compliance costs and maintaining value for their businesses. Source: Water Environment Federation (

Industrial vs. Municipal 

Industrial Wastewater treatment covers the mechanisms and processes used to treat wastewater that is produced as a by-product of industrial or commercial activities. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to surface water in the environment.

Municipal Wastewater (also called sewage) is usually conveyed in a combined sewer or sanitary sewer, and treated at a wastewater treatment plant. Treated wastewater is discharged into receiving water via an effluent pipe. Wastewater generated in areas without access to centralized sewer systems rely on on-site wastewater systems. These typically comprise a septic tank, drain field, and optionally an on-site treatment unit.

The Clean Water Act (CWA) is the primary federal law in the U.S. governing water pollution. Its objective is to restore and maintain the chemical, physical, and biological integrity of the nation’s waters by preventing pollution, providing assistance to publicly owned treatment works POWTs) for the improvement of wastewater treatment, and maintaining the integrity of wetlands. It is one of the country’s first and most influential modern environmental laws. As with many other major U.S. federal environmental statutes, it is administered by the U.S. Environmental Protection Agency (EPA), in coordination with state governments.

Technically, the name of the law is the Federal Water Pollution Control Act. The first FWPCA was enacted in 1948, but took on its modern form when completely rewritten in 1972 in an act entitled the Federal Water Pollution Control Act Amendments of 1972. Major changes have subsequently been introduced via legislation including the Clean Water Act of 1977 and the Water Quality Act of 1987. The Clean Water Act does not directly address ground-water contamination. Groundwater protection provisions are included in the Safe Drinking Water Act, Resource Conservation and Recovery Act, and the Superfund act.

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