Beneath the streets of every city and our many smaller communities, a system of sewers and lift stations convey wastewater away from our homes, industries, offices and other businesses. This wastewater, which may contain a variety of domestic, commercial and industrial wastes, flows through the public sewer systems to a publicly owned treatment works (POTW). At the POTW pollutants are removed and the cleansed water is discharge into an adjacent water body, such as a river, bay, lake or ocean. The residues of the treatment process (sludge) are either used productively as a soil conditioner or disposed of as a solid waste.

Industrial Users (IUs) are only one of many sources of wastewater discharged to the public sewer system. However, the wastewater discharged by IUs are often contaminated by a variety of toxic or otherwise harmful substances not common to other sources. These wastes can pose serious hazards. Because the public sewer collection systems and POTWs have not been designed to treat them, industrial wastes can damage the sewers and interfere with the operation of a POTW. These wastes may pass through the entire system untreated, resulting in the contamination of the nearby water body causing an environmental risk, and increase the cost of sludge treatment and disposal.
The undesirable effects resulting from the discharge of industrial wastewater into the public sewer system can be prevented. IUs using proven pollution prevention control technologies can remove pollutants from their wastewater before discharging them to the public sewer system and the POTW. This practice is called “pretreatment.”
Industry is already pre-treating its wastewater in many communities. The National Pretreatment Program, a cooperative effort of federal, state, and local officials, is implementing this practice on a nationwide basis. By reducing the level of pollutants discharged by industry into the public sewer systems, the program ensures that industrial development vital to the economic well being of our communities will be compatible with a healthy environment.