Wastewater FAQs


Frequently Asked Questions about Wastewater

Q: How is wastewater treated in the U.S.?

Wastewater treatment facilities in the United States receive wastewater from domestic and industrial sources, sometimes including stormwater runoff. Using a combination of physical, chemical, and biological processes, these facilities treat wastewater to levels that meet stringent federal standards which are designed to protect public health and the biological integrity of receiving waters. Although, the complexity of the processes may vary, there are four basic stages including primary treatment, secondary treatment, tertiary treatment, and disinfection/discharge. Click here for a step-by-step schematic.

Q: Does WEF have a list of wastewater treatment plants in the U.S.?

A: WEF recommends contacting U.S. EPA’s Office of Water Resource Center for the latest information. The center is a contractor-operated facility that provides library and information services to the public and EPA staff regarding Office of Water programs.

24-hour Voicemail: +1-202-260-7786
24-hour Fax: +1-202-260-0386
Send e-mail inquiries to: center.water-resource@epa.gov

Q: How does wastewater treatment in the U.S. differ from Europe and other countries?

The flow scheme of wastewater treatment plants is basically the same for all countries.

Q: What is water reuse and recycling?

Water reuse is a process that uses highly treated wastewater in place of potable or drinking water for various purposes including: landscape and agricultural irrigation; heating and cooling; industrial processing; wetland habitat creation, restoration and maintenance; and groundwater recharge. The majority of states in the U.S. have established criteria or guidelines for the beneficial use of recycled water.

Q: What is "point source" pollution?

A: Point source pollution originates from a specific locale, such as a factory discharge pipe. Point source pollution is typically easy to locate and control.

Q: What is "non-point" source pollution?

A: Non-point source pollution comes from various land use practices, air pollutants, and sewer overflows -- plus daily human activity. It is harder to control non-point sources of pollution. An example includes excess farm and lawn nutrients moving throughout the soil and into the groundwater, or the pollutants enter local waters directly through runoff during heavy rains, causing dangerous algal blooms.

Q: What are biosolids and biosolids recycling?

A: Biosolids are a safe and beneficial resource composed of essential plant nutrient and organic matter that is recovered from the treatment of domestic sewage in a wastewater treatment facility.  Biosolids can be recycled and applied as fertilizer to improve and maintain productive soils and to stimulate plant growth. Farmers and gardeners have been recycling biosolids for ages. Biosolids are also used to fertilize gardens and parks and to reclaim mining sites.  They are carefully monitored and must be used in accordance with regulatory requirements.