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We regulate wastewater released from municipal and industrial treatment plants using wastewater discharge permits.

The permits require facilities and municipalities to:

  • Treat their wastewater.
  • Control the discharge quality and quantity.

Wastewater discharge permits are required if your facility or municipality disposes of wastewater into waters of the state. Waters of the state include rivers, lakes, streams, and groundwater.

Some industrial facilities do not discharge to a water of the state. Rather, the industry discharges wastewater to a municipal sanitary sewer that takes sewage to a treatment plant for pollutant removal prior to disposal. This still requires a discharge permit.

What is wastewater?

Wastewater comes from water used in industries, businesses, or homes. After use in a home or in an industrial or commercial activity, this water picks up pollutants and becomes wastewater.

What is wastewater treatment?

All wastewater must receive treatment before it can be discharged into a water of the state to protect human health and aquatic life.

Treatment methods include physical, chemical, and biological processes:

  • Physical treatment removes solids from the raw (untreated) wastewater with processes like screening or settling.
  • Chemical treatment involves the addition of chemicals that change the water chemistry to help increase settling rates or remove specific pollutants.
  • Biological treatment uses special microorganisms to consume organics.

Treatment plants use different combinations of these three treatment process categories. It all depends on the wastewater source and level of treatment required by the discharge permit.