Power Plants: Wastewater Discharge

The Wisconsin DNR administers the National Pollution Discharge Elimination System (NPDES) permit program of the federal Clean Water Act. This law requires that anyone who proposes to discharge pollutants to waters of the state (both surface and ground water) must first obtain a permit, which limits pollutant discharges to protect water quality.

Any proposed discharge permit must include a public notice. In addition to providing comments, five or more individuals may request a public informational hearing, which must be held before the Department makes a final determination on the discharge permit.

In addition to any federal requirements for an industrial category, Wisconsin has numerical standards for many substances, some of which could be of concern at power plants. Examples are chemicals like chlorine that are added to control fouling. These might be present in the blowdown. Wisconsin’s antidegradation law applies to any new discharge, requiring more restrictive limits than those in force for an existing facility.

An additional concern for a steam cycle power plant would be the discharge of heat. Any new plant would be issued a permit that includes heat restrictions to protect aquatic life in the area affected by the discharge.

Power Plant cooling water intakes must be designed to meet state and federal laws to minimize the number of organisms drawn through the power plant cooling system. For example, the velocity of the intake water is limited to protect fish larvae and other small organisms.

For more information on DNR's role in power plant permitting and wastewater discharge please contact:
Duane Schuettpelz
(608) 266-0156
or visit Watershed Management