NPDES > Overview

The process for generating electricity often entails using a boiler fired by natural gas or fuel oil to heat water that is converted to steam that, in turn, drives turbines to generate the electricity. In order to ensure the boiler operates as designed, and efficiently, it needs to be cleaned out periodically. Water is used to rinse out the boiler equipment through which steam is generated. Contaminants in the released water (also known as “blowdown water” or “boiler blowdown”) can include dissolved/suspended minerals, heavy metals, corrosion inhibitors, oil or algaecides.

If your school’s power plant generates boiler blowdown and the treated water is discharged to surface water, a National Pollutant Discharge Elimination System (NPDES) permit is required.

As you may know from having visited other locations on your EVC tour, the United States Environmental Protection Agency (EPA) regulates the discharge of water from facilities through provisions of the Clean Water Act, including provisions of the NPDES program. EPA has authorized many states to implement and monitor the NPDES program. NPDES permits establish the level of performance the discharger must maintain and specify monitoring, inspection, and reporting requirements and other actions necessary to achieve compliance. NPDES permits set specific requirements regulating the characteristics of the discharged water based on national technology-based effluent limitations and applicable water quality standards.

Applicability of NPDES requirements to a typical college or university power plant vary greatly depending on the activities or discharges associated with the facility and the interpretation by the state regulatory agency charged with enforcing the Federal NPDES program (in states where that is the case; not all states have been delegated with this authority).

If you have an NPDES permit for surface water discharges or believe one is required for your power plant, continue on to the expanded content to learn more about NPDES permit requirements.