Skip common site navigation and headers
United States Environmental Protection Agency
National Pollutant Discharge Elimination System (NPDES)
Begin Hierarchical Links EPA Home > OW Home > OWM Home > NPDES Home > NPDES Permit Program Basics > Secondary Treatment Standards End Hierarchical Links
Applications
 
eNOI
 
Permitted Universe and Backlog Reduction
 
State Program Information
 
Statutes and Regulations
 
Tools for Permit Writers
 
Water Quality and Technology-Based Permitting
 
Integrated Municipal Plans
 
Emerging Topics
 
 
 
NPDES Permit Program Basics Home

 

NPDES Topics Alphabetical Index Glossary About NPDES

Secondary Treatment Standards

OVERVIEW

An important aspect of municipal wastewater is that it is amenable to biological treatment. The biological treatment component of a municipal treatment plant is termed secondary treatment and is usually preceded by simple settling (primary treatment). Secondary treatment standards are established by EPA for publicly owned treatment works (POTWs) and reflect the performance of secondary wastewater treatment plants. These technology-based regulations apply to all municipal wastewater treatment plants and represent the minimum level of effluent quality attainable by secondary treatment, as reflected in terms of 5-day biochemical oxygen demand (BOD5) and total suspended solids (TSS) removal.

The secondary treatment standards also provide for special considerations regarding combined sewers, industrial wastes, waste stabilization ponds, and less concentrated influent wastewater for combined and separate sewers. In addition, the secondary treatment standards also provide alternative standards established on a case-by-case basis for treatment facilities considered equivalent to secondary treatment (trickling filters and waste stabilization ponds).

More detailed information related to secondary treatment standards can be found in the following publication:

U.S. EPA NPDES Permit Writer's Manual (PDF) (37 pp, 166K) - Chapter 5, Section 5.2, provides information related to application of secondary treatment standards for municipal discharges.

Petition Requesting Secondary Treatment Nutrient Limits and Performance Data (PDF) (14 pp, 667K) - On December 14, 2012, EPA responded to a petition from the Natural Resources Defense Council (NRDC) requesting EPA to undertake rulemaking to establish numeric limits for nutrients in discharges from publicly owned treatment works as part of the Agency’s secondary treatment regulations, and to publish information on the performance of secondary treatment at publicly owned treatment works.

Report on the Performance of Secondary Treatment Technology (PDF) (4 pp, 81K) describes the performance achieved by secondary treatment facilities in treating for Total Suspended Solids (TSS), Biochemical Oxygen Demand (BOD5), and carbonaceous BOD5 (cBOD5). This report summarizes data reported in the EPA data bases: Permit Compliance System (PCS); and Integrated Compliance Information System -NPDES (ICIS -NPDES).

National Pollutant Discharge Elimination System Home

NPDES Permit Program Basics Information
Recent Additions

FAQs

Publications

Regulations

Training & Meetings

Links

Contacts

 
 Register to Receive NPDES News Alerts!  

You will need Adobe Reader to view some of the files on this page. Files are best viewed in Internet Explorer and Adobe 8.0 or higher. See EPA's PDF page to learn more.

 

Office of Water | Office of Wastewater Management | Disclaimer | Search EPA

Begin Site Footer

EPA Home | Privacy and Security Notice | Contact Us

Last updated on March 12, 2013 4:00 PM
URL:http://cfpub.epa.gov/npdes/techbasedpermitting/sectreat.cfm