Biennial Reviews of Sewage Sludge Standards

The U.S. Environmental Protection Agency is required to “review” the sewage sludge regulations at least every two years “for the purpose of identifying additional toxic pollutants and promulgating regulations for such pollutants” [see 33 U.S.C. § 1345(d)(2)(C)]. The biennial review process helps the EPA accomplish this duty.

During the biennial review process, the EPA collects and reviews data on pollutant occurrence in sewage sludge in the United States from publicly available, peer-reviewed literature. A summary of the biennial review process and the data gleaned is published in the biennial report. 

The concentration of pollutants found in sewage sludge varies across space and time, depending on industrial and other inputs to individual WWTPs. The presence of a pollutant in sewage sludge alone does not necessarily mean that there is risk to human health or the environment from its use or disposal. The EPA assesses risk by estimating potential exposures to humans and environmental receptors by modeling the fate and transport of a pollutant through the environment, taking into account different environmental conditions and exposure scenarios, and then estimates risk by comparing those potential exposures to toxicity values.  

• Risk Assessment of Pollutants in Sewage Sludge

Biennial Reviews:

• Biennial Report No. 9 (Reporting Period 2020-2021) and Fact Sheet
• Biennial Report No. 8 (Reporting Period 2018-2019) and Fact Sheet
• Biennial Report No. 7 (Reporting Period 2016–2017) and Fact Sheet
• Biennial Report No. 6 (Reporting Period 2014–2015) and Fact Sheet
• Biennial Report No. 5 (Reporting Period 2012–2013) and Fact Sheet
• Biennial Report No. 4 (Reporting Period 2010–2011) and Fact Sheet
• Biennial Report No. 3 (Reporting Period 2008–2009)
• Biennial Report No. 2 (Reporting Period 2006–2007)
• Biennial Report No. 1 (Reporting Period 2004–2005)