Jeffrey F. Payne, P.E., BCEE
Reducing the frequency and volume of sanitary sewer overflows and managing wet-weather flows at publicly owned treatment works (POTWs) is fast becoming a top priority for municipalities throughout the country. These have been major goals of the EPA’s National Pollutant Discharge Elimination System (NPDES) program since the early 1990s. Blending of effluents at POTWs during periods of high flow associated with wet weather is a common engineering practice that is used across the country to protect biological treatment processes from damage and to prevent overflows and backups elsewhere in the system. A number of state NPDES authorities, municipal officials, and others have requested clarification of the EPA’s NPDES regulations as they relate to blending scenarios.
The EPA developed the proposed Blending Policy to provide clear, nationally consistent guidance to the interpretation of the NPDES regulations as they relate to the practice of blending. Historically, blending at POTWs has been addressed in a variety of ways by state permitting authorities and EPA regional offices.
Read the full article: Proposed EPA Blending Policy as it Relates to Wet-Weather Management Treatment Alternatives (pdf)
Reprinted with permission from the Florida Water Resources Journal, June 2005