Mixed Liquor Fermentation and Other Alternatives for Providing VFA to EBPR Processes

Abstract

Fermentation of primary sludge to generate a source of volatile fatty acids for enhanced biological phosphorus removal processes is a well-established practice that has been in use since the 1970s. At wastewater treatment plants that do not have primary clarifiers, fermentation of activated sludge solids can offer a promising alternative. This paper provides a review of mixed liquor and return activated sludge solids fermentation configurations along with options for fermenting raw wastewater solids, fermentation of external carbon sources, and utilization of sludge treatment liquors to provide the necessary readily biodegradable carbon source to support EBPR operation.