Developing Better Indicators for Pathogen Presence in Sewage Sludge

Developing Better Indicators for Pathogen Presence in Sewage Sludge

Developing Better Indicators for Pathogen Presence in Sewage Sludge


Today, more than eight million tons of biosolids are generated annually for land application nationwide.  These biosolids contain beneficial plant nutrients, soil conditioners, and may contain pathogenic bacteria, viruses, protozoa and parasites.  The fate of pathogens is a concern for biosolids generators, applicators, and the public.  The ability to detect the presence of microbial pathogens and the resulting health risks in biosolids is a significant issue confronting the wastewater industry.  Ideally, wastewater treatment plants should be able to monitor for specific pathogens in biosolids.  Since it is almost impossible to detect and quantify the presence of all possible pathogens in waste matrices, there is a compelling need to identify a suite of indicators that can be used to predict the presence of pathogenic microorganisms in biosolids. The overall objective of this project was to identify those pathogens and surrogate indicator organisms that are at the highest density in raw sludge and determine their time-temperature-pH relationships in the laboratory under controlled conditions.