Kinetics of pathogen destruction during storage of dewatered biosolids

The kinetics of pathogen destruction were determined during storage of digested and dewatered wastewater treatment biosolids to obtain relationships between temperature and duration of biosolids storage. Biosolids, seeded with Salmonella typhimurium, Yersinia enterocolitica, Campylobacter jejuni, bacteriophage f2, poliovirus, and Ascaris suum eggs were incubated at 5°, 22°, 38°, and 49.5°C, under both aerobic and anaerobic conditions for up to 62 days. Destruction of pathogens in stored biosolids occurred at all temperatures examined; however, rates increased with increasing temperature. There was no significant difference between the destruction of pathogens under aerobic or anaerobic conditions at all temperatures studied. At 50°C, the decay rate of S. typhimurium, Y. enterocolitica, bacteriophage f2, poliovirus, and A. suum eggs was estimated to be 1.13, 1.10, 1.54, 0.81, and 0.21 log10 reductions per day, respectively.