Related Experiment Video
Updated: Jun 10, 2026

Continuously-stirred Anaerobic Digester to Convert Organic Wastes into Biogas: System Setup and Basic Operation
Published on: July 13, 2012
Kinetics of inactivation of indicator pathogens during thermophilic anaerobic digestion
Sudeep C Popat1, Marylynn V Yates, Marc A Deshusses
1Department of Chemical & Environmental Engineering, University of California, Riverside, CA 92521, USA.
Abstract:
Thermophilic anaerobic sludge digestion is a promising process to divert waste to beneficial use, but an important question is the required temperature and holding time to achieve a given degree of pathogen inactivation. In this study, the kinetics of inactivation of Ascaris suum and vaccine strain poliovirus type 1 (PVS-1), selected as indicators for helminth ova and enteric viruses respectively, were determined during anaerobic digestion at temperatures ranging from 51 to 56 °C. Inactivation of both indicator organisms was fast with greater than two log reductions achieved within 2 h for A. suum and three log reductions for PVS-1, suggesting that the current U.S. regulations are largely conservative. The first-order inactivation rate constants k followed Arrhenius relationship with activation energies of 105 and 39 KJ mol(-1) for A. suum and PVS-1, respectively indicating that A. suum was more sensitive to temperature. Although inactivation was fast, the presence of compounds in the sludge that are known to be protective of pathogen inactivation was observed, suggesting that composition-dependent time-temperature relationships are necessary.
Related Concept Videos
Physical Methods for Controlling Microbial Growth: Temperature
Microbial Wastewater Treatment
Microbes and Methanogenesis
Hyperthermophilic Bacteria
Factors Influencing Microbial Growth: Temperature
Diversity of Archaea I

