[Disinfection of sewage sludge by aerobic thermophilic treatment]

Thermal stabilization of sewage sludge, performed in a pilot plant under aerobic conditions, resulted in microbiological and virological decontamination. A minimum temperature of 50 degrees C was necessary to inactivate coliform bacteria, E. coli and Salmonella sp. The rate of inactivation of these bacteria and enteric viruses was dependent on the concentration of microbes in the raw sludge, the temperature and the detention time of the sludge. At a temperature of 56 +/- 1 degree C, which was achieved by autogeneous heating of the processed sludge, pathogens were usually inactivated after two hours, but the time required for inactivation was shorter when the temperature was higher.