Fate of Coxsackievirus B3 During Aerobic and Anaerobic Sludge Stabilization‡

Abstract

The survival of viruses has been measured in bench scale stabilization units. A strain of coxsackievirus B3 was seeded in sludge and recoveries were measured at intervals from 1 h to 70 days. Mesophilic anaerobic digesters were operated at 33°C with detention times of 15 and 33 days. Thermophilic digesters were operated at 50, 53 and 56°C with detention times of 4 to 10 days. Aerobic stabilization was carried out at 5, 20 and 33"C (with detention times of 30, 20 and 15 days, respectively. Controls were run at the same temperature in Hanks' balanced salt solution. Inactivation of virus was slower in thermophilic anaerobic digesters than in the controls and the rate of inactivation often fell off with time (tailing). In mesophilic anaerobic digesters and aerobic stabilization units, the rates of inactivation were greater than in the controls. The rates are, nevertheless, very much faster at the higher temperatures. Up to 3 log units of destruction might be obtained if the interval between feeding and drawing at 53°C were 10 h and 5 log units if it were 24 h. Retention times would have to be serveral days at 33°C to obtain similar reduction in virus content.