The presence of large numbers of enteric viruses in wastewaters has resulted in concern regarding their significance and consequence for humans. This study describes virus isolation methods and a new and efficient multiple extraction-concentration procedure for the enumeration of viruses in wastewater sludges.

As an integral part of a comparison of isolation procedures, several anionic surfactants were examined for extraction of enteric viruses from primary wastewater sludges. Plaquing efficiencies for poliovirus-2 and coxsackievirus B-2 on several common cell lines were determined. The results demonstrate: (1) that the total poliovirus burden in primary sludge may be determined by means of an efficient extraction procedure followed by concentration by centrifugation, and (2) that dewatering by evaporation is virucidal.

The methods described should be useful in monitoring studies of wastewater treatment plant functions, sanitary landfil I operations, or any other areas where health assessments are required for the disposal of wastewater sludges.