Sanitary aspects of sludge treatment

Sludges are treated to reduce their water content and organic matter content. They may also require disinfection. The purpose of this study, is to compare the efficiency of various sludge treatments, viz; dehydration, stabilization and disinfection. The pathogenic microorganisms in sludge survive in unfavourable conditions and their concentration is generally low. Their total removal is hardly compatible with technological and economic necessities. Leclercet al. (1970b) have set forth the reasons which would lead us to codify the bacteriological control over various treatment processes. In this connection, it seems to us essential that information is required on Salmonella, total enterobacteria and on the total count of bacteria. The techniques used have already been described (Leclercet al., 1970a–c, 1971).