Salmonella: Its Presence in and Removal from a Wastewater System

Salmonella examination of influent and effluent waters of a pollution abatement facility in the Netherlands showed that these bacteria are found regularly in both substances. The difficulties of isolation from heavily contaminated material such as influent are discussed. Three of the 12 serotypes responsible for 95 percent of Salmonellosis in humans in the Netherlands were isolated from each sample, namely, S. typhimurium, S. panama, and S. paratyphi B. In order to test the biosystem of the wastewater treatment plant, experiments with artificial contaminations were performed. It was shown that after contamination of influent with 3 × $10^{11}$ S. utrecht germs, approximately $10^{9}$ S. utrecht germs were isolated from the effluent. Disinfection of effluent is advocated in view of these results.