title: Occurrence of Salmonella in a chemical wastewater treatment plant.
abstract: In a chemical wastewater treatment plant located in a pig slaughterhouse, quantitative examinations for Salmonellae were carried out on samples collected from the balancing tank and the proper treatment system. The wastewater coming from the slaughterhouse (influent balancing tank) was highly contaminated: 0.95 log to 2.46 log Salmonellae per ml. During the storage of the wastewater in the balancing tank, the number of Salmonellae increased which resulted in a statistically higher contamination of the effluent. Two sources were detected, namely the sludge and the water from the balancing tank. From the sludge containing high numbers of Salmonellae, wastewater can be contaminated. On the other hand it was shown that at 18-20 degrees C (temperature of the wastewater in the balancing tank) a fast increase of Salmonella is possible in the wastewater. The reduction of Salmonella by chemical treatment process depended on the working-pH. By a pH from 2.3 to 2.5, the mean minimal reduction was at least 4.84 log per ml. When the pH increased somewhat, the removal efficiency decreased to an average of 3.20 log per ml.
mesh_terms: D000003:Abattoirs; D000818:Animals; D004203:Disinfection; D006863:Hydrogen-Ion Concentration; D012475:Salmonella / Q000145:classification / Q000302:isolation & purification*; D012703:Serotyping; D012722:Sewage; D013552:Swine; D014865:Waste Disposal, Fluid; D014871:Water Microbiology
chemical_list: D012722:Sewage