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The removal of Salmonella enteritidis in activated sludge
Author(s) -
Yaziz M.I.,
Lloyd B.J.
Publication year - 1982
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1982.tb04673.x
Subject(s) - activated sludge , aeration , salmonella , chemistry , salmonella enteritidis , protozoa , aerated lagoon , microbiology and biotechnology , giardia , adsorption , sodium , chromatography , bacteria , biology , environmental engineering , wastewater , environmental science , organic chemistry , genetics
Salmonella destruction efficiencies of 99% were obtained after 10 h aeration at 15°C in a laboratory model of the activated sludge process. This study demonstrated that, in a batch process, the removal of salmonellas occurred in three phases. (i) By 4 h, 90% of the original inoculum had disappeared from the activated sludge, probably due mainly to predation by ciliated protozoa. The remaining 10% was distributed between the liquid phase (approximately 90%) and the sludge floc (approximately 10%). (ii) During the next 2 h this situation was inverted so that, by 6 h, more than 80% of the remaining salmonellas were then adsorbed to floc, leaving less than 20% in liquid suspension. (iii) From 6 h onwards there was a much slower decline of the remaining salmonellas attached to floc. The addition of dioctyl sodium sulphosuccinate after 4 h, inactivated the ciliated protozoa populations and completely eliminated the continued reduction of salmonellas from activated sludge observed previously.