We investigated the variations in the numbers of the main groups of indicators of fecal contamination (fecal coliforms, fecal streptococci, and sulfite-reducing clostridia) during various treatments to which cattle slurry was subjected on a farm and in an anaerobic digester in the laboratory. The results indicated that: anaerobic digestion at 35°C for 20 days in a farm, plug-flow, digester produced a reduction (-1 or 2 log10) in the coliform and streptococcus numbers and an increase in the sulfite-reducing clostridia. When the same materials were also subjected to batch anaerobic digestion at ambient temperatures, a drastic reduction (-4 log10) was noted in the numbers of fecal coliforms, a smaller decrease (-3 log10) in the fecal streptococci, but only a slight variation in the clostridial spores; batch anaerobic digestion at 35°C for 50 days produced a reduction (-2 log10) in the fecal coliforms and fecal streptococci, and a slight variation in clostridial spores. After 18 days' digestion at 65°C the fecal coliforms could no longer be found, whereas slight increases were observed in the numbers of fecal streptococci and sulfite-reducing clostridia.
A note on the removal of fecal bacteria in cattle slurry after different farm and laboratory treatments / C. Sorlini, L. Allievi, G. Ranalli, A. Ferrari. - In: BIOLOGICAL WASTES. - ISSN 0269-7483. - 22:1(1987), pp. 39-47.
A note on the removal of fecal bacteria in cattle slurry after different farm and laboratory treatments
C. SorliniPrimo
;
1987
Abstract
We investigated the variations in the numbers of the main groups of indicators of fecal contamination (fecal coliforms, fecal streptococci, and sulfite-reducing clostridia) during various treatments to which cattle slurry was subjected on a farm and in an anaerobic digester in the laboratory. The results indicated that: anaerobic digestion at 35°C for 20 days in a farm, plug-flow, digester produced a reduction (-1 or 2 log10) in the coliform and streptococcus numbers and an increase in the sulfite-reducing clostridia. When the same materials were also subjected to batch anaerobic digestion at ambient temperatures, a drastic reduction (-4 log10) was noted in the numbers of fecal coliforms, a smaller decrease (-3 log10) in the fecal streptococci, but only a slight variation in the clostridial spores; batch anaerobic digestion at 35°C for 50 days produced a reduction (-2 log10) in the fecal coliforms and fecal streptococci, and a slight variation in clostridial spores. After 18 days' digestion at 65°C the fecal coliforms could no longer be found, whereas slight increases were observed in the numbers of fecal streptococci and sulfite-reducing clostridia.Pubblicazioni consigliate
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