The paper deals with the hygienic advantages of sanitation to treat dairy manure in full-scale biogas plants. The slurry samples were collected from two thermophilic biogas plants (55°C) and two mesophilic biogas plants (38°C) in Hokkaido Japan. A detectable number of Coli-aerogenes group and Enterococcus in the slurries after anaerobic digestion (AD) could not be found in either thermophilic biogas plants. However, in both mesophilic biogas plants the viable numbers of Coli-aerogenes group and Enterococcus were detected in the slurries even after anaerobic digestion. The mean decimation reduction time (T(90) ) values of the Coli-aerogenes group and Enterococcus in the slurries during mesophilic digestion were 13.3 days and 16.7 days, respectively.
© 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.