also presented same results for coliform removal (96.3 %) from sludge during anaerobic digestion.
Similarly, MPN index of E. coli was dropped to 150 (86.36 %) and 93 (91.45 %) per 100 ml under aerobic and anaerobic conditions, respectively (Table 1). Decrease in the MPN/100 ml of both the indicator organisms might be related to depleting readily available organic nutrients in the sludge and formation of byproducts
or due to attachment of suspended microbes in the sludge to the biofilm. Similar finding were made by Andersson et al. (2008). Moreover, they associated this decrease in microbial count to deactivate by predation or
natural die off process