The pH of the two digesters fluctuated optimally from between
6.6 and 7.8 for cow dung (Fig. 3) and from between 6.4 and 8.8 for
chicken droppings (Fig. 4).
The daily biogas production of 6.35 103 m3 (65.59% methane
content) and 7.03 103 m3 (61.71% methane content) were
recorded over a 30-day retention period with a standard deviation
of 2.89 103 and 4.83 for cow dung and chicken droppings
respectively.
Table 1 shows the microbial profile of feedstock and biofertilizer
digestate. The mean microbial counts of the cow dung and chicken
droppings feedstock respectively before digestion were 4.0 108
and 2.0 108 for coliform, 3.4 1010 and 1.7 1010 for total aerobic