Digester B increased progressively from the
first day through to the fifth day and droped relatively on the sixth day but then increased sharply on the seventh day to about 7.21 mL. Optimum biogas production was not attained in this case as there was evidence from the Figure 3 to suggest further production. Digester C rose progressively from 0 mL from the start of the experiment to about 6.72 mL on the fifth day and then decreased the two remaining days of the study.