C. citratus (6 kg) was mixed with 500 ml of water and
was introduced into reactor C. The slurry was allowed to occupy
three quarter of the digester space leaving a clear height of about
0.0625 m as space for gas production. A 100-ml of partly decomposed slaughter house waste (rumen content of cattle) was
collected and used as seed material (inoculum) for all the reactors.
The characteristics of the inoculum are shown in Table 1. A separate
blank reactor containing only the inoculum and water was operated simultaneously with reactors AeC. This was used to correct the
biogas volume produced from the experimental substrates. Total
solids content of the three digesters was set at 7.5% following the
recommendation of Ref. [23].