Abstract
This work investigated the use of laboratory
batch anaerobic digester to derive kinetics parameters for
anaerobic co-digestion of pig waste and grass clippings.
Laboratory experiment data from 10 litres batch anaerobic
digester operating at ambient mesophilic temperature of 37
0C and pH of 6.9 was used to derive parameters for modified
Gompertz model. The carbon/nitrogen (C/N) ratio of Pig
waste was found to be 16.16 and grass clippings to be 20.54.
Through co-digestion in ratio of 1:1, the C/N ratio settled at
17.28. The actual biogas yield was found to be 7725 ml/g
COD. In the model of biogas production prediction, the
kinetics constants of A (ml/g COD), μ (ml/g COD. day), λ
(day) was 7920.70, 701.35, 1.61 respectively with coefficient
of determination (R2) of 0.9994. Modified Gompertz plot
showed better correlation of cumulative biogas production
and these results show biogas production can be enhanced
from co-digestion of substrates.