A Simulation of Biogas Production from Lignocellulosic Biomass Co-Digested with Agricultural Waste under the Influence Bentonite Catalyst

Abstract

This study aimed to simulate the effects of bentonite catalyst (B-cat) at different times into the digester containing maize cob, cow dung and food waste, using three different models. Data such as lag phase, maximum biogas production rate and cumulative biogas production were mined from an experiment, initially executed to determine whether difference in the application time of B-cat may cause any significant difference. Findings suggest that the data fitted well with both the modified Gompertz and Transference function models with R² in the range of 0.998 to 0.999 and fitting has been confirmed by the root mean squared error (RMSE) of 0.08 to 0.54, and 0.29 to 2.73 respectively for digesters where B-cat was applied at the onset of the experiment. For the dataset obtained when B-cat was applied one week after the commencement of the experiment, the RMSE was found in the range of 0.22 to 0.71 and 2.23 to 3.21 for MG and TF models respectively. The RMSE for the LF model in both cases of times of application ranged from 0.54 to 4.86. Together, these suggest that the modified Gompertz and Transference function models have demonstrated the best fit with the experimental data compared with the Logistic function model. In the design of a digester for digesting maize cob with cow dung and food waste as co-substrates, the use of modified Gompertz and Transference function models are appropriate for the output estimation.