A mathematical study on anaerobic digestion process treating vegetable waste for energy recovery

This work primarily deals with a simple time-lag model for biogas production from anaerobic digestion (AD) of vegetable wastes in a batch digester. The model is capable of predicting the S-shaped nature of the cumulative biogas yield as a function of retention time observed experimentally. The model is calibrated against biogas production results obtained from anaerobic digestion of vegetable wastes by variation of process parameters, like total solids, particle size and operating temperature, respectively. For these studies, the fit of the model to the experimental data has an average root-mean-square (RMS) deviation of 19%. The model also led to the formulation of two measures/indexes of biodegradability of vegetable wastes. These measures are proportional to the biogas potential of vegetable waste showing susceptibility towards anaerobic digestion.