Prediction of biogas production from co-digestion of winery solid waste and zebra manure using modified gompertz model (GM) and logistic equation (LE)

Abstract

The effect of anaerobic co-digestion (ACoD) of winery solid waste (WSW) and Zebra manure (ZM) on the enhancement of biogas production was investigated. Biogas was produced by means of an automated single batch anaerobic digester equipped with a pH and temperature control. The fermentation of WSW and ZM was conducted as mono anaerobic digestion (MAD) separately as well as ACoD (1WSW: 2ZM) at 37°C for 30days. Gas production was predicted using Gompertz Model (GM) and Logistic Equation (LE) and measured through downward displacement of acidified water. Results showed the ACoD (1WSW: 2ZM) method produced higher amount of cumulative biogas (952.6mL) as compared to MAD with 30.4mL for WSW and 139.9mL for ZM respectively, after 30 days of retention time. A close fit between the predicted and measured biogas values was observed with correlation coefficient of 0.965 and 0.953 for GM and LE model respectively. Hence, the models can be used to predict biogas yields from ACoD of biodegradable organic waste and ZM. The findings showed the effect of combining WSW with ZM, which could provide essential information and direction for scaling up of biogas production by high-performance ACoD system