Response Surface Optimisation of Biogas Potential in Co-Digestion of Miscanthus Fuscus and Cow Dung

In this study, the effects of co-digestion operating conditions for the enhancement of biogas production from Miscanthus Fuscus mixed with cow dung, was investigated. The aforementioned organic wastes are good substrate resources for anaerobic co-digestion (AD) due to their high content of easily biodegradable materials. This source of   effective and eco-friendly technology as AD is for generating energy from organic waste. Response surface methodology (RSM) based on the Box-Behnken (BBD) design was employed to evaluate and optimise four process variables: pH, temperature, and hydraulic retention time (HRT) and feedstock inoculum (F/I) ratio on the biogas production. This study signifies the interactions between the process conditions, and identifies the most significant variables of control in order to maximise the biogas production. A developed regression model established the relationship between the significant effect of the input variables and the response. The analysis of variance (ANOVA) showed a high coefficient of determination value (R²= 0.9997) at 95% confidence level. The results show that the F/I ratio has a major impact on biogas production. The model developed predicted values which were well fitted (P<0.005) with the values obtained from the experimental data. Thus, the regression model confirmed findings. The RSM and BBD employed proved to be economical and a reliable tool for modelling, optimizing and studying the interactive effects of the four process factors (pH, temperature, HRT and F/I ratio) for the biogas production.

In this study, the effects of co-digestion operating conditions for the enhancement of biogas production from Miscanthus Fuscus mixed with cow dung, was investigated. The aforementioned organic wastes are good substrate resources for anaerobic co-digestion (AD) due to their high content of easily biodegradable materials. This source of   effective and eco-friendly technology as AD is for generating energy from organic waste. Response surface methodology (RSM) based on the Box-Behnken (BBD) design was employed to evaluate and optimise four process variables: pH, temperature, and hydraulic retention time (HRT) and feedstock inoculum (F/I) ratio on the biogas production. This study signifies the interactions between the process conditions, and identifies the most significant variables of control in order to maximise the biogas production. A developed regression model established the relationship between the significant effect of the input variables and the response. The analysis of variance (ANOVA) showed a high coefficient of determination value (R²= 0.9997) at 95% confidence level. The results show that the F/I ratio has a major impact on biogas production. The model developed predicted values which were well fitted (P<0.005) with the values obtained from the experimental data. Thus, the regression model confirmed findings. The RSM and BBD employed proved to be economical and a reliable tool for modelling, optimizing and studying the interactive effects of the four process factors (pH, temperature, HRT and F/I ratio) for the biogas production.