Effect of acidity level of substrate by lime water and acetic acid addition on biogas production

Biogas is an environmentally friendly alternative biomass and combustible gas. It contains a mixture of methane (CH4), Carbon dioxide (CO2) and other gases, which is obtained from the fermentation of organic materials by anaerobic bacteria. Biogas production needs to be developed in order to address the environmental and energy concerns. The aim of the present study is to obtain the highest biogas volume production through acetic and base solution into substrate. The research was performed in 30 days to know a better understanding on the effect of substrate pH level on the produced biogas. Five different pH levels of substrate were obtained by adding lime water and acetic acid. The pH level of the substrate without any treatment is 7, and a higher pH level is gained by adding acetic acid while a lower pH level is gained by adding lime water. The results reveal that the substrate pH level increases during the fermentation followed by a reduction of biogas volume production. The drawback is overcome by reducing the pH level of the substrate, in which it shows better result in producing biogas volume compared to those with higher pH levels. It also verifies that the rate of biogas formation is better on lower substrate pH.