Dry Anaerobic Co-digestion of Cow Dung with Excess Sludge at Low Temperature

Ajay Kumar Jha

Low evolution rate of anaerobic microbes during psychrophilic condition (<20oC) affects anaerobic digestion process severely. It is also observed that the constituent bacterial consortiums are less active at low ambient temperatures and consequently it causes the drop off in the efficiency of anaerobic fermentation process. The performance of bioreactors even more decreases with the increment in solid content in the feedstocks. It is therefore great challenge to stabilize organic solid waste economically in cold and hilly regions. The purpose of this single-stage batch cultured investigation was to assess the effect of increment in inoculum amount on semi-dry anaerobic digestion process of cow dung with excess sludge at 15±1oC for 84 days. The biogas yields for 15%, 30%, 45% and 60% inoculum based on wet-weight were 13.33, 19.37, 23.99, and 21.64 L/kg with methane of 8.41, 12.19, 15.15 and 13.66 L/kg, respectively. Moreover, the specific methane yield was highest when the psychrophilic semi-dry anaerobic digestion process was inoculated with a mass of 45% of the substrate.

https://dx.doi.org/10.31873/IJEAS.5.7.22