Study of household biodigesters

Tunnel or tubular type of bio-digester has been widely developed in many countries for producing a renewable clean fuel gas named bio-gas. This digester type only requires minimum maintenance and simple construction for ensuring its lower cost compared to others with similar capacity. Mostly, polyethylene (PE) plastic bag is used for construction materials of the tubular digester. In this research, the tubular type has been constructed using large diameter PVC (Poly Vinyl Chloride) pipe for increasing the durability and safety. The performance of PVC digester has been tested by measuring bio-gas production rate and CH4 concentration in the gas. COD (Chemical Oxygen Demand) and BOD (Biological Oxygen Demand) drop between inlet and outlet sludge have been measured for examining the digester efficiency. Then, the performance was compared with PE plastic digester data from several literature which still needs some improvements for enhancing its capability and performance.