Development of underground solid state biogas plant of 2M³ capacity

An attempt has been made to develop a biogas plant which requires no water for dilution of cattle waste and generates lesser amount of relatively more concentrated spent slurry. An existing Janta biogas plant was modified by fixing 200mm diameter PVC pipe at inlet and rest of the inlet chamber was closed with sand and brick masonary work. The inlet was kept 1200mm above the height of oulet to facilitate easy feeding of dung. This plant was run at 100 days retention time on undiluted cattle waste for last 12 months, which produces more biogas (31.2 L kg⁻¹ dung) as compared to conventional KVIC biogas plant (20.9 L kg⁻¹). The second plant modified with 300 mm inlet RCC pipe produces 46.71 L kg⁻¹ dung of an average running period of six months and has no problem in feeding and out coming of digested dung from the digester.