Q4. A small community of 50 members in Bidiya has decided to build a mini biogas plant in their area.
The waste required for biogas production was collected from different the cows grazing in the farm. Daily
consumption of gas per person is a person is 500 liters. Take the specific gravity of the slurry as 1.165
gram/cm$^3$. For a retention period of sixty-three days design a bio digester. What would be your
conclusion regarding the amount of biogas produced in a day, energy generated by the plant in a year,
number of cows required to produce the required waste? If 20 more members are joined to this
community, what is your suggestion on meeting their daily requirement of gas? Justify your answers with
valid data. Also discuss the factors influencing the performance of various stages such as collection stage,
anaerobic stage and power generation stage of the entire system.
(10 marks)