Class 12th Biology 2011 Set1 Delhi Board Paper Solution
Question 25
The diagram above is that of a typical biogas plant. Explain the sequence of events occurring in a biogas plant. Identify a, b and c.
Answer
Biogas is defined as the mixture of gas (mostly methane) produced by microbe during its growth and metabolism, different type of gases are produced by different microbe depending upon their substrate. Bacteria which grows anarobically on cellulose materials are called as methanogens e.g Methanobacterium, commonly found in sewage treatment.
A biogas plant consists of concrete tank for collection of slurry. Floating cover keeps on rising as the gas is produced in the tank in response of microbial activity. The plant is added with outlet for the supply of gas to house, and rest of the slurry is removed by outlet opening near farm field for utilization as fertilizer.
Labelling
a. Sludge tank
b. Gas holder
c. Dung water
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