A biogas plant is where biogas is produced by fermenting biomass.
5.1 In which of the parts would you find anaerobic bacteria?
a) A
b) B
c) C
d) D
Answer
5.1 b) B
B is the digester where the sludge is treated with anaerobic organisms
5.2 Which one of the following is NOT correct for biogas -
a) its carbon neutral
b) its non-renewable
c) it depends on micro-organisms
d) yields rich manure
Answer
5.2 b) its non-renewable
Biogas is a renewable resource
5.3 Which of the following best indicates the steps of anaerobic digestion
a) Waste water feed → biogas storage → generator → biogas
b) Waste water feed → digester → biogas → biogas storage → generator
c) Generator → waste water feed → digester → biogas → biogas storage
d) Waste water feed → biogas → digester → biogas storage → generator
Answer
5.3 (b) Waste water feed → digester → biogas → biogas storage → generator
5.4 Biogas is a better fuel than animal dung cake because
a) Biogas is a renewable source of energy
b) Animal dung cake has higher calorific value
c) Biogas has high heating capacity
d) Biogas burns without smoke.
i. (a) only
ii. (b) only
iii. (c) and (d)
iv. (a) and (b)
Answer
5.4 iii. (c) and (d)
Biogas has high heating capacity and Biogas burns without smoke
The other statements are wrong as:
- a) Biogas is a renewable source of energy → Animal dung cake is also a renewable resource
- b) Animal dung cake has higher calorific value → High calorific value makes it able to produce more energy than biogas hence it doesn’t justify why biogas is a better fuel
5.5 Biogas is formed in the
a) presence of air only
b) presence of water only
c) presence of air and absence of water
d) presence of water and absence of air
Answer
5.5 (d) presence of water and absence of air
The microorganisms acting on sludge to produce biogas are anaerobic bacteria
Anaerobic bacteria cannot survive in the presence of air
However, water is required