Question 1

Explain biogas plant with a labelled diagram.

Accepted Answer

Biogas or gobar gas is a combustible gas.It is produced through the anaerobic breakdown of waste biomass.The biogas plant consists of the following parts:- 1) Inlet or charge pit:- for passage of slurry into the digester.The raw material used is cattle dung, farm refuse, organic waste.2) Digester:- cylindrical tank which is airtight, above which is present a  floating gas holder of metal with an outlet of gas and pit for removal of sludge.Here the organic wastes get solubilized into simpler substances called monomers (solubilisation).Monomers change to organic acid by fermenting microbes (acidogenesis).Organic acid mostly formed is acetic acid.Methanogens become active and act on components of microbial digestion and form methane gas (methanogenesis).3) Outlet:- consists of sludge which is used as manure.The methane gas formed in this process is used for cooking and lighting.

Question 2

The technology of biogas production was developed in India mainly by

Accepted Answer

Biogas is an alternate source of energy produced by the anaerobic digestion of biomass such as animal excreta and kitchen wastes. The biogas plant was first installed in 1941 at IARI. The distinctive features of the plant were a well type digester and a mild steel gasholder, which was balanced by a counterweight connected through ropes and supporting poles. The KVIC and the Planning Research and Action Division (PRAD), tried to promote the IARI design. Thus, the correct answer is option C.

Question 3

During anaerobic digestion of organic waste, such as in producing biogas, which one of the following is left undergraded?

Accepted Answer

Lignin is the most important factor affecting the hydrolysis of the cellulose component in lignocellulosic material. The initial degradation step is difficult because the lignin-carbohydrate complexes create a barrier for microbial conversion due to the crystalline structure. Thus, lignin is left untreated during the anaerobic digestion of organic wastes.

Question 4

Methanogenic bacteria are not found in

Accepted Answer

Methanogenic bacteria (bacteria that produce methane) are not found in activated sludge. Methanogenic bacteria are anaerobic bacteria.The microbes found in activated sludge are aerobic bacteria that grow rapidly and form flocs.Hence, Methanogenic bacteria are not found in activated sludge.So, the correct answer is option D.

Question 5

Draw a neat labelled diagram of a typical biogas plant.

Accepted Answer

The image represents the labelled diagram of the biogas plant.

Question 6

Describe the biogas plant with a neat labelled diagram.

Accepted Answer

a) The biogas plant consists of concrete tank (10 - 15 ft deep) in which bio-wastes are collected and slurry of dung is fed.b) A floating cover is placed over the slurry, which keeps on rising as the gas is produced in the tank due to microbial (methanogens) activity.c) The biogas plant has an outlet, which is connected to a pipe to supply biogas to nearby houses.d) Used slurry is removed through another outlet and may be used as fertilizer.e) The biogas thus produced is used for cooking and lighting.

Question 7

Give the advantages of biogas.

Accepted Answer

Advantages of biogas are as followed: (i)  It is a cheap, safe and renewable source of energy. (ii)  It can be used for domestic lighting, cooking, street lighting as well as small scale industries. (iii)  It burns with a blue flame and without smoke. (iv)  It helps to improve sanitation of the surrounding.

Question 8

Which fuels can be obtained by microbial process ? Why is it necessary to increase the use of such fuels?

Accepted Answer

Natural gases( biogas, ethane, methane) can be obtained from the microbial process.It is necessary to use or increase this because it is man-made and natural gas so it is eco-friendly as well as cheaper than other fuels and also it is a renewable source and for fuels.

Question 9

What are methanogens? How do they help to generate biogas?

Accepted Answer

The group of methane-producing anaerobic bacteria is called as methanogens.Biogas is a mixture of methane and carbon dioxide. Methanogens produce methane, carbon dioxide and hydrogen gas by the anaerobic digestion of cellulosic plant part. Thus, methanogens helps in producing biogas.

Question 10

Observe the following figures and answer the questions :(a) Identify the process shown in the figure. (b) Explain the process in short.

Accepted Answer

a) The process represented in the picture is of production of biogas (methane) from organic waste.b) In this process biowaste or organic waste is crushed and mixed with water to form a slurry and subjected to anaerobic digestion in digestion plant.

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Microbes in Biogas Production

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Microbes helps in production of biogas.

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