Bio-gas- concepts

Any gas fuel derived from the decay of organic matter, as the mixture of methane and carbon dioxide produced by the bacterial decomposition of sewage, manure, garbage, or plant crops.

Principal:

Biogas is produced on principal of anaerobic digestion with the help of anaerobic bacteria or fermentation of biodegradable materials such as manure, sewage, municipal waste, green waste, plant material, and crops.

Temperature: The digester is heated to 30 – 35 C and the feedstock remains in the digester typically for 15-30 days. Some time the digester is heated to 55oC (sunlight) and the residence time is typically 12-14 days.

Biogas plant:

 Biogas plant consist of fermentation tank or biogas digester; a warmed, sealed airless container (the digester) which creates the ideal conditions for the bacteria to ferment the organic material in oxygen-free conditions.  The digestion tank needs to be warmed and mixed thoroughly to create the ideal conditions for the bacteria to convert organic matter into biogas.  Fermentation tanks allow production and collection of methane from the anaerobic process.

This collected gas is derived through pipes and water content and sulphur is removed by installing filters between piping. 

Material used for Biogas Production:

Different types of organic materials can be used in a biogas plant. It should be in solution form or more diluted with water, as fermentation process show efficiency in solution form not in solid form.

It includes the following:

1)      Source separated bio waste.

2)      Mechanically-separated municipal waste.

3)      Commercial catering waste.

4)      Sewage sludge.

5)      Animal slurry.

6)      Vegetable and pack house waste.

7)      Energy crops – maize/grass.

8)      House hold waste.

Composition of Biogas:

Typical biogas consists of following gas composition and percentage.

Component	Symbol	Percentage content of gas
Methane	CH4	40-70
Carbon dioxide	CO2	30-60
Hydrogen	H2	1.0
Nitrogen	N2	0.5
Carbon monoxide	CO	0.1
Oxygen	O2	0.1
Hydrogen sulphide	H2 S	0.1

Benefits of Biogas:

1)      Preventing the uncontrolled emissions of CH4 from organic manure or organic waste.

2)      The production of biogas is sustainable, renewable waste to energy solution.

3)      As it is closed system process thus emission of GHGs is reduced.

4)      Reducing the transport of waste and also reduce pollution.

5)      N: P ratio is maintained by residue left as fertilizer.

6)      Effect of Ozone Depletion is also reduced.

7)      Pathogen level is reduced to minimal level.

8)      Odorless organic manure is produced.

9)      Source of income to some extent.

10)  Waste management.

11)  Alternate to fuel.