Biogas

 

                                                               What is biogas?

Biogas originates from bacteria in the process of bio-degradation of organic material under anaerobic (without air) conditions. In the absence of oxygen, anaerobic bacteria decompose organic matter and produce a gas mainly composed of methane (60%) and carbon dioxide called biogas. This gas can be compared to natural gas which is 99% methane.

Each year some 590-880 million tons of methane are released worldwide into the atmosphere through microbial activity. About 90% of the emitted methane derives from biogenic sources, i.e. from the decomposition of biomass. The remainder is of fossil origin (e.g. petrochemical processes). In the northern hemisphere, the present tropospheric methane concentration amounts to about 1.65 ppm(parts per million).  

Unlike fossil fuel combustion, biogas production from biomass is considered CO2 neutral and therefore does not emit additional Greenhouse Gases (GHG) into the atmosphere. 

However, if biogas is not recovered properly, it will contribute to a GHG effect 20 times worst than if methane is simply combusted. Therefore, there is a real incentive to transfer biogas combustion energy into heat and/or electricity.

Finally, biogas production from anaerobic digester presents the additional advantage of treating organic waste and reducing the environmental impact of these wastes. It contributes to a better image of the farming community while reducing odor, pathogens and weeds from the manure and producing an enhance fertilizer easily assimilated by plants.  

Benefits of Biogas

 Biogas unit can yield a whole range of benefits for their users, the society and the environment in general, the chief benefits being;

1.      Production of energy (heat, light, electricity).
2.      Transformation of organic wastes into high quality fertilizer.
3.      Improvement of hygienic conditions through reduction of pathogens, worm eggs and flies.
4.      Reduction of workload, mainly for women, in firewood collection and cooking.
5.      Environmental advantages through protection of forests, soil, water and air.
6.      Global Environmental Benefits of Biogas Technology.


Biogas can have significant health benefits. According to the Integrated Environmental Impact Analysis carried out by BSP** for 600 biogas users and 600 non-users, four percent more non-biogas users have respiratory diseases than those who own biogas plants (1). Qualitative information from various household surveys carried out by BSP has revealed that problems like respiratory illness, eye infection, asthma and lung problems have decreased after installing a biogas plant