Abstract: Energy is an essential prerequisite for accelerated economic development and improved quality of life for citizens of any country. Due to rapid industrialization and urbanization in last few decades, there is a huge pressure on crude oil, coal and other fossil fuels. This resulted into need for finding some alternative sources of energy. Biogas is produced by anaerobic digestion of biomass such as cattle dung, vegetable waste, poultry droppings, industrial waste water, municipal solid waste, and landfill etc. In rural areas cattle dung and vegetable waste whereas in cities and urban area municipal solid waste are available in abundant quantity, from which biogas can be generated. Biogas is constituted of different component gases the majority of them being methane (CH4), Carbon Dioxide (CO2) with traces of Hydrogen Sulfide, and water vapour. It is possible to improve quality of biogas by removal of CO2, H2S and enriching its methane content up to the natural gas level. After methane enrichment and compression it can be used as vehicle fuel like compressed natural gas (CNG). Any low cost technique to remove carbon dioxide and hydrogen sulfide from biogas can make biogas a techno-commercially viable fuel and equivalent to natural gas. In this paper low cost biogas purification system using water scrubbing is proposed and is shown that using this system we can covert raw biogas into bio CNG which can be used as a vehicular fuel. It is the cheapest and easiest method of biogas up gradation in which pressurized water is used as absorbent. Water scrubbing involves physical absorption of CO2 and H2S in water at high pressure and regeneration by a release in pressure with very little change in temperature.

Keywords: Raw Biogas, Removal of CO2 /H2S from biogas, Water scrubbing of biogas.