Experimental evaluation of purification methods for biogas produced from pig manure in rural biodigesters

Biogas contains a mixture of gases, of whom methane isof the most interest, the rest of the contaminant gases are the product of the activity of microorganisms involved in the anaerobic digestion process. These contaminants limit the use of biogas as a fuel, especially in the generation of electrical energy. The search for alternative technologies for the treatment of biogas is of great interest to promote the use of this renewable energy source. Biogas purification methods make use of chemical and physical processes that generate polluting waste, which must be effectively managed,and the removalof CO2often requires specialized equipment, limiting this processto industrial scale productions. Activated carbon is effective in removing contaminants butis inaccessibleto rural farmsdue to its cost. Iron sponge is often used in domestic facilitiesdue to the low cost and ease of access, nonetheless this method generates solid wastes that are difficult to dispose of.Commercial copper sulfate can remove hydrogen sulfate but requires adequate pressure conditions to be effective.