Biogas production

Abstract

Non-conventional renewable energy (NCRE) is increasingly prominent, providing an inexhaustible energy source compatible with human and environmental sustainability. The various forms of NCRE include wind, solar, small hydro, tidal, geothermal and biomass. Biomass uses biological, chemical and physical processes to generate liquid or gaseous biofuels, such as biodiesel, bioethanol and biogas. Biogas is a viable and essential form of energy in agricultural and rural areas, obtained from the processing of organic waste through anaerobic digestion. In addition to biogas (comprising mainly methane and carbon dioxide, plus other trace gases), the process also produces a stabilized organic waste, digestate (also known as biol or biofertilizer), which can be used as a soil conditioner or biofertilizer (Varnero, 1991, 2001). The biodegradation rate of organic residues is related to the microbial activity in the anaerobic system. This activity depends on the type of raw material, the pH of the medium, the total level of solids, the temperature of the process and other parameters that determine the digestion period for the production of biogas and biofertilizer.