Introduction to biogas

As years advance, the demand of fossil fuels is increasing and rapidly depleting the natural reserves. Usually those fossil fuels are obtained from natural formation of coal and oil but it is a very slow process which takes ages. So, to ensure the continuity of supply of fossil fuels in future there is a lot of research effort is put into finding renewable fuels nowadays. Renewable fuels are in balance with environment and contribute to a far lesser extent to the greenhouse effect. On of type of renewable fuel is biogas. Biogas is a gas typically comprised of sixty percent of methane (CH4) and carbon dioxide (CO2). it is produced through the breakdown of organic matter in the absence of oxygen which is referred to as anaerobic digestion. Major sources of methane are animal excrement, waste landfills and any other organic material that is left untreated such as leftovers from restaurants, past-dated foods and slaughterhouse waste. Besides, the bacteria involved in the process are methanogenic bacteria which are subdivided into psychrophilic, mesophilic and thermophilic strains according to their optimum temperature range. For mesophilic bacteria, their optimum temperature normally is between 38 ° C and 40 ° C and for thermophilic group is between 50° C to 60° C. Generally, the whole process generates when organic materials like manure, food scraps, crop residue are fed into reactor where it is heated to 40° C, biological decomposition takes place where the bacteria are producing the biogas. The biomass stays in the reactor for about two to three weeks. Biogas can be used for production of heat and electricity. One significant advantage of biogas is reducing the greenhouse gas emission into atmosphere, which occurs when the gasses are gathered, extracted and burnt during the process of biogas. Thus by utilizing biogas as an energy source, dependency on fossil based carbon such as coil, oil and natural gas can be reduce.

Reference :

1. What is biogas.Retrieved at 22nd May 2014 from http://www.biogas.de/en/technology/what-is-biogas

2. Introduction to biogas.Copyright ©2014 The University of Adelaide. Retrieved at 22nd May 2014 from http://www.adelaide.edu.au/biogas/basic/