Chapter 12 - Biogas from organic wastes

Abstract

The production of biogas from organic waste has gained attention as a promising alternative energy technology with numerous potential uses. In order to design a system for the use of this energy in a particular location, unique study is required. This is due to the fact that the quantity and quality of biowaste vary depending on the level and kind of human activity in that area. Because of its high organic and moisture content, kitchen waste (KW) from hostels, canteens, cafeterias, and other educational facilities pollutes surface water, rubbish, and odors. Avoiding such harm requires proper waste treatment and disposal. The current waste disposal systems are expensive and do not give any value addition to the wastes. The anaerobic digestion (AD) of KW through biochemical conversion could yield biogas and biofertilizers, which could generate power and fertilize plants. Due to the high oil content of KW waste, lactic acid accumulates early in the digesting process, causing a severe pH drop. Ammonia, sulfide, and long-chain fatty acids impede digestion. Novel process approaches, such as codigestion using substrates high in ammonium nitrogen and alkalinity to compensate for their absence in KW, have been recommended to improve organic waste characteristics to promote biogas production and particle organic solubilization. Mixing substrates improves methane recovery rates, life cycle costs, and organic load removal efficiency due to the carbon-to-nitrogen ratio correction, pH balancing, and treatment system buffering capacity. This study analyzes and experiments on biogas production using cow dung, rice waste, vegetable waste, and a blend of rice and vegetable wastes gathered from a university campus. The methane content of biogas derived from the aforementioned wastes was 61.13%, 52.98%, 52.01%, and 51.11%, respectively. Thus, this study showed that organic wastes from educational institutions in the selected region of study could produce biogas with the required methane content for heating and power generation applications.