Design of Biogas Production Plant from Wolkite University Student’s Cafeteria Food Waste

Abstract

Anaerobic digestion is a microbial process for production of biogas, which consists of primarily methane (CH4) & carbon dioxide (CO2). Co-digestion is also critical determinant for stable and ef icient anaerobic digestion process. Biogas production requires anaerobic digestion. Anaerobic decomposition of dif erent wastes which biodegradable in nature that can produce biogas. It can be used as healthy cooking alternative. The main objectives of the study are to design a biogas plant for food waste generated in our university. The materials used as feed were Injera with wot, Rice, Bread, Beef, Cabbage rolls, carrots and potato peels waste. The total solid, volatile solids, moisture content and ash content of the wastes were examined. Anaerobic digestion is very sensitive to change in pH and it was maintained and adjusted for healthy system. The temperature of the digester and the environment also af ects the anaerobic digestion process. In this small scale study the ef ect of dif erent food waste to water ratio, the ef ect of inoculants and treatment with alkaline on the biogas production was investigated for the period of 2-4 weeks. The fixed dome biogas plant was designed according to the obtained value. Generation of biogas is enhanced by combination of co-digester mixture water cow dung with proportion of 1:1. Six batch experiments carried out to know the optimum mixing ratio of food sample to water. The anaerobic digester had a hydraulic retention time of 25 days and operated at 47 0C, since it was greater than 45 0C and which was at termoophylic conditions. From the simulation, it was observed that a total of 93.187m3 /day biogas is produced from a feed rate of 497.882kg/day. The biogas yield was optimized by mixing food waste with water in 1:4 ratios and by introducing