Potential assessment, design and implementation of biogas system from dining hall and kitchen wastes at Kito Furdisa Campus

Abstract

Energy from waste is about taking waste and turning it into a useable form of energy. This can include electricity, heat and methane from waste source. Waste to Energy Conversion (WEC) technology provides an alternative source of renewable energy in a world with limited or challenged fossil reserves. The most common conversion method is through biological treatment method via anaerobic digestion. Anaerobic digestion is a waste-to-fuel application that waste can be converted into purified biogas which can then be used to power and to create heat or electricity. Food wastes and kitchen wastes reduction is the first step to food waste management. As long as proper food safety and handling practices are followed, reusing leftover food can save money and reduce waste. Creatively repurpose leftovers and trimmings to efficiently use excess food for other meals. Flexibility in menu planning to accommodate the use of excess food from previous meals is a good way to extract energy from those wastes. Also, diverting wasted food to anaerobic digestion can generate renewable energy (biogas) and create a valuable soil amendment. Jimma University, JiT, Kito Furdisa Campus currently generates approximately 33,902 Kg/month of food waste and kitchen waste by the on-campus dining halls. Production of dining hall wastes is seasonal, as food preparation needs decrease significantly in mid of July and August. While dining hall and kitchen wastes provides a significant potential source for feedstock energy and in anaerobic digestion processes. These wastes should be an acceptable feedstock for the anaerobic digestion process. From food and kitchen wastes of Kito Furdisa Campus of Jimma Institute Technology about 33,902 kg of wastes is assessed within a month and biogas plant of 322m 3 volumes is designed and also total biogas produced is calculated 113m 3 / day. This gas produced using energy conversion gives us 722kwh of power per day. Based on biogas produced it diverted to combined heat and power (CHP) system to generate electricity and heat that recovered to produce hot water using stove for cafeteria of Kito Furdisa and its kitchen itself. Energy consumption of this anaerobic digestion of system in dining hall & kitchen wastes give us 41.03 kwhr and the net energy used is 681 kWh which used for CHP. This means the production of electricity will be 75.42MWh/y and the production of heat will be 138.27MWh/y.