Design of Biogas Plant for Injera Baking Stove Using Food Waste as Feedstock (A Case Study of Assosa University)

Abstract

In rural communities and Ethiopian university, wood is the most sources of fuel for baking injera and cooking. The burning of wood in open fires is causing a number of health problems but is also deteriorating for the rural household economy as well as for the local and global environment. When looking for sustainable energy systems that are environmentally friendly, clean and versatile, Biogas plays a significant role. Moreover, converting food waste into Biogas helps to generate energy and reduce greenhouse gas emission by avoiding food waste from going to landfill since methane is a greenhouse gas, if it is not properly handled, can create global warming and cause health problem. Women and children are the main groups exposed to indoor smoke produced while cooking. The overall aim of this thesis project is to use biogas stove burner injera baking, to avoid the problems that are caused due to burning of fossil fuels and to assure the environmental sustainability. Injera is the staple bread in Ethiopia; almost all Ethiopian people on a daily basis perhaps consume it.Current number of student found in Assosa university those use the ASU cafeteria are around 6000, as the result of such increment, high amount of food wastes from cafeteria and kitchen can be collected. Collecting data have been made using interview and direct measurement of the waste using balance, meter, and different literatures. The food waste and water were mixed in a ratio of 1 to 4 to optimize the biogas yield. The appropriate amount of waste and total influent per day that delivered from the cafeteria was 1100kg per day, 5500 kg respectively. Then after analyzing the data the digester, which has volume capacity 148.25 m3, and 110 m3 per day total biogas produced, energy that can be produced from the biogas 715.5 kWh of power of per day. From the performance evaluation made the gas generated per day from food waste the potential of the biogas in reducing firewood dependence of Injera baking process can be evaluated. Biogas stove having a gas consumption rating of 0.5083m3/h for baking was designed for Injera baking. So amout of gas generated 110m3 per day from food waste can bake 2536 of injeras and 788.5kg/day wood was saved, wich is 21% of wood consumed per day , wood saved was approximated ETB 945960 per year and amount GHGs emitted to the environmental saved by using biogas stove was 25444475.5kg/annuam. Biogas burner was analytically designed.In addition, the total investment cost of the plant 541839ETB, and the payback period of the plant is 0.57 years for baking of injera. and the total installed cost could be analyzed.