Codigestion of Food Waste with Used Lipids as Substrate Material to Produce Biogas

Abstract

Anaerobic co-digestion of food wastes process is represents an active technique to enhance the production of biogas as one of the clean energy sources. The effects of adding lipids as substrate material to the food waste mixture for producing biogas by anaerobic co-digestion are experimentally investigated and evaluated at various mixing ratios in the present work. The influence of lipids and food waste (potatoes, tomato, Carrots, Cellulose) mixing ratios, digestion time and other factors on production of the biogas and CH4, CO2 and H2S percent are investigated experimentally. Seven samples of substrate mixtures (used edible oil, waste food, cow dung and water) with various mixing ratios were tested during 32 days as digestion period to investigate the influence of lipids percent compared to food waste on biogas yield. The results show that, average biogas production was in range of 100-160 ml per day and the maximum percent of Ch4 and CO2 were 52% and 46% respectively for the produced biogas. Increasing the lipids percent in the substrates mixture could enhanced the biogas and CH4 production. The mixing sample containing 70% lipids and 30% food waste percent was produced significantly higher biogas and CH4 yields compared to the other mixing samples. Best digestion time of the food waste-lipid mixtures was observed in range of 12-16 days for the tested samples. The maximum cumulative biogas was 5120 ml which was produced by substrate mixture (70% lipid and 30% solid waste) during digestion time 32 days.