Co-digestion of cow-dung with kitchen waste for biogas production

Abstract

Kitchen waste, cow dung and a mixture of kitchen waste and cow dung were anaerobically digested. The performance of a single substrate and co-digestion of kitchen waste with cow dung were compared. The samples containing 400 grammes of the sample of kitchen waste, cow dung produced 55.0cm3 of gas after 18 days. The results obtained on co-digestion of kitchen waste to cow dung in a ratio of 3:1 had produced 86cm3 yet that in a ratio of 1:1 formed 82.3cm3 and that in 1:3 produced 84cm3 by the 18th day. The increase was attributed to the synergistic effect of co-digestion process and the high nutrient contents in the kitchen waste (cellulose, carbohydrates, proteins, fats and oils among others). The results showed that co-digestion could obtain better and stable performances and might be one of the many options for efficient biogas production. The kinetics of single substrate digestion closely followed the first order yet co-digestion deviated greatly from first order