Comparative Study of Composting and Anaerobic Digestion as a means of Animal manure stabilization: A Case of Cow dung

. Abstract: The practice of using cow dung for soil conditioning and fertilization dates back to the early history of man, even though, it has received greater attention in recent times due to high cost of chemical fertilizer as well as the environmental impacts on sustainable agriculture. This study explores the three methods of cow dung stabilization namely: composting in 3m depth compost pit, composting on plain earth surface and anaerobic digestion in a biodigester. Standard analytical methods were used to determine proximate composition, total viable and coliform counts in each case before and after degradation. Temperature, pH and odour levels of the surroundings were also monitored for ten days using thermometer, Jeanway pH meter and sensory panellists respectively. Microbial identification was based on biochemical analyses. Results show that anaerobic digestion of cow dung is most efficient and effective in cow dung stabilization with very significant odour control within the vicinity. Unlike the composting methods which reduced the values of fat, protein and fibre by less than 70%, anaerobic digestion recorded 100% degradation of fat, protein and fibre respectively. Degradation of other constituents showed similar trend, with composting on earth surface having the least effect. Bacterial identified were similar in all the cases and include Klebsiella, bacillus pumilus, P. restrictum, Aspergillus niger and Psudomonas aeroginnosa while the total viablet and mould countss were slightly higher in the waste treated by anaerobic digestion.