Methane production from anaerobic co‐digestion of maize and cow dung

Anaerobic digestion (AD) treatment of agricultural and animal waste can be considered as a means of enabling environmental remediation. This research investigated two conditions of anaerobic co‐digestion of maize waste and cow dung. This was done by placing a mixture of cow dung and maize waste together in a floating drum digester that was run at two different cow dung/maize ratios of 10:1 and 10:5. Batch conditions were on a bench‐scale of AD, 5 L in volume, developed to operate under mesophilic (36 ± 1°C). Results showed that biogas and methane yields from mesophilic digestion at the ratio of 10:1 were lower than yields obtained at ratio tested in the second run (10:5). Biogas yields were 250 and 480 L/kg VS for first and second runs, respectively. In the case of methane, these amounts were presented at 130 and 300 L/kg VS. Furthermore, the average methane content of biogas was calculated as 51 and 62%, in first and second runs respectively. The total biogas production of the reactor increased by 92% when substrates were fed in second condition ratio compared to biogas production during the first condition ratio. In continue the effect of adding maize waste on biogas yield from cow dung was evaluated in batch digesters under mesophilic conditions. The addition of maize waste to cow dung presents a viable method to improve biogas yield, as well as a means to use maize waste. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 597–601, 2014