METHANE PRODUCTION EMISSION IN STORAGES FOR ANIMAL MANURE

Results of extended research on laboratory scale have shown that relatively high gas productions can occur at digestion of animal manure in fed-batch (=Storage)- systems at ambient temperatures. High gas productions are also reported at on-farm storage of animal manure. In order to predict the gas production during the storage of animal manure at different conditions, a model is developed based on first order kinetics for the hydrolysis and on Monod kinetics for methanogenesis. Results of anaerobic digestion of manure in both CSTR- and fed-batch systems have been used for the estimation of constants. The model predicts that, when continuously 15% of the storage is filled, no gas production is produced, at a temperature of 15-degrees-C and a storage capacity less-than-or-equal-to 100 days and at a temperature of 10-degrees-C and a storage capacity less-than-or-equal-to 150 days. At higher temperatures and longer storage capacities methane gas is always produced.