Anaerobic digestion of animal manure is an effective method of both animal waste disposal and energy demand fulfillment sustainably. However, recent studies revealed that biogas yield of sole manure is relatively low due to its low carbon content. Thus, anaerobic digestion with other organic wastes, so called co-digestion, has gained attention in recent years. The aim of this study was to evaluate the biochemical methane potentials of cow manure and barley with respect to four different operating parameters in order to achieve the optimum methane yield. Effects of temperature (mesophilic vs. thermophilic), inoculum to substrate (I:S) ratio and different types of inoculums were investigated in anaerobic batch tests. Highest specific methane yield (278 CH4/g VS) was found in the digester containing anaerobic seed sludge and cow rumen fluid as a supportive inocula which was operated with an I:S ratio of 1:2. The next highest specific methane yields were obtained in the digester operated at thermophilic temperature (55°C) and in the digester operated with an I:S ratio of 1:1, as 259 CH4/g VS and 256 CH4/g VS, respectively. As a major indicator of stability in anaerobic digesters, no volatile fatty acids accumulation was observed in the digesters during the operation period. The results indicated that the combination of different types of inoculums can be a promising alternative to increase methane production from similar agricultural biomass, instead of energy input in thermophilic anaerobic digesters.

Enhancement of methane production by varying operating conditions in anaerobic digesters fed with cow manure and barley

253rd National Meeting (2017)

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