Effect of temperature and stirrer on energy indices biogas production from animal manure

Nowadays, one of the main applications and management challenges for various activities is the study of the energy efficiency. In this study, effects of temperature and stirrer on energy indices and biogas production from animal manure were determined. The biogas was generated by using an anaerobic digestion with volume of 925 (lit) in industrial scale of manure in different temperature and stirrer conditions. Experiments were performed in 8 treatment groups containing (20 to 25°C), (26 to 30° C), (31 to 35° C) and (36 to 40° C) temperature, with and without stirrer, through a completely random factorial design test. Maximum amount of biogas produced with temperature (36 to 40° C), when the apparatus reaches certain stability with stirrer and also least amount of biogas which it related to temperature (20 to 25° C) without stirrer, was 61 and 8.7 (lit/ kg) fresh manure, respectively. The amount of energy ratio for the treatment which has maximum biogas produced was equal to 0.8. Maximum amount of energy ratio (with temperature (31 to 35° C) and stirrer), and least amount of energy ratio (with temperature (20 to 25° C) without stirrer) was 1.13 and 0.58, respectively.