Effect of addition of biogas slurry for anaerobic fermentation of deer manure on biogas production

By determining the methane production, volatile fatty acids (VFA) and ammonia nitrogen content of deer manure anaerobic fermentation system we explored the effects of adding biogas slurry on biogas production for the anaerobic fermentation of deer manure. The initial mushroom slag amount that was added was 35 g, total solid content was 6%, and temperature was 35 °C. One set of experiments was not added to the biogas slurry during the experiment, and for the other three groups, the amounts of biogas slurry that were originally added to the fermentation mixture were 10%, 30% and 50%. The results showed that the addition of biogas slurry during the fermentation of raw materials improved biogas total production and CH4 total production and also produced CH4 in advance. The total amounts of biogas and CH4 produced were the largest when the amount of biogas slurry added to the fermented mixture was 30%. Upon increasing the amount of biogas slurry, the trend of the VFA content in the fermented material first increased, then decreased and finally increased again. The content of VFA was the smallest when 30% biogas slurry was added to the fermented mixture because this was the most favorable condition for CH4 production.