Anaerobic Digestion of Aerobic Pretreated Organic Waste

Anaerobic digestion is a biotechnology that can be used to convert various biodegradable organic materials into methane-rich biogas fuel. The anaerobic digestion of municipal solid waste and sewage sludge is a process that has become a promising technology in waste management throughout the world .Digestion occurs in a four-step process: hydrolysis, acidogenesis, acetogenesis and methanogenesis. Hydrolysis is the rate limiting step in the anaerobic digestion. Composting and anaerobic digestion (AD) are seen as the most favored options to deal with organic fraction of municipal solid waste (OFMSW). Both treatment options reduce the environmental burden and enable the generation of a nutrient rich fertilizer. Thus, the objective of this study is to analyze the effect of rotary drum pretreatment (pre-composting) on mesophilic anaerobic digestion of a mixture of vegetable waste and dairy sludge. Aerobic pretreatment prior to anaerobic co-digestion of fruit waste, vegetable waste, yard waste and cow dung. Aerobic pretreated organic waste was investigated using biogas plant inoculum in batch reactors at mesophilic condition. Effect of pretreatment on biogas production and TS and VS reduction was studied using batch anaerobic tests. At a F/M ratio of 1, there were a biogas production, TS and VS reduction of 465mLgVS -1 , 52.4% and 57.2% respectively for pretreated mixture and 340mLgVS -1 , 47.6% and 51.3% respectively for mixture without pretreatment. At F/M ratio of 0.5 there were a biogas production, TS and VS reduction of 325m LgVS -1 , 44.9% and 48.7% respectively for pretreated mixture and 275m Lg VS -1 , 41.1% and 46.4% respectively for mixture without pretreatment.