Comparison and Evaluation of GHG Emissions during Simulated Thermophilic Composting of Different Municipal and Agricultural Feedstocks.

Composting is widely used to recycle a variety of different organic wastes. In this study, dairy manure, chicken litter, biosolids, yard trimmings and food waste were selected as representative municipal and agricultural feedstocks and composted in simulated thermophilic composting reactors to compare and evaluate the GHG emissions. The results showed that the highest cumulative emissions of CO, CH and NO were observed during yard trimmings composting (659.14 g CO kg DM), food waste composting (3308.85 mg CH kg DM) and chicken litter composting (1203.92 mg NO kg DM), respectively. The majority of the carbon was lost in the form of CO. The highest carbon loss by CO and CH emissions and the highest nitrogen loss by NO emission occurred in dairy manure (41.41%), food waste (0.55%) and chicken litter composting (3.13%), respectively. The total GHG emission equivalent was highest during food waste composting (365.28 kg CO-eq ton DM) which generated the highest CH emission and second highest NO emissions, followed by chicken litter composting (341.27 kg CO-eq ton DM), which had the highest NO emissions. The results indicated that accounting for GHG emissions from composting processes when it is being considered as a sustainable waste management practice was of great importance.