Abstract
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(2), CH(4) and N(2)O were observed during yard trimmings composting (659.14 g CO(2) kg(-1) DM), food waste composting (3308.85 mg CH(4) kg(-1) DM) and chicken litter composting (1203.92 mg N(2)O kg(-1) DM), respectively. The majority of the carbon was lost in the form of CO(2). The highest carbon loss by CO(2) and CH(4) emissions and the highest nitrogen loss by N(2)O 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(2)-eq ton(-1) DM) which generated the highest CH(4) emission and second highest N(2)O emissions, followed by chicken litter composting (341.27 kg CO(2)-eq ton(-1) DM), which had the highest N(2)O 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.