Co-composting of chicken manure with organic wastes: characterization of gases emissions and compost quality

Co-composting of organic wastes is globally recognized to be effective method to dispose two or more wastes at once and minimize drawbacks of composting such as gases emissions and nutrient reduction. In this study, pilot-scale experiments were conducted to characterize the co-composting process of chicken manure with cow manure (CC), swine manure (CS), plant residues plus mushroom media (CRM), on emissions of greenhouse gas, and ammonia, compost quality, maturity and their correlations. The results showed that cumulative flux of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and ammonia (NH3) widely ranged like 38,211-50,830, 172-417, 98-142 and 118-927 g kg dm(-1) day(-1) respectively. It indicated the importance of selection for co-composting material. The NH3 emission was significantly increased by 4.3-7.9 times in CS and CRM, compared to OC and CC. Both of CS and CRM also showed longer thermophilic phase and later maturation were also observed in both treatments. Temperature was positively correlated with gases (P < 0.001) except CH4, and nitrogen content, C/N ratio and nitrate nitrogen significantly affected emission of carbon and nitrogen (P < 0.001). In conclusion, for chicken manure composting, sole chicken manure or combination with cow manure could be suitable composting method to improve compost quality and minimize gases losses.