Effects of carbon-based additive and ventilation rate on nitrogen loss and microbial community during chicken manure composting

Abstract

Aerobic composting is a sustainable method for recycling of chicken manure, while its unsuitable porosity and carbon to nitrogen ratio limit the oxygen supply, which must result in high nitrogen loss because of anaerobic micro-zones in the materials. Treatments with five carbon-based additives and two ventilation rates (0.18 and 0.36 L{middle dot}min-1{middle dot}kg-1 DM) were set in chicken manure composting, to investigate their effects on biodegradation process, ammonia (NH3) emission, nitrogen loss, physiochemical properties and microbial community. The additives and ventilation rates influenced the CO2 production from the 2nd week, meanwhile varied the physiochemical parameters all the process. No inhibitory effect on the maturity were observed in all treatments. With woody peat as additive, the NH3 emission amount and nitrogen loss rate were shown as 15.86 mg and 4.02 %, when compared with 31.08-80.13 mg and 24.26-34.24 % in other treatments. The high aeration rate increased the NH3 emission and nitrogen loss, which were varied with different additives. The T-RFLP results showed that the additives and the ventilation rates changed the microbial community, while the prominent microbial clones belonged to the class of Bacilli and Clostridia (in the phylum of Firmicutes), and Alphaproteobacteria, Deltaproteobacteria and Gammaproteobacteria (in the phylum of Proteobacteria). Bacillus spp. was observed to be the most dominant bacteria in all the composting stages and treatments. We concluded that woody peat could improve chicken manure composting more than other additives, especially on controlling nitrogen loss. 0.18 L{middle dot}min-1{middle dot}kg-1 DM was suitable for chicken manure composting with different additives.