Simultaneous reduction of odorous and greenhouse gases emissions by thermophilic microbial agents during chicken manure composting

Abstract

Odorous and greenhouse gases emissions from animal manure composting cause air pollution and nutrient loss. This research examined the effects of thermophilic fungal agent (F) and bacterial agent (B) on the emissions of odorous and greenhouse gases during chicken manure composting and explored the underlying mechanisms. The results indicated that the cumulative emission of ammonia (NH₃), hydrogen sulfide (H₂S), methane (CH₄) and nitrous oxide (N₂O) in F treatment decreased by 20.1 %, 34.2 %, 8.3 % and 26.1 %, respectively, in comparison to 25.3 % reduction in H₂S and 9.3 % reduction in N₂O in B treatment. F treatment increased the relative abundance of amoA, pmoA and nosZ, while lowering that of ureC, dsrB, mcrA and nirK. Furthermore, inoculation of thermophilic microbial agent significantly altered the evolution of bacterial communities during composting. Pearson correlation and co-occurrence network analysis revealed that Bacillus, Ammoniibacillus, Acinetobacter, Escherichia-Shigella and Oceanobacillus were closely related to gaseous emissions during composting. This study demonstrated that thermophilic fungal inoculation was efficient for mitigating odorous and greenhouse gases emissions during animal manure composting.