Food waste composting based on patented compost bins: Carbon dioxide and nitrous oxide emissions and the denitrifying community analysis.

Mature compost and rice bran were used as bulking agents to perform Food Waste Rapid Composting (FWRC) in a patented composting bin. The characteristics of CO and NO emission and the denitrifying community were investigated. The release of CO and NO concentrated in the early composting stage and reduced greatly after 28 h, and the NO emission peak of the treatment with mature compost was 8.5 times higher than that of rice bran. The high NO generation resulted from massive denitrifying bacteria and NO-N in the composting material. The relative abundances of denitrifiers, correspondingly genes of narG and nirK were much higher in the treatment with mature compost, which contributed to the NO emission. Moreover, the correlation matrices revealed that NO fluxes correlated well with moisture, pH, temperature, and the abundances of nirK and nosZ genes during FWRC.