Insights into the effect of iron-carbon particle amendment on food waste composting: Physicochemical properties and the microbial community

The effects of iron-carbon (Fe-C) particle amendment on organic matter degradation, product quality and functional microbial community in food waste composting were investigated. Fe-C particles (10%) were added to the material and composted for 32 days in a lab-scale composting system. The results suggested that Fe-C particle enhanced organic matter degradation by 12.3%, particularly lignocellulose, leading to a greater humification process (increased by 15.5%). In addition, NO3--N generation was enhanced (15.9%) by nitrification with more active ammonia monooxygenase and nitrite oxidoreductase activities in the cooling and maturity periods. Fe-C particles not only significantly increased the relative abundances of Bacillus and Aspergillus for organic matter decomposition, but also decreased the relative abundances of acid-producing bacteria. RDA analysis demon-strated that the bacterial community was significantly influenced by dissolved organic matter, C/N, NO3--N, humic acid, volatile fatty acids and pH, while electrical conductivity was the key factor affecting the fungal community.

Automated summary

Iron-carbon particle amendment can enhance organic matter degradation and promote the formation of humus, as well as increase the generation of NO3--N during food waste composting. It also influences the microbial community, increasing the abundance of decomposing bacteria and decreasing acid-producing bacteria.