Addition of chemical oxidation catalysts accelerates heating and humification in biodrying-enhanced composting...

The biodrying-enhanced composting (BEC) process shortens kitchen waste composting to 10-15 d, yet the addition of high-moisture fresh waste often disrupts established thermophilic microbial communities and delays temperature rise. To overcome this limitation, BEC was coupled with chemical catalytic oxidation. In a laboratory BEC system, three treatments were established using Mn/Ce bimetallic catalyst addition (CT), unmodified zeolite addition (SP), and no additive (CK). Results showed that the catalyst increased reactive oxygen species (ROS: H₂O₂, ·OH, and ·O₂^-) levels by 21.8-37.4 % and boosted lipid and protein degradation within 24 h by 97.5 % and 41.0 %, respectively (p < 0.05). Enhanced early-stage oxidation in CT released 60 % more heat than CK, advancing and extending the thermophilic phase by 10  h and 19  h. The ROS-rich environment and rapid heating enriched thermophilic functional microbes (Melanocarpus and Saccharomonospora), markedly upregulated lignin-degrading genes, and elevated associated enzyme activities by 11.5-61.5 % (p < 0.05). This synergy of ROS and microbes enhanced lignin degradation by 46.7 % (p < 0.01), facilitating the release of humic precursors. Consequently, the germination index and humic to fulvic acid ratio significantly increased by 9.9 % and 32.5 % (p < 0.05). ICP-MS showed that the total and leachable Mn and Ce in the compost were within safe limits, ensuring soil safety under reasonable use. Overall, catalyst-assisted BEC couples chemical oxidation with microbial activity to accelerate heating and humification, offering a solution for more rapid, stable, and high-quality composting.