Unraveling the impact of intervention strategies and oxygen disparity in humification during domestic waste composting

[Display omitted] •Three photovoltaic-assisted composting systems were developed for rural waste treatment.•Monthly turning and ventilation-dehydration treatment is recommended as the optimized process for the system.•Oxygen disparity at gradient heights of the compost pile significantly affects the physicochemical properties and maturity process of composting.•Manual turning and ventilation-dehydration optimize compost maturity.•The humification process at gradient heights is influenced by oxygen disparity and has different mechanisms. This study constructs three different photovoltaic assisted composting systems to treat rural domestic waste, and explores the interaction pathways between biomacromolecules and other factors under oxygen disparity at gradient heights of the compost. The optimized mode of regular turning and ventilation-dehydration significantly reduced the moisture content by 53.6% and increased the seed germination index by 35.6%. The oxygen content at different heights under the optimized mode significantly affects the physicochemical properties of the compost, and the degradation of cellulose, hemicellulose, and protein in the middle is higher than other parts. The structural equation model shows that the physicochemical properties at the bottom are affected by biomacromolecules, which may be related to volatile fatty acids(VFAs) produced under low oxygen conditions.The research results show that using manual turning and ventilation-dehydration as the optimized process can promote compost maturity, and oxygen concentration has an important impact on the humification process of the compost.