The optimization of the multi-component organic wastes in mixed aerobic composting ratio based on antibiotic resistance gene reduction

In recent years, the co-processing of agricultural and rural domestic waste for composting has emerged as a primary approach to promote resource recycling. However, the presence of antibiotics and other harmful chemicals in the raw materials can induce the generation of antibiotic resistance genes (ARGs) during the composting process, thereby triggering multiple potential risks, including environmental and ecological risks and human health risks. Currently, the production patterns of ARGs in the co-processing of multiple raw materials remain unclear, and research on reduction technologies is also inadequate. Therefore, this study aimed to develop a multi-material ratio scheme for achieving high compost maturity and effective ARG reduction. Aerobic composting experiments used varying ratios of four agricultural and rural organic wastes with a simple centroid design. The results demonstrated that special cubic response models for E4/E6 and the total reduction rates of four ARG types were successfully fitted. The optimal ratios were 40.5 % kitchen waste, 11.5 % pig manure, 28 % human feces, and 20 % wheat straw. Under these optimal conditions, the total reduction rates of ARGs increased by 0.31 %–19.64 %. These findings provide valuable theoretical support for enhancing ARG removal through mixed composting. • Four-component mixed composting was optimized using the simplex centroid design. • E4/E6 and total reduction rate of four types of ARGs were fitted and verified. • The optimal proportion was 40.5 % kitchen waste, 11.5 % pig manure, 28 % human feces. • The total reduction rate of four types of ARGs was 21.87 % at the optimal ratio.