不同原料配比对沼渣和厨余垃圾共堆肥的理化性质和腐熟度的影响

Aerobic composting is an effective way for resource utilization of digestate and kitchen waste. Co-composting of digestate and kitchen waste can effectively improve the physicochemical properties of the compost pile and thus increase the composting efficiency,but the compounding ratio of the two co-composts still needs to be explored. In this study,five treatment groups were set up for co-composting with the mass ratio of digestate to kitchen waste of 10.0∶0,7.5∶ 2.5,5.0∶ 5.0,2.5∶ 7.5,and 0∶ 10.0. The physicochemical indexes in the composting process as well as the degree of humification of the final product were used as the evaluation indexes in order to determine the optimal ratio of co-composting of kitchen waste to digestate,which could provide a reference for the improvement of the efficiency of the joint resource utilization of digestate and kitchen waste. The results showed that when the mass ratio of digestate to kitchen waste was 2.5∶ 7.5,it could enter the high-temperature period quickly and maintain for seven days in the high-temperature period,which met GB 7959—2012 Hygienic Requirements for Harmless Disposal of Night Soil. The pH,organic content, and seed germination index of the five treatments were all in line with the requirements of NY/T 525—2021 Organic Fertilizer. The lower water-soluble NH₄⁺ in the compost product with the mass ratio of digestate to kitchen waste of 2.5∶7.5 indicated that it had less plant toxicity. Results analysis of humic acid content and ratio of humic acid and fulvic acid showed that the final product with mass ratio of digestate to kitchen waste of 2.5∶7.5 had the highest degree of humification,but it contained high levels of Na⁺ and Cl^- ,and the adverse effects of salts on plants should be taken into account in land application. In conclusion,the mass ratio of digestate to kitchen waste of 2.5∶7.5 was the optimal ratio for co-composting, which had the highest humification efficiency,the better quality of final product,and a high potential for land application.