Synergistic Composting of Urban and Rural Multi-Source Organic Waste and Product Quality Evaluation: A Case Study of a Treatment Center in the Taihu Lake Region
Urban and rural multi-source organic waste faces bottlenecks including high compositional heterogeneity, single resource recovery pathways, and uneven product quality. In the Taihu Lake region, active tourism and catering, high greening, and dense water networks generate large volumes of diverse waste with high moisture content, exacerbating these issues. This study evaluated a coupled bio-drying and aerobic composting process at a demonstration center in Linhu Town, Suzhou, Jiangsu Province, employing a three-stage control strategy: gradient dewatering, high-temperature stabilization, and maturation enhancement. Continuous operation showed that kitchen waste moisture content decreased from 77.70% to 58.69% after 1 day of bio-drying, to 23.22% after 7 days of silo reactor composting, and to 17.70% after at least 20 days of maturation. The aerobic composting phase maintained temperatures above 55°C for over 5 days, reaching a maximum of 68.1°C, meeting the harmless treatment requirements of CJJ 52—2014. After 20 days of maturation, the organic fertilizer product had an electrical conductivity below 4.00 mS·cm−1, organic matter content of 51.22%, total nutrient content of 5.61%, and heavy metal concentrations below the limits of NY/T 525—2021. The results provide technical support for efficient treatment and resource utilization of urban and rural organic waste.