Chen Zhou, Li Yanzeng, Peng Yanyan, Mironov Vladimir, Chen Jinxi, Jin Huixia, Zhang Shenghua
Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China; University of Chinese Academy of Science, Beijing 100049, People's Republic of China.
Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China.
Sci Total Environ. 2022 Jun 15;825:154047. doi: 10.1016/j.scitotenv.2022.154047. Epub 2022 Feb 21.
Co-composting of sludge and food waste eliminates the disadvantages of composting these waste products separately. Specifically, co-composing neutralizes the pollutants and improves the organic matter that occur in sewage sludge, and solves the problem of the low pH values and high moisture content of food waste. However, little is known about the functional microorganisms, microbial metabolic capacity, and biosecurity risks involved in sewage sludge and food waste co-composting. Therefore, this study established four lab-scale composting reactors [T1 (separate composting of food waste), T2 (separate composting of sewage sludge), T3 (sewage sludge and food waste co-composting at a C/N ratio of 25), and T4 (equal proportions composting of sewage sludge and food waste)] to assess the feasibility of sewage sludge and food waste aerobic co-composting. Our findings indicated that polysaccharides and proteins in T3 could be effectively degraded, and the total nutrient levels in T3 were higher than those in the other groups. After composting, the microbial diversity and richness of T3 were higher than that of T1. In later composting stages, the functional microorganisms in T1 maintained higher metabolic activity, however, it also had a higher biosecurity risk than T3 due to the presence of pathogenic bacteria such as Enterococcus_faecalis and Bacillus_circulan. Although the product of T3 could not be used as a microbial fertilizer, its biosecurity risk was lower than that of T1 and could therefore be used as an organic fertilizer. Redundancy analysis (RDA) results indicated that changing the microbial community structure by adjusting key environmental factors could improve composting quality and reduce microbial safety risks. Collectively, our results provide a theoretical basis for the development of co-composting strategies for the biodegradation of perishable solid organic waste, in addition to proposing the risk of pathogenic bacteria exposure that could endanger human and animal health.
污泥与食物垃圾的共堆肥消除了分别堆肥这些废弃物的弊端。具体而言，共堆肥可中和污水污泥中存在的污染物并提高有机质含量，还能解决食物垃圾pH值低和水分含量高的问题。然而，对于污水污泥与食物垃圾共堆肥过程中涉及的功能微生物、微生物代谢能力及生物安全风险，人们了解甚少。因此，本研究建立了四个实验室规模的堆肥反应器 [T1（食物垃圾单独堆肥）、T2（污水污泥单独堆肥）、T3（碳氮比为25的污水污泥与食物垃圾共堆肥）和T4（污水污泥与食物垃圾等比例堆肥）]，以评估污水污泥与食物垃圾好氧共堆肥的可行性。我们的研究结果表明，T3中的多糖和蛋白质能够有效降解，且T3中的总养分水平高于其他组。堆肥后，T3的微生物多样性和丰富度高于T1。在堆肥后期，T1中的功能微生物保持较高的代谢活性，然而，由于存在粪肠球菌和环状芽孢杆菌等病原菌，其生物安全风险高于T3。虽然T3的产物不能用作微生物肥料，但其生物安全风险低于T1，因此可作为有机肥料使用。冗余分析（RDA）结果表明，通过调整关键环境因素改变微生物群落结构可提高堆肥质量并降低微生物安全风险。总体而言，我们的研究结果为开发易腐固体有机废弃物生物降解的共堆肥策略提供了理论依据，同时也提出了可能危害人类和动物健康的病原菌暴露风险。
