Ye Pingping, Fang Linfa, Song Dan, Zhang Muyuan, Li Ronghua, Awasthi Mukesh Kumar, Zhang Zengqiang, Xiao Ran, Chen Xinping
Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China.
Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China; Key Laboratory of Low-carbon Green Agriculture in Southwestern China, Ministry of Agriculture and Rural Affairs, Chongqing 400715, China.
Sci Total Environ. 2023 Mar 1;862:160787. doi: 10.1016/j.scitotenv.2022.160787. Epub 2022 Dec 9.
Carbon neutrality is now receiving global concerns for the sustainable development of human societies, of which how to reduce greenhouse gases (GHGs) emissions and enhance carbon conservation and sequestration becomes increasingly critical. Therefore, this study conducted a meta-analysis and literature review to assess carbon loss and to explore the main factors that impact carbon loss during organic solid waste (OSW) composting. The results indicated that over 40 % of carbon was lost through composting, mainly as CO-C and merely as CH-C. Experimental scale, feedstock varieties, composting systems, etc., all impacted the carbon loss, and there was generally higher carbon loss under optimal conditions (i.e., C/N ratio (15-25), pH (6.5-7.5), moisture content (65-75 %)). Most mitigation strategies in conventional composting (CC) systems (e.g., additive supplementary, feedstock adjustment, and optimized aeration, etc.) barely mediated the TC and CO-C loss but dramatically reduced the emission of CH-C through composting. Among them, feedstock adjustment by elevating the feedstock C/N ratio effectively reduced the TC loss, and chemical additives facilitated the conservation of both carbon and nitrogen. By comparison, there was generally higher carbon loss in the novel composting systems (e.g. hyperthermophilic and electric field enhanced composting, etc.). However, the impacts of different mitigation strategies and novel composting systems on carbon loss reduction through composting were probably underestimated for the inappropriate evaluation methods (composting period-dependent instead of maturity originated). Therefore, further studies are needed to explore carbon transformation through composting, to establish methods and standards for carbon loss evaluation, and to develop novel techniques and systems for enhanced carbon conservation through composting. Overall, the results of this study could provide a reference for carbon-friendly composting for future OSW management under the background of global carbon neutrality.
碳中和目前正受到全球对人类社会可持续发展的关注，其中如何减少温室气体排放以及加强碳的固定和封存变得愈发关键。因此，本研究进行了一项荟萃分析和文献综述，以评估碳损失，并探索影响有机固体废物堆肥过程中碳损失的主要因素。结果表明，超过40%的碳在堆肥过程中损失，主要以CO-C形式损失，仅有少量以CH-C形式损失。实验规模、原料种类、堆肥系统等均会影响碳损失，且在最佳条件下（即碳氮比（15-25）、pH值（6.5-7.5）、水分含量（65-75%））通常碳损失更高。传统堆肥（CC）系统中的大多数减排策略（如添加补充剂、调整原料、优化曝气等）几乎无法调节总碳（TC）和CO-C损失，但能显著减少堆肥过程中CH-C的排放。其中，通过提高原料碳氮比来调整原料可有效减少TC损失，化学添加剂有助于碳和氮的保留。相比之下，新型堆肥系统（如嗜热堆肥和电场强化堆肥等）中的碳损失通常更高。然而，由于评估方法不当（依赖堆肥周期而非腐熟度），不同减排策略和新型堆肥系统对堆肥过程中碳损失减少的影响可能被低估。因此，需要进一步研究以探索堆肥过程中的碳转化，建立碳损失评估方法和标准，并开发通过堆肥增强碳保留的新技术和系统。总体而言，本研究结果可为全球碳中和背景下未来有机固体废物管理的碳友好型堆肥提供参考。
