Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
Fondazione Edmund Mach, Environmental, Energy and Livestock Resources Unit, Trento, Italy.
J Environ Manage. 2022 May 1;309:114688. doi: 10.1016/j.jenvman.2022.114688. Epub 2022 Feb 15.
The best available technique (BAT) for managing the organic fraction of municipal solid waste (OFMSW) is represented by anaerobic digestion (AD) and subsequent composting. This research explored a new industrial model in the framework of the C2Land international project, with the insertion of hydrothermal carbonization (HTC) as a post-treatment for OFMSW digestate. The reaction was set for 3 h at three different temperatures (180 ÷ 220 °C); the wet solid hydrochar obtained after filtration was then co-composted with greenery waste as a bulking agent and untreated OFMSW digestate in four different proportions in bench-scale bioreactors. The hydrochars and the hydrochar co-composts were suitable for agro-industrial applications, while the HTC liquors were tested in biochemical methane potential (BMP) for internal recirculation to AD. The scenarios proposed can be beneficial for plant enhancement and increased biogas production. This study reports results connected to the production phase. Mass balances confirmed that, during HTC, phosphorus precipitated into the solid products, organic nitrogen partially mineralized into ammonium, and oxidizable organic matter solubilized. The selected hydrochar obtained at 200 °C had mean (dry) solid, liquid, and gaseous yields equal to 77, 20, and 3 %, respectively. The dynamic respirometric index (DRI) confirmed that the reproduced BAT for the composting process was effective in producing high-quality hydrochar co-composts in terms of biological stability. The BMP tests on HTC liquors showed some inhibitory effects, suggesting the need for future studies with inoculum adaptation and co-digestion, to dilute toxic compounds and enhance biogas production. Part 2 of this study describes the agro-environmental properties of hydrochars and hydrochar co-composts, including the beneficial effect of composting on hydrochars phytotoxicity.
管理城市固体废物有机部分（OFMSW）的最佳可用技术（BAT）是厌氧消化（AD）和随后的堆肥。本研究在 C2Land 国际项目框架内探索了一种新的工业模式，其中插入水热碳化（HTC）作为 OFMSW 消化物的后处理。反应在三个不同温度（180°C-220°C）下设置 3 小时；过滤后获得的湿固体水炭然后与绿肥作为膨胀剂和未经处理的 OFMSW 消化物在四个不同比例在台式生物反应器中进行共堆肥。水炭和水炭共堆肥适合农业工业应用，而 HTC 废液则在生化甲烷潜力（BMP）中进行内部循环以进行 AD 测试。所提出的方案对植物增强和增加沼气生产可能有益。本研究报告了与生产阶段相关的结果。质量平衡证实，在 HTC 过程中，磷沉淀到固体产物中，有机氮部分矿化为铵，可氧化有机物溶解。在 200°C 下获得的选定水炭具有 77%（干）固体、20%液体和 3%气体的平均（干）固体、液体和气体产率。动态呼吸计量指数（DRI）证实，对于堆肥过程，再现的 BAT 有效地生产了具有生物稳定性的高质量水炭共堆肥。HTC 废液的 BMP 测试显示出一些抑制作用，表明需要进行未来的研究，包括接种物适应和共消化，以稀释有毒化合物并提高沼气产量。本研究的第二部分描述了水炭和水炭共堆肥的农业环境特性，包括堆肥对水炭植物毒性的有益影响。
