This study addresses the challenges of efficiently processing the organic fraction of municipal solid waste (OFMSW) through dry anaerobic digestion in a vertical plug digester under mesophilic conditions. The focus is on optimizing hydraulic retention time (HRT) and digestate recirculation (REC) to enhance system performance. During the start-up phase, a mixture of digestate from a wet biogas plant and organic municipal solid waste (OFMSW) was employed, with a gradual introduction of 15 % garden waste to improve the carbon-to-nitrogen ratio and increase the total solids content. Various HRT levels (25, 30, and 40 days) and REC rates (17 % and 35 %) were assessed during steady-state operation. The start-up stage results suggest that increasing the feedstock C/N ratio, gradually removing excess water from the digestate, and achieving a 60 % REC are effective strategies to expedite the start-up process. Optimal performance was observed at HRT of 40 days and REC of 35 %, yielding a specific methane production (SMP) of 311.6 NL/kg VS. Maximum volumetric methane production (VMP) of 2.55 L/L/day and methane content of 62.2 % were recorded at HRT of 25 days with the same REC rate. Additionally, energy balance analysis revealed that digester heating constituted the highest energy consumption, with a maximum surplus energy of 44.0 % of gross biogas energy achieved under optimal volumetric methane production treatment. The study highlights the potential for implementing this system like Dranco process in heterogeneous waste treatment plants, emphasizing the advantages of moderate digestate recirculation. Future research should explore energy balance and scalability.

中文翻译：

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在立式活塞式消化池中对城市固体废物的有机部分进行干式厌氧消化：启动程序、消化液再循环、有机负荷率和能量平衡分析


本研究解决了在嗜温条件下通过在立式活塞消化器中干式厌氧消化有效处理城市固体废物 （OFMSW） 有机部分的挑战。重点是优化水力停留时间 （HRT） 和沼渣再循环 （REC） 以提高系统性能。在启动阶段，采用了来自湿沼气厂的沼渣和有机城市固体废物 （OFMSW） 的混合物，并逐步引入 15% 的花园废物，以提高碳氮比并增加总固体含量。在稳态手术期间评估各种 HRT 水平 （25 、 30 和 40 天） 和 REC 率 （17% 和 35 %）。启动阶段的结果表明，增加原料 C/N 比、逐渐从沼渣中去除多余的水以及实现 60% REC 是加快启动过程的有效策略。在 40 天的 HRT 和 35% 的 REC 下观察到最佳性能，产生 311.6 NL/kg 的比甲烷产生 （SMP） VS。在 25 天的 HRT 下，在相同的 REC 率下，最大体积甲烷产量 （VMP） 为 2.55 L/L/天，甲烷含量为 62.2%。此外，能量平衡分析表明，沼气池加热构成了最高的能源消耗，在最佳体积甲烷生产处理下，最大剩余能源为沼气总能的 44.0%。该研究强调了在异质废物处理厂中实施该系统（如 Dranco 工艺）的潜力，强调了适度沼渣再循环的优势。未来的研究应该探索能量平衡和可扩展性。