BioResource Systems Research Group, School of Civil Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom; Department of Agricultural and Bioresources Engineering, Federal University of Technology, Minna P.M.B. 65, Niger State, Nigeria.
School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom.
Waste Manag. 2021 Jul 1;130:12-22. doi: 10.1016/j.wasman.2021.04.053. Epub 2021 May 24.
The increasing rate of food waste (FW) generation globally, makes it an attractive resource for renewable energy through anaerobic digestion (AD). The biogas recovered from AD can be upgraded by the methanation of internally produced carbon dioxide, CO with externally sourced hydrogen gas, H (biomethanation). In this work, H was added to AD reactors processing FW in three successive phases, with digestate from preceding phases recycled in succession with the addition of fresh inoculum to enhance acclimation. The concentration of H was increased for succeeding phases: 5%, 10% and 15% of the reactor headspace in Phase 1 (EH1), Phase 2 (EH2) and Phase 3 (EH3), respectively. The H utilisation rate and biomethane yields increased as acclimation progressed from EH1 through EH3. Biomethane yield from the controls: EH1_Control, EH2_Control and EH3_Control were 417.6, 435.4 and 453.3 NmL-CH/gVS accounting for 64.8, 73.9 and 77.8% of the biogas respectively. And the biomethane yield from the test reactors EH1_Test, EH2_Test and EH3_Test were 468.3, 483.6, and 499.0 NmL-CH/gVS, accounting for 77.2, 78.1 and 81.0% of the biogas respectively. A progressive in-situ biomethanation could lead to biomethane production that meets higher fuel standards for gas-to-grid (GtG) injections and vehicle fuel - i.e. >95% CH. This would increase the energy yield and carbon savings compared to conventional biogas upgrade methods. For example, biogas upgrade for GtG by in-situ biomethanation could yield 7.3 MWh/t energy and 1343 kg-COe carbon savings, which is better than physicochemical upgrade options (i.e., 4.6-4.8 MWh/t energy yield and 846-883 kg-COe carbon savings).
全球食物浪费（FW）的增长率使其成为通过厌氧消化（AD）生产可再生能源的有吸引力的资源。从 AD 中回收的沼气可以通过内部产生的二氧化碳（CO）与外部来源的氢气（H）的甲烷化来升级，即生物甲烷化。在这项工作中，在三个连续阶段向处理 FW 的 AD 反应器中添加 H，前一阶段的消化物连续回收，并添加新鲜接种物以增强驯化。H 的浓度在前三个阶段逐渐增加：第 1 阶段（EH1）、第 2 阶段（EH2）和第 3 阶段（EH3）的反应器顶部空间分别为 5%、10%和 15%。随着驯化从 EH1 到 EH3 的进行，H 的利用率和生物甲烷产量增加。对照物的生物甲烷产量：EH1_Control、EH2_Control 和 EH3_Control 分别为 417.6、435.4 和 453.3 NmL-CH/gVS，分别占沼气的 64.8%、73.9%和 77.8%。测试反应器 EH1_Test、EH2_Test 和 EH3_Test 的生物甲烷产量分别为 468.3、483.6 和 499.0 NmL-CH/gVS，分别占沼气的 77.2%、78.1%和 81.0%。逐步原位生物甲烷化可导致生物甲烷产量满足更高的用于气体到电网（GtG）注入和车辆燃料的燃料标准，即>95% CH。与传统的沼气升级方法相比，这将增加能源产量和碳节约。例如，通过原位生物甲烷化对 GtG 进行沼气升级可产生 7.3 MWh/t 的能量和 1343 kg-COe 的碳节约，优于物理化学升级选项（即 4.6-4.8 MWh/t 的能量产量和 846-883 kg-COe 的碳节约）。
