Anaerobic digestion of food waste (FW) is typically limited to large reactors due to high hydraulic retention times (HRTs). Technologies such as anaerobic membrane reactors (AnMBRs) can perform anaerobic digestion at lower HRTs while maintaining high chemical oxygen demand (COD) removal efficiencies. This study evaluated the effect of HRT and organic loading rate (OLR) on the stability and performance of a side-stream AnMBR in treating diluted fresh food waste (FW). The reactor was fed with synthetic FW at an influent concentration of 8.24 (± 0.12) g COD/L. The OLR was increased by reducing the HRT from 20 to 1 d. The AnMBR obtained an overall removal efficiency of >97 and >98% of the influent COD and total suspended solids (TSS), respectively, throughout the course of operation. The biological process was able to convert 76% of the influent COD into biogas with 70% methane content, while the cake layer formed on the membrane gave an additional COD removal of 7%. Total ammoniacal nitrogen (TAN) and total nitrogen (TN) concentrations were found to be higher in the bioreactor than in the influent, and average overall removal efficiencies of 17.3 (± 5) and 61.5 (± 3)% of TAN and TN, respectively, were observed with respect to the bioreactor concentrations after 2 weeks. Total phosphorus (TP) had an average removal efficiency of 40.39 (± 5)% with respect to the influent. Membrane fouling was observed when the HRT was decreased from 7 to 5 d and was alleviated through backwashing. This study suggests that the side-stream AnMBR can be used to successfully reduce the typical HRT of wet anaerobic food waste (solids content 7%) digesters from 20 days to 1 day, while maintaining a high COD removal efficiency and biogas production.

中文翻译：

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AnMBR 处理消费后餐厨垃圾的性能：水力停留时间和有机负荷率对沼气生产和膜污染的影响

由于较高的水力停留时间 (HRT)，食物垃圾 (FW) 的厌氧消化通常仅限于大型反应器。厌氧膜反应器 (AnMBR) 等技术可以在较低的 HRT 下进行厌氧消化，同时保持高化学需氧量 (COD) 去除效率。本研究评估了 HRT 和有机负载率 (OLR) 对侧流 AnMBR 在处理稀释的新鲜食物垃圾 (FW) 中的稳定性和性能的影响。向反应器中加入进水浓度为 8.24 (± 0.12) g COD/L 的合成 FW。通过将 HRT 从 20 天减少到 1 天来增加 OLR。在整个运行过程中，AnMBR 的总体去除效率分别为进水 COD 和总悬浮固体 (TSS) 的 >97% 和 >98%。生物过程能够将 76% 的进水 COD 转化为甲烷含量为 70% 的沼气，而在膜上形成的滤饼层可额外去除 7% 的 COD。发现生物反应器中的总氨氮 (TAN) 和总氮 (TN) 浓度高于进水，TAN 和 TN 的平均总体去除效率分别为 17.3 (± 5) 和 61.5 (± 3)% ，观察 2 周后生物反应器浓度的变化。相对于进水，总磷 (TP) 的平均去除效率为 40.39 (± 5)%。当 HRT 从 7 天降低到 5 天并通过反冲洗得到缓解时，可以观察到膜污染。