Ariunbaatar Javkhlan, Bair Robert, Ozcan Onur, Ravishankar Harish, Esposito Giovanni, Lens Piet N L, Yeh Daniel H
Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy.
Department of Civil and Environmental Engineering, University of South Florida, Tampa, FL, United States.
Front Bioeng Biotechnol. 2021 Jan 18;8:594936. doi: 10.3389/fbioe.2020.594936. eCollection 2020.
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.
由于水力停留时间（HRT）较长，食物垃圾（FW）的厌氧消化通常限于大型反应器。诸如厌氧膜生物反应器（AnMBR）等技术能够在较低的HRT下进行厌氧消化，同时保持较高的化学需氧量（COD）去除效率。本研究评估了HRT和有机负荷率（OLR）对侧流式AnMBR处理稀释的新鲜食物垃圾（FW）的稳定性和性能的影响。向该反应器中投喂进水浓度为8.24（±0.12）g COD/L的合成食物垃圾。通过将HRT从20天降至1天来提高OLR。在整个运行过程中，AnMBR对进水COD和总悬浮固体（TSS）的总体去除效率分别>97%和>98%。生物过程能够将76%的进水COD转化为沼气，沼气中甲烷含量为70%，而膜上形成的滤饼层额外去除了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，2周后，相对于生物反应器中的浓度，TAN和TN的平均总体去除效率分别为17.3（±5）%和61.5（±3）%。总磷（TP）相对于进水的平均去除效率为40.39（±5）%。当HRT从7天降至5天时观察到膜污染，通过反冲洗得以缓解。本研究表明，侧流式AnMBR可成功将湿式厌氧食物垃圾（固体含量7%）消化器的典型HRT从20天降至1天，同时保持较高的COD去除效率和沼气产量。
