The low-pressure reverse osmosis (LPRO) process is a recent development of reverse osmosis (RO) technology for the reduction in RO energy consumption and operation cost. The goal of this study was to investigate the performance of LPRO processes for the treatment and reuse of effluent discharged from brewery upflow anaerobic sludge blanket bioreactors (UASB). In this study, three different commercially available LPRO membranes were tested to evaluate the water quality that can be achieved under different operational and pretreatment conditions. It was found that the filtration performance and the effluent quality of the LPRO membranes can be considerably affected by the operation conditions and the selection of the pretreatment processes. The ultrafiltration (UF) pretreatment and the control of the operation pressure were found to be essential for mitigating LPRO membrane fouling, which could be caused by Ca²⁺ associated precipitates and organic gelation, in the treatment of the brewery UASB effluent. Water quality analyses showed that an integrated process of the UASB + UF + LPRO could achieve an effluent quality characterized by concentrations of 10.4–12.5 mg/L of chemical oxygen demand (COD), 1.8–2.1 mg/L of total nitrogen (TN), 1.3–1.8 mg/L of ammonia nitrogen (NH₃-N) and 0.8–1.2 mg/L of total phosphorus (TP). The effluent quality and the LPRO performance could be further improved by adding a granular activated carbon (GAC) adsorption process between the UF and LPRO processes, which reduced the concentration of COD to 7–10 mg/L and those of TN, TP, NH₃-N to below 1 mg/L. For the treatment of the UASB effluent tested in this study, the UF, UF + GAC (retention time 4 hrs), UF + LPRO, and UF + GAC + LPRO, respectively, achieved overall COD removal efficiencies of 89.6–93.7%, 94.5–96.7%, 99.3–99.1% and 99.3–99.4%; TN removal efficiencies of 73.0–78.2%, 89.2–97.2%, 97.1–98.2% and 94.3–99.7%; and TP removal efficiencies of 29.3–46.2%, 77.0–95.4%, 95.9–97.6z% and 98.0–98.3%. This study showed that both UASB + UF + LPRO and UASB + UF + GAC + LPRO are effective treatment processes for treating brewery wastewater toward reuse water quality standards set by the United States Environmental Protection Agency (US EPA). Therefore, the results of this study would help to answer whether a LPRO can treat the brewery UASB effluent to meet the requirements of wastewater reuse standards.

中文翻译：

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上流式厌氧污泥毯式生物反应器出水回用的处理

低压反渗透 (LPRO) 工艺是反渗透 (RO) 技术的最新发展，用于降低 RO 能耗和运行成本。本研究的目的是研究 LPRO 工艺在处理和再利用啤酒厂上流式厌氧污泥床生物反应器 (UASB) 排放的废水方面的性能。在这项研究中，测试了三种不同的市售 LPRO 膜，以评估在不同操作和预处理条件下可以获得的水质。结果表明，LPRO 膜的过滤性能和出水质量受操作条件和预处理工艺选择的影响很大。²⁺相关沉淀和有机凝胶，用于处理啤酒厂 UASB 废水。水质分析表明，UASB + UF + LPRO 的集成工艺可以实现化学需氧量 (COD) 浓度为 10.4–12.5 mg/L、总氮 (TN) 浓度为 1.8–2.1 mg/L 的出水水质, 1.3–1.8 mg/L 氨氮 (NH ₃ -N) 和 0.8–1.2 mg/L 总磷 (TP)。通过在超滤和 LPRO 工艺之间添加颗粒活性炭 (GAC) 吸附工艺，可以进一步提高出水水质和 L​​PRO 性能，将 COD 浓度降低至 7-10 mg/L，TN、TP、NH 浓度降低₃-N 低于 1 mg/L。对于本研究中测试的 UASB 废水的处理，UF、UF + GAC（保留时间 4 小时）、UF + LPRO 和 UF + GAC + LPRO 分别实现了 89.6-93.7%、94.5 的总体 COD 去除效率–96.7%、99.3–99.1% 和 99.3–99.4%；TN去除效率为73.0-78.2%、89.2-97.2%、97.1-98.2%和94.3-99.7%；TP 去除效率分别为 29.3-46.2%、77.0-95.4%、95.9-97.6z% 和 98.0-98.3%。该研究表明，UASB + UF + LPRO 和 UASB + UF + GAC + LPRO 都是处理啤酒废水的有效处理工艺，可达到美国环境保护署 (US EPA) 制定的回用水质标准。因此，本研究的结果将有助于回答 LPRO 是否可以处理啤酒厂 UASB 废水以满足废水回用标准的要求。