Abstract The role of submerged and sidestream forward osmosis (FO) membrane module configuration in osmotic membrane bioreactors (OMBRs) was investigated. Experiments were performed under identical conditions (solids retention time, bioreactor volume, feed solution, draw solute, and draw solution concentration) to isolate the effect of FO module configuration and associated hydrodynamics on water flux, reverse salt flux, and membrane fouling. Steady-state water flux of fouled membranes was the same for submerged and sidestream configurations and two draw solution concentrations, leading to the concept of a homeostatic flux in OMBRs similar to the critical flux in conventional membrane bioreactors. For the 35 g/L NaCl draw solution, specific reverse salt flux (SRSF) was 1.61 ± 0.01 and 0.59 ± 0.07 g/L for submerged and sidestream configurations, respectively and for the 100 g/L NaCl draw solution, SRSF was 2.22 ± 0.25 and 1.05 ± 0.35 g/L for submerged and sidestream configurations, respectively. Despite a significant increase in driving force, fouled membranes did not have higher steady-state water flux; instead, the 100 g/L draw solution resulted in greater membrane fouling; foulant cake layers were 2 to 4 times thicker, likely due to higher initial water flux that resulted in more foulants being transported to the membrane surface. Experimental results were used as model inputs to predict results for a larger scale system. Model results predicted lower steady-state bioreactor salinities in the sidestream configuration, particularly when longer solids retention times were used.

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淹没或侧流？组件配置对渗透膜生物反应器污染和盐度的影响

摘要 研究了浸没式和侧流正向渗透 (FO) 膜组件配置在渗透膜生物反应器 (OMBR) 中的作用。在相同条件（固体保留时间、生物反应器体积、进料溶液、驱动溶质和驱动溶液浓度）下进行实验，以隔离 FO 模块配置和相关流体动力学对水通量、反向盐通量和膜污染的影响。污染膜的稳态水通量对于浸没式和侧流配置以及两种驱动溶液浓度是相同的，从而导致 OMBR 中稳态通量的概念类似于传统膜生物反应器中的临界通量。对于 35 g/L NaCl 汲取溶液，浸没和侧流配置的特定反向盐通量 (SRSF) 为 1.61 ± 0.01 和 0.59 ± 0.07 g/L，对于 100 g/L NaCl 汲取溶液，浸没和侧流配置的 SRSF 分别为 2.22 ± 0.25 和 1.05 ± 0.35 g/L。尽管驱动力显着增加，污染膜没有更高的稳态水通量；相反，100 g/L 的汲取溶液会导致更大的膜污染；污垢饼层厚 2 到 4 倍，这可能是由于较高的初始水通量导致更多污垢被输送到膜表面。实验结果被用作模型输入来预测更大规模系统的结果。模型结果预测侧流配置中的稳态生物反应器盐度较低，特别是当使用较长的固体保留时间时。浸没和侧流配置分别为 35 g/L。尽管驱动力显着增加，污染膜没有更高的稳态水通量；相反，100 g/L 的汲取溶液会导致更大的膜污染；污垢饼层厚 2 到 4 倍，这可能是由于较高的初始水通量导致更多污垢被输送到膜表面。实验结果被用作模型输入来预测更大规模系统的结果。模型结果预测侧流配置中的稳态生物反应器盐度较低，特别是当使用较长的固体保留时间时。浸没和侧流配置分别为 35 g/L。尽管驱动力显着增加，污染膜没有更高的稳态水通量；相反，100 g/L 的汲取溶液会导致更大的膜污染；污垢饼层厚 2 到 4 倍，这可能是由于较高的初始水通量导致更多污垢被输送到膜表面。实验结果被用作模型输入来预测更大规模系统的结果。模型结果预测侧流配置中的稳态生物反应器盐度较低，特别是当使用较长的固体保留时间时。100 g/L 汲取溶液导致更大的膜污染；污垢饼层厚 2 到 4 倍，这可能是由于较高的初始水通量导致更多污垢被输送到膜表面。实验结果被用作模型输入来预测更大规模系统的结果。模型结果预测侧流配置中的稳态生物反应器盐度较低，特别是当使用较长的固体保留时间时。100 g/L 汲取溶液导致更大的膜污染；污垢饼层厚 2 到 4 倍，这可能是由于较高的初始水通量导致更多污垢被输送到膜表面。实验结果被用作模型输入来预测更大规模系统的结果。模型结果预测侧流配置中的稳态生物反应器盐度较低，特别是当使用较长的固体保留时间时。