Assessing the removal of organic micro-pollutants from anaerobic membrane bioreactor effluent by fertilizer-drawn forward osmosis
Assessing the removal of organic micro-pollutants from anaerobic membrane bioreactor effluent by fertilizer-drawn forward osmosis
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DOI：
10.1016/j.memsci.2017.03.027
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发表时间：
2017-07-01
影响因子：
9.5
通讯作者：
Shon, Ho Kyong
中科院分区：
文献类型：
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作者：
Kim, Youngjin;Li, Sheng;Shon, Ho Kyong
在本研究中，在厌氧膜生物反应器（AnMBR）废水处理过程中，评估了化肥正向渗透（FDFO）中有机微污染物（OMP）传输（包括膜污染）的行为。当 FO 膜以面向进料溶液 (AL-FS) 的活性层定向时，通量下降可以忽略不计，而对于以磷酸二铵 (DAP) 肥料作为 DS 的活性层面向驱动溶液 (AL-DS)，由于膜支撑层内的鸟粪石结垢，观察到通量下降严重。然而，与其他两种肥料（即磷酸一铵 (MAP) 和 KCl）相比，DAP DS 表现出最低的 OMP 前向通量或更高的 OMP 截留率。 MAP 和 KCl 肥料 DS 具有较高的水通量，可诱导较高的外部浓差极化 (ECP) 并增强通过 FO 膜的 OMP 通量。在膜取向的 AL-DS 模式下，使用 MAP 和 KCl 作为 DS，由于增强了集中内部浓度极化，OMP 传输进一步增加，而使用 DAP 时，内部结垢增强了传质阻力，从而降低了 OMP 通量。物理或水力清洗可以成功恢复在 AL-FS 模式下运行的 FO 膜的水通量，但由于支撑层中的内部结垢和污垢，在 AL-DS 模式下运行的膜仅观察到部分通量恢复。然而，渗透反洗可以显着提高清洁效率。
In this study, the behavior of organic micro-pollutants (OMPs) transport including membrane fouling was assessed in fertilizer-drawn forward osmosis (FDFO) during treatment of the anaerobic membrane bioreactor (AnMBR) effluent. The flux decline was negligible when the FO membrane was oriented with active layer facing feed solution (AL-FS) while severe flux decline was observed with active layer facing draw solution (AL-DS) with di-ammonium phosphate (DAP) fertilizer as DS due to struvite scaling inside the membrane support layer. DAP DS however exhibited the lowest OMPs forward flux or higher OMPs rejection rate compared to other two fertilizers (i.e., mono-ammonium phosphate (MAP) and KCl). MAP and KCl fertilizer DS had higher water fluxes that induced higher external concentration polarization (ECP) and enhanced OMPs flux through the FO membrane. Under the AL-DS mode of membrane orientation, OMPs transport was further increased with MAP and KCl as DS due to enhanced concentrative internal concentration polarization while with DAP the internal scaling enhanced mass transfer resistance thereby lowering OMPs flux. Physical or hydraulic cleaning could successfully recover water flux for FO membranes operated under the AL-FS mode but only partial flux recovery was observed for membranes operated under AL-DS mode because of internal scaling and fouling in the support layer. Osmotic backwashing could however significantly improve the cleaning efficiency.