King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Division of Biological and Environmental Science and Engineering (BESE), Thuwal 23955-6900, Saudi Arabia.
Department of Environmental Engineering, Sejong Campus, Korea University, 2511, Sejong-ro, Jochiwon-eup, Sejong-si, Republic of Korea.
Water Res. 2021 Jun 15;198:117157. doi: 10.1016/j.watres.2021.117157. Epub 2021 Apr 16.
Forward osmosis-membrane distillation (FO-MD) hybrids were recently found suitable for produced water treatment. Exclusion of synthetic chemical draw solutions, typically used for FO, can reduce FO-MD operational costs and ease its onsite application. This study experimentally validates a novel concept for the simultaneous treatment of different produced water streams available at the same industrial site using an FO-MD hybrid system. The water oil separator outlet (WO) stream was selected as FO draw solution and it generated average fluxes ranging between 8.30 LMH and 26.78 LMH with four different feed streams. FO fluxes were found to be governed by the complex composition of the feed streams. On the other hand, with WO stream as MD feed, an average flux of 14.41 LMH was achieved. Calcium ions were found as a main reason for MD flux decline in the form of CaSO scaling and stimulating the interaction between the membrane and humic acid molecules to form scale layer causing reduction in heat transfer and decline in MD flux (6%). Emulsified oil solution was responsible for partial pore clogging resulting in further 2% flux decline. Ethylenediaminetetraaceticacid (EDTA) was able to mask a portion of calcium ions and resulted in a complete recovery of the original MD flux. Under hybrid FO-MD experiments MD fluxes between 5.62 LMH and 11.12 LMH were achieved. Therefore, the novel concept is validated to produce fairly stable FO and MD fluxes, with few streams, without severe fouling and producing excellent product water quality.
正向渗透-膜蒸馏（FO-MD）混合系统最近被发现适用于处理采出水。不使用通常用于 FO 的合成化学汲取液，可以降低 FO-MD 的运营成本，并简化其现场应用。本研究通过 FO-MD 混合系统实验验证了一种同时处理同一工业现场不同采出水的新概念。选择水油分离器出口（WO）流作为 FO 汲取液，并用四种不同的进料流产生平均通量在 8.30 LMH 和 26.78 LMH 之间。FO 通量受进料流的复杂组成控制。另一方面，用 WO 流作为 MD 进料，可实现平均通量 14.41 LMH。发现钙离子以 CaSO 结垢的形式是 MD 通量下降的主要原因，并刺激膜和腐殖酸分子之间的相互作用形成结垢层，导致传热减少和 MD 通量下降（6%）。乳化油溶液导致部分孔堵塞，导致通量进一步下降 2%。乙二胺四乙酸（EDTA）能够掩蔽部分钙离子，从而使 MD 通量完全恢复到原始水平。在混合 FO-MD 实验中，可实现 5.62 LMH 和 11.12 LMH 之间的 MD 通量。因此，该新概念被验证为能够在没有严重结垢的情况下，以少量的水流产生相当稳定的 FO 和 MD 通量，并生产出优质的产品水。
