Seawater-driven forward osmosis for direct treatment of municipal wastewater
Seawater-driven forward osmosis for direct treatment of municipal wastewater
复制标题
海水驱动的正向渗透直接处理城市废水
DOI：
10.12989/mwt.2017.8.5.449
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Cui Fuyi
中科院分区：
文献类型：
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作者：
Sun Yan;Bai Yang;Tian Jiayu;Gao Shanshan;Zhao Zhiwei;Cui Fuyi
以人工合成海水为提取液，对正渗透（FO）工艺直接处理城市污水的水通量衰减、盐的逆向扩散、污染物截留率和浓缩效率进行了评价。发现当在PRO模式（活性层面向汲取溶液）下操作时，尽管FO膜表现出更高的渗透水通量，但由于膜支撑层中污染物的更严重结垢以及伴随的结垢增强的浓差极化，也观察到更严重的通量下降和反向盐扩散。此外，尽管FO模式（活性层面向进料溶液）的水通量下降较低，但在PRO和FO模式中均发现了不可逆的膜污染，因为水通量无法通过物理冲洗恢复到初始值，这突出了长期运行中化学清洗的必要性。在实验中进行的7个过滤循环期间，FO膜对TOC、COD、TP和NH 4表现出相当高的截留率
+-N存在于废水中。通过优化海水汲取溶液/废水进料溶液的体积比，对于FO和PRO模式分别获得3.1和3.7的浓缩因子。结果表明，FO工艺的有效性直接处理城市污水，通过使用海水作为汲取溶液，同时促进后续利用浓缩废水的生物能源生产，这可能有特殊的影响，沿海地区。
Direct treatment of municipal wastewater by forward osmosis (FO) process was evaluated in terms of water flux decline, reverse salt diffusion, pollutants rejection and concentration efficiency by using synthetic seawater as the draw solution. It was found that when operating in PRO mode (active layer facing the draw solution), although the FO membrane exhibited higher osmotic water flux, more severe flux decline and reverse salt diffusion was also observed due to the more severe fouling of pollutants in the membrane support layer and accompanied fouling enhanced concentration polarization. In addition, although the water flux decline was shown to be lower for the FO mode (active layer facing the feed solution), irreversible membrane fouling was identified in both PRO and FO modes as the water flux cannot be restored to the initial value by physical flushing, highlighting the necessity of chemical cleaning in long-term operation. During the 7 cycles of filtration conducted in the experiments, the FO membrane exhibited considerably high rejection for TOC, COD, TP and NH4
+-N present in the wastewater. By optimizing the volume ratio of seawater draw solution/wastewater feed solution, a concentration factor of 3.1 and 3.7 was obtained for the FO and PRO modes, respectively. The results demonstrated the validity of the FO process for direct treatment of municipal wastewater by using seawater as the draw solution, while facilitating the subsequent utilization of concentrated wastewater for bioenergy production, which may have special implications for the coastline areas.