Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
Water Res. 2016 Nov 15;105:370-382. doi: 10.1016/j.watres.2016.09.017. Epub 2016 Sep 12.
Extensive research in recent years has explored numerous new features in the forward osmosis membrane bioreactor (FOMBR) process. However, there is an aspect, which is revolutionary but not yet been investigated. In FOMBR, FO membrane shows high rejection for a wide range of soluble contaminants. As a result, hydraulic retention time (HRT) does not correctly reflect the nominal retention of these dissolved contaminants in the bioreactor. This decoupling of contaminants retention time (CRT, i.e. the nominal retention of the dissolved contaminants) from HRT endows FOMBR a potential in significantly reducing the HRT for wastewater treatment. In this work, we report our results in this unexplored treatment potential. Using real municipal wastewater as feed, both a hybrid microfiltration-forward osmosis membrane bioreactor (MF-FOMBR) and a newly developed hybrid biofilm-forward osmosis membrane bioreactor (BF-FOMBR) achieved high removal of organic matter and nitrogen under HRT of down to 2.0 h, with significantly enhanced phosphorus recovery capacities. In the BF-FOMBR, the used of fixed bed biofilm not only obviated the need of additional solid/liquid separation (e.g. MF) to extract the side-stream for salt accumulation control and phosphorus recovery, but effectively quarantined the biomass from the FO membrane. The absence of MF in the side-stream further allowed suspended growth to be continuously removed from the system, which produced a selection pressure for the predominance of attached growth. As a result, a significant reduction in FO membrane fouling (by 24.7-54.5%) was achieved in the BF-FOMBR due to substantially reduced bacteria deposition and colonization.
近年来，大量研究探索了正向渗透膜生物反应器（FOMBR）工艺的许多新特性。然而，有一个方面具有革命性但尚未得到研究。在 FOMBR 中，FO 膜对多种可溶性污染物表现出高截留率。因此，水力停留时间（HRT）不能正确反映这些溶解污染物在生物反应器中的名义保留时间。这种污染物保留时间（CRT，即溶解污染物的名义保留时间）与 HRT 的解耦赋予了 FOMBR 显著减少废水处理 HRT 的潜力。在这项工作中，我们报告了在这个未开发的处理潜力方面的研究结果。使用实际的城市污水作为进料，混合微滤-正向渗透膜生物反应器（MF-FOMBR）和新开发的混合生物膜-正向渗透膜生物反应器（BF-FOMBR）在 HRT 低至 2.0 h 的条件下均实现了有机物和氮的高效去除，同时具有显著增强的磷回收能力。在 BF-FOMBR 中，固定床生物膜的使用不仅省去了额外的固液分离（例如 MF）来提取侧流以进行盐积累控制和磷回收的需要，而且有效地将生物量与 FO 膜隔离。侧流中没有 MF 进一步允许悬浮生长从系统中不断去除，这对附着生长的优势产生了选择压力。结果，BF-FOMBR 中的 FO 膜污染显著减少（减少了 24.7-54.5%），因为细菌沉积和定殖大大减少。
