Water Technology Unit (WTU), Center for Advanced Materials (CAM). Qatar University, P.O. Box 2713, Doha, Qatar.
Dept. of Building, Civil and Environmental Engineering, Concordia University, 1455 Blvd de Maisonneuve W., Montreal, Quebec, H3G 1M8, Canada.
Chemosphere. 2023 Oct;339:139693. doi: 10.1016/j.chemosphere.2023.139693. Epub 2023 Aug 1.
Treating and reusing wastewater has become an essential aspect of water management worldwide. However, the increase in emerging pollutants such as polycyclic aromatic hydrocarbons (PAHs), which are presented in wastewater from various sources like industry, roads, and household waste, makes their removal difficult due to their low concentration, stability, and ability to combine with other organic substances. Therefore, treating a low load of wastewater is an attractive option. The study aimed to address membrane fouling in the submerged membrane bioreactor (SMBR) used for wastewater treatment. An aluminum electrocoagulation (EC) device was combined with SMBR as a pre-treatment to reduce fouling. The EC-SMBR process was compared with a conventional SMBR without EC, fed with real grey water. To prevent impeding biological growth, low voltage gradients were utilized in the EC deviceThe comparison was conducted over 60 days with constant transmembrane pressure and infinite solid retention time (SRT). In phase I, when the EC device was operated at a low voltage gradient (0.64 V/cm), no significant improvement in the pollutants removal was observed in terms of color, turbidity, and chemical oxygen demand (COD). Nevertheless, during phase II, a voltage gradient of 1.26 V/cm achieved up to 100%, 99.7%, 92%, 94.1%, and 96.5% removals in the EC-SMBR process in comparison with 95.1%, 95.4%, 85%, 91.7% and 74.2% removals in the SMBR process for turbidity, color, COD, ammonia nitrogen (NH-N), total phosphorus (TP), respectively. SMBR showed better anionic surfactant (AS) removal than EC-SMBR. A voltage gradient of 0.64 V/cm in the EC unit significantly reduced fouling by 23.7%, while 1.26 V/cm showed inconsistent results. Accumulation of Al ions negatively affected membrane performance. Low voltage gradients in EC can control SMBR fouling if Al concentration is controlled. Future research should investigate EC-SMBR with constant membrane flux for large-scale applications, considering energy consumption and operating costs.
处理和再利用废水已成为全球水管理的重要组成部分。然而，由于新兴污染物（如多环芳烃（PAHs））的浓度低、稳定性高且易于与其他有机物质结合，因此从工业、道路和家庭废物等各种来源的废水中去除这些污染物变得困难。因此，处理低负荷废水是一个有吸引力的选择。本研究旨在解决用于废水处理的浸没式膜生物反应器（SMBR）中的膜污染问题。将铝电凝聚（EC）装置与 SMBR 结合作为预处理以减少污染。将 EC-SMBR 工艺与未使用 EC 的常规 SMBR 进行比较，并用实际的灰色水进料。为了防止阻碍生物生长，在 EC 装置中使用低电压梯度。在 60 天的时间内，使用恒定的跨膜压力和无限的固体保留时间（SRT）进行比较。在第一阶段，当 EC 装置以低电压梯度（0.64 V/cm）运行时，在颜色、浊度和化学需氧量（COD）的去除方面没有观察到污染物去除的显著改善。然而，在第二阶段，与 SMBR 工艺相比，在 EC-SMBR 工艺中，电压梯度为 1.26 V/cm 时，浊度、颜色、COD、氨氮（NH-N）、总磷（TP）的去除率分别达到 100%、99.7%、92%、94.1%和 96.5%，而 SMBR 工艺的去除率分别为 95.1%、95.4%、85%、91.7%和 74.2%。SMBR 对阴离子表面活性剂（AS）的去除效果优于 EC-SMBR。EC 单元中的 0.64 V/cm 电压梯度可将污染减少 23.7%，而 1.26 V/cm 则显示出不一致的结果。Al 离子的积累会对膜性能产生负面影响。如果控制 Al 浓度，EC 中的低电压梯度可以控制 SMBR 污染。未来的研究应在考虑能源消耗和运营成本的情况下，针对大规模应用，研究恒定膜通量的 EC-SMBR。
