The Experts below are selected from a list of 1662 Experts worldwide ranked by ideXlab platform
Xiaoxiang Cheng - One of the best experts on this subject based on the ideXlab platform.
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ferrous activated sodium percarbonate pre oxidation for membrane Fouling control during ultrafiltration of algae laden water
Science of The Total Environment, 2020Co-Authors: Zixiao Ren, Xiaoxiang Cheng, Congwei Luo, Fengxun Tan, Weiwei Zhou, Wenchen Liu, Lu ZhengAbstract:Membrane technology has been shown to be promising for the treatment of algae-laden water, but membrane Fouling is still an obstacle influencing the purification efficiency and effluent quality. To mitigate ultrafiltration membrane Fouling during Microcystis aeruginosa-laden water treatment, a strategy of sodium percarbonate pre-oxidation activated with ferrous ion (Fe2+/SPC) was put forward in this study. Due to the synergistic effect of Fe2+ and SPC, this process was significantly more efficient with the terminal specific flux increased from 0.097 to 0.397, and the Reversible Fouling resistance reduced by approximately 80%. It was also found that subsequent sedimentation followed by Fe2+/SPC could further improve the Fouling control efficiency. The model fitting results indicated that Fe2+/SPC pre-oxidation delayed the transition from standard blocking to cake filtration. Extracellular organic matter and algal cells were extracted from algal foulants to explore the contribution of each component, and the Fouling control efficiencies were systematically studied. The characteristics of the algal foulants were determined with fluorescence excitation-emission matrix spectrum, and the results suggested that macromolecular proteinaceous substances were more efficiently removed by Fe2+/SPC, in comparison with humic-like matters. The alleviation of membrane Fouling was also verified by the characterization methods of scanning electron microscopy and attenuated total reflection-Fourier infrared spectroscopy. Overall, the proposed strategy of Fe2+/SPC has an application prospect for membrane Fouling control in algal-laden water treatment.
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application of sodium percarbonate activated with fe ii for mitigating ultrafiltration membrane Fouling by natural organic matter in drinking water treatment
Journal of Cleaner Production, 2020Co-Authors: Xiaoxiang Cheng, Zixiao Ren, Congwei Luo, Fengxun Tan, Weiwei Zhou, Lu Zheng, Xuewu ZhuAbstract:Abstract It remains challenging to efficiently mitigate membrane Fouling caused by natural organic matter (NOM) for the widespread application of ultrafiltration process. In this study, sodium percarbonate activated with Fe(II) (Fe(II)/SPC) was proposed as a feedwater pretreatment strategy for membrane Fouling control. Typical NOM fractions, i.e., humic acid (HA), bovine serum albumin (BSA) were employed as membrane foulants, as well as natural surface water. The results showed that Fe(II)/SPC pretreatment apparently alleviated membrane Fouling by BSA and HA-BSA, and the performance outperformed Fe(II) pre-coagulation and SPC pre-oxidation alone. Considering HA Fouling, more severe flux decline and increased Reversible Fouling resistance were obtained, while irReversible Fouling was slightly mitigated. The filtration of HA-BSA was well fitted to intermediate blocking followed by cake filtration, and Fe(II)/SPC noticeably increased the filtration volume corresponding to the formation of cake filtration. With Fe(II)/SPC pretreatment, a sparser and more homogeneous foulant layer with lower resistances was observed on membrane surface, and Fourier transform infrared spectroscopy indicated that the peak intensities of major functional groups for organic pollutants were significantly decreased. In surface water treatment, Fe(II)/SPC could effectively improve membrane filtration behavior and pollutants removal, with a distinct decrease of both fluorescent fractions and different molecular weight organic compounds. It seemed that hydroxyl radical oxidation and coagulation with in-situ formed Fe(III) were the main mechanisms of contaminants removal and membrane Fouling control. Overall, this combined process exhibited a great potential for actual application during drinking water treatment.
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effect of sulfate radical based oxidation pretreatments for mitigating ceramic uf membrane Fouling caused by algal extracellular organic matter
Water Research, 2018Co-Authors: Xiaoxiang Cheng, Heng Liang, Xuewu Zhu, Xiaobin Tang, Zhendong Gan, Jiajian Xing, Xinsheng LuoAbstract:Abstract Algal extracellular organic matter (EOM) released from Microcystis aeruginosa can cause severe membrane Fouling during algae-laden water treatment. To solve this problem, three typical sulfate radical-based advanced oxidation processes (SR-AOPs), i.e., ferrous iron/peroxymonosulfate (Fe(II)/PMS), UV/PMS and UV/Fe(II)/PMS, were employed as membrane pretreatment strategies. Their performance on mitigating EOM Fouling of a ceramic UF membrane was systematically investigated and compared in the present study. The results indicated that SR-AOPs pretreatments could promote the reduction of DOC and UV254, and the removal performance showed an apparent regularity of UV/Fe(II)/PMS > Fe(II)/PMS > UV/PMS. The pretreatments were very effective for decomposing high-MW biopolymers (>20,000 Da) into low-MW humic substances (1000–20,000 Da), thus reducing the accumulation of high-MW biopolymers on membrane surface. With respect to membrane Fouling control, Fe(II)/PMS significantly mitigated both Reversible and irReversible membrane Fouling, whereas UV/PMS only reduced Reversible Fouling, and exhibited little effect on irReversible Fouling. By contrast, UV/Fe(II)/PMS showed the best performance for Fouling reduction due to the synergistic effect of UV and Fe(II) for PMS activation. The dominating Fouling mechanism was governed by both pore blockage and cake filtration, likely due to the bimodal MW distribution of EOM, and SR-AOPs pretreatments delayed the transition from pore blockage to cake filtration. In addition, SR-AOPs prior to UF membrane were also very effective to improve the removal of micropollutants (i.e., ATZ, SMT and p-CNB). These results demonstrate the potential application of SR-AOPs as pretreatment for membrane Fouling control during algae-laden water treatment.
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microcystis aeruginosa laden surface water treatment using ultrafiltration membrane Fouling cell integrity and extracellular organic matter rejection
Water Research, 2017Co-Authors: Bin Liu, Heng Liang, Bart Van Der Bruggen, Xiaoxiang ChengAbstract:Despite its superb separation performance, ultrafiltration (UF) still faces challenges in treating the Microcystis aeruginosa-laden water of lakes or reservoirs, due to membrane Fouling and poor rejection of soluble organics. In this work, to better understand the mechanisms of membrane Fouling, cell breakage and organic rejection and their mutual influence, a comparative UF experiment was conducted under a variety of transmembrane pressures (TMPs, 50–250 kPa) with lab-cultured Microcystis aeruginosa. Membrane Fouling was characterized with respect to flux decline and Fouling reversibility, and cell breakage during UF filtration was evaluated using a flow cytometer. Moreover, the rejection of extracellular organic matter (EOM) by UF was investigated with respect to the dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm (UV254) and microcystin-LR (MCLR). The results indicated that the accumulation of Microcystis cells and EOM on the membrane surface caused serious Reversible Fouling that substantially aggravated with the increasing TMP and was successively governed by pore blocking and cake filtration. The cell breakage during filtration was less than 5% and mainly occurred in the cake layer due to hydraulic shear, but the breakage did not substantially vary with increasing TMP. EOM removal by UF ranged from 40% to 70% (in terms of DOC removal), and the removal performance increased with the Reversible resistance, implying a trade-off between organic removal and permeability. Regarding soluble and small organics such as MCLR, a higher degree of removal was also found at higher TMP, despite of some variations over the duration of the filtration tests, and the cake layer retention proved to be the principle removal mechanism, especially during steady filtration stages.
Xihui Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of pre ozonation on mitigation of ceramic uf membrane Fouling caused by algal extracellular organic matters
Chemical Engineering Journal, 2016Co-Authors: Dequan Wei, Yi Tao, Zhenghua Zhang, Xihui ZhangAbstract:Abstract Soluble extracellular organic matters (EOM) resulting from algal blooms in water sources can cause severe membrane Fouling in water treatment. The effect of pre-ozonation on mitigation of ceramic UF membrane Fouling caused by EOM released from Microcystis aeruginosa and the associated Fouling mitigation mechanism were investigated through the characterization of hydraulic performance, dissolved organic carbon (DOC), fluorescence excitation–emission matrix (EEM) spectra, molecular weight (MW) distribution, hydrophilicity and model fit of five combined Fouling models. Pre-ozonation achieved a remarkable effect of hydraulically Reversible Fouling mitigation as a result of the selective oxidation of the very high MW hydrophobic biopolymers (⩾20 kDa) to lower MW and more hydrophilic compounds. However, pre-ozonation had a very limited effect on mitigation of hydraulically irReversible Fouling dominated by the high MW (1–10 kDa) hydrophilic organics. Modeling results indicated that the EOM-related membrane Fouling mitigation by pre-ozonation was more likely ascribed to the alleviation of cake layer and standard pore blocking with standard pore blocking playing a more important role.
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effect of pre ozonation on mitigation of ceramic uf membrane Fouling caused by algal extracellular organic matters
Chemical Engineering Journal, 2016Co-Authors: Zhenghua Zhang, Xihui ZhangAbstract:Abstract Soluble extracellular organic matters (EOM) resulting from algal blooms in water sources can cause severe membrane Fouling in water treatment. The effect of pre-ozonation on mitigation of ceramic UF membrane Fouling caused by EOM released from Microcystis aeruginosa and the associated Fouling mitigation mechanism were investigated through the characterization of hydraulic performance, dissolved organic carbon (DOC), fluorescence excitation–emission matrix (EEM) spectra, molecular weight (MW) distribution, hydrophilicity and model fit of five combined Fouling models. Pre-ozonation achieved a remarkable effect of hydraulically Reversible Fouling mitigation as a result of the selective oxidation of the very high MW hydrophobic biopolymers (⩾20 kDa) to lower MW and more hydrophilic compounds. However, pre-ozonation had a very limited effect on mitigation of hydraulically irReversible Fouling dominated by the high MW (1–10 kDa) hydrophilic organics. Modeling results indicated that the EOM-related membrane Fouling mitigation by pre-ozonation was more likely ascribed to the alleviation of cake layer and standard pore blocking with standard pore blocking playing a more important role.
Heng Liang - One of the best experts on this subject based on the ideXlab platform.
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effect of sulfate radical based oxidation pretreatments for mitigating ceramic uf membrane Fouling caused by algal extracellular organic matter
Water Research, 2018Co-Authors: Xiaoxiang Cheng, Heng Liang, Xuewu Zhu, Xiaobin Tang, Zhendong Gan, Jiajian Xing, Xinsheng LuoAbstract:Abstract Algal extracellular organic matter (EOM) released from Microcystis aeruginosa can cause severe membrane Fouling during algae-laden water treatment. To solve this problem, three typical sulfate radical-based advanced oxidation processes (SR-AOPs), i.e., ferrous iron/peroxymonosulfate (Fe(II)/PMS), UV/PMS and UV/Fe(II)/PMS, were employed as membrane pretreatment strategies. Their performance on mitigating EOM Fouling of a ceramic UF membrane was systematically investigated and compared in the present study. The results indicated that SR-AOPs pretreatments could promote the reduction of DOC and UV254, and the removal performance showed an apparent regularity of UV/Fe(II)/PMS > Fe(II)/PMS > UV/PMS. The pretreatments were very effective for decomposing high-MW biopolymers (>20,000 Da) into low-MW humic substances (1000–20,000 Da), thus reducing the accumulation of high-MW biopolymers on membrane surface. With respect to membrane Fouling control, Fe(II)/PMS significantly mitigated both Reversible and irReversible membrane Fouling, whereas UV/PMS only reduced Reversible Fouling, and exhibited little effect on irReversible Fouling. By contrast, UV/Fe(II)/PMS showed the best performance for Fouling reduction due to the synergistic effect of UV and Fe(II) for PMS activation. The dominating Fouling mechanism was governed by both pore blockage and cake filtration, likely due to the bimodal MW distribution of EOM, and SR-AOPs pretreatments delayed the transition from pore blockage to cake filtration. In addition, SR-AOPs prior to UF membrane were also very effective to improve the removal of micropollutants (i.e., ATZ, SMT and p-CNB). These results demonstrate the potential application of SR-AOPs as pretreatment for membrane Fouling control during algae-laden water treatment.
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microcystis aeruginosa laden surface water treatment using ultrafiltration membrane Fouling cell integrity and extracellular organic matter rejection
Water Research, 2017Co-Authors: Bin Liu, Heng Liang, Bart Van Der Bruggen, Xiaoxiang ChengAbstract:Despite its superb separation performance, ultrafiltration (UF) still faces challenges in treating the Microcystis aeruginosa-laden water of lakes or reservoirs, due to membrane Fouling and poor rejection of soluble organics. In this work, to better understand the mechanisms of membrane Fouling, cell breakage and organic rejection and their mutual influence, a comparative UF experiment was conducted under a variety of transmembrane pressures (TMPs, 50–250 kPa) with lab-cultured Microcystis aeruginosa. Membrane Fouling was characterized with respect to flux decline and Fouling reversibility, and cell breakage during UF filtration was evaluated using a flow cytometer. Moreover, the rejection of extracellular organic matter (EOM) by UF was investigated with respect to the dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm (UV254) and microcystin-LR (MCLR). The results indicated that the accumulation of Microcystis cells and EOM on the membrane surface caused serious Reversible Fouling that substantially aggravated with the increasing TMP and was successively governed by pore blocking and cake filtration. The cell breakage during filtration was less than 5% and mainly occurred in the cake layer due to hydraulic shear, but the breakage did not substantially vary with increasing TMP. EOM removal by UF ranged from 40% to 70% (in terms of DOC removal), and the removal performance increased with the Reversible resistance, implying a trade-off between organic removal and permeability. Regarding soluble and small organics such as MCLR, a higher degree of removal was also found at higher TMP, despite of some variations over the duration of the filtration tests, and the cake layer retention proved to be the principle removal mechanism, especially during steady filtration stages.
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performance of mesoporous adsorbent resin and powdered activated carbon in mitigating ultrafiltration membrane Fouling caused by algal extracellular organic matter
Desalination, 2014Co-Authors: Kai Li, Fangshu Qu, Heng Liang, Senlin Shao, Haiqing Chang, Xing Du, Guibai LiAbstract:This paper focused on the control of ultrafiltration (UF) membrane Fouling caused by extracellular organic matter (EOM) extracted from Microcystis aeruginosa through pretreatment with mesoporous adsorbent resin (MAR) and powdered activated carbon (PAC). The influence of MAR and PAC pretreatments on characteristics of EOM was investigated using molecular weight (MW) fractionation, DAX-8/XAD-4 resin fractionation and fluorescence excitation-emission matrix (EEM) spectroscopy. The results suggested that MAR mainly removed high-MW (> 100 kDa) fraction of EOM, while PAC primarily adsorbed low-MW (< 1 kDa) fraction. Both MAR and PAC adsorption removed more hydrophobic fraction than hydrophilic fraction. UF experiments were carried out to evaluate the efficacies of MAR and PAC pretreatments in EOM Fouling control. MAR pretreatment significantly reduced the Reversible Fouling due to the efficient removal of high-MW fraction and the consequent reduction of cake formation; whereas PAC exhibited little ability in alleviating the Reversible Fouling. Nevertheless, the irReversible Fouling, which accounted for a small part of the total Fouling, was mitigated by both MAR and PAC pretreatments because they both reduced irReversible adhesion caused by hydrophobic EOM. Overall, with respect to EOM Fouling control, MAR was much more efficient than PAC.
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characterization of dissolved extracellular organic matter deom and bound extracellular organic matter beom of microcystis aeruginosa and their impacts on uf membrane Fouling
Water Research, 2012Co-Authors: Heng Liang, Zhaozhi WangAbstract:Extracellular organic matter (EOM) of cyanobacteria was classified into the dissolved EOM (dEOM) which was released into culture solution and the bound EOM (bEOM) which surrounded the cells. The dEOM and bEOM extracted from Microcystis aeruginosa in stationary phase were used to study their characteristic differences and then their impacts on ultrafiltration (UF) membrane Fouling. Component analyses showed that dEOM was comprised of proteins, polysaccharides and humic-like substances, while that bEOM contained only proteins and polysaccharides. Additionally, polysaccharides dominated in dEOM with a polysaccharide/DOC ratio of 1.11 mg mg(-1), while proteins were the primary components of bEOM with a protein/DOC ratio of 1.08 mg mg(-1). Results of size fractionation and XAD resin fractionation revealed that bEOM was mainly distributed in the high-MW and hydrophobic fractions, while that dEOM was more hydrophilic. Result of UF experiments indicated that dEOM which had a higher organic content and stronger hydrophilicity caused more severe flux decline and Reversible Fouling, and that bEOM led to slower flux decline but more irReversible Fouling due to less electrostatic repulsive and more hydrophobic adhesion. The impacts of these two kinds of EOM on the UF Fouling caused by cyanobacterial cells were also investigated. It was found that both flux decline and irReversible membrane Fouling caused by the cells were aggravated when cells were together with EOM, especially for bEOM which might increase the surface hydrophobicity of the cells.
Jianfu Zhao - One of the best experts on this subject based on the ideXlab platform.
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increasing the vibration frequency to mitigate Reversible and irReversible membrane Fouling using an axial vibration membrane in microalgae harvesting
Journal of Membrane Science, 2017Co-Authors: Fangchao Zhao, Huaqiang Chu, Yalei Zhang, Xuefei Zhou, Shuhong Jiang, Jianfu ZhaoAbstract:Abstract During algae harvesting using membrane technology, membrane Fouling caused by the deposition of algae cells and extracellular organic matter (EOM) poses a major challenge. In this study, axial vibration membrane (AVM) filtration was conducted at 0, 5 and 10 Hz. As the frequency increased, AVM could effectively reduce the Reversible Fouling caused by the deposition of algae cells on the membranes. With the increase of frequency from 0 to 10 Hz in the 2-h filtration experiments, the amount of algae deposited on the membranes sharply decreased from 8.64 to 0.03 g/m 2 . For the Reversible EOM on the membranes, with increasing frequency, the protein and polysaccharide contents exhibited declining trends, and no humic-like material was observed. It was also found that both low-MW ( 200 kDa) EOM easily caused Reversible membrane Fouling. The irReversible EOM adhesion to the membrane consisted of protein, polysaccharide and humic-like material. With the increase of frequency the MW peak of irReversible EOM had a right shift tendency. At 0, 5 and 10 Hz, EOM with MW of 3.5, 4 and 5 kDa, respectively, was more easily adsorbed on the membranes and caused irReversible membrane Fouling.
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comparison of axial vibration membrane and submerged aeration membrane in microalgae harvesting
Bioresource Technology, 2016Co-Authors: Fangchao Zhao, Libin Yang, Huaqiang Chu, Xiaobo Tan, Yalei Zhang, Xuefei Zhou, Jianfu ZhaoAbstract:Abstract The submerged aeration membrane (SAM) system and axial vibration membrane (AVM) system can mitigate membrane Fouling. In this study, both systems were investigated to compare the performance of filtration and the membrane Fouling in algae filtration. In 5-h filtration, the transmembrane pressure (TMP) of SAM reached to 70.0 kPa, while there was almost no increase in TMP for AVM. After continuous filtration, it could be found that there was hardly any algae cells on the membrane of AVM (0.11 g/m 2 ), which was about 32.4 times less than that of SAM (3.56 g/m 2 ). Compared with the SAM system, AVM had a lesser membrane Fouling, regardless of the Reversible Fouling or irReversible Fouling. By SEM, FTIR and EEM, it could be found there was less irReversible extracellular organic matter (EOM) on the membrane of AVM. By MW distribution, it could be observed that less EOM with high-MW adhered to membrane of AVM.
Xuewu Zhu - One of the best experts on this subject based on the ideXlab platform.
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application of sodium percarbonate activated with fe ii for mitigating ultrafiltration membrane Fouling by natural organic matter in drinking water treatment
Journal of Cleaner Production, 2020Co-Authors: Xiaoxiang Cheng, Zixiao Ren, Congwei Luo, Fengxun Tan, Weiwei Zhou, Lu Zheng, Xuewu ZhuAbstract:Abstract It remains challenging to efficiently mitigate membrane Fouling caused by natural organic matter (NOM) for the widespread application of ultrafiltration process. In this study, sodium percarbonate activated with Fe(II) (Fe(II)/SPC) was proposed as a feedwater pretreatment strategy for membrane Fouling control. Typical NOM fractions, i.e., humic acid (HA), bovine serum albumin (BSA) were employed as membrane foulants, as well as natural surface water. The results showed that Fe(II)/SPC pretreatment apparently alleviated membrane Fouling by BSA and HA-BSA, and the performance outperformed Fe(II) pre-coagulation and SPC pre-oxidation alone. Considering HA Fouling, more severe flux decline and increased Reversible Fouling resistance were obtained, while irReversible Fouling was slightly mitigated. The filtration of HA-BSA was well fitted to intermediate blocking followed by cake filtration, and Fe(II)/SPC noticeably increased the filtration volume corresponding to the formation of cake filtration. With Fe(II)/SPC pretreatment, a sparser and more homogeneous foulant layer with lower resistances was observed on membrane surface, and Fourier transform infrared spectroscopy indicated that the peak intensities of major functional groups for organic pollutants were significantly decreased. In surface water treatment, Fe(II)/SPC could effectively improve membrane filtration behavior and pollutants removal, with a distinct decrease of both fluorescent fractions and different molecular weight organic compounds. It seemed that hydroxyl radical oxidation and coagulation with in-situ formed Fe(III) were the main mechanisms of contaminants removal and membrane Fouling control. Overall, this combined process exhibited a great potential for actual application during drinking water treatment.
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effect of sulfate radical based oxidation pretreatments for mitigating ceramic uf membrane Fouling caused by algal extracellular organic matter
Water Research, 2018Co-Authors: Xiaoxiang Cheng, Heng Liang, Xuewu Zhu, Xiaobin Tang, Zhendong Gan, Jiajian Xing, Xinsheng LuoAbstract:Abstract Algal extracellular organic matter (EOM) released from Microcystis aeruginosa can cause severe membrane Fouling during algae-laden water treatment. To solve this problem, three typical sulfate radical-based advanced oxidation processes (SR-AOPs), i.e., ferrous iron/peroxymonosulfate (Fe(II)/PMS), UV/PMS and UV/Fe(II)/PMS, were employed as membrane pretreatment strategies. Their performance on mitigating EOM Fouling of a ceramic UF membrane was systematically investigated and compared in the present study. The results indicated that SR-AOPs pretreatments could promote the reduction of DOC and UV254, and the removal performance showed an apparent regularity of UV/Fe(II)/PMS > Fe(II)/PMS > UV/PMS. The pretreatments were very effective for decomposing high-MW biopolymers (>20,000 Da) into low-MW humic substances (1000–20,000 Da), thus reducing the accumulation of high-MW biopolymers on membrane surface. With respect to membrane Fouling control, Fe(II)/PMS significantly mitigated both Reversible and irReversible membrane Fouling, whereas UV/PMS only reduced Reversible Fouling, and exhibited little effect on irReversible Fouling. By contrast, UV/Fe(II)/PMS showed the best performance for Fouling reduction due to the synergistic effect of UV and Fe(II) for PMS activation. The dominating Fouling mechanism was governed by both pore blockage and cake filtration, likely due to the bimodal MW distribution of EOM, and SR-AOPs pretreatments delayed the transition from pore blockage to cake filtration. In addition, SR-AOPs prior to UF membrane were also very effective to improve the removal of micropollutants (i.e., ATZ, SMT and p-CNB). These results demonstrate the potential application of SR-AOPs as pretreatment for membrane Fouling control during algae-laden water treatment.