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Haiqing Chang - One of the best experts on this subject based on the ideXlab platform.
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Smart ultrafiltration membrane fouling control as desalination pretreatment of shale gas fracturing wastewater: The effects of Backwash water.
Environment international, 2019Co-Authors: Haiqing Chang, Baicang Liu, Chen Chen, John C. CrittendenAbstract:Abstract Background Increasing attention is being paid to the treatment of shale gas fracturing wastewater, including flowback and produced water (FPW). Energy-efficient pretreatment technologies suitable for desalinating and reusing FPW are of paramount importance. Objectives This work focused on enhanced fouling alleviation of ultrafiltration (UF) as a pretreatment for desalinating shale gas FPW in Sichuan Basin, China. The UF fouling behaviors under various Backwash water sources or coagulant dosages were evaluated, and membrane surface characteristics were correlated with UF fouling. The feasibility of Fourier transform infrared (FTIR) microscope mapping technique in quantifying UF fouling was also assessed. Methods Various Backwash water sources, including UF permeate, ultrapure water, nanofiltration (NF) permeate, reverse osmosis (RO) permeate, RO concentrate and forward osmosis (FO) draw solution, were used to clean UF membranes fouled by shale gas FPW. The UF fouling behaviors were characterized by total and non-Backwashable fouling rates. Membrane surface characteristics were analyzed by scanning electron microscopy (SEM), total tension surface and FTIR spectra. Results Protein-like substances in terms of fluorescence intensity in the Backwash water decreased with the order of UF permeate, RO concentrate, NF permeate, RO permeate and FO draw solution. Compared with UF permeate Backwashing, alleviated UF fouling was observed by using demineralized Backwash water including ultrapure water and RO permeate, irrespective of hollow fiber and flat-sheet membranes. NF permeate and RO concentrate after NF used as Backwash water resulted in low and comparable membrane fouling with that in integrated coagulation-UF process under optimal dosage. Among the Backwash water tested, FO draw solution Backwashing corresponded to the lowest UF fouling rates, which were even lower than that in the presence of coagulant under optimal dosage. The superiority of these Backwash water sources to UF permeate was further confirmed by SEM images and FTIR spectra. The residual foulant mass on membrane surface and the total surface tension correlated well with non-Backwashable and total fouling rates, respectively. Conclusions FTIR microscopy was a powerful surface mapping technique to characterize UF membrane fouling caused by shale gas FPW. Backwash water sources significantly influenced the fouling of UF membranes. In the integrated UF-NF-RO or UF-FO process, RO concentrate or FO draw solution were proposed as Backwash water to enhance UF fouling control and decrease waste discharge simultaneously.
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hydraulic Backwashing for low pressure membranes in drinking water treatment a review
Journal of Membrane Science, 2017Co-Authors: Haiqing Chang, Baicang Liu, Heng Liang, Shane A SnyderAbstract:Conventional drinking water treatment processes have faced several obstacles that are severely affected by water pollution and shortage, which makes it difficult to produce potable water effectively. Low-pressure membrane filtration, which includes ultrafiltration (UF) and microfiltration (MF), is one of the most promising treatment technologies for improving water quality. Periodic hydraulic Backwashing is a necessity for the routine operation of UF/MF membranes, but only sparse data are available regarding the optimization of Backwashing procedures, while more attention has been directed toward membrane fouling and cleaning. In the current work, we critically review the Backwashing parameters of UF/MF membranes used in municipal water supplies. These parameters include pressure, flux, permeability (or resistance), mass balance, and membrane characterization techniques. The factors affecting Backwash performance, which include membrane properties, feed water properties and operating conditions, are discussed in detail. The pretreatments of feed water, such as peroxidation, adsorption, coagulation and filtration influence the performance of UF/MF membranes to varying extents. The impacts of the Backwash interval, Backwash duration, Backwash strength, air-assisted Backwashing, chemically enhanced Backwashing, and Backwash water quality on Backwash performance are summarized to provide more comprehensive data, which can improve Backwash performance in full-scale drinking water and water reuse treatment plants.
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Role of Backwash water composition in alleviating ultrafiltration membrane fouling by sodium alginate and the effectiveness of salt Backwashing
Journal of Membrane Science, 2016Co-Authors: Haiqing Chang, Senlin Shao, Heng Liang, Bin Liu, Wei GaoAbstract:Abstract To obtain a better hydraulic cleaning strategy for ultrafiltration (UF) membranes fouled by sodium alginate (SA), various types of Backwash water, including UF permeate, ultrapure water, NaCl solution, CaCl 2 solution and SA solution, were compared with respect to hydraulic cleaning efficiency (HCE), hydraulically irreversible fouling index, Fourier transform infrared spectra analysis, normalized transmembrane streaming potential coefficient and foulant release. The results indicated that UF permeate Backwash or CaCl 2 solution Backwash significantly decreased the HCE. On the contrary, NaCl solution Backwash greatly alleviated the SA fouling, and Backwashing with ultrapure water or organic compounds was also efficient when both Na + and Ca 2+ were present in feed water. Moreover, the amount of released SA from the fouling layer during Backwashing was closely related to that of released Ca 2+ . Electric double layer release involved in Backwashing with ultrapure water and SA solution, and ion exchange played significant roles in the effective hydraulic cleaning associated with Na + . Further, monovalent salt Backwashing was quite effective for a wide range of salt concentrations, and the approach was effective irrespective of monovalent salt types. Moreover, the results obtained from natural organic matter (NOM) and effluent organic matter (EfOM) further proved the efficiency of NaCl solution Backwash.
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Towards a better hydraulic cleaning strategy for ultrafiltration membrane fouling by humic acid: Effect of Backwash water composition.
Journal of environmental sciences (China), 2015Co-Authors: Haiqing Chang, Heng Liang, Nanqi RenAbstract:As a routine measurement to alleviate membrane fouling, hydraulic cleaning is of great significance for the steady operation of ultrafiltration (UF) systems in water treatment processes. In this work, a comparative study was performed to investigate the effects of the composition of Backwash water on the hydraulic cleaning performance of UF membranes fouled by humic acid (HA). Various types of Backwash water, including UF permeate, Milli-Q water, NaCl solution, CaCl2 solution and HA solution, were compared in terms of hydraulically irreversible fouling index, total surface tension and residual HA. The results indicated that Milli-Q water Backwash was superior to UF permeate Backwash in cleaning HA-fouled membranes, and the Backwash water containing Na(+) or HA outperformed Milli-Q water in alleviating HA fouling. On the contrary, the presence of Ca(2+) in Backwash water significantly decreased the Backwash efficiency. Moreover, Ca(2+) played an important role in foulant removal, and the residual HA content closely related to the residual Ca(2+) content. Mechanism analysis suggested that the Backwash process may involve fouling layer swelling, ion exchange, electric double layer release and competitive complexation. Ion exchange and competitive complexation played significant roles in the efficient hydraulic cleaning associated with Na(+) and HA, respectively.
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hydraulic irreversibility of ultrafiltration membrane fouling by humic acid effects of membrane properties and Backwash water composition
Journal of Membrane Science, 2015Co-Authors: Haiqing Chang, Fangshu Qu, Huarong Yu, Kai Li, Guibai Li, Heng LiangAbstract:Abstract Five commercially available ultrafiltration (UF) membranes: polyethersulfone (PES, 100 kDa), polyvinylidene fluoride (PVDF, 100 kDa) and cellulose acetate (CA, 100, 30 and 10 kDa), were fouled with humic acid (HA) solutions and cleaned using various compositions of Backwash water including ultrapure water, monovalent cations (Na + ), divalent cations (Ca 2+ ), an organic compound (HA) and UF permeate. The hydraulically irreversible fouling and the hydraulic cleaning efficiency (HCE) for each combination of membrane and Backwash water composition were analyzed. In summary, both the membrane properties and the Backwash water composition affected hydraulically irreversible fouling. The membrane properties significantly affected the total fouling, and the HCE was primarily affected by the Backwash water composition. Further, the adhesive free energy between HA and the membranes correlated well with the total fouling. Ultrapure water was superior to UF permeate for Backwashing, and the presence of appropriate components (e.g., Na + or HA) further improved the HCE; however, Ca 2+ exerted detrimental impacts on the HCE. In addition, the removal of the deposited HA was consistent with the amount of Ca 2+ released from the fouling layer during Backwashing. Mechanistic analysis suggested that the Backwashing process involves fouling layer swelling, ion exchange, electric double layer release and competitive complexation.
Heng Liang - One of the best experts on this subject based on the ideXlab platform.
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hydraulic Backwashing for low pressure membranes in drinking water treatment a review
Journal of Membrane Science, 2017Co-Authors: Haiqing Chang, Baicang Liu, Heng Liang, Shane A SnyderAbstract:Conventional drinking water treatment processes have faced several obstacles that are severely affected by water pollution and shortage, which makes it difficult to produce potable water effectively. Low-pressure membrane filtration, which includes ultrafiltration (UF) and microfiltration (MF), is one of the most promising treatment technologies for improving water quality. Periodic hydraulic Backwashing is a necessity for the routine operation of UF/MF membranes, but only sparse data are available regarding the optimization of Backwashing procedures, while more attention has been directed toward membrane fouling and cleaning. In the current work, we critically review the Backwashing parameters of UF/MF membranes used in municipal water supplies. These parameters include pressure, flux, permeability (or resistance), mass balance, and membrane characterization techniques. The factors affecting Backwash performance, which include membrane properties, feed water properties and operating conditions, are discussed in detail. The pretreatments of feed water, such as peroxidation, adsorption, coagulation and filtration influence the performance of UF/MF membranes to varying extents. The impacts of the Backwash interval, Backwash duration, Backwash strength, air-assisted Backwashing, chemically enhanced Backwashing, and Backwash water quality on Backwash performance are summarized to provide more comprehensive data, which can improve Backwash performance in full-scale drinking water and water reuse treatment plants.
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Role of Backwash water composition in alleviating ultrafiltration membrane fouling by sodium alginate and the effectiveness of salt Backwashing
Journal of Membrane Science, 2016Co-Authors: Haiqing Chang, Senlin Shao, Heng Liang, Bin Liu, Wei GaoAbstract:Abstract To obtain a better hydraulic cleaning strategy for ultrafiltration (UF) membranes fouled by sodium alginate (SA), various types of Backwash water, including UF permeate, ultrapure water, NaCl solution, CaCl 2 solution and SA solution, were compared with respect to hydraulic cleaning efficiency (HCE), hydraulically irreversible fouling index, Fourier transform infrared spectra analysis, normalized transmembrane streaming potential coefficient and foulant release. The results indicated that UF permeate Backwash or CaCl 2 solution Backwash significantly decreased the HCE. On the contrary, NaCl solution Backwash greatly alleviated the SA fouling, and Backwashing with ultrapure water or organic compounds was also efficient when both Na + and Ca 2+ were present in feed water. Moreover, the amount of released SA from the fouling layer during Backwashing was closely related to that of released Ca 2+ . Electric double layer release involved in Backwashing with ultrapure water and SA solution, and ion exchange played significant roles in the effective hydraulic cleaning associated with Na + . Further, monovalent salt Backwashing was quite effective for a wide range of salt concentrations, and the approach was effective irrespective of monovalent salt types. Moreover, the results obtained from natural organic matter (NOM) and effluent organic matter (EfOM) further proved the efficiency of NaCl solution Backwash.
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Towards a better hydraulic cleaning strategy for ultrafiltration membrane fouling by humic acid: Effect of Backwash water composition.
Journal of environmental sciences (China), 2015Co-Authors: Haiqing Chang, Heng Liang, Nanqi RenAbstract:As a routine measurement to alleviate membrane fouling, hydraulic cleaning is of great significance for the steady operation of ultrafiltration (UF) systems in water treatment processes. In this work, a comparative study was performed to investigate the effects of the composition of Backwash water on the hydraulic cleaning performance of UF membranes fouled by humic acid (HA). Various types of Backwash water, including UF permeate, Milli-Q water, NaCl solution, CaCl2 solution and HA solution, were compared in terms of hydraulically irreversible fouling index, total surface tension and residual HA. The results indicated that Milli-Q water Backwash was superior to UF permeate Backwash in cleaning HA-fouled membranes, and the Backwash water containing Na(+) or HA outperformed Milli-Q water in alleviating HA fouling. On the contrary, the presence of Ca(2+) in Backwash water significantly decreased the Backwash efficiency. Moreover, Ca(2+) played an important role in foulant removal, and the residual HA content closely related to the residual Ca(2+) content. Mechanism analysis suggested that the Backwash process may involve fouling layer swelling, ion exchange, electric double layer release and competitive complexation. Ion exchange and competitive complexation played significant roles in the efficient hydraulic cleaning associated with Na(+) and HA, respectively.
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hydraulic irreversibility of ultrafiltration membrane fouling by humic acid effects of membrane properties and Backwash water composition
Journal of Membrane Science, 2015Co-Authors: Haiqing Chang, Fangshu Qu, Huarong Yu, Kai Li, Guibai Li, Heng LiangAbstract:Abstract Five commercially available ultrafiltration (UF) membranes: polyethersulfone (PES, 100 kDa), polyvinylidene fluoride (PVDF, 100 kDa) and cellulose acetate (CA, 100, 30 and 10 kDa), were fouled with humic acid (HA) solutions and cleaned using various compositions of Backwash water including ultrapure water, monovalent cations (Na + ), divalent cations (Ca 2+ ), an organic compound (HA) and UF permeate. The hydraulically irreversible fouling and the hydraulic cleaning efficiency (HCE) for each combination of membrane and Backwash water composition were analyzed. In summary, both the membrane properties and the Backwash water composition affected hydraulically irreversible fouling. The membrane properties significantly affected the total fouling, and the HCE was primarily affected by the Backwash water composition. Further, the adhesive free energy between HA and the membranes correlated well with the total fouling. Ultrapure water was superior to UF permeate for Backwashing, and the presence of appropriate components (e.g., Na + or HA) further improved the HCE; however, Ca 2+ exerted detrimental impacts on the HCE. In addition, the removal of the deposited HA was consistent with the amount of Ca 2+ released from the fouling layer during Backwashing. Mechanistic analysis suggested that the Backwashing process involves fouling layer swelling, ion exchange, electric double layer release and competitive complexation.
Tzyy Haur Chong - One of the best experts on this subject based on the ideXlab platform.
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recycling rainwater by submerged gravity driven membrane gdm reactors effect of hydraulic retention time and periodic Backwash
Science of The Total Environment, 2019Co-Authors: Genevieve Soon, Tzyy Haur ChongAbstract:Abstract Rainwater recycling has been considered as an alternative cost-effective decentralized water supply. The low cost and effective gravity-driven membrane (GDM) filtration technology has been introduced to treat the rainwater prior use. In this study, we investigated the effects of hydraulic retention time (HRT; 27 h, 51 h, and 156 h) and periodic Backwash durations (2 min, 5 min, 10 min, and 30 min per 2–3 days' filtration) on the permeate quality, flux and fouling mechanism in lab-scale submerged GDM reactors. Compared to the performance at HRT of 51 h (40% of DOC removal and ~2.9 L/m2 h), better permeate quality and higher membrane flux were achieved at HRT of 27 h (51% of DOC removal and ~4.2 L/m2 h) and 156 h (48% of DOC removal and ~5.0 L/m2 h). Although the hydraulically reversible resistance was predominant (up to 90% of the total fouling resistance), the permeate flux could not be fully recovered by periodic Backwash, regardless of the Backwash durations. After several filtration-Backwash cycles, the stabilized flux of GDM reactor with Backwash was even worse than those without Backwash. However, no correlation can be established between the stabilized flux (i.e., cake layer resistance) and the soluble organics and microbial cells in the cake layer of the GDM system during rainwater treatment.
A G Fane - One of the best experts on this subject based on the ideXlab platform.
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evaluation of fouling deposition fouling reversibility and energy consumption of submerged hollow fiber membrane systems with periodic Backwash
Journal of Membrane Science, 2014Co-Authors: Ebrahim Akhondi, Filicia Wicaksana, A G FaneAbstract:Abstract The filtration behavior and energy consumption of submerged hollow fiber membranes were investigated in a dead-end mode under constant flux operation with periodic Backwash. Various operating parameters such as filtration flux, feed concentration, Backwash duration, Backwash strength, and the aid of air scouring during Backwash were investigated to optimize the filtration performance and energy consumption. Baker's yeast was used as the model foulant. The transmembrane pressure (TMP) profiles obtained with this model foulant indicated the existence of two regions: a low fouling region followed by a high fouling region. In the low fouling region, periodic Backwash could effectively remove the fouling layer. The percentage of reversible fouling by Backwash was significantly lower in the second region which led to a rapid increase in TMP. The Taguchi experimental design method was used to determine the critical parameters, the effect of individual parameters and the optimum conditions. Since the transition into the second region of filtration is not favorable, the fouling rate in the first 10 cycles, the net permeate volume and specific energy consumption at the end of the first region were chosen as the design method responses. The results showed that filtration flux and feed concentration have significant effects on the membrane fouling rate. In order to maximize the net permeate volume, filtration flux, Backwash duration and Backwash strength were found to be the most important parameters, which must be carefully selected. To minimize the specific energy consumption, filtration flux, Backwash duration and aeration rate during Backwash were the most important factors.
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effects of operating conditions on submerged hollow fibre membrane systems used as pre treatment for seawater reverse osmosis
Journal of Membrane Science, 2010Co-Authors: Yun Ye, Bram Herulah, Vicki Chen, A G FaneAbstract:The potential of submerged hollow fibre membrane systems without the aid of coagulant was investigated as a pre-treatment for seawater reverse osmosis in this paper. The operation parameters such as filtration duration, Backwash duration, Backwash strength and the aid of air scouring during Backwash were investigated in order to optimize the filtration performance and fouling control. The underlying fouling limitation mechanisms which result in those optimized operation parameters were also explored. It was found that periodical Backwash with the permeate can provide effective removal of fouling layer and reduce the fouling rate during the filtration cycle. Results also indicated the strong inter-correlation among Backwash strength and filtration duration and their effect on fouling rate. Excessive Backwash strength was found unable to minimize fouling, and in fact, resulted in higher fouling rate during filtration. The percentage of removable fouling by Backwash was also significantly affected by the inter-correlation between the Backwash strength and Backwash duration. By analyzing the composition of the feed, permeate and the solution after Backwash, it was found that UF membrane (pore size 0.04 μm) can remove more than 60% of biopolymers. The biopolymers rejected by the UF membrane formed the cake on the membrane surface, and this fouling cake can be easily removed by periodical Backwash.
Corinne Cabassud - One of the best experts on this subject based on the ideXlab platform.
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evaluation of Backwash efficiency definition of remaining fouling and characterisation of its contribution in irreversible fouling case of drinking water production by air assisted ultra filtration
Journal of Membrane Science, 2010Co-Authors: P J Remize, Christelle Guigui, Corinne CabassudAbstract:Abstract In ultra-filtration or micro-filtration plants the commonly used method for fouling characterisation is based on an analysis of easily measurable process parameters such as membrane permeability. The results presented in this paper are included in a research project aiming to optimize membrane plant operation for drinking water production with a Backwash procedure using air and water flow in dead-end ultra-filtration using inside-out hollow-fibres. Experiments on both semi-industrial and laboratory scale pilot plants were first performed with a clay suspension for different filtration conditions and Backwash procedures. A comparison of Backwash efficiency assessed by initial permeability recovery and by mass balances on particles was performed. From these experiments, it can be pointed out that: - Permeability at the beginning of the filtration cycle is constant whatever the Backwash procedures (with or without air). However this cannot be considered as a criterion of good Backwash efficiency, because of the following results. - Mass balances on Backwash waters show that, despite total permeability recovery, some particles remain on the membrane surface, creating a so-called “remaining particulate fouling”. In addition, the quantity of particles remaining on the membrane surface is influenced by Backwash parameters and procedure. Air injection during Backwash enhances particle removal. So this study demonstrates that there is remaining particulate fouling after Backwash in spite of total permeability recovery. This remaining particulate fouling depends on both filtration and Backwash conditions and might contribute to the long-term fouling. Indeed, experiments with natural surface water showed that the long-term decrease in initial membrane permeability (i.e. permeability at the beginning of each filtration cycle) was mainly due to the particles remaining at the end of a classical Backwash and only slightly due to irreversible fouling by natural organic matter adsorption. In contrast, when the Backwash procedure was hydraulically enhanced by air injection, the remaining particulate fouling was significantly lowered and the long-term decrease in membrane permeability was mainly due to irreversible fouling phenomena, which leads to an increase in process runtime.
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Air sparging Backwash in ultrafiltration hollow fibres for drinking water production
Water Science & Technology: Water Supply, 2003Co-Authors: Christelle Guigui, Marion Mougenot, Corinne CabassudAbstract:Air sparging Was applied to improve Backwash efficiency for an ultrafiltration inside/out hollow-fibre module operating in dead-end mode. Air was injected into the retentate side only during the Backwash period. The filtration experiments were performed on a semi-industrial scale pilot using a clay suspension as a model of surface waters. The Backwash procedure consisted of two steps: in a first step (phase A), air was added to the feed water inside the fibre lumen at the bottom of the module. In a second step (phase B), cleaned water Backwash was performed. Different air velocities were used and the kinetics of particle removal were studied with turbidity measurements of Backwash waters. The experimental results showed that using an air-fluid mixing allows one to increase the quantity of particles removed from the hollow fibres. For the phase A, the removed mass is higher when the air velocity and duration of air injection increased. But, even at very low air velocity (0.08 m/s), a high Backwash efficiency was observed. Experiments with filtration/air-sparging Backwash cycles concluded that using air-fluid mixing in the Backwash sequence allowed prevention of long-term fouling and reduced the rate of fouling during the filtration period.