Ultrafiltration Fouling Research Articles

Insights into the roles of membrane pore size and feed foulant concentration in ultrafiltration membrane fouling based on collision-attachment theory.

Membrane property and feed characteristics play critical roles in membrane fouling. This paper aims to clarify the roles of membrane pore size (φ) and feed foulant concentration (Cb ) in ultrafiltration fouling induced by polysaccharides. The fouling behaviors were expounded by collision-attachment theory, where the rate of membrane fouling is mainly determined by collision frequency (JCb ) and attachment efficiency (γ). At the initial fouling stage, rapid flux decline was observed at large φ or high Cb due to the great JCb and/or γ. At the later fouling stage, there existed a nearly identical maximum stable flux attributing to the same JCb and γ, which was independent of φ and Cb . Moreover, the smaller φ can lead to less foulants passed through the membrane and thus more foulants attaching on the membrane, while the higher Cb can give rise to more foulants on both the membrane surface and in the permeate. The results presented in current study provide fundamental basis in understanding membrane fouling. PRACTITIONER POINTS: Collision-attachment theory was employed to expound the UF fouling behavior. Rapid flux decline occurred at large membrane pore size or high feed foulant concentration in the initial fouling stage. Membranes with different pore size or feed foulant concentration had an identical flux at the latter fouling stage. Lowering membrane pore size or increasing feed foulant concentration can lead to more foulants attaching on the membrane surface.

Fouling characterization during initial stage of cross-flow ultrafiltration

Ultrafiltration (UF) membrane is an attractive pretreatment technology used in desalination water system. However, the unavoidable membrane fouling over time is the key problem in the development of this technology. Fouling evaluation in the initial stage may provide relevant information about the fouling tendencies. In this work, the extent of fouling was investigated through a new method allows evaluating the fouling in cross-flow UF in the initial filtration stage. An empirical adjustment of flux decline data based on a bi-exponential equation with 4 coefficients is proposed for determining the Rcfi and RV − CF parameters. The first parameter Rcfi is defined as the initial cross-flow resistance. The second parameter RV − CF is defined as increasing resistance per specific volume of permeate in cross-flow. The measurement of the fouling parameters is evaluated in a laboratory facility with the following established conditions: (1) operation in cross-flow mode and (2) a flow measurement period limited to roughly 1 h. The procedure is intended to detect two different flow decline zones with different fouling processes at the initial stage of cross-flow filtration. The method applicability was tested with two cellulosic membranes of 10 kDa and 20 kDa and solutions of 4 kDa and 35 kDa polyethylene glycol (PEG) and alginate at different concentrations. In the case of the Rcfi parameter, the results show measurable values with high colloidal concentration of PEG. The RV − CF results shows a sensitive increase with foulant concentration, in different degree, depending on the type of solution and membrane used.

Effect of filter depth of biological activated carbon on fouling control of ultrafiltration: performance and mechanism

Biological activated carbon (BAC) prefiltration is a common method to control fouling in ultrafiltration (UF) processes. BAC filter depth is a critical parameter for both design and operation of a prefiltration system. Here, the effect of filter depth on the performance and mechanism of contaminant removal and UF fouling characteristics was investigated. The results indicated that contaminants were mostly removed by the upper filter (0–10 cm), including organics, particles, and protein-like substances, while the deeper filter (10–50 cm) removed additional organics, which were mostly humic-like substances. The upper layer intercepted particles, which not only reduced the number of particles, but also significantly reduced the average particle size. The fouling control capability of BAC prefiltration was mostly attributed to the upper filter, whose function was greater than that of the deeper filter. However, the primary fouling mechanism did not vary with filter depth. In summary, during the combined process of BAC prefiltration and UF, when membrane fouling control is the main objective, the filter layer could be set as a thin layer (such as 10 cm). However, when the combined process needs to reduce the concentration of organic matter at the same time, a thicker layer is indispensable to achieve the desired performance.

Fouling Mechanisms Analysis via Combined Fouling Models for Surface Water Ultrafiltration Process.

Membrane fouling is still the bottleneck affecting the technical and economic performance of the ultrafiltration (UF) process for the surface water treatment. It is very important to accurately understand fouling mechanisms to effectively prevent and control UF fouling. The rejection performance and fouling mechanisms of the UF membrane for raw and coagulated surface water treatment were investigated under the cycle operation of constant-pressure dead-end filtration and backwash. There was no significant difference in the UF permeate quality of raw and coagulated surface water. Coagulation mainly removed substances causing turbidity in raw surface water (including most suspended particles and a few organic colloids) and thus mitigated UF fouling effectively. Backwash showed limited fouling removal. For the UF process of both raw and coagulated surface water, the fittings using single models showed good linearity for multiple models mainly due to statistical illusions, while the fittings using combined models showed that only the combined complete blocking and cake layer model fitted well. The quantitative calculations showed that complete blocking was the main reason causing flux decline. Membrane fouling mechanism analysis based on combined models could provide theoretical supports to prevent and control UF fouling for surface water treatment.

Preparation of low-fouling polyethersulfone ultrafiltration membranes by incorporating high-molecular-weight chitosan with the help of a surfactant

Increasing the resistance of polyethersulfone ultrafiltration (PES UF) membrane to fouling remains a challenging endeavor when developing UF membrane. This paper concerns the incorporation of chitosan into PES UF membrane to produce low-fouling PES UF membrane. The membranes were produced by means of phase inversion with chitosan as an additive. In order to increase the content of chitosan in PES solution, Tween 80 surfactant was incorporated. The membranes were characterized in terms of pure water permeability, contact angle, and surface morphology. The membrane performance was evaluated by static adsorption and filtration experiments. The results showed that the surfactant could significantly decrease the viscosity of chitosan solution; consequently, the chitosan content of the membrane also increased. The presence of chitosan increased both the membrane water permeability and hydrophilicity of PES UF membranes. Furthermore, these membranes showed higher resistance to both adsorptive and ultrafiltration fouling, and their ability to repel protein was slightly higher than that of chitosan-free membranes.

Effect of Two Stages Adsorption as Pre-Treatment of Natural Organic Matter Removal in Ultrafiltration Process for Peat Water Treatment

Natural Organic Matter (NOM) content in peat water is a major problem of membrane fouling in ultrafiltration (UF). For that, two stages adsorption as pre-treatment was employed to minimize the membrane fouling of NOM content. This research was carried out to investigate the effect of two stages adsorption on ultrafiltration performance for NOM removal that remains in peat water. This method was using powdered activated carbon (PAC) dosage of 80, 160, 240, 320, 400, 480, 560, 640, 720, 800, 880 dan 960 mg.L-1. Then, Polysulfone (Psf) material was employed for Ultra filtration process. Membrane was applied in a dead-end mode with various operating pressure (1; 1.5; 2; 2.5; 3 bar). As a results, the optimum dose of PAC was 800 mg L-1 with dosage ratio of 3/4:1/4. Two stages adsorption-UF PSf provided the range from 86.9 to 92.8% of KMnO4 and 74.1-88.1% of UV254. For the experimental condition of 3 bar, the highest flux was achieved up to 39.919 L h-1.m-2.

Carbon doped Fe3O4 peroxidase-like nanozyme for mitigating the membrane fouling by NOM at neutral pH

Oxidation is a widely used method in drinking water treatment to mitigate the membrane fouling caused by the natural organic matters (NOM) from the surface water during ultra-filtration (UF) and nano-filtration (NF) processes, and H2O2 is one of the common oxidants for it. However, the oxidation capability of H2O2 at neutral pH is lower, compared to the acidic and alkaline conditions. In order to improve the efficiency of NOM oxidation at neutral pH, a carbon-doped Fe3O4 peroxidase-like nanozyme (CFPN) was synthesized in this study and used as a high-performance catalyst for H2O2 to generate hydroxyl radical. The oxygen-containing groups on the carbon structure of CFPN can form an acidic microenvironment, allowing H2O2 to produce hydroxyl radical by catalysis in neutral conditions. The results of hydrophilicity analysis, zeta potential, high-performance liquid size exclusion chromatography (HPSEC), Fourier transform infrared spectrum (FTIR) and flux indicated that the hydroxyl radical can oxidize the hydrophobic matters of humic acid (HA) into hydrophilic matters by Fenton reaction or electrophilic addition reaction, which can mitigate the fouling of NF membranes. The results of the same test for the bovine serum albumin (BSA) indicated that the hydroxyl radical can mitigate the fouling of UF membranes by degrading the tertiary and secondary structures of BSA and partly oxidizing the side chain groups. In addition, two types of surface water samples were used to verify the above mechanism, and the results indicated that the hydroxyl radical treatment at neutral pH is a new viable and effective strategy to significantly mitigate the NOM fouling of UF and NF membranes.

Irreversible fouling in hollow-fiber PVDF MF/UF membranes filtering surface water: Effects of precoagulation and identification of the foulant

In this study, microfiltration (MF) and ultrafiltration (UF) of surface water were compared in terms of irreversible fouling and effective pretreatment. Hollow-fiber MF/UF membranes made from the same polymer (polyvinylidene fluoride (PVDF)) were examined with multiple samples of surface water used for drinking water production. Experiments were carried out in a realistic style: with a constant flow rate and periodic backwashing. Regardless of the source of the feed water, evolution of fouling was less significant in the case of UF. In the case of MF, anion exchange followed by coagulation using poly-aluminium chloride (PACl) efficiently mitigated membrane fouling, whereas PACl coagulation alone was sufficient for UF. Artificial alteration of the composition of natural organic matter (NOM) in the feed water was carried out by MF/UF with different pore sizes, and it was revealed that different fractions of NOM were responsible for evolution of irreversible fouling in MF and UF: large biopolymers and small biopolymers were responsible for irreversible fouling in MF and UF, respectively. The mechanism of fouling mitigation by coagulation was also investigated. Cake (coagulated flocs) deposited on the membrane surface mitigated irreversible fouling in UF, whereas it did not affect irreversible fouling in MF. It was postulated that advection flow caused by membrane filtration made more adsorption sites available inside the flocs for removal of small biopolymers (i.e., UF foulants).

Adsorptive Removal of Cetyltrimethyl Ammonium Bromide (CTAB) Surfactant from Aqueous Solution: Crossbreed Pilot Plant Membrane Studies

Abstract Magnetic carbon nanocomposite (MCNC) was prepared from peanut shells and then characterized by FTIR, SEM, TGA/DTA and BET surface area. The removal of cetyltrimethyl ammonium bromide (CTAB) surfactant from aqueous solution was carried out by MCNC and membrane. The effect of contact time, initial concentration of CTAB and the temperature on the adsorption of CTAB was also investigated. Initially, the adsorption of CTAB on MCNC was rapid up to 20 min and then gradually slowed down. Different kinetic models i. e. 2nd pseudo order kinetics, power function and intraparticle diffusion were applied to determine different kinetic parameters. Intraparticle diffusion model showed that the adsorption of CTAB is a diffusion controlled process. Thermodynamic parameters i. e. ΔH° (–33.74 kJ/mol), ΔS° (0.98 J/mol K) and ΔG° (–62.91 kJ/mol, −64.37 kJ/mol and −66.33 kJ/mol) were calculated and the process was found to be exothermic and spontaneous in nature. The prepared adsorbent (MCNC) was used for controlling fouling of ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes caused by CTAB. Improved permeate fluxes and percent retention of CTAB were observed for MCNC crossbreed membrane. About 100 % retention with no effect on permeate flux was observed with RO membrane when MCNC pretreatment was applied.

Combining Magnetic Ion Exchange Media and Microsand before Coagulation as Pretreatment for Submerged Ultrafiltration: Biopolymers and Small Molecular Weight Organic Matter

In order to reduce the fouling of ultrafiltration (UF) systems caused by influent organic matter and microbial activities in the membrane tank, a novel pretreatment process has been evaluated involving the combination of magnetic ion exchange media (MIEX), microsand, and alum coagulation. Using a continuous flow bench-scale UF membrane apparatus and synthetic water, the influence of MIEX and microsand with alum pretreatment on membrane fouling was studied in comparison to a conventional pretreatment by alum alone. It was found that the continuous addition of low doses of MIEX and microsand substantially reduced (∼50%) membrane fouling for nearly 60 days of operation, both in terms of reversible and irreversible fouling. MIEX adsorption increased the removal of dissolved organic matter, particularly hydrophobic and proteinaceous substances, and some fractions of humic-type substances, while the addition of microsand increased the density of flocs, and thus improved the removal of flocs and microorganisms (...

Novel H2O2–MnO2 system for efficient physico-chemical cleaning of fouled ultrafiltration membranes by simultaneous generation of reactive free radicals and oxygen

The novel H2O2–MnO2 system was developed to achieve highly efficient membrane cleaning for both fouled PVDF and PES membranes in this study. Compared with conventional chemical cleaning process in which the whole membrane module had to be soaked in highly concentrated solution of chemical reagent for long period of time, the H2O2–MnO2 cleaning process conducting for only 5 min in 0.5 wt% H2O2 solution could achieve more than 95% recovery of permeate flux and almost total removal of the irreversible foulants. More importantly, the permeate flux and filtration efficiency of the membrane could be still kept stable after 6 runs of consecutive fouling and cleaning. Based on the systematic microscopic analyses, Electron Spin Resonance (ESR), Fourier Transform Infrared Spectroscopy (FTIR), as well as the quenching experiments with different free radical scavengers, the outstanding performance of H2O2–MnO2 system was attributed to the generation of both free radicals and abundant oxygen simultaneously, leading to the physico-chemical membrane cleaning. Conclusively, the newly developed H2O2–MnO2 system demonstrated noteworthy advantages on efficient membrane cleaning, and exhibited highly potential for the wide application in practical water treatment process.

In-situ graft-polymerization modification of commercial ultrafiltration membranes for long-term fouling resistance in a pilot-scale membrane bioreactor

Despite significant advances in the design of submerged membrane bioreactors for wastewater treatment, membrane organic- and biofouling remain major obstacles to effective operation, decreasing process performance and membrane lifetime. In this work, we report an improved methodology to minimize fouling in commercial polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes using redox-initiated copolymer grafting. To effectively bind a copolymer that possesses oppositely charged groups to the surface, we modified the membranes during filtration using positively charged [2-(methacryloyloxy)ethyl]-tri-methylammonium (MOETMA) and negatively charged 3-sulphopropyl methacrylate (SPM) monomers, which provide the polyampholyte coating. The binding of the grafted copolymer was verified using Fourier-transform infrared spectroscopy and contact angle measurements. Bench-scale dynamic fouling experiments were employed to optimize the modification time and verify the effectiveness of the modification in mitigating fouling from soluble microbial products and extracellular polymeric substances extracted from municipal wastewater. After demonstrating fouling resistance at the bench scale, membrane fibers were tested in a custom-made membrane bioreactor treating municipal wastewater. During 22 days of testing, fouling was consistently reduced in the case of modified membranes due to the presence of the polyampholyte copolymer barrier that hinders foulant adsorption. At the end of the testing period, the flux of modified fibers was 123% higher than that of the PVDF control. Overall, this work demonstrates a facile and effective modification technique to reduce fouling in ultrafiltration with proven performance during long-term treatment of municipal wastewater.

Smart ultrafiltration membrane fouling control as desalination pretreatment of shale gas fracturing wastewater: The effects of backwash water

BackgroundIncreasing 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. ObjectivesThis 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. MethodsVarious 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. ResultsProtein-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. ConclusionsFTIR 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.

Organic carbon source-dependent properties of soluble microbial products in sequencing batch reactors and its effects on membrane fouling

This study investigated the influence of three different organic carbon sources including sodium acetate (SOD), glucose (GLU), and starch (STAR), on soluble microbial products (SMP), which presumably have dissimilar uptake rates and metabolic pathways, in sequencing batch reactors (SBR) and their subsequent effects on membrane fouling of ultrafiltration (UF). SMP were mainly characterized by fluorescence excitation emission matrix coupled with parallel factor analysis (EEM-PARAFAC) and size exclusion chromatography (SEC). SMP produced in SOD-fed SBR showed higher abundances of protein-like fluorescent component and large sized aliphatic biopolymer (BP) than GLU- or STAR-fed counterpart did, while the STAR-based operation resulted in more SMP enriched with humic-like fluorescence. The differences in SMP exerted marked effects on UF membrane fouling as indicated by the highest fouling potential with reversibility shown for the SMP from the SOD-fed reactor. Regardless of the carbon source, BP fraction and protein-like component exhibited the greatest extent of reversible fouling, suggesting that size exclusion plays a critical role. However, notable differences in the reversible fouling propensity of relatively smaller size fractions among the three SBRs signified the possible involvement of chemical interactions as a secondary fouling mechanism and its dependency on different carbon sources. Our results provide a new insight into the roles of carbon sources in the characteristics of SMP in biological treatment systems and their effects on the post-treatment using membrane filtration, which is ultimately beneficial to the optimization of biological treatment design and membrane filtration operation.

Impact of low coagulant dosages on protein fouling of ultrafiltration membranes

Biopolymers have been identified as the primary source of fouling for ultrafiltration (UF) membranes, however the relative contribution of its components (e.g., proteins and polysaccharides) to fouling are still unclear. Previous natural water studies have shown that applying low doses of coagulant (< 1 mg metal/L) significantly reduces membrane fouling. The impact of inline coagulation on UF fouling for three different model protein solutions was examined at bench-scale. Results show that when compared to no coagulant addition, a low coagulant dose (2 μM Al or 0.3 mg/L alum) is capable of significantly reducing membrane fouling when considering feed solutions containing bovine serum albumin (BSA) and ovalbumin (OVA). Conversely, the same alum dose resulted in the most fouling when considering β-lactoglobulin (BLG). Protein rejection was also correlated with irreversible fouling resistance, suggesting fouling mitigation was due to weakened protein-membrane interactions instead of a more reversible fouling layer. Fouling trends for BSA and OVA were similar to those in previous studies with natural surface waters, which suggest that proteins are major contributors to UF fouling which may be mitigated with low dosages of coagulant. It is hypothesized that at low alum doses, the surface hydrophobicity of the protein and the fouling layer is altered, leading to weaker interactions and thereby reducing fouling.

Peroxymonosulfate-assisted electro-oxidation/coagulation coupled with ceramic membrane for manganese and phosphorus removal in surface water

This study considers peroxymonosulfate (PMS)-assisted iron electrolysis for electro-oxidation/coagulation (EO/EC) pretreatment combined with a ceramic ultrafiltration (UF) membrane for simultaneous manganese (0–1.0 mg/L) and phosphorus (0–0.8 mg/L) removal from surface water. The results indicated that the optimum EO/EC operation conditions appear to be current(I) of 0.2 A with an electrolysis time of 60 s at pH 7.5 (corresponding to nearly 0.5 mg/L Fe2+) under a PMS dosage of 100 µM. Electron paramagnetic resonance (EPR) spectroscopy suggested that sulfate radicals (SO4−) or hydroxyl radicals (OH) were produced during the PMS activation process, and manganese oxide formation after the EO/EC process was elucidated on the basis of the results of X-ray photoelectron spectroscopy (XPS). In addition, EO/EC pretreatment might favour the generation of large flocs and significantly decrease the UF fouling, and SEM-EDS indicated the existence of Mn, P and Fe in the flocs. In real applications, the combined process achieved trace levels of manganese and phosphorous, and membrane fouling was caused by the remaining manganese/ferric oxide. This combined process could treat pollutants in remote regions where electricity supplies are not available.

Analysis of fouling and juice quality in crossflow ultrafiltration of watermelon juice

Abstract Raw watermelon juice was clarified in a laboratory scale flat plate ultrafiltration system incorporating polyethersulphone membranes with a molecular weight cut-off of 50 kDa. The experiments have been carried out over a wide range of trans-membrane pressures (1-3 bar). The effect of ultrafiltration with molecular weight cut-off (MWCO) of 50 kDa PES membrane on permeate properties is reported. The effects of trans-membrane pressure (TMP) on permeate flux and resistances were studied. The flux decay was analyzed through the resistance in series model which showed increase of both reversible and irreversible resistance with trans-membrane pressure, The TSS content of the permeate was found to be almost the same with feed while the ascorbic acid content in the permeate was on the lower side as compared to in feed.

Prevention of UF membrane fouling in drinking water treatment by addition of H2O2 during membrane backwashing

Although conventional coagulation pre-treatment can mitigate the fouling of ultrafiltration (UF) membrane when treating raw waters, it is insufficient to restrict the development of irreversible fouling and reversible fouling to a low level. In this paper we demonstrate that the intermittent addition of H2O2 into the membrane tank during backwash events (after coagulation pre-treatment) successfully prevented the development of any significant membrane fouling. Laboratory-scale tests were undertaken using two membrane systems operated in parallel over 60 days, one serving as a reference coagulation-ultrafiltration (CUF) process, and the other receiving the H2O2 (CUF-H2O2), with a decreasing dose in three successive phases: 10, 5 and 2 mg/L. The results showed that the addition of H2O2 (via a separate dosing tube) during a 1 min backwash process (at 30 min intervals) reduced the growth of bacteria in the membrane tank, and the associated concentrations of soluble microbial products (SMP, including protein and polysaccharide). This resulted in a much reduced cake layer, which contained significantly less high MW organic matter (>50%), such as EPS, thereby improving the interaction between particles in the cake layer and/or particles and the membrane surface. There was also less organic matter, of all MW fractions, adsorbed in the membrane pores of the CUF-H2O2 system. The addition of H2O2 in the membrane tank appeared to alter the nature of the organic matter with a conversion of hydrophobic to hydrophilic fractions, which induced less organics adsorption within the hydrophobic PVDF membrane pores, and a reduced bonding ability for particles. There was no physico-chemical evidence of any deterioration of the membrane from exposure to H2O2, which indicates the feasibility of applying this novel method of fouling control for full-scale UF based water treatment processes.

Fouling behaviours of two stages microalgae/membrane filtration system applied to palm oil mill effluent treatment

Fouling by solids and microorganisms is the major obstacle limiting the efficient use of membrane wastewater treatment. In our previous study, two stages microalgae/membrane filtration system was proposed to treat anaerobic digested palm oil mill effluent (AnPOME). This two stages microalgae/membrane filtration system had showed great potential for the treatment of AnPOME with high removal of COD, NH3-N, PO43-, TSS, turbidity, and colour. However, fouling behavior of the membrane in this two stages microalgae/membrane filtration system was still unknown. In this study, empirical models that describe permeate flux decline for dead-end filtration (pore blocking - complete, intermediate, and standard; and cake layer formation) presented by Hermia were used to fit the experimental results in identifying the fouling mechanism under different experimental conditions. Both centrifuged and non-centrifuged samples were taken from the medium with 3 days RT intervals, from day 0 to day 12 to study their influence on fouling mechanisms described by Hermia for ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) filtration mode. Besides, a more detailed study on the use of resistance-in-series model for dead-end filtration was done to investigate the fouling mechanisms involved in membrane filtration of AnPOME collected after microalgae treatment. The results showed that fouling of UF and NF membrane was mainly caused by cake layer formation and it was also supported by the analysis for resistance-in-series model. Whereas, fouling of RO membrane was dominated by concentration polarization.

Performance of Activated Carbon Adsorption and Ultrafiltration Membrane Hybrid Process for Leachate Treatment

Leachate is wastewater that contains pollutants dominated by organic matter. Conventional leachate treatments have some disadvantages therefore alternative treatments are needed. One of that alternative treatments is ultrafiltration membrane and adsorption as pretreatment. The aims of this study are to analyze adsorption isotherm and kinetic model for UV254 (UV adsorbance at 254 nm wavelength) adsorption, the performance of powdered activated carbon (PAC) adsorption and ultrafiltration membrane hybrid process for UV254 of leachate removal, and the effect of pretreatment towards membrane fouling. The result of this study are Freundlich isotherm and pseudo second order kinetic model best fitted model for ultrafiltration membrane hybrid process condition for UV254 removal level are at pH 6; 120 minutes contact time; and 4 g/L PAC doses. Adsorption as pretreatment can reduce membrane ultrafiltration fouling.