Dynamic Membrane Filtration Research Articles

Effect of powder activated carbon (PAC) addition on the performance of anaerobic dynamic membrane bioreactor (AnDMBR): Stratification analysis of dynamic membrane characteristics

Powdered activated carbon (PAC), proved to be an effective performance enhancer in membrane bioreactor studies, has yet been applied in anaerobic dynamic membrane bioreactors (AnDMBRs). A better understanding of dynamic membrane (DM) characteristics is important for optimizing AnDMBR performance. In this study, three AnDMBRs were operated for synthetic municipal wastewater treatment with PAC dosages of 0, 1, and 3 g/L. Particular efforts were devoted to understanding the DM characteristics in layers. It was found that PAC addition increased COD removal efficiency (10 %) and decreased DM filtration resistance (60 %). The extent of performance enhancement, particularly the decrease of DM filtration resistance, appears to be much more substantial in AnDMBR than aerobic DMBR. PAC addition significantly reduced the fouling potential of suspended sludge and consequently the filtration resistance of DM. Compared with inner DM layer, the outer DM layer exhibited relatively higher fouling characteristics, such as less porous structure, higher EPS content (mainly proteins), hydrophobicity, and relative abundance of biofouling-related bacteria. The positive effect of PAC addition on reducing DM fouling characteristics turned out to be more significant for outer DM layer, mainly because of its higher PAC content associated with the higher amount of small particles.

Pre-coating of stainless-steel mesh support material with wastewater treatment plant sludges in a dynamic membrane filtration process

This study focuses on wastewater treatment plant sludges to be deposited on large aperture meshes. In a column reactor that is filled with treatment plant sludges, a series of batch experiments were performed with varying sizes of stainless-steel mesh modules (75 to 300 μm) as a support media to form a dynamic membrane. Primary, secondary, and polyelectrolyte-added sludges were used both individually and in combination to investigate the performance (filterability, permeate quality, and dynamic layer formation ability) of the varying pore-size meshes at high fluxes. The results were superior when primary and secondary sludges were combined in the creation of a dynamic cake layer, as opposed to individual sludge usage. Mesh sizes were shown to have no effect on performance, providing turbidity of <10 NTU for a short duration (10 min) of filtration. Cake formation rates were calculated as 23.0 NTU/min, 19.48 NTU/min, 7.62 NTU/min, and 6.94 NTU /min for 100, 150, 200, and 300 μm support meshes, respectively. For the first time in literature, effluent water turbidity decreases to <5 NTU for 300 μm support mesh at high fluxes. Scanning electron microscope images showed that fibers that may originate from the primary sludge could enhance the formation of stable cake layer. This study is important for creating high-performing dynamic membrane filtration on large aperture meshes, which can be used as a cost-effective and reliable filter for wastewater treatment.

Mechanistic insights into different illumination positions control algae production in anaerobic dynamic membrane filtration (AnDM) during decentralized wastewater treatment

Sunlight illumination has the potential to control the stability and sustainability of dynamic membrane (DM) systems. In this study, an up-flow anaerobic sludge blanket (UASB) reactor was combined with DM under different illumination positions (direct, indirect and no illumination) to treat wastewater. Results indicated that the UASB achieved a COD removal up to 87.05 % with an average methane production of 0.28 L/d. Following treatment by the UASB, it was found that under illumination, the removal of organic substances by DM exhibited poor performance due to algal proliferation. However, the DM systems demonstrated efficient removal of ammonia nitrogen, ranging from 96.21 % to 97.67 % after stabilization. Total phosphorus removal was 45.72 %, and membrane flux remained stable when directly illuminated. Conversely, the DM system subjected to indirect illumination showed unstable membrane flux and severe fouling resistance. These findings offer valuable insights into optimizing illumination positions in DM systems under anaerobic conditions.

Disc ceramic membrane modified with nano-TiO2 for separating oil-water emulsion under dynamic membrane filtration

A disc ceramic membrane was modified nano-TiO2 via an impregnation and in-situ hydrolysis method, resulting in the generation of nano-TiO2 particles on the surface and inside the pores of disc ceramic membrane. The uniform distribution of nano-TiO2 enhanced the superior hydrophilic property of the membrane surface, and improved pure water flux and increased anti-fouling capacity. The modified disc ceramic membrane was employed to effectively separate stable oil-water emulsions under dynamic membrane filtration mode. Here, the preparation process of nano-TiO2 and operational parameters of equipment on the separation efficiency of the modified disc ceramic membrane were investigated. The findings indicate that an increase in the permeability and separation rate of the modified disc ceramic membrane. Moreover, the modified disc ceramic membrane maintained a steady flux for a continuous separation time of 120-min at a TMP of 0.04 MPa. The rejection rate of oil-water emulsion also reached 99.9%. The excellent performance of the modified disc ceramic membrane was ascribed to the nano-TiO2 modification and the dynamic membrane filtration applied together to alleviate membrane fouling, leading to improve the oil-water separation efficiency and permeate flux. This study presents a new technique for the separation of oil-water emulsions with high concentration, achieving outstanding separation stability and cost-effectiveness.

Dynamic membrane filtration accelerates electroactive biofilms in bioelectrochemical systems

Bioelectrochemical systems (BES) have emerged as a dual-function technology for treating wastewater and recovering energy. A vital element of BES is the rapid formation and maintenance of electroactive biofilms (EABs). Previous attempts to accelerate EAB formation and improve electroactivities focused on enhancing the bacterial adhesion process while neglecting the rate-limiting step of the bacterial transport process. Here, we introduce membrane filtration into BES, establishing a dynamic membrane filtration system that enhances overall performance. We observed that optimal membrane flux considerably reduced the startup time for EAB formation. Specifically, EABs established under a 25 L m−2 h−1 flux (EAB25 LMH) had a formation time of 43.8 ± 1.3 h, notably faster than the 51.4 ± 1.6 h in the static state (EAB0 LMH). Additionally, EAB25 LMH exhibited a significant increase in maximum current density, approximately 2.2 times higher than EAB0 LMH. Pearson correlation analysis indicated a positive relationship between current densities and biomass quantities and an inverse correlation with startup time. Microbial analysis revealed two critical findings: (i) variations in maximum current densities across different filtration conditions were associated with redox-active substances and biomass accumulation, and (ii) the incorporation of a filtration process in EAB formation enhanced the proportion of viable cells and encouraged a more diverse range of electroactive bacteria. Moreover, the novel electroactive membrane demonstrated sustained current production and effective solid-liquid separation during prolonged operation, indicating its potential as a viable alternative in membrane-based systems. This approach not only provides a new operational model for BES but also holds promise for expanding its application in future wastewater treatment solutions.

Preparation of alumina disc ceramic membrane with enhanced abrasion resistance for dynamic membrane filtration

Although disc ceramic membranes for dynamic filtration provide notable benefits in reducing membrane contamination, enhancing their resistance to erosive wear remains a challenging task. In this work, boehmite sol was employed as an effective additive to establish tightly connections between the membrane particles, and narrow the pore size of ceramic membrane with the increase of boehmite content. Alumina ceramic membranes with 15 wt% of boehmite sol and sintered at 1250 °C exhibited exceptional mechanical strength of 94 MPa, a porosity of 34 %, and an average pore size of 450 nm. Accelerated erosive wear tests were conducted by adjusting variables such as wear time, rotational speed and silica slurry concentration. It was observed that membranes prepared with 15 % boehmite sol exhibited a wear rate only 1/25th that of the without boehmite sol. Furthermore, the membrane displayed a consistent permeate flux of 1510 L m−2 h−1 bar−1 and a retention rate exceeding 99.5 % when filtering slurry containing 150 g/L of solid contents. After an extended duration of dynamic filtration, the flux and retention rate of the disc membrane exhibit a consistent and stable behavior. This disc ceramic membrane demonstrates promising potential for the filtration of suspensions with high solids content.

Antiscalants for mitigating silica scaling in membrane desalination: Effects of molecular structure and membrane process

Silica scaling is a major type of mineral scaling that significantly constrains the performance and efficiency of membrane desalination. While antiscalants have been commonly used to control mineral scaling formed via crystallization, there is a lack of antiscalants for silica scaling due to its unique formation mechanism of polymerization. In this study, we performed a systematic study that investigated and compared antiscalants with different functional groups and molecular weights for mitigating silica scaling in membrane distillation (MD) and reverse osmosis (RO). The efficiencies of these antiscalants were tested in both static experiments (for hindering silicic acid polymerization) as well as crossflow, dynamic MD and RO experiments (for reducing water flux decline). Our results show that antiscalants enriched with strong H-accepters and H-donors were both able to hinder silicic acid polymerization efficiently in static experiments, with their antiscaling performance being a function of both molecular functionality and weight. Although poly(ethylene glycol) (PEG) with abundant H-accepters exhibited high antiscaling efficiencies during static experiments, it displayed limited performance of mitigating silica scaling during MD and RO. Poly (ethylene glycol) diamine (PEGD), which has a PEG backbone but is terminated by two amino groups, was efficient to both hinder silicic acid polymerization and reduce water flux decline in MD and RO. Antiscalants enriched with H-donors, such as poly(ethylenimine) (PEI) and poly(amidoamine) (PAMAM), were effective of extending the water recovery of MD but conversely facilitated water flux decline of RO in the presence of supersaturated silica. Further analyses of silica scales formed on the membrane surfaces confirmed that the antiscalants interacted with silica via hydrogen bonding and showed that the presence of antiscalants governed the silica morphology. Our work indicates that discrepancy in antiscalant efficiency exists between static experiments and dynamic membrane filtration as well as between different membrane processes associated with silica scaling, providing valuable insights on the design principle and mechanisms of antiscalants tailored to silica scaling.

Designing a fault detection classifier framework for an industrial dynamic ultrafiltration membrane process using wavelet-based feature analysis

In recent years, due to the increase in population and the number of industrial sites, water reclaim has become more relevant. Dynamic membrane filtration systems can play an important role for water reuse. Therefore, process monitoring of dynamic membrane systems is of great importance to ensure the water quality while considering environmental and economic factors. The exploitation of on-line monitoring of dynamic membrane systems in industrial operation is challenged by intentional disturbances such as backflush and backshock (i.e. used as cleaning strategies) and unintentional input fluctuations. Consequently, process inherent behaviour is hidden within very complex sensors signals. Therefore, critical flux identification or fouling characterization for process monitoring is not straightforward, leading to suboptimal operation. The present study establishes a fault detection framework from a classification viewpoint, capable of handling industrial data that is prone to noise and disturbances, while offering an effective yet straightforward approach. The case study is a pilot-scale dynamic ultrafiltration process which has been tested previously within an industrial facility for produced water reclamation. The dataset contains 18 experiments, where three of the experiments are faulty. These experiments were implemented in an oil recovery facility located in the Orinoquía region, Colombia. A feature analysis approach based on wavelets is developed to identify the key characteristics of the installed sensors while alleviating the noise effects. The process conditions are pinpointed by feeding the extracted features into several widely used classification methods including Multilayer Perceptron Neural Network (MLPNN), Support Vector Machine (SVM), and Principal Component Analysis (PCA) based classifiers. The results indicated that the MLPNN classifier has the highest detection accuracy of 99.7% with a low percentage of false alarms. The framework developed in this study is a vital part of a membrane system digitalization strategy, which can be integrated into automated surveillance strategies for monitoring of membrane systems toward effective fault detection.

Adsorptive dynamic membrane for water purification: Model and optimization

Adsorptive dynamic membrane, consisting of adsorption and filtration, exhibits a desirable efficiency for water purification. However, the entire adsorption-filtration process is affected by many influencing factors, and the operating regulation and process optimization remain still uncertain. The present work deals with the process optimization for adsorptive dynamic membrane treating micro-polluted water. A Box-Behnken response surface methodology was utilized to investigate the effect of operating conditions (dye concentration, agitation speed, carbon nanotubes dosage, Transmembrane Pressure and pH) on the dye removal and flux. The response surface methodology with high coefficients of determination values were fitted to the experimental data, which demonstrated that the polynomial response models fitted well for describing dye removal and adsorptive dynamic membrane filtration efficiency. Based on the design, the optimized conditions for obtaining highest dye removal rate (100%) were dye concentration = 5 mg/L, agitation speed = 210 rpm, carbon nanotubes dosage = 13 g/m2, Transmembrane Pressure = 0.2 mPa and pH = 5.8. The graphical optimization of superimposed contour plots fulfilled the conditions to obtain dye removal >95% and flux >100 L m−2 h−1, as well the interactions among various operating conditions. The work indicated that response surface methodology can be applied for analyzing the effect of operating conditions and acquiring the optimized conditions for adsorptive dynamic membrane treating water/wastewater.

Preparation of disc ceramic membrane by a printing and dip-coating method for oil-water separation

Efficient separating oil-water emulsion, it is required that ceramic membranes have the suitable membrane pore size, narrow pore size distribution and low membrane fouling. To realize it, thin and defect-free membrane separation layer should be directly prepared on the large pore size support surface, and the membrane under a dynamic filtration mode. In the present work, disc ceramic membrane without any transition layer was fabricated directly on the surface of support with a pore-size of 3.8 µm via a printing and dip-coating method. The mesh aperture and printing times regulate the thickness of printing layer, preventing the small alumina particles from penetrating into the support. Meanwhile, Dip-coating layer effectively eliminate the defects of the printing layer. Compared with common ceramic membranes, the prepared disc ceramic membrane has a low-cost and high permeability of 1946.6 L/m2·h·bar. Furthermore, the disc ceramic membrane can significantly mitigate membrane fouling and improve the oil-water separation efficiency (>99.5%) under a dynamic membrane filtration mode. This study suggests the practicability of printing and dip-coating method to prepare the disc ceramic membrane with high performance.

Use of hollow fibre membrane contactors to remove dissolved gases from effluents of UASB reactors treating sewage after its conditioning with dynamic membrane filtration

Dissolved gases in the effluent of anaerobic reactors, such as dissolved methane (D-CH4) and sulphide (S2−), are a drawback for anaerobic-based sewage treatment plants. Hollow fibre membrane contactors (HFMCs) have been tested for the removal of these compounds, and this paper evaluated a novel configuration with pressurised dynamic membrane modules (PDMMs) for conditioning an anaerobic effluent (from UASB reactor fed with sewage) as a means to reduce HFMCs clogging and fouling. Three PDMMs were used for the anaerobic effluent conditioning before two types of HFMCs (dense and microporous membranes). An automated backwash with a tap water cleaning protocol complemented with a chemical cleaning protocol (NaOH and citric acid) was applied for fouling control. The microporous HFMC could not maintain a stable performance (D-CH4 and S2− removal drop of 30 % and 40 %, respectively, in 10 days of operation), arguably due to membrane wetting, meanwhile the dense HFMC showed a more stable behaviour (removal efficiencies close to 100 % and 90 % for S2− and D-CH4, respectively in >30 days). The water backwash removed an important fraction of the entrapped organic solids. Meanwhile, the NaOH cleaning was efficient in removing inorganic compounds. Citric acid contributed to the removal of calcium and phosphate.

Modeling of a Dynamic Membrane Filtration Process Using ANN and SVM to Predict the Permeate Flux

Modeling of a Dynamic Membrane Filtration Process Using ANN and SVM to Predict the Permeate Flux

Separation of oil–water emulsion by disc ceramic membrane under dynamic membrane filtration mode

The disc ceramic membrane under a dynamic membrane filtration is applied to separate oil–water emulsion. The dynamic membrane filtration means that the membrane is rotating to obtain the flow velocity of membrane surface but the feed solution is almost still. In this case, the trans-membrane pressure (TMP) and the flow velocity of membrane surface can be controlled separately. Here, the effects of operation parameters on the separation performance and re-generation of disc ceramic membrane are studied. The membrane fouling and stability and practicability of disc ceramic membrane are evaluated. The results show that the permeate flux of disc ceramic membrane increases with the increment of rotating speed and the rejection increases with the TMP decreases. Furthermore, the rejection efficiency of oil achieved up to ＞99.9% during a 90 min continuous separation if the TMP was only 0.2 bar. High flow velocity but low TMP of disc ceramic membrane alleviates the membrane fouling caused by concentration polarization layer and gel layer, and reduces the deformation and penetration of oil droplets. This work provides a new method to separate the high-concentration of oil–water emulsion.

A Novel Anaerobic Gravity-Driven Dynamic Membrane Bioreactor (AnGDMBR): Performance and Fouling Characterization.

Despite numerous studies undertaken to define the development and significance of the dynamic membrane (DM) formed on some coarse materials, the optimization of reactor configuration and the control of the membrane fouling of anaerobic dynamic membrane bioreactor (AnDMBR) need to be further investigated. The aim of this study was to design a novel anaerobic gravity-driven dynamic membrane bioreactor (AnGDMBR) for the effective and low-cost treatment of municipal wastewater. An 800 mesh nylon net was determined as the optimal support material based on its less irreversible fouling and higher effluent quality by the dead-end filtration experiments. During the continuous operation period of 44 days, the reactor performance, DM filtration behavior and microbial characteristics were studied and compared with the results of recent studies. AnGDMBR had a higher removal rate of chemical oxygen demand (COD) of 85.45 ± 7.06%. Photometric analysis integrating with three-dimensional excitation–emission matrix fluorescence spectra showed that the DM effectively intercepted organics (46.34 ± 16.50%, 75.24 ± 17.35%, and 66.39 ± 17.66% for COD, polysaccharides, and proteins). The addition of suspended carriers effectively removed the DM layer by mechanical scouring, and the growth rate of transmembrane pressure (TMP) and the decreasing rate of flux were reduced from 18.7 to 4.7 Pa/h and 0.07 to 0.01 L/(m2·h2), respectively. However, a dense and thin morphological structure of the DM layer was still observed in the end of reactor operation and plenty of filamentous microorganisms (i.e., SJA-15 and Anaerolineaceae) and the acidogens (i.e., Aeromonadaceae) predominated in the DM layer, which was also embedded in the membrane pore and led to severe irreversible fouling. In summary, the novel AnGDMBR has a superior performance (higher organic removal and lower fouling rates), which provides useful information on the configuration and operation of AnDMBRs for municipal wastewater treatment.

Effects of applying external voltage on development of anaerobic dynamic membrane under high suspended solids conditions

Maintaining proper dynamic membrane (DM) thickness and structure is the key factor for effective filtration and biomass retention in DM bioreactors. This study investigated the effects of negative and positive applied voltages on the development and characteristics of anaerobic DM under high suspended solids conditions. The DM filtration experiments with anaerobic sludge were performed using submerged DM modules with stainless steel support material at applied voltages of –1.2 to +1.2 V. Negative applied voltage (i.e., cathodic DM) delayed the DM fouling, while positive applied voltage (i.e., anodic DM) accelerated the DM growth, within certain voltage ranges by the combined effect of electrostatic forces and electrochemical reactions. Too large negative or positive voltages caused electrochemical corrosion of support material and precipitation of mineral scales, resulting in serious chemical fouling. The cathodic and anodic DMs formed at different applied voltages achieved high suspended solids rejection efficiencies of 86.4–89.6%. The applied voltage had a significant effect not only on the DM growth and filtration resistance but also the surface morphology, cell viability (live/dead cell ratio), and extracellular polymeric substances distribution of DM. Cell damage by electrochemically formed reactive species was observed at high electrode potentials. The overall results suggest that applying external voltage within an appropriate range can be an effective way to control the DM development. Although much more research is needed, the findings of this study offer a new possibility to improve the feasibility of DM technology and its applicability in anaerobic DM bioreactors.

Gravity-driven high flux filtration behavior and microbial community of an integrated granular activated carbon and dynamic membrane bioreactor for domestic wastewater treatment

A gravity-driven dynamic membrane bioreactors (DMBR) with GAC addition (G-DMBR) was operated under constant pressure filtration mode (using 20 cm water head) for real domestic wastewater treatment. During the stable operation period, the treatment performance, DM filtration behavior and mechanism as well as microbial properties were studied and compared with a control DMBR (C-DMBR). Both DMBRs showed stable removal of chemical oxygen demand (COD) and ammonia (NH4+-N) with average removal rates over 88% and 98%, respectively. GAC addition effectively enhanced dynamic membrane (DM) permeability with a stable flux of 17 to 65 L/m2h, which was approximately four times higher than that in the C-DMBR without GAC addition. Filtration resistance analysis indicated the DM formation can be divided to three stages: the formation of the initial DM layer, the development of mature DM layer and dynamic equilibrium stage of the DM layer. Filtration model analysis illustrated that added GAC could be the skeleton of the DM, resulting in a more porous and incompressible DM layer. Additionally, microbial community analysis revealed that in the G-DMBR several fouling-causing phyla including Proteobacteria reduced while other phyla preferring attached growth such as Bacteroidetes and Gemmatimonadetes increased. Thus, adding GAC to the DMBR can be an effective strategy for achieving stable and high-flux operation by modifying DM properties and regulating DM formation process and structure.

Humic acid non-covalent functionalized multi-walled carbon nanotubes composite membrane and its application for the removal of organic dyes

It was the first time that humic acid (HA) was used to non-covalent functionalize multi-walled carbon nanotubes (MWCNTs). The MWCNT and HA-MWCNT was characterized by X-ray photoelectron spectroscopy (XPS), infrared spectra (IR) and transmission electron microscopy (TEM). Then, a HA non-covalent functionalized multi-walled carbon nanotubes (HA-MWCNTs) membrane was prepared by vacuum filtration and used to remove organic dyes. To investigate the removal mechanism of organic dyes by HA-MWCNTs membrane, the dynamic filtration effectiveness of HA-MWCNTs membrane was compared with the adsorption ability of HA-MWCNTs. The results proved that HA-MWCNTs membrane had a higher effectiveness for the removal of dyes as it had shorter filtration time compared with the static adsorption experiment. Especially, the HA-MWCNTs membrane had a higher removal efficiency for cationic dye methylene blue (MB) than the raw MWCNTs (P-MWCNTs) membrane. The electrostatic interaction played an important role on the removal of MB, and the functionalization of MWCNTs with HA increased the surface electronegativity of MWCNTs membrane, and promoted the removal of MB during filtration process. As for RB19, in addition to π–π stacking interaction, electrostatic interaction also influenced its removal by MWCNTs membrane. Compared with P-MWCNTs membrane, HA-MWCNTs membrane slightly decreased the effectiveness of RB19 removal during filtration due to the increased electrostatic repulsion. Generally, the dynamic membrane filtration based on MWCNTs composite membrane could avoid the ecological risk caused by the release of MWCNTs. It provided a new idea for the further innovation of low-pressure membrane technology in the field of dye wastewater treatment.

Technical Note 7 - Applicability of dynamic membrane filtration for post-treatment of UASB reactor effluents

Despite the many advantages of UASB reactors for sewage treatment a posttreatment stage may be necessary. An emerging post-treatment alternative is the use of dynamic membranes (DM). In DMs, the removal of pollutants occurs mainly due to a dynamic layer of solids that is formed on a mesh support. Its main advantage is the possibility of using low-cost support materials. The present technical note aims to present fundamentals and practical aspects of this emerging technology, in view of its high application potential for improving the quality of effluents from anaerobic reactors. The applicability and limitations of the technology, the fundamentals of the process, the most important design criteria and aspects related to its operation and maintenance are discussed. With this technical note, it is intended to encourage a discussion in Brazil regarding the potential use of DMs in the post-treatment of anaerobic reactor effluents.

Integrated self-forming dynamic membrane (SFDM) and membrane-aerated biofilm reactor (MABR) system enhanced single-stage autotrophic nitrogen removal

The membrane aerated biofilm reactor (MABR) is a novel bioreactor technology, facilitating single-stage autotrophic nitrogen removal. Two laboratory-scale MABRs equipped with non-woven fabrics were operated simultaneously without and with a self-forming dynamic membrane (SFDM) filtration module. After 87 days of operation (system start-up), the reactor incorporated with SFDM filtration showed better performance in terms of total nitrogen removal (>80%) and effluent suspended solid (less than1 mg/L) than the MABR in the up flow anaerobic sludge blanket (UASB) configuration (i.e., without SFDM). The incorporation of SFDM has the ability to retain more slow growing biomass (anammox) inside the reactor. Microbial characterization by 16S rRNA-based amplicon sequencing shows that the abundance and composition of microbial communities in two MABR systems were different, i.e., the genusRhodanobacterwas abundant in UASB-MABR, while Calorithrixwas dominant in SFDM-MABR. PCA-based statistical analysis demonstrated a positive association between reactor performance, membrane characteristics and microbial communities.

Self-forming dynamic membrane filtration for drinking water treatment

Abstract Lab-scale continuous operation of self-forming microfiltration (MF) or ultrafiltration (UF) dynamic membranes were investigated simultaneously by applying iron oxide as an alternative treatment option in those waters having natural organic matter (NOM), iron and manganese. Both dynamic membranes gave high removal rates and effluent concentrations of pollutants were below the limit values in synthetic water. 60 and 62% (of DOC) and 75 and 78% (of UV254) were removed in low dissolved organic carbon (DOC) synthetic (LS) water by MF and UF dynamic membranes, respectively. Although only 42 and 49% (of DOC) and 48 and 53% (of UV254) could be removed by MF and UF dynamic membranes, respectively, a remarkable effect on fouling alleviation was observed in high DOC synthetic (HS) water. Iron oxide did not enhance the removal of organic matter in low DOC natural (LN) water as much as it did in synthetic water. Iron oxide led to the removal of high molecular weight organics, thus reversible fouling was reduced almost 2 orders of magnitude through both types of dynamic membranes in high DOC natural (HN) water. Reversible and irreversible resistances were reduced by iron oxide to some extent in LN water. Nevertheless the effect of iron oxide on fouling alleviation was much higher in HN rather than in LN water.