Organic Membrane Fouling Research Articles

Understanding the fouling characteristics in ultrafiltration membrane for marine algae-laden seawater pretreatment: Focus on the role of algal extracellular organic matter

The increasing frequency and extent of harmful algal blooms (HABs) due to global warming and environmental pollution pose significant challenges to the ultrafiltration (UF)-seawater reverse osmosis (SWRO) desalination process. The UF process is a dominant pretreatment method to reduce HAB fouling potential in subsequent SWRO processes. Herein, we systematically evaluate the UF membrane fouling characteristics at different growth phases of HAB algae in terms of reversible/irreversible fouling and pinpoint the fouling mechanisms on UF membranes in the real seawater matrix. We employed Prorocentrum donghaiense as a model marine HAB specie to characterize algal derivatives, including extracellular organic matter (EOM) and granule particles. LC-OCD, MFIs, 3D-EEM, and GPC were used to analyze algae-derived matters. Results from the multiple fouling model revealed that algal solution in both stationary and decline phases exhibit severe membrane fouling, characterized by rapid cake layer formation, swift flux decline, and high membrane resistance. Soluble EOM (S-EOM) was the primary contributor to membrane fouling, linked to its elevated concentrations of dissolved organic matters, polysaccharides, proteins, and humic substances, which are predominantly hydrophobic. Additionally, granule particles mitigated organic membrane fouling, as evidenced by the smaller permeate volume required for S-EOM cake layer formation (<5 mL), resulting in a faster initial flux decline. These results revealed a shift in released organic matter from protein-centric to humic substance-centric during the transition from exponential growth to the decline phase, with correlation analysis further underscoring the substantial contribution of humic substances to membrane resistance. This research highlights the distinct UF membrane fouling characteristics at different marine algal growth stages, offering theoretical support for predicting and managing HABs.

Effect of Mn2+ on RO membrane organic fouling: Insights into the complexation and interfacial interaction

RO process is commonly used to treat and reuse manganese-containing industrial wastewater. Nevertheless, even after undergoing multi-stage treatment, the secondary biochemical effluent still exhibits a high concentration of Mn2+ coupled with organics entering the RO system, leading to membrane fouling. In this work, we systematically analyze the RO membrane organic fouling processes and mechanisms, considering the coexistence of Mn2+ with humic acid (HA), sodium alginate (SA), bovine serum albumin (BSA) and their mixtures (HBS). The impact of Mn2+ on membrane fouling was HBS > SA > HA > BSA, controlling polysaccharide pollutant concentrations should be a priority for mitigating membrane fouling. In the presence of Mn2+ with HA, SA, or HBS, membrane fouling is primarily attributed to the complexation of organics and Mn2+ and the facilitation of interfacial interaction energy. RO membrane BSA fouling was not directly affected by Mn2+, the addition of Mn2+ induced a salting-out effect, leading to the deposition of BSA in a single molecular on the membrane. Simultaneously, adhesion energy hinders the deposition of BSA on the membrane, resulting in milder membrane fouling. This study provided the theoretical basis and suggestions for RO membrane organic fouling control in the presence of Mn2+.

Investigating mechanism of enhanced anti-fouling performance of MXene modified Janus MD membrane by XDLVO theory combined with surface elemental integration method

Organic membrane fouling is a major obstacle to the application of membrane distillation in low surface tension wastewater treatment. Membrane modification might be an effective way to mitigate membrane fouling. This study mainly explored the mechanism of enhanced anti-fouling performance of the MXene modified PVDF membrane by applying XDLVO theory combined with surface elemental integration (SEI) method. The rough membrane surfaces were first reconstructed using fractal function. Then, the interaction energy between low surface tension substances and the membranes before and after modification was calculated. The results showed that oil droplets and surfactant fouling were mainly caused by hydrophobic attraction due to Lewis acid-base (AB) interaction energy. By modifying the virgin PVDF membrane with MXene nanoparticles, the polar component of membrane surface tension (γAB) increased significantly, so that the interaction energy between all contaminants and membrane surface changed from attraction to repulsion. In addition, roughness weakened the interaction energy between contaminants and membrane surface but significantly lengthened the range of interaction distance, which together determined the ability of the membrane to attract or repel the contaminants. These findings may improve the understanding of the structure-effect relationship between membrane modification and anti-fouling ability, and provide new insights into the membrane modification for MD.

On the Disproportionate Contribution of Membrane Electron Donor Functionality in Membrane Biofouling.

This study set out to uncover which interfacial properties have the greatest impact on membrane organic fouling, biofouling, and fouling resistance. A relatively simple manipulation of the basic equations used in determining Lifshitz-van der Waals (LW) and Lewis acid-base (AB) surface tensions for solid materials reveals that the high electron accepticity of water makes the electron donicity of membrane and biofouling materials the key component governing their interfacial free energy of adhesion (ΔG132), which defines the favorability (or unfavorability) of one material (1) adhering to another (2) when immersed in a liquid (3). Various biofoulant and membrane LW and AB surface tensions were systematically characterized. Static bacterial adhesion, alginic acid filtration, and wastewater filtration tests were conducted to determine the fouling propensities of three different polymeric membrane materials. Experimental results of microbial adhesion, alginate fouling, and biofouling tests all correlated well with membrane electron density, where higher electron density produced less organic fouling or biofouling. These combined theoretical and experimental results confirm the importance of surface electron donicity in determining the fouling propensity of polymeric membranes.

Quantitative source tracking for organic foulants in ultrafiltration membrane using stable isotope probing approach

Quantitatively identifying the primary sources of organic membrane fouling is essential for the effective implementation of membrane technology and optimal water resource management prior to the treatment. This study leveraged carbon stable isotope tracers to estimate the quantitative contributions of various organic sources to membrane fouling in an ultrafiltration system. Effluent organic matter (EfOM) and aquatic natural organic matter (NOM), two common sources, were combined in five different proportions to evaluate their mixed effects on flux decline and the consequent fouling behaviors. Generally, biopolymer (BP) and low molecular weight neutral (LMWN) size fractions - abundantly present in EfOM - were identified as significant contributors to reversible and irreversible fouling, respectively. Fluorescence spectroscopy disclosed that a protein-like component notably influenced overall membrane fouling, whereas humic-like components were predominantly responsible for irreversible fouling rather than reversible fouling. Fluorescence index (FI) and biological index (BIX), common fluorescence source tracers, showed promise in determining the source contribution for reversible foulants. However, these optical indices were insufficient in accurately determining individual source contributions to irreversible fouling, resulting in inconsistencies with the observed hydraulic analysis. Conversely, applying a carbon stable isotope-based mixing model yielded reasonable estimates for all membrane fouling. The contribution of EfOM surpassed 60 % for reversible fouling and increased with its content in DOM source mixtures. In contrast, aquatic NOM dominated irreversible fouling, contributing over 85 %, regardless of the source mixing ratios. This study emphasizes the potential of stable isotope techniques in accurately estimating the contributions of different organic matter sources to both reversible and irreversible membrane fouling.

BiOCl as the role of cleaner for the fabrication of self-cleaning PES membranes based on the RTIPS method

Due to its cost-effectiveness and productivity, membrane separation technology is widely utilized in the treatment of wastewater, but a major barrier to its further development is organic membrane fouling, which is mainly caused by humic acid (HA). To address this issue, BiOCl/polyvinylpyrrolidone (PVP) composites were produced using the ambient stirring method, while polyethersulfone (PES)/BiOCl/PVP self-cleaning membranes were manufactured using the reverse thermally induced phase separation (RTIPS) method. Considering the pure water flux of 3566.67 L m−2 h−1 and HA retention of 87.24 %, the 0.3 wt% PES/BiOCl/PVP (PB2–65) composite membrane had excellent permeability. The flux recovery of the composite membrane was 76.19 % after three photocatalytic cycles, and cycling experiments proved that the PB2–65 self-cleaning mechanism was stable. The performance of PB2–65 was not compromised when the use cycle was noticeably prolonged under light irradiation. The membranes in this study offer beneficial strategies and solutions for membrane contamination issues.

A Comprehensive Analysis of the Impact of Inorganic Matter on Membrane Organic Fouling: A Mini Review.

Membrane fouling is a non-negligible issue affecting the performance of membrane systems. Particularly, organic fouling is the most persistent and severe form of fouling. The complexation between inorganic and organic matter may exacerbate membrane organic fouling. This mini review systematically analyzes the role of inorganic matter in membrane organic fouling. Inorganic substances, such as metal ions and silica, can interact with organic foulants like humic acids, polysaccharides, and proteins through ionic bonding, hydrogen bonding, coordination, and van der Waals interactions. These interactions facilitate the formation of larger aggregates that exacerbate fouling, especially for reverse osmosis membranes. Molecular simulations using molecular dynamics (MD) and density functional theory (DFT) provide valuable mechanistic insights complementing fouling experiments. Polysaccharide fouling is mainly governed by transparent exopolymer particle (TEP) formations induced by inorganic ion bridging. Inorganic coagulants like aluminum and iron salts mitigate fouling for ultrafiltration but not reverse osmosis membranes. This review summarizes the effects of critical inorganic constituents on fouling by major organic foulants, providing an important reference for membrane fouling modeling and fouling control strategies.

Performance of resin adsorption and ozonation pretreatment in mitigating organic fouling of reverse osmosis membrane

Effective pretreatment of reverse osmosis (RO) influent is of great importance for reducing membrane fouling risks during coking wastewater desalination. In this study, the combined resin adsorption and ozonation pretreatment was investigated on alleviating RO membrane organic fouling. The performance of combined process was compared with only resin adsorption or ozonation, which was evaluated in terms of changes in chemical oxygen demand (COD), ultraviolet-visible index, and three-dimensional excitation-emission matrix fluorescence spectra. RO membrane fouling tests were conducted to examine the effects of pretreatment on flux decline and filtration resistance. The surface morphology and functional groups of membrane before and after fouling was characterized by scanning electron microscopy and infrared spectroscopy. The correlation between major organic matter in the wastewater and normalized RO membrane flux was established via multiple linear regression equations. The results showed that ozonation was more effective in removing COD and fluorescent organics than resin adsorption. Moreover, the combined bifunctional resin adsorption/ozonation unit showed the best performance, with COD and UV254 removal rates of 49.4 % and 88.0 %, respectively. The fluorescence intensity of each component decreased significantly. Meanwhile, the polysaccharide and protein components of the RO membrane fouling layer were effectively reduced by 67.2 % and 80.8 %, respectively. Most importantly, the combined pretreatment substantially reduced the decline in membrane flux and filtration resistance. Meanwhile, the fulvic acid-like organics in the wastewater showed high correlations with normalized membrane flux. The regression equation was beneficial for RO membrane fouling evaluation.

An autopsy study of hollow fiber and multibore ultrafiltration membranes from a pilot-scale ultra high-recovery filtration system for surface water treatment

The organic fouling characteristics of hollow fiber ultrafiltration (HFUF) and multibore ultrafiltration (MBUF) membranes from long-term ultrafiltration (UF) membrane systems were systemically investigated in this study. The objective was to obtain insights into the fouling behavior of dissolved organic matter (DOM) in a pilot-scale ultra-high-recovery membrane filtration system (p-UHMS) used for surface water treatment. The pilot system consisted of a series of two different UF membranes (1st stage: polyvinylidene fluoride (PVDF) HFUF and 2nd stage: polyethersulfone (PES) MBUF). It was designed to feed the HFUF concentrate to the MBUF membranes to achieve ≥99.5 % total water recovery for surface water treatment, as these advances might enhance the production efficiencies of drinking water. The experimental results confirmed that hydrophobic DOM controlled the formation of HFUF membrane organic fouling, whereas hydrophilic DOM, including polysaccharide-like and protein-like matter, promoted MBUF membrane fouling. These opposing trends were attributed to the hydrophilic characteristics of the MBUF membrane surfaces (contact angle: PVDF = 90–130° and PES ≤ 80°), which reduced the hydrophobic interactions between the UF membrane surfaces and foulants. The performance declines of the MBUF membrane due to fouling layer formation was considerably severer than those of the HFUF membrane, decreasing total permeate water in the p-UHMS. Moreover, the quantity of the desorbed MBUF membrane foulants via 0.1 N NaOH was roughly 7.2 times larger than that of the desorbed HFUF membrane foulants through 0.1 N NaOH, indicating that alkaline-based cleaning agent could much more efficiently recover the performance of the fouled MBUF membranes. Hence, adequate cleaning strategies using alkaline-based agent for the MBUF membrane appeared to be essential for preventing the performance deterioration of the p-UHMS.

Membrane distillation bioreactor (MDBR) for wastewater treatment, water reuse, and resource recovery: A review

Membrane bioreactors (MBRs) have been well established as an advanced wastewater treatment technology that combines activated sludge with a pressure-driven membrane separation process. They have been widely applied in municipal and industrial wastewater treatment systems due to their advantages over conventional activated sludge systems. However, MBRs still face major issues hindering their widespread implementation such as poor effluent quality due to low retention of trace organic contaminants, instability due to changing operating conditions, and organic membrane fouling. Membrane distillation (MD) bioreactor (MDBR) is a novel wastewater treatment technology that combines MBRs with an MD unit either separated at a side stream or submerged in the bioreactor. The concept of hybrid MDBR configuration was firstly introduced in 2007 which was followed by numerous journal articles. These studies demonstrated the MDBR potential for water, nutrients, bioenergy, and other value-added product recovery from domestic and industrial wastewater; however, there is still a lack of a comprehensive study that shows the full MDBR potential. Hence there is a need for a dedicated review that summarize and critically analyse these research findings and highlight the research gaps to provide clear path for future research. This review presents system availability and applications of hybrid MDBR. In particular, the review presents brief introduction of MBR and MD technologies followed by covering the evolution of MDBR as a novel technology for municipal and industrial wastewater treatment. Several applications of MDBR systems are reviewed with a focus on system performance and removal efficiencies. The potential of MDBR to widen wastewater reuse and achieve nutrient and biogas recovery is also presented. Finally, the main challenges that hinder the development of MDBR are discussed while recommendations on future perspectives towards MDBR commercialization are suggested.

The design of multi-stage open-loop hollow fiber membrane contactor and its application in ammonia capture from hydrolyzed human urine

Hollow fiber membrane contactor (HFMC) is a promising technology for removing or recovering wastewaters' volatile components. Developing a rational design method is very important for guiding its further application. In this study, we proposed a method to design the multi-stage open-loop hollow fiber membrane contactor (HFMC) employing shell-side influent. In addition, a three-stage HFMC was designed to capture ammonia from real hydrolyzed human urine. A continuous 1344 h performance was conducted. The results showed that the experimental effluent total ammonium nitrogen (TAN) concentration and ammonia mass transfer coefficient matched the predicted results well, which indicated that the design method was feasible and accurate. The three-stage HFMC showed excellent ammonia capture capacity with a TAN recovery efficiency of 93.29%, and the final effluent TAN concentration was 30.98±14.70 mg/L which met our design requirement (lower than 50 mg/L). More than 98.92% of the inorganic ions and 96.85% of the organic matter were retained in the effluent. The stripping solution after ammonia capture was the high-purity ammonium sulfate solution with low concentration of small molecular weight hydrophilic organic substances. The inorganic and organic membrane fouling was mild and randomly distributed. The inorganic membrane fouling was attributed to the deposition of calcium-, magnesium-, phosphate-related inorganic compounds, while the organic membrane fouling was mainly protein and carbohydrate. After the ammonia capture process, the surface hydrophobicity and pore properties of the membranes had no significant changes. These results demonstrated that the multi-stage open-loop HFMC could be a potential alternative for ammonia recovery from the high concentration of ammonium nitrogen wastewater.

Characterizing the degradation of refractory organics from incineration leachate membrane concentrate by VUV/O3

In this study, we used a combined vacuum-ultraviolet (VUV) and O3 process treating the chemical precipitation pre-treated incineration leachate membrane concentrate to further decompose substantial refractory organics which led to membrane organic fouling in the subsequent membrane distillation process. The highest removal of COD (88.1%) was achieved when 50 mg/min of O3 dosage was used at a pH of 11.5–12. Multi-spectrum methods, molecular weight distribution (MW), gas chromatography-mass spectrometry (GC–MS), two-dimensional correlation spectroscopy (2D-COS), and hetero-spectral 2D-COS were used to investigate the organics degradation mechanism. The combined action of O3 and hydroxyl radicals (•OH) effectively degraded macromolecular organics with high aromaticity and high conjugation (mainly distributed at 1–3 kDa) into aliphatic products with lower molecular weight (<1 kDa) and simple structures. The order of organics that were oxidized were humic-like acids > fulvic-like acids > protein-like substances. Organic acids (acetate, propionate, and butyrate) also accumulated in the VUV/O3 systems.

Electrified Membranes for Water Treatment Applications

Electrified membranes (EMs) have the potential to address inherent limitations of conventional membrane technologies. Recent studies have demonstrated that EMs exhibit enhanced functions beyond separation. Electrification could enhance the performance and sustainability of membrane technologies and stimulate new applications in water and wastewater treatment. Herein, we first describe EM materials, synthesis methods, electrofiltration modules, and operating modes. Next, we highlight applications of EMs in water decontamination, purification, and disinfection. Additionally, we discuss state-of-the-art electrification methods for controlling membrane organic fouling, biofouling, and inorganic scaling. We also evaluate the energy consumption of EMs for water treatment and fouling control. We conclude by discussing the challenges for improving the stability and practicality of EMs and by proposing pathways for future research and development. On the basis of our discussion, we suggest that EMs may be viable for ultrafiltration and microfiltration but not for salt-rejecting reverse osmosis and nanofiltration applications. Further, we find that EMs are promising for decontamination and organic fouling control, and these systems could be deployed for fit-for-purpose distributed treatment applications.

UV/H2O2-assisted forward osmosis system for extended filtration, alleviated fouling, and low-strength landfill leachate concentrate

The forward osmosis (FO) membrane process is a good option for treating complex wastewater, such as landfill leachate, owing to its high rejection. However, organic membrane fouling and the generation of high-strength concentrate hamper efficient and environmentally friendly operation. To overcome these limitations, an integrated FO system combined with UV/H2O2 oxidation is proposed in this paper. Changes in the heterogeneous organic composition of the leachate were tracked along the treatment processes via size exclusion chromatography and excitation emission matrix combined with parallel factor analysis, which allowed us to pinpoint the organic fractions responsible for FO membrane fouling and evaluate their removal efficiency. Three fluorescent components, including tryptophan-like (C1), fulvic-like (C2), and humic-like (C3) components, were identified in the landfill leachate. A separate UV/H2O2 oxidation system led to selective removal of the organic leachate fractions, causing membrane fouling by ~80% along with the overall removal of bulk leachate by ~45%. Compared to traditional FO, the integrated system resulted in improved filtered volume (by 40%), decreased overall membrane resistance (by 30%), complete flux recovery after physical cleaning, and 50% reduction of organic carbon in the membrane concentrate. Moreover, the concentrate from the integrated FO system was characterized by a much lower abundance of large molecules, which is beneficial for the reclamation of concentrate due to its high biodegradability. This study demonstrated the effectiveness of UV/H2O2 oxidation as an integrated option for an FO system used for extended filtration, membrane fouling mitigation, and the production of low-strength landfill leachate concentrate.

Impact of pretreatment on RO membrane organic fouling: composition and adhesion of tertiary wastewater effluent organic matter

Organic fouling in RO desalination of tertiary wastewater is of major concern in the decline in membrane performance.

Activation of peroxymonosulfate by metal oxide nanoparticles for mitigating organic membrane fouling in surface water treatment

Recent work has demonstrated the feasibility of peroxymonosulfate (PMS) activated by metal oxide (MeOx) nanoparticles for organic micropollutants removal, whereas little is known about its performance on membrane fouling control. In this work, PMS oxidation activated by typical MeOx nanoparticles (i.e., MnO2, CuO and Co3O4) were proposed for reducing organic membrane fouling in surface water treatment. The results showed that PMS alone and MnO2/PMS were only effective for alleviating reversible fouling, whereas the mitigation effect for irreversible fouling was relatively limited. By contrast, CuO/PMS and Co3O4/PMS dramatically alleviated both reversible and irreversible fouling. To identify the organic composition in surface water, fluorescence excitation-emission matrix coupled with parallel factor and molecular weight distribution analyses were conducted. MeOx/PMS oxidation decreased each fluorescent component to varying degrees, and also converted macromolecular organics into low molecular weight substances. The oxidation ability of MeOx/PMS was affected by the type of MeOx, which followed the order: Co3O4 > CuO > MnO2. The effect of natural organic matter fraction on fouling control was further studied with humic acid, bovine serum albumin, and sodium alginate. The effectiveness of Co3O4/PMS in alleviating membrane fouling by multiple pollutants was further verified via scanning electron microscope and Fourier transform infrared spectrometer. The presence of MeOx nanoparticles significantly accelerated the consumption of PMS, and the generation of both •OH and SO4•− radicals was confirmed by electron paramagnetic resonance spectroscopy and radical quenching tests. The model fitting results suggested that the conversion of fouling mechanism from pore blocking to cake filtration was delayed to varying degrees by MeOx/PMS. The results suggest that MeOx/PMS oxidation has the potential for membrane fouling control in practical applications.

Tracking metal ion-induced organic membrane fouling in nanofiltration by adopting spectroscopic methods: Observations and predictions

Natural organic matter (NOM) with the size approaching to membrane pore size is commonly considered as the crucial component leading to severe pore blocking and superfluous energy consumption. Aquatic metal ions coexisting with this NOM constituent (target NOM) exert a significant influence on membrane filtration performance; however, little work elucidated their interactions and the impacts on nanofiltration (NF). Therefore, we systematically investigated this issue by titrating three environmentally-relevant metal ions (Al3+, Fe3+ and Cu2+) into the target NOM sample obtained by pre-filtering using NF membrane. Fast spectrophotometric techniques were employed to observe the interactive performance. Results suggested that all metal ions at their critical concentrations caused severe flux decline; Cu2+ at a very low concentration of 5 μM, Al3+ and Fe3+ at 20 μM. NF performance recovered when the concentrations were beyond their critical values, and was improved at excessive concentration when flocs formed. Relationship between spectroscopic characteristics and NF performance was particularly addressed. UV–vis spectrum can be expected to be useful and predictive in membrane fouling control when Al3+ or Fe3+ presented. However, fluorescence fingerprint was not likely that effective since fluorescence intensity continuously reduced with the increasing metal ion concentration, attributed to their quenching effect on NOM fluorophores.

Application of membrane distillation to anaerobic digestion effluent treatment: Identifying culprits of membrane fouling and scaling

Membrane distillation (MD) has great potential in the treatment of high-salinity and low-biodegradability wastewater, but membrane fouling restricts its real applications. In this work, MD was applied to treat anaerobic digestion effluent, and the feed pH was adjusted to investigate the membrane organic fouling and inorganic scaling. The results show that the fouling of MD membranes during the treatment of anaerobic digestion effluent was substantially alleviated at a low feed pH (pH=5). Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) were used to characterize the fouled membranes. The MD membrane scaling was primarily attributed to the deposition of calcium-, magnesium-, phosphate-, and silicon-related inorganic compounds during the treatment of cow dung anaerobic digestion effluent. Feed acidification significantly decreased inorganic scaling as well as fouling by organic matter, and organic fouling dominated the fouling process in the low-pH environment. By comparing the components in acid and alkaline cleaning solutions, it was found that the deposition of organics on the membranes via adsorption to inorganic scaling was the primary cause of more severe organic fouling with increasing feed pH. Hence, restricting inorganic scaling could be an effective way to control MD membrane fouling by organics during treatment of anaerobic digestion effluent.

Anion exchange membrane organic fouling and mitigation in salt valorization process from high salinity textile wastewater by bipolar membrane electrodialysis

To achieve a cleaner production, textile wastewater with high organic and salt content can be treated by using Bipolar Membrane Electrodialysis (BMED) to minimize acid and base consumption in a dyeing process. While the dye molecules may foul the ion exchange membranes and strongly affect the desalination process. This work aimed to investigate the performance and fouling mechanisms of BMED during desalination of sodium sulfate from Remazol Brilliant Blue R (RBBR). Results showed that maintaining the zeta potential of RBBR above −25 mV may mitigate fouling of AEM during the BMED process. This confirms that, zeta potential of charged foulants (RBBR) plays a key role in terms of controlling membrane fouling. Accordingly, a new parameter “critical salt concentration” was introduced to control membrane fouling. Furthermore, energy dispersive X-ray spectroscopy (EDS), FT-IR and electrochemical analysis confirmed that fouling of anion exchange membrane by RBBR was due to electrostatic interaction. Finally, it was calculated that 72.02% of sodium and 66.9% of sulfate in the feed were converted to NaOH and H2SO4, respectively. This study proves that BMED process may be an alternative way treating textile wastewater with high salinity and the presence of dye molecules.

Advanced Dynamic Simulation of Membrane Desalination Modules Accounting for Organic Fouling

A reliable dynamic simulator (based on a sound process model) is highly desirable for optimizing the performance of individual membrane modules and of entire desalination plants. This paper reports on progress toward development of a comprehensive model of the complicated physical-chemical processes occurring in spiral wound membrane (SWM) modules, that accounts for the temporal system variability caused by organic membrane fouling. To render the mathematical modeling-problem tractable, justifed simplifcations (retaining the physical parameter interdependencies) lead to a system of basic equations in two spatial planar coordinates, enabling to obtain a realistic temporal evolution of all process parameters at retentate and permeate flow channels of SWM modules. The developed flexible model structure, and process simulator, allow incorporation of sub-models (for phenomena occurring at small spatial scales during desalination) that account for a) feed-spacer effects on friction losses and mass transfer and b) membrane fouling. These sub-models, in the form of generalized expressions, are obtained for the former case through advanced numerical simulations, and for the latter by correlating experimental data of specifc fouling resistance with permeation flux. Typical parametric study results presented herein, for realistic combinations of design and operating system parameters, demonstrate the versatility and reliability of the new model/simulator and its potential to analyze the complicated interaction of mechanisms involved during fouling evolution. The new results warrant further model development that would include other types of fouling and scaling, thus leading to a comprehensive simulator useful for practical applications.