Membrane-based Wastewater Treatment Research Articles

Emerging trends in membrane-based wastewater treatment: electrospun nanofibers and reticular porous adsorbents as key components

Exploring material trends with reticular porous materials (MOFs, COFs) and electrospun nanofibers in hybrid membrane design for wastewater remediation.

Energy-efficient trehalose-based polyester nanofiltration membranes for zero-discharge textile wastewater treatment

Recovery of water, salts, and hazardous dye from complex saline textile wastewater faces obstacles in separating dissolved ionic substances and recovering organic components during desalination. This study realized the simultaneous fractionation, desalination, and dye removal/recovery treatment of textile wastewater by using trehalose (Tre) as an aqueous monomer to prepare polyester loose nanofiltration (LNF) membrane with fine control microstructure via interfacial polymerization. Outperforming the NF270 commercial membrane, the Tre-1.05/TMC optimized membrane achieves zero-discharge textile wastewater treatment, cutting energy consumption by 295% and reducing water consumption by 42.8%. This efficiency surge results from remarkable water permeability (130.83 L m−2 h−1 bar−1) and impressive dye desalination (NaCl/ Direct Red 23 separation factor of 275) of the Tre-1.05/TMC membrane. For a deeper comprehension of filtration performance, the sieving mechanism of polyester LNF membranes was systematically elucidated. This strategic approach offers significant prospects for energy conservation, carbon emission mitigation, and enhanced feasibility of membrane-based wastewater treatment systems.

Aging behavior and mechanism of polyvinylidene fluoride membrane by intensified UV irradiation and NaOCl: A comparative study

Membrane technology plays a critical role in solving worldwide water scarcity and security issues. However, membrane aging causes deterioration or complete failure of membrane performance. In this work, polyvinylidene fluoride (PVDF) membrane aging induced by ultraviolet (UV) and NaOCl were investigated and compared. The skin layer was completely destroyed in 2d by UV irradiation under a dry state, which further caused deformation in the sublayer and pore shrinkage. The water layer on the membrane surface protected the skin layer from damage by UV till 8d under the wet state. NaOCl had a moderate influence, the flux was firstly decreased as the hydrophobicity of the membrane increased, and then increased due to pore enlargement. Membrane aging also resulted in a lower virus rejection, which highlighted the biosafety concern in membrane-based wastewater treatment. Infrared and two-dimensional correlation spectroscopy confirmed that the hydrophilic additive was first oxidated in both processes. β-PVDF segment changed before α-PVDF under UV, during which the CC bond was formed by the dehydrofluorination reaction. But the α-PVDF segment was attacked firstly by NaOCl, the radical reaction occurred both at CH2-CF2 and CH=CF segments. This work studied two aging patterns in the membrane lifecycle and demonstrated the aging mechanism, which shed light on membrane development and maintenance in the future.

Chemical cleaning−solvent treatment−hydrophilic modification strategy for regenerating end-of-life PVDF membrane

Membrane will inevitably reach its end of life during long-term application. The current disposal approach of replacing end-of-life (EOL) membranes by new membranes constrains the economic efficiency and sustainability of the membrane-based wastewater treatment. Herein, we conducted a proof-of-concept study of regenerating EOL polyvinylidene fluoride (PVDF) membranes from a full-scale membrane bioreactor (MBR), to achieve an economical and sustainable membrane-based wastewater treatment. A novel chemical cleaning−solvent treatment−hydrophilic modification strategy was proposed for regenerating the EOL PVDF membranes. After the regeneration, the water permeance of the EOL membrane could be recovered from 43.7 ± 8.8 to 426.0 ± 40.3 L m−2 h−1 bar−1, which was comparable with that of the new membrane. The solvent treatment slightly dissolved the membrane matrix and facilitated the detachment of recalcitrant foulants, which was responsible for the markedly recovered water permeance. The hydrophilic modification using polydopamine coating effectively improved surface hydrophilicity of membrane, endowing the regenerated membrane with better antifouling performance over the solvent treated membrane. The regenerated membrane was tested in an MBR for real municipal wastewater treatment, where the regenerated membrane possessed a comparable effluent quality, as well as a lower fouling rate over EOL, chemical cleaned, and solvent treated membranes. Compared with the conventional way of membrane replacement, the reduction in expenditure and carbon emission of membrane regeneration was ∼3.0 USD/m2-membrane/year and 0.059 kg CO2-e/membrane module, respectively. This proof-of-concept study offers a promising strategy of the EOL membrane regeneration to achieve economical and sustainable membrane-based wastewater treatment.

Recycling the High-Salinity Textile Wastewater by Quercetin-Based Nanofiltration Membranes with Minimal Water and Energy Consumption.

Effective recovery of dyes and salts from textile wastewater by nanofiltration (NF) remains a serious challenge due to the high consumption of water and energy caused by the limited performance of the available membranes. Herein, a novel strategy is described to prepare loose polyester NF membranes by using renewable quercetin as the aqueous monomer for fractionation of high salinity textile wastewater with minimal water and energy consumption. Compared with NF270, taken as the reference membrane, the QE-0.2/TMC-0.2 membrane significantly improved the efficiency for dye/salt fractionation by 288%. The water consumption was also decreased by 42.9%. The efficiency is attributed to an ultrahigh water permeance of 198 ± 2.1 L-1 m-2 h-1 bar-1 with a high selectivity of 123 (extremely low NaCl rejection of 1.6% and high Congo red rejection of 99.2%). The optimal quercetin-based membrane had an ultrathin separation layer of about 39 ± 1.2 nm with good hydrophilicity and negative charge density. Moreover, this work includes a novel method of comparison with a theoretically ideal membrane, which shows that both the energy and water consumption are near their theoretical minimum. This strategy is expected to save energy and minimize carbon emissions for membrane-based wastewater treatment systems.

A fluid imaging flow cytometry for rapid characterization and realistic evaluation of microplastic fiber transport in ceramic membranes for laundry wastewater treatment

Microplastics have recently been recognized as emerging contaminants in wastewater, however there is no standardized quantification protocol even though various microscopic approaches exist, many of which are not appropriate for fibrous particles. In this study, a fluid imaging flow cytometry was employed for the first time to quantify microplastic fibers by capturing images, extracting particle parameters, and justifying those parameters with high-speed measurements. We present preliminary results from the high-throughput analysis of microplastic fibers in real laundry wastewater produced at different laundry loads and chemical additives. A bench-scale filtration experiments were conducted to evaluate the performance of silicon carbide and alumina ceramic membranes. Variation in the shape-based volumetric, morphological, and geometrical parameters of each microplastic fiber in the feed and permeate samples were comprehensively compared to evaluate their realistic transport through statistical analysis. Most of microplastic fibers were removed by ceramic membranes when evaluating the retention performance based on the number of units. However, their morphological and geometrical properties had a significant influence on the retention behavior whereby fibers attaining higher curl, lower straightness, and longer geodesic length were better retained due to size exclusion. Interestingly, the circularity of microplastic fibers after both ceramic membrane filtrations was increased due to the shift toward a cylindrical shape with the gradual compression during pressure-driven membrane filtration. These findings provide valuable insights into the advantages and limitations of fluid imaging flow cytometry and represent a significant step in the quantification of microplastics and in clarifying their transport and retention in ceramic membrane-based wastewater treatment.

Robust PANI-entangled CNTs Electro-responsive membranes for enhanced In-situ generation of H2O2 and effective separation of charged contaminants

Electro-responsive membranes provide a promising strategy to overcome the trade-off between water recovery and water quality in membrane-based wastewater treatment. However, the successful deployment of these membranes is restricted by their low mechanical stability and poor electrochemical reactivity. Herein, we strived to overcome these challenges by constructing a polyaniline-entangled oxidized CNTs (PANI@O-CNTs) cathodic membrane via a sequential laminating technique. The effective in-situ polymerization of the PANI network on the CNTs skeleton and the superior conductivity of the PANI@O-CNTs membrane was demonstrated by extensive characterizations. Durability test results showed the excellent mechanical and electrochemical stability of the robust PANI@O-CNTs membranes. Cyclic voltammetry (CV) analysis confirmed that the modification of nitrogen-rich PANI on CNTs boosted their reactivity for electro-generation of H2O2. By applying an external voltage of −2.0 V, the PANI@CNTs membrane displayed an enhanced rejection from 35.2 % to 77.4 % for negatively charged methyl orange (MO) dye and from 41.5 % to 79.8 % for positively charged methylene blue (MB) dye at 50 min operation time. Moreover, the rejection efficiencies further increased to 89.7 % for MO and 93.4 % for MB through the synergistic effect of electrostatic interactions and H2O2 oxidation. Additionally, antifouling experiments performed with oppositely charged dyes indicated that H2O2 oxidation played a critical role in flux recovery and fouling alleviation. Our results raise the prospect of utilizing electro-responsive membranes to remove specific organic matter from wastewater.

UV/O3 assisted ceramic membrane reactor for efficient fouling control and DOM transformations in real textile wastewater

A ceramic membrane reactor (CMR) coupled with an up-flow anaerobic sludge blanket (UASB) reactor has been investigated to treat real textile wastewater, focusing on the synergetic effects of UV and O3 on fouling control and dissolved organic matter (DOM) transformation. The ozone treatment showed high potential in color removal but resulted in a linear (R2 = 0.996) increase in the membrane fouling rate with the increasing ozone dose; the continuous UV (254 nm) exposure significantly retarded membrane fouling by 16 folds but increased soluble chemical oxygen demand. In contrast, when intermittent (15 min ON: 15 min OFF) UV exposure and ozonation (UV/O3) were applied simultaneously, 94% color removal was reached and a synergistic effect on membrane fouling control was prominent, which increased the fouling time by 2.92 and 10.1 folds as compared to the standalone application of UV or ozone, respectively. Confocal laser scanning microscopy observation revealed proteins and polysaccharides as prominent foulants during O3 and UV treatment, respectively. UV–Vis spectroscopy and 3-D excitation-emission matrix fluorescence spectra confirmed the synergistic effects of UV/O3 in the degradation of UV280 and UV254 absorbance and fluorescent DOM. The HO• radicals played a primary role in degrading organic pollutants during UV/O3 treatment. These results provide new insights into the fouling mechanism and DOM transformation in ceramic membrane-based wastewater treatment systems, and recommend simultaneously intermittent application of UV/O3 in an external CMR coupled to UASB as a promising technology for the treatment of textile or other industrial wastewater.

Triclosan biodegradation performance of adapted mixed cultures in batch and continuous operating systems at high-concentration levels

Pollutants like triclosan (TCS) of medium to high logKow value tend to be mainly adsorbed and poorly biodegraded during waste water treatment, complicating removal after release. Complete mineralization of TCS is crucial, since transformation products may be even more toxic, but has been proven only in a few cases. In this study, the performance of different batch (cultivation flask, TCSmix100) and continuous operating systems (submerged biotrickling filter, TCSmix100; biomembrane reactor, TCSmix200) was tested with two pre-adapted mixed cultures named TCSmix100 and TCSmix200, and compared to non-adapted cultures in a biotrickling filter and a sand filter as reference systems. Mineralization rates up to 172 mg TCS/L/d were observed during batch conditions for TCSmix100 at 1.45 g TCS/L as initial concentration. Triclosan was completely mineralized by both cultures, as shown by stoichiometric release of chloride at conversion rates of 5,7–11.4 mg TCS/L/d (biotrickling filter) and 0.72–1.45 mg TCS/L/d (biomembrane reactor) at 20 and 7.5–15 mg TCS/L as influent concentrations. In TCSmix100, Achromobacter sp. was identified as the relevant strain in TCS biodegradation. Community analysis of TCSmix200 revealed Nitrosomonas europaea, Nitrospira moscoviensis, Nitrosospira multiformis , and Rhodanobacter lindaniclasticus as the predominant strains. In contrast, chloride formation and triclosan elimination in the non-adapted biotrickling filter was less than 12% of the expected chloride concentration at hydraulic retention times up to 60 d. In the reference sand filter, TCS abatement was 42.8% in average with neither formation of chloride nor increase in biofilm density, indicating mostly sorptive or precipitative effects for elimination. With mineralization levels surpassing those of comparable references by a factor of 3–11, both adapted fixed-biomass reactor systems proved highly suitable for treatment of effluents containing high concentrations of TCS as they occur in industrial discharges or concentrates of membrane-based wastewater treatment plants. • Two aerobic mixed cultures were enriched able to completely mineralize triclosan (TCS) • Mixed cultures were dominated by Achromobacter sp. or nitrifying bacteria • Turnover rates were up to two orders higher than in literature (172 mg TCS L −1 d −1 ) • Fixed biomass systems showed stable performance during 110 d and 137 d of operation • TCS was solely eliminated by sorptive effects in a sand filter as reference system

Membrane Applications in the Dairy Industry

The membrane separation process is a promising technique to be employed in the dairy industry. It can be used to treat effluents and for the recovery of molecules of interest to add value to product formulations. The study aspired to present the potential industrial use of membranes for dairy industries. Detailed research for scientific articles on the subject was conducted from the Scopus® scientific database, and the use of wastewater treatment in the dairy industry has increased significantly over the years. The findings presented are expected to provide a valuable theoretical framework for producers and industries related to milk production and whose objective is to optimize production performance and expressive benefits from an economic and environmental viewpoint. Moreover, membrane-based wastewater treatment has low energy demand, high volume recovery, significant water quality, multiple applications of purified water, eco-friendly performance, and favorable future perspectives.

Scaling control of forward osmosis-membrane distillation (FO-MD) integrated process for pre-treated landfill leachate treatment

Membrane fouling is a major challenge for membrane-based wastewater treatment. In this study, we investigated the integrated forward osmosis-membrane distillation (FO-MD) process for landfill leachate treatment. However, severe scaling induced by the formation of calcium sulfate happened at the FO membrane selective layer. Herein, an organic phosphonic acid scale inhibitor, hexamethylene diamine tetra (methylene phosphonic acid) (HDTMPA), was added in draw solution (DS) to control the scaling behavior. HDTMPA chelated with Ca2+ to prevented the nucleation and growth of gypsum scale crystals and alleviated membrane scaling. For FO membrane cleaning, the water flux recovery rate was greater than 90% after three scaling-cleaning cycles owing to the formation of deformed crystals and loose scaling layer via addition of HDTMPA. The mechanism of scaling with the existence of HDTMPA were further explored. In addition, we conducted long-term FO-MD experiment using NaCl DS with HDTMPA. The efficiency of the integrated system was much superior to that of the FO alone system with an extreme high contaminant rejection of 99%. HDTMPA not only alleviated FO scaling, but also prevented wetting of the MD membrane, and then promoted the efficiency and operation stability of the integrated FO-MD system.

Controlled dehumidification to extract clean water from a multicomponent gaseous mixture of organic contaminants

Rapid expansion of the unconventional oil and gas extraction has increased American energy independence, but also led to increased production of large amounts of contaminated water. Wastewater from the oil and gas industry contains a wide range of contaminants. Injecting such contaminated water into disposal wells or discharging it to the environment jeopardizes freshwater resources. Conventional and membrane-based wastewater treatment techniques are often not effective choices to treat highly contaminated wastewater; however, a suitable way to remove contaminants from wastewater is to selectively separate water in a process analogous to humidification-dehumidification (HDH). Only a few studies have investigated the use of HDH for wastewater treatment. In this study, a novel HDH system is introduced for treating highly contaminated water, such as oil and gas flowback and produced water. In this HDH process, a non-condensable gas, such as air, mixes with wastewater vapor to facilitate the separation of contaminants. As a result, clean water condenses from the multicomponent gaseous mixture while air carries organic contaminants out of the dehumidification section. A laboratory apparatus was constructed and experiments were performed to investigate the HDH process for wastewater treatment and to study the effects of flow dynamics including air flow rate on the composition of treated water. Different contaminants including benzene, toluene, 2-propanol and 2-butoxyethanol were tested. Experimental results showed that the system can be successfully applied for removing volatile and/or toxic organic contaminants from wastewater. A representative multicomponent mixture of fracking wastewater was successfully treated using the experimental setup and clean water with quality of 98.3% was obtained. It was revealed that increasing the air-to-vapor mass ratio improves purity of treated water. Quantitative analysis showed that by increasing the air-to-vapor mass ratio from 0.6 to 5.9, the fraction of separated 2-propanol through the air was improved from 43% to more than 96% of the initial amount. ASPEN software was employed to simulate equilibrium conditions. Experimental results were observed to have lower mass fraction of residual contaminant in the treated water compared to equilibrium state.

Development and analysis of a new renewable energy-based industrial wastewater treatment system

In this research study, a new solar energy-based integrated system is developed for treating industrial brine wastewater. An integrated solar-powered evaporation and membrane-based water treatment technique is utilized. Both forced convection as well as falling film evaporators are incorporated to treat high-concentration rejected brine. The system performance is assessed through a comprehensive thermodynamic investigation at varying operating parameters. The energetic performance is evaluated to vary from 12.5% to 15.9% across the year. Furthermore, the peak efficiency in terms of exergy is found to be 11.1%. Also, the membrane-based wastewater treatment subsystem is found to entail an energetic performance of 73.3% and an exergetic performance of 34.6% in terms of efficiencies. Moreover, an energetic performance of 15.4% and an exergetic performance of 2.9% is found for the evaporation-based subsystem. The exergy destructions in each system component are evaluated and the power generation subsystem is determined to have the highest exergy destruction rate of 15.4 MW. To investigate the effects of varying design parameters and operating conditions on the system performance, several parametric studies are also performed.

Biofilm formation of benthic diatoms on commercial polyvinylidene fluoride membrane

Marine benthic microalgae always have their own ubiquitous nature to adhere to diverse submerged substrates. Immobilized submerged biofilm system offers huge reduction of liquid culture volume, high biomass production and ease of harvesting of biomass. The studies on the biofilm formation and properties towards membrane surfaces are rare therefore the objectives of this paper were to investigate the relationships between the algal attachment rate onto membranes via biofilm and the compositional changes of the extracellular polymeric substances in the biofilm. To delve further into the biofilm-forming capacity of three benthic diatoms (Amphora coffeaeformis, Cylindrotheca fusiformis and Navicula incerta) onto polyvinylidene fluoride membrane (PVDF), a simple adhesion test was run for 96 h under controlled temperature and light conditions. Attached biomass was carefully scraped for cell count and extracellular polymeric substances (EPS) were extracted for characterization in terms of its biochemical compositions. As a result, A. coffeaeformis and N. incerta were found to adhere well with membrane substrate with equal cell attachment (3 × 108 cells/m2) at the end of the experiment while the lowest was observed for C. fusiformis (1.33 × 108 cells/m2). Biofilm of three diatoms was observed to form as soon as 2 h after inoculation and its development was aided by the high accumulation of TEP amount at 96th hour ranging from 91 mg X eq/m2to 170.61 mg X eq/m2. EPS excreted was found to re-accumulate after 48 h with polysaccharides as major component (>59.87%) for N. incerta and C. fusiformis except A. coffeaeformis which was mainly composed of proteins (>50%). The biofilm formed by A. coffeaeformis was considered the most robust because of its hydrophobic-hydrophobic interaction between the cells and the membrane. Understanding of biofilm physiology will pave the way for describing biofilm systems and membrane-based wastewater treatment systems.

A solar membrane-based wastewater treatment system for high-quality water production

Abstract This study proposes a novel solar wastewater treatment system comprising efficient solar energy absorption and contaminant separation processes. The proposed system aims to overcome the drawbacks of previous membrane-based systems especially high energy demand and lack of a complex wastewater consideration. Synthetic wastewater was prepared and the solar system was experimentally analysed under climatic conditions of Perth, Western Australia in summer and winter. The findings revealed that the solar thermal efficiency of the system fluctuated mainly around 63% in summer and 52% in winter. The system reached its maximum exergy efficiency in the afternoon with 5.54% and 4.82% for summer and winter, respectively. Moreover, the highest rate of treated water in summer and winter were 4.21 and 2.85 L/m2h, respectively. The results also indicated that the removal percentages of Fe, Mn, Cu, Na, K, and Ca were 96, 89, 96, 100, 100, and 94%, respectively. In addition, almost 100% of organics and nutrients were removed. The highest recorded gained output ratio and overall efficiency were 0.71 and 49.6% in summer, while these parameters were 0.58 and 46.6% in winter. Overall, the proposed solar-driven membrane-based system is a feasible and efficient option in the separation of contaminants from wastewater.

Membrane modification with semiconductor diode laser to reduce membrane biofouling for external MBR system and modelling study

Membrane biofouling is one of the major problem for membrane-based wastewater treatment. In this study, we used laser technology to modify ultrafiltration polyethersulfone (UP150) membrane in order to decrease membrane biofouling. Semiconductor laser diodes with different wavelengths of 405, 520, and 658 nm and different power density of 1.5, 2.0, 2.5 mW were used to improve membrane structure against biofouling. The pure water permeability (Lp), contact angle, porosity, and the average pore size were determined for pristine and modified membranes. Lp value of the pristine UP150 membrane (721.18 L/(m2 h bar)) was higher than modified membrane (22.08 L/(m2 h bar)). The contact angle values were presented that hydrophilicity was decreased from 75.1° to 61.2° for 2 h at 2.5 mW laser irradiation. Membrane porosity increased from 63.2 to 67.7%; however, the average pore size decreased from 88 to 23 nm after laser modification. The impact of laser wavelength and irradiation time on the rejection of protein (bovine serum albumin, BSA) and the fractions of soluble microbial products (as protein and carbohydrate) was systematically investigated. A maximum rejection of 32.17% and 41.86% was obtained for carbohydrate and protein when activated sludge was filtrated through modified membrane. Moreover, 100% BSA rejection was obtained by the modified membrane when BSA solution was filtrated. The modified membranes were extensively characterized by AFM, FTIR, SEM, and mechanical strength test analyses to observe morphological changes of the membrane before and after modification. The results showed that laser irradiation was changed the membrane morphology. Our results presented that laser-modified membranes with red wavelength changed the pore size, porosity, hydrophilicity of the pristine membrane. Also, membrane surface melting was revealed with a study called “Thermal Analysis on Membrane Surface Modelled 3D” using Solidworks CAD/CAM software. The results obtained from Solidworks thermal analysis was presented with 98.7% ratio of successful approach.

Preparation and characterization of nano-filtration and its photocatalytic abilities via pre-coated and self-forming dynamic membranes developed by ZnO, PAC and chitosan.

In the current work, novel dynamic membranes (DM) were tested and introduced for cheese whey wastewater treatment based on resistant and inexpensive materials, polyesters, and chitosan. For the investigation of dynamic membrane (pre-coated and self-forming) characterizations, polyester as a low-cost and natural material with chitosan were chosen to provide the support of the target membrane. The inherent antifouling character of chitosan accompanied by its high hydrophilicity have made this polymer known as an attractive agent for membrane-based wastewater treatment operations. Zinc oxide (ZnO) and powdered activated carbon (PAC) were employed as the dynamic layer. Neat polyester had a chemical oxygen demand (COD) rejection ratio of about 57.61%, but the flux declined sharply. The higher removal efficiency was for the self-forming type: total phosphate (94%) and citrate (95.5%). Fouled dynamic membranes were backwashed by sodium dodecyl-sulphate (SDS), warm water, and distilled water. Results demonstrated that the pre-coated was reduced and fouling increased the flux recovery rate (FRR) (9.1%) while use of the self-forming DM exhibited an aggravation of fouling by decreasing of support FRR (11.1%). It was found that by substitution of deionized water and hot water with SDS, FRR was enhanced. In the following, the photocatalytic ability of the product was investigated. The UV light source increased the removal ratio and FRR. For example, self-forming COD rejection was enhanced (6.63%).

Surface-concentrated chitosan-doped MIL-100(Fe) nanofiller-containing PVDF composites for enhanced antibacterial activity

Antibacterial properties are a major issue for the membrane-based wastewater treatment since the biofilm on membranes generated by bacterial growth can significantly reduce water flux. Here, the surface-concentrated MIL-100(Fe)/chitosan (MIL100-CS)-embedded polyvinylidene fluoride (PVDF) composite membranes (i.e., PVDF-S/MIL100-CS) were successfully fabricated by the newly developed fabrication method, so-called solvent-assisted nanoparticle embedding (SANE). The SANE method was modified from the conventional nonsolvent-induced phase separation method by the addition of an intermediate step for the selective arrangement of hydrophilic nanofillers on top of the nascent PVDF film. The additional step in the SANE method enabled the surface-selective filler distribution with the open surface of fillers, resulting in the hydrophilic surface. Also, it facilitated to form the sponge-like pore structures mostly due to the dilution effect of additional solvent. The PVDF/MIL100-CS microfiltration (MF) composite membranes acquired by SANE exhibited the higher antibacterial activity and the substantially enhanced biofouling resistance for E. coli cells than those of the pristine PVDF due to the surface-selective arrangement of MIL100-CS fillers which include both hydrophilic and biocidal properties. The live/dead test for antibacterial activities with E. coli cells further confirmed the enhanced suppression of the biofouling resistance in the asymmetric PVDF/MIL100-CS composite membranes relative to that of PVDF. Our current study offers a new platform for fabricating asymmetric MF composite membranes with enhanced antibacterial activity and biofouling resistance.

Recent Advances in Membrane Based Waste Water Treatment Technology: A Review

Recent Advances in Membrane Based Waste Water Treatment Technology: A Review

A novel membrane-based integrated process for fractionation and reclamation of dairy wastewater

An integrated isoelectric precipitation (IP) – ultrafiltration (UF) – nanofiltration (NF) – lactic acid (LA) fermentation process was established for recovering water, proteins, cells and LA from model dairy wastewater (MDW). This process could solve the problems of sludge/retentate disposal and membrane fouling during membrane-based wastewater treatment. The IP process greatly retarded concentration polarization and fouling of UF. However, PES membrane was still severely fouled by whey proteins. XPS results showed that carboxyl groups (CO) belonging to the proteins was on PES10 surface, but it was not found on Ultracel PLGC membrane. Proteins in MDW with IP were completely retained by Ultracel PLGC UF membrane and lactose almost passed through. After IP-UF pretreatment, the fouling of NF membrane was greatly retarded (irreversible fouling decreased from 44.4% to 11.1% in a pilot-plant test). Thus, the volume reduction ratio was highly increased to 37 and the retentate with high strength lactose of 44.2gL−1 was obtained. With a model NF retentate (45.0gL−1 of lactose) without proteins, 5.42gL−1 of cell mass and 37.6gL−1 of LA concentration were produced by the LA producer B. coagulans IPE22.