Evaluating backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane fouled by yeast and sodium alginate

This collection is the result of an investigation into the backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane fouled by yeast and sodium alginate. In this experiement, poly(vinylidene fluoride) (PVDF) membrane was used to filter two types of organic foulants from suspensions in a dead-end stirred cell. The organic foulants including yeast and sodium alginate were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PVDF membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. The data collection contains image data of poly(vinylidene fluoride) (PVDF) membranes' fouling layer when two types of organic foulants (yeast and sodium alginate) are present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. The collection would be useful to researchers evaluating the backwashing efficiency of poly(vinylidene fluoride) (PVDF) membrane in order to optimize frequency and operational conditions of backwashing by membrane materials and by water.

Evaluating backwashing efficiency of polycarbonate (PC) membrane fouled by protein, sodium alginate and yeast

This collection is the result of an investigation into the backwashing efficiency of polycarbonate (PC) membrane fouled by three types of organic foulants, protein, sodium alginate and yeast. In this experiement, polycarbonate (PC) membrane was used to filter those organic foulants from suspensions in a dead-end stirred cell. The organic foulants were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PC membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. It contains image data of polycarbonate (PC) membranes' fouling layer when three types of organic foulants (protein, sodium alginate and yeast) are present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. This data collection would be useful to researchers who are evaluating the backwashing efficiency of PC membrane in order to optimize frequency and operational conditions of backwashing by membrane materials and by water..

Evaluating backwashing efficiency of polycarbonate (PC) membrane fouled by protein and yeast

This collection is the result of an investigation into the backwashing efficiency of polycarbonate (PC) membrane fouled by two types of organic foulants, protein and yeast. In this experiment, polycarbonate (PC) membrane was used to filter those organic foulants from suspensions in a dead-end stirred cell. The organic foulants were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PC membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. It contains image data of polycarbonate (PC) membranes' fouling layer when two types of organic foulants (protein and yeast) present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. This data collection would be useful to researchers evaluating the backwashing efficiency of PC membrane in order to optimize frequency and operational conditions of backwashing by membrane materials and by water.

Evaluating backwashing efficiency of polycarbonate (PC) membrane fouled by sodium alginate and yeast

This collection is the result of an investigation into the backwashing efficiency of polycarbonate (PC) membrane fouled by two types of organic foulants, sodium alginate and yeast. In this experiement, polycarbonate (PC) membrane was used to filter those organic foulants from suspensions in a dead-end stirred cell. The organic foulants were stained with fluorescent dyes before filtration. After filtration, the PC membrane was backwashed. Consequently, a stack of images were captured from the fouling layers on the PC membrane surface using confocal laser scanning microscope (CLSM) and its associated image acquisition software. It contains image data of polycarbonate (PC) membranes' fouling layer when two types of organic foulants (sodium alginate and yeast) present. By comparing with the same membrane without backwashing, the efficiency of backwashing was computed. This data collection would be useful to researchers evaluating the backwashing efficiency of PC membrane in order to optimize frequency and operational conditions of backwashing by membrane materials and by water..

Reducing herbicide discharge to sensitive environments using membrane bioreactors

A hybrid MBR/UV/GAC treatment system was researched to remove Ametryn, which is a commonly used herbicide in Australian farmlands, from wastewater. The research revealed that the hybrid system could be successfully used for 100% removal of Ametryn. Two mathematical models were developed to predict the frequency of chemical cleaning of MBR-membrane and the mechanism of fouling of membrane.

Comparison of the performance of ceramic microfiltration and ultrafiltration membranes in the reclamation and reuse of secondary wastewater

Advanced treatment of secondary wastewater generally has been achieved using polymeric microfiltration and ultrafiltration membranes. Newly developed ceramic membranes offer distinctive advantages over the currently employed membranes and were recently introduced for the purpose. This paper presents results of a pilot study designed to investigate the application of ceramic microfiltration (MF) and ultrafiltration (UF) membranes in the recovery of water from secondary wastewater. Synthetic wastewater similar to the quality of secondary treated wastewater was fed to ceramic MF and UF system in a cross-flow mode. The filtration experiments revealed that the flux recovery through tubular ceramic MF membrane was more sensitive to the variation in TMP compared with the tubular ceramic UF membrane over the range of TMP studied. The resistance in series model was used for the evaluation of the resistance to the permeate flux. The results revealed that for ceramic UF membrane, the contribution to the total resistance of fouling was higher than the inherent of the clean membrane resistance. However, both the clean membrane resistance and the fouling resistance contribute equally in the case of MF membrane. Various wastewater indices were measured to evaluate the effectiveness of the filtration treatment. The ceramic UF membrane consistently met water quality in the permeate in terms of colour, turbidity, chemical oxygen demand and absorbance, suggesting that the permeate water could be made to be reused or recycled for suitable purposes. However, MF membrane appeared to be incompetent with respect to the removal of colour. The unified membrane fouling index (UMFI) was used to measure the fouling potential of both the membranes. The result showed that for UF membrane, the value of UMFI is one order of magnitude higher than MF membrane. The overall results suggest that there were significant differences in the performance of both the ceramic UF and MF membranes that are likely to impact on the operation and maintenance of the membrane system.

Performance of reverse osmosis (RO) for water recovery from permeates of membrane bio-reactor (MBR)

In this study, permeate from a hollow fiber polyethylene (PE) membrane bio-reactor (MBR) system treating synthetic agricultural wastewater was fed into a cellulose acetate brackish water reverse osmosis (BWRO30 2540) membrane system; three different trans-membranes pressures (TMPs) of 1000, 2500, and 4000 kPa were selected to evaluate the system performance in terms of general operating parameters as well as the removal of chosen important potential fouling water quality parameters. The results showed that highest corrected permeate flux rate was at a TMP of 2500 kPa, whereas lowest recorded at a TMP of 4000 kPa. Similar situation prevailed in water recovery rate. But temperature corrected specific fluxes decreased as the applied TMPs increased. In all selected TMPs, more than 96% of salinity was removed. Permeate from MBR as feed to reverse osmosis required frequent chemical cleaning than the microfiltration/ultrafiltration (MF/UF) permeates and granular media filter (GMF) filtered in order to maintain the required rate of product water. One of the reasons for this frequent chemical cleaning is due to higher total organic carbon as well as total nitrogen (TN) in the MBR permeate. This result needs to be further evaluated through field trials.

Promoted water transport across graphene oxide-poly(amide) thin film composite membranes and their antibacterial activity

Hybrid composite membranes have great potential for desalination applications since water transport can be favorably promoted by selective diffusion at the interface between matrix and reinforcement materials. In this paper, graphene oxide nano-sheets were successfully incorporated across 200nm thick poly(amide) films by interfacial polymerization to form novel thin-film composite membranes. The impact of the graphene oxide on the morphology, chemistry, and surface charge of the ultra-thin poly(amide) layer, and the ability to desalinate seawater was investigated. The graphene oxide nano-sheets were found to be well dispersed across the composite membranes, leading to a lower membrane surface energy and an enhanced hydrophilicity. The iso-electric point of the samples, key to surface charge repulsion during desalination, was found to be consistently shifted to higher pH values with an increasing graphene oxide content. Compared to a pristine poly(amide) membrane, the pure water flux across the composite membranes with 0.12wt.% of graphene oxide was also found to increase by up to 80% from 0.122 to 0.219L·μm·m-2·h-1·bar-1 without significantly affecting salt selectivity. Furthermore, the inhibitory effects of the composite membrane on microbial growth were evaluated and the novel composite membranes exhibited superior anti-microbial activity and may act as a potential anti-fouling membrane material.

Lubricin: a versatile, biological anti-adhesive with properties comparable to polyethylene glycol

Lubricin is a glycoprotein found in articular joints which has been recognized as being an important biological boundary lubricant molecule. Besides providing lubrication, we demonstrate, using a quartz crystal microbalance, that lubricin also exhibits anti-adhesive properties and is highly effective at preventing the non-specific adsorption of representative globular proteins and constituents of blood plasma. This impressive anti-adhesive property, combined with lubricin's ability to readily self-assemble to form dense, highly stable telechelic polymer brush layers on virtually any substrates, and its innate biocompatibility, makes it an attractive candidate for anti-adhesive and anti-fouling coatings. We show that coatings of lubricin protein are as effective as, or better than, self-assembled monolayers of polyethylene glycol over a wide range of pH and that this provides a simple, versatile, highly stable, and highly effective method of controlling unwanted adhesion to surfaces.

Enhancement of the antifouling properties and filtration performance of poly(ethersulfone) ultrafiltration membranes by incorporation of nanoporous titania nanoparticles

Nanoporous titania nanoparticles (NTNs) were synthesized and used as an additive at a low concentration of 0.1-1 wt % in the fabrication of poly(ethersulfone) (PES) ultrafiltration membranes via non-solvent-induced phase separation. The structure and properties of nanoparticles were characterized using nitrogen sorption, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The NTNs have a size distribution with a particle size of mainly <100 nm and have a Brunauer, Emmett, and Teller surface area of ∼100 m2 g-1. The modified membranes were fabricated and investigated in terms of their pure water flux, solute rejection, and fouling resistance. The water permeability and molecular weight cutoffs (MWCOs) of membranes were determined under constant-pressure filtration in dead-end mode at 100 kPa. The membrane fouling resistance was characterized under constant flux operation using bovine serum albumin as a model foulant. The membranes were characterized in terms of morphology, porosity, pore size distribution, energy-dispersive X-ray spectroscopy, contact angle goniometry, surface free energy, and viscosity of the dope solution. Overall, the modified membrane showed increased wettability and reduced surface free energy and pore size. The modified UF membrane with 0.5 wt % NTN loading exhibited improved fouling resistance (fouling rate of 0.58 kPa/min compared to a rate of 0.70 kPa/min for the control membrane) with ∼80% water flux recovery. The same membrane showed an ∼20% increase in water flux, an improvement in MWCO, and a narrower pore size distribution.

Treatment of textile wastewater with membrane bioreactor: a critical review

Membrane bioreactor (MBR) technology has been used widely for various industrial wastewater treatments due to its distinct advantages over conventional bioreactors. Treatment of textile wastewater using MBR has been investigated as a simple, reliable and cost-effective process with a significant removal of contaminants. However, a major drawback in the operation of MBR is membrane fouling, which leads to the decline in permeate flux and therefore requires membrane cleaning. This eventually decreases the lifespan of the membrane. In this paper, the application of aerobic and anaerobic MBR for textile wastewater treatment as well as fouling and control of fouling in MBR processes have been reviewed. It has been found that long sludge retention time increases the degradation of pollutants by allowing slow growing microorganisms to establish but also contributes to membrane fouling. Further research aspects of MBR for textile wastewater treatment are also considered for sustainable operations of the process.