Showing papers on "Fouling published in 2005"
TL;DR: In this paper, the authors reviewed the literature on the fouling phenomena in reverse osmosis (RO) membrane systems, the analytical techniques used to quantify fouling, preventive methods, and membrane cleaning strategies and made specific recommendations on how scientists, engineers, and technical staff can assist in improving the performance of these systems through fundamental and applied research.
Abstract: Desalination by using reverse osmosis (RO) membranes has become very popular for producing freshwater from brackish water and seawater. Membrane lifetime and permeate flux, however, are primarily affected by the phenomena of concentration polarization and fouling at the membrane surface. The scope of the current paper was to critically review the literature on the fouling phenomena in RO and ultrafiltration (UF) membrane systems, the analytical techniques used to quantify fouling, preventive methods, and membrane cleaning strategies. The paper also makes specific recommendations on how scientists, engineers, and technical staff can assist in improving the performance of these systems through fundamental and applied research.
468 citations
TL;DR: In this article, a comprehensive overview of the wide range of techniques used in the control of fouling in both MF and UF membranes is presented, as well as the amount of research that has gone into the various techniques used and the results achieved after experimental work.
Abstract: Membrane‐based processes are very susceptible to flux decline due to concentration polarization and fouling problems and the concept of fouling control via process optimization, membrane surface modification, and cleaning have been the focus of research in wastewater and water treatment. MF and UF membranes are utilized in many areas of industry. The main sector of application includes water and wastewater. There has been emphasis on the various methods used to reduce and, where possible, eliminate fouling. This review is a comprehensive insight into the wide range of techniques used in the control of fouling in both MF and UF membranes. It also addresses the amount of research that has gone into the various techniques used and the results achieved after experimental work.
421 citations
TL;DR: It was shown that high F/M would make the foulant more proteinaceous, while Carbohydrates were dominant in membrane foulants in this study, while features of humic substances were not apparent.
Abstract: The main obstacle for wider use of membrane bioreactors (MBRs) for wastewater treatment is membrane fouling (i.e., deterioration of membrane permeability), which increases operating costs. For more efficient control of membrane fouling in MBRs, an understanding of the mechanisms of membrane fouling is important. However, there is a lack of information on membrane fouling in MBRs, especially information on features of components that are responsible for the fouling. We conducted a pilot-scale experiment using real municipal wastewater with three identical MBRs under different operating conditions. The results obtained in this study suggested that the food−microorganisms ratio (F/M) and membrane filtration flux were the important operating parameters that significantly influenced membrane fouling in MBRs. Neither concentrations of dissolved organic matter in the reactors nor viscosity of mixed liquor, which have been thought to have influences on fouling in MBRs, showed clear relationships with membrane fou...
326 citations
TL;DR: In this article, six independent research projects are presented, starting from different angles, all groups finally ended up analysing the organic fraction in the effluent and activated sludge supernatant, respectively.
303 citations
TL;DR: In this paper, the authors present a new model which takes into account the simultaneous action of all fouling mechanisms and describes the experimental results successfully, in order to contribute to the understanding of fouling phenomena by organic matter and the efficiency of the backwashing technique, which is applied in practice to restore membrane flux.
277 citations
TL;DR: Treatment optimization to serve these purposes was performed using jar tests and applying a response surface methodology (RSM) to the results, where 78% of water recovery with a 20 NTU turbidity value can be obtained at the optimum value of coagulant dosage, flocculent dosage, and pH.
Abstract: The coagulation-flocculation process incorporated with membrane separation technology will become a new approach for palm oil mill effluent (POME) treatment as well as water reclamation and reuse. In our current research, a membrane pilot plant has been used for POME treatment where the coagulation-flocculation process plays an important role as a pretreatment process for the mitigation of membrane fouling problems. The pretreated POME with low turbidity values and high water recovery are the main objectives to be achieved through the coagulation-flocculation process. Therefore, treatment optimization to serve these purposes was performed using jar tests and applying a response surface methodology (RSM) to the results. A 2(3) full-factorial central composite design (CCD) was chosen to explain the effect and interaction of three factors: coagulant dosage, flocculent dosage, and pH. The CCD is successfully demonstrated to efficiently determine the optimized parameters, where 78% of water recovery with a 20 NTU turbidity value can be obtained at the optimum value of coagulant dosage, flocculent dosage, and pH at 15 000 mg/L, 300 mg/L, and 6, respectively.
247 citations
TL;DR: In this article, the authors investigated the role of suspended solids, colloids and solutes in the initiation of cake layer formation on the membrane surface and pore wall in UF ultrafiltration.
229 citations
TL;DR: In this paper, the combined influence of natural organic matter (NOM) and colloidal particles on the fouling of thin-film composite nanofiltration (NF) membranes is systematically investigated.
224 citations
TL;DR: In this paper, the effect of tangential flow and crossflow on membrane fouling was analyzed by the resistance-in-series model where the reason for flux decline was subdivided into adsorption, concentration polarization, and reversible and irreversible fouling.
221 citations
TL;DR: In this article, the effect of nanoscale interfacial roughness on the adhesion of single (SW8) and mixed cultures of micro-foulant for periods of up to 6 months was assessed using visual and wettability measurements.
219 citations
TL;DR: In this paper, dead end unstirred filtration of sodium alginate, a model polysaccharide, was carried out and analyzed using classic pore blockage and cake formation model, and it was found that the cake model appears to fit the entire range of the ultrafiltration data while the standard pore blocking model and cake model are more applicable to microfiltration membranes.
TL;DR: In this paper, the evolution of fouling of sodium alginate, a microbial polysaccharide was studied during crossflow ultrafiltration and microfiltration, and an initial slow and gradual TMP increase was followed by a sudden transition to a rapid TMP rise.
TL;DR: The experiments demonstrate that the MBR is highly effective in drinking water treatment for the removal of organic pollutants, ammonia, and UV absorbance and the adsorption of biopolymers on the membrane modified its surface property and led to easier biomass attachment and tighter sludge cake deposition, which resulted in a progressive sludge Cake growth and serious membrane fouling.
Abstract: A submerged membrane bioreactor (MBR) with a working volume of 1.4 L and a hollow fiber microfiltration membrane was used to treat a contaminated raw water supply at a short hydraulic retention time (HRT) of approximately 1 h. Filtration flux tests were conducted regularly on the membrane to determine various fouling resistances, and confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were employed to characterize the biofouling development and sludge cake formation on the membrane. The experimental results demonstrate that the MBR is highly effective in drinking water treatment for the removal of organic pollutants, ammonia, and UV absorbance. During the MBR operation, the fouling materials were not uniformly distributed on the entire surface of all of the membrane fibers. The membrane was covered partially by a static sludge cake that could not be removed by the shear force of aeration, and partially by a thin sludge film that was frequently washed away by aeration turbulence. The filtration resistance coefficients were 308.4 x 10(11) m(-1) on average for the sludge cake, 32.5 x 10(11) m(-1) on average for the dynamic sludge film, and increased from 10.5 x 10(11) to 59.7 x 10(11) m(-1) for the membrane pore fouling after 10 weeks of MBR operation at a filtration flux of 0.5 m3/m2 x d. Polysaccharides and other biopolymers were found to accumulate on the membrane, and hence decreased membrane permeability. More important, the adsorption of biopolymers on the membrane modified its surface property and led to easier biomass attachment and tighter sludge cake deposition, which resulted in a progressive sludge cake growth and serious membrane fouling. The sludge cake coverage on the membrane can be minimized by the separation, with adequate space, of the membrane filters, to which sufficient aeration turbulence can then be applied.
TL;DR: In this paper, the influence of cross-flow velocity on the formation of fouling layer during microfiltration and ultrafiltration of biological suspension with 5 g/l of mixed liquor suspended solids was studied.
TL;DR: In this paper, a short survey is focused on reported evidences of membrane fouling under sub-critical conditions and examines possible links between operational paramenters, mixed liquor characteristics and fouling propensity.
TL;DR: In this article, the effects of pH, ionic strength, and divalent ion on fouling were studied with a 0.22-μm PVDF flat-sheet membrane in a direct contact membrane distillation unit.
TL;DR: Two similar membrane bioreactors of 2 m3 each were operated in parallel over two years under the same operational conditions, fed with the same municipal wastewater, and exhibited different fouling rates and decreases in permeability.
TL;DR: In this article, a cost-effective autocatalytic graded Ni-Cu-P-PTFE composite coating with corrosion-resistant properties was applied to reduce biofouling formation.
TL;DR: Key factors which have been determined to result in successful operation of large-scale plants, and data from major RO wastewater treatment plants will be presented to show how the RO membranes operate under actual conditions, utilizing many of these design features.
TL;DR: In this paper, the authors describe an experimental investigation and the specific water yields from a four-bed adsorption desalination plant with respect to major assorted coolant and feed conditions.
TL;DR: In this article, carbon dioxide plasmas were used to modify hydrophobic polysulfone ultrafiltration membranes to create hydrophilic surfaces throughout the membrane structure, and water flux recovery measured after protein fouling was significantly higher than that for control membranes, with nearly 100% recovery after gentle cleaning in water.
TL;DR: In this paper, a detailed investigation of fouling mechanisms for ultrafiltration membranes with polysaccharides obtained by studying membrane-solute (static adsorption) and membrane−solute(solute)-solute interactions (ultrafiltration) was presented.
TL;DR: Although biofouling layer over the membrane reduced flux, biofOUling development improved brine rejection (50–70%).
TL;DR: Titania membranes, with a molecular weight cut-off of 15 kD were used in an ozonation/membrane system that was fed with water from Lake Lansing, which had been pre-filtered through a 0.45 microm glass fiber filter, and resulted in significant decreases in membrane fouling.
TL;DR: In this article, the authors investigated the ability of TiO2 self-assembled nanocomposite membranes to mitigate fouling effects during the filtration of membrane bioreactor (MBR) mixed liquor.
TL;DR: In this paper, an account of the complex problem of colloidal fouling of desalination membranes and filtration membranes in general is presented, and the complicated subject of understanding and modeling colloid fouling is touched upon with the aim of highlighting key issues and current trends.
TL;DR: In this paper, the effect of chemical cleaning on the surface of MF and UF membranes was investigated using various cleaning agents and their concentration, time of clean-in-place treatment and frequency of cleanings.
TL;DR: In this paper, a novel membrane bioreactor system with aerobatic granular sludge (MGSBR) was developed to treat municipal wastewater in which the main goal was to control the membrane fouling by changing the configuration of aerobic sludge, also to examine the feasibility of the MGSBR used to treat wastewater.
TL;DR: The results suggest that the EPS production was linked to growth of microorganisms, with the biomass growth rate analysis suggesting that the faster he growth, the less EPS production.
TL;DR: In this paper, the performance of microfiltration, ultra-filtration (UF), nanofiltration (NF), and reverse osmosis (RO) was evaluated in a paper mill in Italy.