Fouling and long-term durability of an integrated forward osmosis and membrane distillation system

2015 ◽  
Vol 72 (11) ◽  
pp. 2000-2005 ◽  
Author(s):  
T. Husnain ◽  
B. Mi ◽  
R. Riffat
Keyword(s):  
Membrane Fouling ◽  
Tap Water ◽  
Membrane Surface ◽  
Wastewater Reuse ◽  
Forward Osmosis ◽  
Cross Flow ◽  
Domestic Wastewater ◽  
Membrane Distillation ◽  
Hydrophobic Membrane

An integrated forward osmosis (FO) and membrane distillation (MD) system has great potential for sustainable wastewater reuse. However, the fouling and long-term durability of the system remains largely unknown. This study investigates the fouling behaviour and efficiency of cleaning procedures of FO and MD membranes used for treating domestic wastewater. Results showed that a significant decline in flux of both FO and MD membranes were observed during treatment of wastewater with organic foulants. However, shear force generated by the increased cross-flow physically removed the loosely attached foulants from the FO membrane surface and resulted in 86–88% recovery of flux by cleaning with tap water. For the MD membrane, almost no flux recovery was achieved due to adsorption of organic foulants on the hydrophobic membrane surface, thus indicating significant irreversible fouling/wetting, which may not be effectively cleaned even with chemical reagents. Long-term (10 d) tests showed consistent performance of the FO membrane by rejecting the contaminants. However, organic foulants reduced the hydrophobicity of the MD membrane, caused wetting problems and allowed contaminants to pass through. The results demonstrate that combination of the FO and MD processes can effectively reduce irreversible membrane fouling and solve the wetting problem of the MD membrane.

Influence of humic acid on the long-term performance of direct contact membrane distillation

2018 ◽  
Vol 30 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Dong-Wan Cho ◽  
Gihoon Kwon ◽  
Jeongmin Han ◽  
Hocheol Song
Keyword(s):  
Humic Acid ◽  
Membrane Fouling ◽  
Coalbed Methane ◽  
Direct Contact ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Direct Contact Membrane Distillation ◽  
High Level

In this study, the influence of humic acid on the treatment of coalbed methane water by direct contact membrane distillation was examined with bench-scale test unit. During short-term distillation (1000 min), high level of humic acid above 50 ppm resulted in significant decrease in permeate flux, while low level of humic acid (∼2 ppm) had little influence on the flux. For the long-term distillation (5000 min), the flux decline began at 3400 min in the presence of 5 ppm humic acid and 5 mM Ca2+, and decreased to ∼40% of initial flux at 5000 min. The spectroscopic analysis of the membrane used revealed that the surface was covered by hydrophilic layers mainly composed of calcite. The membrane fouling effect of humic acid became more significant in the presence of Ca2+ due to more facile calcite formation on the membrane surface. It was demonstrated that humic acid enhanced CaCO3 deposition on the membrane surfaces, thereby expediting the scaling phenomenon.

Study on Membrane Fouling Experiment of Stacked AGMD Module in Low Temperature

2011 ◽  
Vol 396-398 ◽  
pp. 458-462
Author(s):  
Xiao Hong Yang ◽  
Rui Tian ◽  
Shu Juan Ma ◽  
Hai Li Lv
Keyword(s):  
Membrane Fouling ◽  
Tap Water ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Thermal Mass ◽  
Initial Value ◽  
Air Gap Membrane Distillation ◽  
Membrane Flux ◽  
Before And After ◽  
New Type

In this paper, it has studied membrane fouling experiments at a certain temperature conditions and with untreated tap water as thermal mass, which applied unique multi-layered stacked air-gap membrane distillation module. It has analyzed the original membrane flux and conductivity changes in the experiments, and carried out SEM and EDS analysis before and after acid washed fouling membrane. The results show that: New type membrane module will produce fouling even at lower temperatures. Membrane surface was covered by a lot of uneven accumulation granular pollutants and cuboid crystals, so the mass flux reduced. Fouling membrane washed with 5 % hydrochloric acid solution was removed inorganic scale. The flux recovered to the initial value.

scholarly journals Forward osmosis membrane fouling and cleaning for wastewater reuse

2016 ◽  
Vol 7 (2) ◽  
pp. 111-120 ◽  
Author(s):  
Youngbeom Yu ◽  
Seockheon Lee ◽  
Sung Kyu Maeng
Keyword(s):  
Activated Sludge ◽  
Flow Velocity ◽  
Membrane Fouling ◽  
Suspended Solids ◽  
Wastewater Reuse ◽  
Forward Osmosis ◽  
Cross Flow ◽  
Short Period ◽  
Cross Flow Velocity ◽  
Cleaning Methods

Membrane fouling properties and different physical cleaning methods for forward osmosis (FO) and reverse osmosis (RO) laboratory-scale filtration systems were investigated. The membrane fouling, with respect to flux reduction, was lower in FO than in RO when testing an activated sludge effluent. Cross-flow velocity, air-scouring, osmotic backwashing and effect of a spacer were compared to determine the most effective cleaning method for FO. After a long period of fouling with activated sludge, the flux was fully recovered in a short period of osmotic backwashing compared with cleaning by changing cross-flow velocity and air-scouring. In this study, the osmotic backwashing was found to be the most efficient way to clean the FO membrane. The amount of RNA recovered from FO membranes was about twice that for RO membranes; biofouling could be more significant in FO than in RO. However, the membrane fouling in FO was lower than that in RO. The spacer increased the flux in FO with activated sludge liquor suspended solids of 2,500 mg/L, and there were effects of spacer on performance of FO–MBR membrane fouling. However, further studies are required to determine how the spacer geometry influences on the performance of the FO membrane.

scholarly journals SMP Production in an Anaerobic Submerged Membrane Bioreactor (AnMBR) at Different Organic Loading Rates

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 317
Author(s):  
Sandra C. Medina ◽  
Nataly Zamora-Vacca ◽  
Hector J. Luna ◽  
Nicolas Ratkovich ◽  
Manuel Rodríguez Susa
Keyword(s):  
Membrane Fouling ◽  
Energy Demand ◽  
Membrane Surface ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Term Operation ◽  
Submerged Membrane Bioreactor ◽  
Anaerobic Membrane Bioreactors ◽  
Microbial Products

Anaerobic membrane bioreactors (AnMBRs) have demonstrated an excellent capability to treat domestic wastewater. However, biofouling reduces membrane permeability, increasing operational costs and overall energy demand. Soluble microbial products (SMPs) that build up on the membrane surface play a significant role in the biofouling. In this study, the production of SMPs in a 32 L submerged AnMBR operated at three different organic loads (3.0, 4.1 and 1.2 kg chemical oxygen demand (COD)/m3d for phases 1, 2 and 3, respectively) during long-term operation of the reactor (144, 83 and 94 days) were evaluated. The samples were taken from both the permeate and the sludge at three different heights (0.14, 0.44 and 0.75 m). Higher production of SMPs was obtained in phase 2, which was proportional to the membrane fouling. There were no statistically significant differences (p > 0.05) in the SMPs extracted from sludge at different heights among the three phases. In the permeate of phases 1, 2 and 3, the membrane allowed the removal of 56%, 70% and 64% of the SMP concentration in the sludge. SMPs were characterized by molecular weight (MW). A bimodal behavior was obtained, where fractions prevailed with an MW < 1 kDa, associated with SMPs as utilization-associated products (UAPs) caused fouling by the pore-blocking mechanism. The chemical analysis found that, in the SMPs, the unknown COD predominated over the known COD, such as carbohydrates and proteins. These results suggest that further studies in SMP characterization should focus on the unknown COD fraction to understand the membrane fouling in AnMBR systems better.

scholarly journals Membrane Distillation: Recent Configurations, Membrane Surface Engineering, and Applications

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 934
Author(s):  
Sundararajan Parani ◽  
Oluwatobi Samuel Oluwafemi
Keyword(s):  
Membrane Fouling ◽  
Surface Engineering ◽  
Membrane Separation ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Operating Conditions ◽  
Toxic Heavy Metals ◽  
Hydrophobic Membrane ◽  
Future Directions ◽  
Vapor Pressure Gradient

Membrane distillation (MD) is a developing membrane separation technology for water treatment that involves a vapor transport driven by the vapor pressure gradient across the hydrophobic membrane. MD has gained wide attention in the last decade for various separation applications, including the separation of salts, toxic heavy metals, oil, and organic compounds from aqueous solutions. Compared with other conventional separation technologies such as reverse osmosis, nanofiltration, or thermal distillation, MD is very attractive due to mild operating conditions such as low temperature and atmospheric pressure, and 100% theoretical salt rejection. In this review, membrane distillation’s principles, recent MD configurations with their advantages and limitations, membrane materials, fabrication of membranes, and their surface engineering for enhanced hydrophobicity are reviewed. Moreover, different types of membrane fouling and their control methods are discussed. The various applications of standalone MD and hybrid MD configurations reported in the literature are detailed. Furthermore, studies on the MD-based pilot plants installed around the world are covered. The review also highlights challenges in MD performance and future directions.

Domestic wastewater treatment by forward osmosis-membrane distillation (FO-MD) integrated system

2018 ◽  
Vol 77 (6) ◽  
pp. 1514-1523 ◽  
Author(s):  
Jie Li ◽  
Deyin Hou ◽  
Kuiling Li ◽  
Yong Zhang ◽  
Jun Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Forward Osmosis ◽  
Domestic Wastewater ◽  
Membrane Distillation ◽  
Integrated System ◽  
Water Yield ◽  
Separation Performance ◽  
Domestic Wastewater Treatment

Abstract In this study, real domestic wastewater treatment by forward osmosis-membrane distillation (FO-MD) integrated system was investigated in laboratory scale. The integrated membrane system presented a good separation performance and the removal efficiency of most contaminants in the domestic wastewater was higher than 90%. High molecular weight contaminants were completely removed, while a few low molecular weight contaminants permeated through the membrane. The FO membrane fouling layer mainly consisted of organic substances like polysaccharides and proteins, and was very loose and could be effectively removed by rinsing the membrane surface with tap water. By comparison, the MD membrane fouling was mainly induced by inorganic salts and was not as severe as that of the FO membrane. During 120 h continuous operation, the FO-MD integrated system exhibited satisfying performance stability and maintained a high water yield and high product water quality. The results indicated the potential of the FO-MD integrated system for municipal wastewater treatment in coastal cities, water purification and desalination.

Comparison of four types of membrane bioreactor systems in terms of shear stress over the membrane surface using computational fluid dynamics

2013 ◽  
Vol 68 (12) ◽  
pp. 2534-2544 ◽  
Author(s):  
N. Ratkovich ◽  
T. R. Bentzen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Membrane Fouling ◽  
Two Phase Flow ◽  
Membrane Surface ◽  
Cross Flow ◽  
Membrane Bioreactors ◽  
Phase Flow ◽  
Two Phase ◽  
Computational Fluid Dynamics Cfd

Membrane bioreactors (MBRs) have been used successfully in biological wastewater treatment to solve the perennial problem of effective solids–liquid separation. A common problem with MBR systems is clogging of the modules and fouling of the membrane, resulting in frequent cleaning and replacement, which makes the system less appealing for full-scale applications. It has been widely demonstrated that the filtration performances in MBRs can be greatly improved with a two-phase flow (sludge–air) or higher liquid cross-flow velocities. However, the optimization process of these systems is complex and requires knowledge of the membrane fouling, hydrodynamics and biokinetics. Modern tools such as computational fluid dynamics (CFD) can be used to diagnose and understand the two-phase flow in an MBR. Four cases of different MBR configurations are presented in this work, using CFD as a tool to develop and optimize these systems.

Surface modification of reverse osmosis membranes with zwitterionic polymer to reduce biofouling

2015 ◽  
Vol 15 (5) ◽  
pp. 999-1010 ◽  
Author(s):  
Ahmed E. Abdelhamid ◽  
Mahmoud M. Elawady ◽  
Mahmoud Ahmed Abd El-Ghaffar ◽  
Abdelgawad M. Rabie ◽  
Poul Larsen ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Tap Water ◽  
Membrane Surface ◽  
Salt Content ◽  
Cross Flow ◽  
Membrane Properties ◽  
Cleaning Efficiency ◽  
Bacteria Growth ◽  
Cross Flow Filtration

The zwitterionic homopolymer poly[2-(methacryloyloxy)ethyl-dimethyl-(3-sulfopropyl) ammonium hydroxide was coated onto the surface of commercial polyamide reverse osmosis (RO) membranes. Aqueous solutions of the polymer at different concentrations were applied to modify the polyamide membranes through an in situ surface coating procedure. After membrane modification, cross-flow filtration testing was used to test the antifouling potential of the modified membranes. The obtained data were compared with experimental data for unmodified membranes. Each test was done by cross-flow filtering tap water for 60 hours. Yeast extract was added as a nutrient source for the naturally occurring bacteria in tap water, to accelerate bacteria growth. Fourier transform infrared spectroscopy, contact angle, scanning electron microscopy, atomic force microscopy, and permeation tests were employed to characterize membrane properties. The results confirmed that modifying the membranes enhanced their antifouling properties and cleaning efficiency, the fouling resistance to bacteria improving due to the increased hydrophilicity of the membrane surface after coating. In addition, the water permeability and salt rejection improved. This in situ surface treatment approach for RO membranes could be very important for modifying membranes in their original module assemblies as it increases water production and reduces the salt content.

scholarly journals Long-term evaluation of a forward osmosis-nanofiltration demonstration plant for wastewater reuse in agriculture

2018 ◽  
Vol 338 ◽  
pp. 383-391 ◽  
Author(s):  
Beatriz Corzo ◽  
Teresa de la Torre ◽  
Carmen Sans ◽  
Raquel Escorihuela ◽  
Susana Navea ◽  
...  
Keyword(s):  
Wastewater Reuse ◽  
Forward Osmosis ◽  
Term Evaluation ◽  
Demonstration Plant

scholarly journals Reduction of Biofouling of a Microfiltration Membrane Using Amide Functionalities—Hydrophilization without Changes in Morphology

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1379
Author(s):  
Daniel Breite ◽  
Marco Went ◽  
Andrea Prager ◽  
Mathias Kühnert ◽  
Agnes Schulze
Keyword(s):  
Membrane Fouling ◽  
Average Pore Size ◽  
Membrane Surface ◽  
Aqueous Media ◽  
Soxhlet Extraction ◽  
Hydrophobic Membrane ◽  
Average Pore ◽  
Water Contact ◽  
Microfiltration Membrane ◽  
Membrane Performance

A major goal of membrane science is the improvement of the membrane performance and the reduction of fouling effects, which occur during most aqueous filtration applications. Increasing the surface hydrophilicity can improve the membrane performance (in case of aqueous media) and decelerates membrane fouling. In this study, a PES microfiltration membrane (14,600 L m−2 h−1 bar−1) was hydrophilized using a hydrophilic surface coating based on amide functionalities, converting the hydrophobic membrane surface (water contact angle, WCA: ~90°) into an extremely hydrophilic one (WCA: ~30°). The amide layer was created by first immobilizing piperazine to the membrane surface via electron beam irradiation. Subsequently, a reaction with 1,3,5-benzenetricarbonyl trichloride (TMC) was applied to generate an amide structure. The presented approach resulted in a hydrophilic membrane surface, while maintaining permeance of the membrane without pore blocking. All membranes were investigated regarding their permeance, porosity, average pore size, morphology (SEM), chemical composition (XPS), and wettability. Soxhlet extraction was carried out to demonstrate the stability of the applied coating. The improvement of the modified membranes was demonstrated using dead-end filtration of algae solutions. After three fouling cycles, about 60% of the initial permeance remain for the modified membranes, while only ~25% remain for the reference.

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