scholarly journals Application of Zwitterions in Forward Osmosis: A Short Review

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 583
Author(s):  
Yu-Hsuan Chiao ◽  
Arijit Sengupta ◽  
Micah Belle Marie Yap Ang ◽  
Shu-Ting Chen ◽  
Teow Yeit Haan ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Municipal Wastewater ◽  
Separation Efficiency ◽  
Interfacial Polymerization ◽  
Membrane Surface ◽  
Forward Osmosis ◽  
Short Review ◽  
Chemical Cleaning ◽  
Membrane Performance

Forward osmosis (FO) is an important desalination method to produce potable water. It was also used to treat different wastewater streams, including industrial as well as municipal wastewater. Though FO is environmentally benign, energy intensive, and highly efficient; it still suffers from four types of fouling namely: organic fouling, inorganic scaling, biofouling and colloidal fouling or a combination of these types of fouling. Membrane fouling may require simple shear force and physical cleaning for sufficient recovery of membrane performance. Severe fouling may need chemical cleaning, especially when a slimy biofilm or severe microbial colony is formed. Modification of FO membrane through introducing zwitterionic moieties on the membrane surface has been proven to enhance antifouling property. In addition, it could also significantly improve the separation efficiency and longevity of the membrane. Zwitterion moieties can also incorporate in draw solution as electrolytes in FO process. It could be in a form of a monomer or a polymer. Hence, this review comprehensively discussed several methods of inclusion of zwitterionic moieties in FO membrane. These methods include atom transfer radical polymerization (ATRP); second interfacial polymerization (SIP); coating and in situ formation. Furthermore, an attempt was made to understand the mechanism of improvement in FO performance by zwitterionic moieties. Finally, the future prospective of the application of zwitterions in FO has been discussed.

scholarly journals Membrane Fouling Monitoring in a Submerged Membrane Bioreactor

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 653
Author(s):  
Konstantinos Azis ◽  
Marianthi Malioka ◽  
Spyridon Ntougias ◽  
Paraschos Melidis
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Membrane Surface ◽  
Cross Flow ◽  
Pilot Scale ◽  
Municipal Wastewater Treatment ◽  
Membrane Performance ◽  
Conventional Activated Sludge ◽  
Major Disadvantage

Use of Membrane Bioreactor (MBR) technology for municipal wastewater treatment has been increased in recent years, as it successfully overcomes the disadvantages of the conventional activated sludge process. Membrane fouling is the major disadvantage of MBRs and leads to decreased membrane performance and expanded operational expenses. In this study, fouling was monitored in a pilot-scale submerged MBR system fed with municipal wastewater. TMP was directly measured on the membrane module during the operation. To control TMP increase owing to biosolids accumulation on membrane surface, successive backwashes and air-cross flow velocity increase were applied. These measures lowered TMP and improved flux.

Short Review of Ultrafiltration of Polymer Membrane as a Self-Cleaning and Antifouling in the Wastewater System

2013 ◽  
Vol 795 ◽  
pp. 318-323 ◽  
Author(s):  
Siti Hawa Mohamad ◽  
M.I. Idris ◽  
Hasan Zuhudi Abdullah ◽  
Ahmad Fauzi Ismail
Keyword(s):  
Membrane Fouling ◽  
Surface Coating ◽  
Membrane Structure ◽  
Membrane Surface ◽  
Short Review ◽  
Polymer Membrane ◽  
Membrane Performance ◽  
Wastewater Systems ◽  
Self Cleaning ◽  
Almost All

This paper focuses on ultrafiltration polymer membrane for wastewater systems as a self-cleaning and antifouling. Fouling is one of the most important problems in almost all membrane processes. In this review, membrane antifouling and self-cleaning properties can be improved by using titanium dioxide (TiO2) particles and UV radiation on membrane structure and surface. Coating TiO2particles on membrane surface is an advanced method to minimize membrane fouling. Hence, these properties can be improved the membrane performance.

scholarly journals Engineered Nanoparticles with Decoupled Photocatalysis and Wettability for Membrane-Based Desalination and Separation of Oil-Saline Water Mixtures

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1397
Author(s):  
Bishwash Shrestha ◽  
Mohammadamin Ezazi ◽  
Gibum Kwon
Keyword(s):  
Membrane Fouling ◽  
Municipal Wastewater ◽  
Uv Light ◽  
Saline Water ◽  
Membrane Surface ◽  
Sio2 Nanoparticles ◽  
Engineered Nanoparticles ◽  
Water Mixture ◽  
Organic Substances ◽  
Suspended Substances

Membrane-based separation technologies are the cornerstone of remediating unconventional water sources, including brackish and industrial or municipal wastewater, as they are relatively energy-efficient and versatile. However, membrane fouling by dissolved and suspended substances in the feed stream remains a primary challenge that currently prevents these membranes from being used in real practices. Thus, we directly address this challenge by applying a superhydrophilic and oleophobic coating to a commercial membrane surface which can be utilized to separate and desalinate an oil and saline water mixture, in addition to photocatalytically degrading the organic substances. We fabricated the photocatalytic membrane by coating a commercial membrane with an ultraviolet (UV) light-curable adhesive. Then, we sprayed it with a mixture of photocatalytic nitrogen-doped titania (N-TiO2) and perfluoro silane-grafted silica (F-SiO2) nanoparticles. The membrane was placed under a UV light, which resulted in a chemically heterogeneous surface with intercalating high and low surface energy regions (i.e., N-TiO2 and F-SiO2, respectively) that were securely bound to the commercial membrane surface. We demonstrated that the coated membrane could be utilized for continuous separation and desalination of an oil–saline water mixture and for simultaneous photocatalytic degradation of the organic substances adsorbed on the membrane surface upon visible light irradiation.

scholarly journals Membrane Fouling Controlled by Adjustment of Biological Treatment Parameters in Step-Aerating MBR

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 553
Author(s):  
Dimitra C. Banti ◽  
Manassis Mitrakas ◽  
Petros Samaras
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Municipal Wastewater ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Aeration Tank ◽  
Filamentous Bacteria ◽  
Membrane Performance ◽  
Low Concentrations ◽  
Fouling Reduction

A promising solution for membrane fouling reduction in membrane bioreactors (MBRs) could be the adjustment of operating parameters of the MBR, such as hydraulic retention time (HRT), food/microorganisms (F/M) loading and dissolved oxygen (DO) concentration, aiming to modify the sludge morphology to the direction of improvement of the membrane filtration. In this work, these parameters were investigated in a step-aerating pilot MBR that treated municipal wastewater, in order to control the filamentous population. When F/M loading in the first aeration tank (AT1) was ≤0.65 ± 0.2 g COD/g MLSS/d at 20 ± 3 °C, DO = 2.5 ± 0.1 mg/L and HRT = 1.6 h, the filamentous bacteria were controlled effectively at a moderate filament index of 1.5–3. The moderate population of filamentous bacteria improved the membrane performance, leading to low transmembrane pressure (TMP) at values ≤2 kPa for a great period, while at the control MBR the TMP gradually increased reaching 14 kPa. Soluble microbial products (SMP), were also maintained at low concentrations, contributing additionally to the reduction of ΤΜP. Finally, the step-aerating MBR process and the selected imposed operating conditions of HRT, F/M and DO improved the MBR performance in terms of fouling control, facilitating its future wider application.

scholarly journals Influence of Membrane Vibration on Particles Rejection Using a Slotted Pore Membrane Microfiltration

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 709
Author(s):  
Asmat Ullah ◽  
Kamran Alam ◽  
Saad Ullah Khan ◽  
Victor M. Starov
Keyword(s):  
Membrane Fouling ◽  
Produced Water ◽  
Separation Efficiency ◽  
Membrane Surface ◽  
Water Separation ◽  
Oil Droplet ◽  
Pore Blockage ◽  
Oil Water Separation ◽  
Microfiltration Membranes ◽  
Membrane Vibration

A new method is proposed to increase the rejection in microfiltration by applying membrane oscillation, using a new type of microfiltration membrane with slotted pores. The oscillations applied to the membrane surface result in reduced membrane fouling and increased separation efficiency. An exact mathematical solution of the flow in the surrounding solution outside the oscillating membrane is developed. The oscillation results in the appearance of a lift velocity, which moves oil particles away from the membrane. The latter results in both reduced membrane fouling and increased oil droplet rejection. This developed model was supported by the experimental results for oil water separation in the produced water treatment. It was proven that the oil droplet concentration was reduced notably in the permeate, due to the membrane oscillation, and that the applied shear rate caused by the membrane oscillation also reduced pore blockage. A four-times lower oil concentration was recorded in the permeate when the membrane vibration frequency was 25 Hz, compared to without membrane vibration. Newly generated microfiltration membranes with slotted pores were used in the experiments.

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.

scholarly journals Optimization of In Situ Backwashing Frequency for Stable Operation of Anaerobic Ceramic Membrane Bioreactor

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 545 ◽  
Author(s):  
Rathmalgodage Thejani Nilusha ◽  
Tuo Wang ◽  
Hongyan Wang ◽  
Dawei Yu ◽  
Junya Zhang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Pure Water ◽  
Ex Situ ◽  
Stable Operation ◽  
Chemical Cleaning ◽  
Cake Layer

The cost-effective and stable operation of an anaerobic ceramic membrane bioreactor (AnCMBR) depends on operational strategies to minimize membrane fouling. A novel strategy for backwashing, filtration and relaxation was optimized for stable operation of a side stream tubular AnCMBR treating domestic wastewater at the ambient temperature. Two in situ backwashing schemes (once a day at 60 s/day, and twice a day at 60 s × 2/day) maintaining 55 min filtration and 5 min relaxation as a constant were compared. A flux level over 70% of the initial membrane flux was stabilized by in situ permeate backwashing irrespective of its frequency. The in situ backwashing by permeate once a day was better for energy saving, stable membrane filtration and less permeate consumption. Ex situ chemical cleaning after 60 days’ operation was carried out using pure water, sodium hypochlorite (NaOCl), and citric acid as the order. The dominant cake layer was effectively reduced by in situ backwashing, and the major organic foulants were fulvic acid-like substances and humic acid-like substances. Proteobacteria, Firmucutes, Epsilonbacteria and Bacteroides were the major microbes attached to the ceramic membrane fouling layer which were effectively removed by NaOCl.

Impact of chemical cleaning and air-sparging on the critical and sustainable flux in a flat sheet membrane bioreactor for municipal wastewater treatment

2008 ◽  
Vol 57 (12) ◽  
pp. 1873-1879 ◽  
Author(s):  
G. Guglielmi ◽  
D. Chiarani ◽  
D. P. Saroj ◽  
G. Andreottola
Keyword(s):  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Membrane Surface ◽  
Municipal Wastewater Treatment ◽  
Chemical Cleaning ◽  
Critical Flux ◽  
Submerged Membrane Bioreactor ◽  
Flat Sheet ◽  
Exponential Trend ◽  
Flat Sheet Membrane

The paper discusses the experimental optimisation of both chemical and mechanical cleaning procedures for a flat-sheet submerged membrane bioreactor fed with municipal wastewater. Fouling was evaluated by means of the critical flux concept, which was experimentally measured by short-term flux-stepping tests. By keeping constant most important parameters of the biological process (MLSS, sludge age), two different chemical cleaning protocols (2,000 mg L−1 NaOCl and 200 mg L−1 NaOCl) were applied with different frequency and, after approximately 9 months of operation, the criticality threshold was determined under different values of SADm (specific aeration demand per unit of membrane surface area). The weaker and more frequent chemical cleaning regime (200 mg L−1, monthly) proved much more effective than the stronger and less frequent strategy (2,000 mg L−1, once every three months). The improvement of performances was quantified by two TMP-based parameters, the fouling rate and the ΔTMP (difference between TMP values during the increasing and decreasing phase of hysteresis). The best performing configuration was then checked over a longer period by running four long-term trials showing an exponential trend of the sub-critical fouling rate with the imposed flux.

scholarly journals A novel In-situ Enzymatic Cleaning Method for Reducing Membrane Fouling in Membrane Bioreactors (MBRs)

2016 ◽  
Vol 1 (1) ◽  
pp. 1 ◽  
Author(s):  
M. R. Bilad ◽  
M. Baten ◽  
A. Pollet ◽  
C. Courtin ◽  
J. Wouters ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
High Performance ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Anion Exchange Chromatography ◽  
Magnetic Activity ◽  
Exchange Chromatography ◽  
Membrane Bioreactors ◽  
Cleaning Method

A novel in-situ enzymatic cleaning method was developed for fouling control in membrane bioreactors (MBRs). It is achieved by bringing the required enzymes near the membrane surface by pulling the enzymes to a magnetic membrane (MM) surface by means of magnetic forces, exactly where the cleaning is required. To achieve this, the enzyme was coupled to a magnetic nanoparticle (MNP) and the membrane it self was loaded with MNP. The magnetic activity was turned by means of an external permanent magnet. The effectiveness of concept was tested in a submerged membrane filtration using the model enzyme-substrate of Bacillus subitilis xylanase-arabinoxylan. The MM had almost similar properties compared to the unloaded ones, except for its well distributed MNPs. The enzyme was stable during coupling conditions and the presence of coupling could be detected using a high-performance anion-exchange chromatography (HPAEC) analysis and Fourier transform infrared spectroscopy (FTIR). The system facilitated an in-situ enzymatic cleaning and could be effectively applied for control fouling in membrane bioreactors (MBRs).

Application of the ADUFR Process to Brewery Effluent on a Laboratory Scale

1992 ◽  
Vol 25 (10) ◽  
pp. 95-105 ◽  
Author(s):  
N. K. H. Strohwald ◽  
W. R. Ross
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Rest Period ◽  
Substantial Effect ◽  
Test Period ◽  
High Rate ◽  
Chemical Cleaning ◽  
Solids Concentration ◽  
Load Rate ◽  
Brewery Effluent

The application of the high rate ADUFR (Anaerobic Digestion - Ultrafiltration) process to brewery effluent was investigated over an 80 day test period. Performance data on both the anaerobic digester and ultrafiltration unit is presented. At stabilised conditions, space load rates of 15 kgCOD.m−3.d−1 could be achieved at hydraulic residence times of 0.5-0.8 days, with COD removal efficiencies between 96 and 99%. Linear flow velocity across the membrane surface and suspended solids concentration of the biomass were found to have a substantial effect on ultrafiltration membrane flux. No membrane fouling was experienced throughout the test period and flux values of 10-18 l.m−2.h−1 (LMH) could be maintained without resorting to chemical cleaning. Dormant sludge was reactivated rapidly, after a two month rest period. A space load rate of 8 kgCOD.m−3.d−1 at a retention time of 0.5 days could be reached within seven days from restart.

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