Exerting ultrasound to control the membrane fouling in filtration of anaerobic activated sludge—mechanism and membrane damage

In this study, ultrasound was applied to control membrane fouling development online in an anaerobic membrane bioreactor (AMBR). Experimental results showed that membrane fouling could be controlled effectively by ultrasound although membrane damage may occur under some operational conditions. Based upon the observation on the damaged membrane surface via SEM, two mechanisms causing membrane damage by exerting ultrasound are inferred as micro particle collide on the membrane surface and chemical interaction between membrane materials and hydroxyl radicals produced by acoustic cavitations. Not only membrane damage but also membrane fouling control and membrane fouling cleaning were resulted from these mechanisms. Properly selecting ultrasonic intensity and working time, and keeping a certain thickness of cake layer on membrane surface could be effective ways to protect membrane against damage.

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Ozone Chemically Enhanced Backwash for Ceramic Membrane Fouling Control in Cyanobacteria-Laden Water

Membranes ◽

10.3390/membranes10090213 ◽

2020 ◽

Vol 10 (9) ◽

pp. 213

Author(s):

Stéphane Venne ◽

Onita D. Basu ◽

Benoit Barbeau

Keyword(s):

Surface Water ◽

Surface Waters ◽

Membrane Fouling ◽

Ceramic Membrane ◽

Membrane Surface ◽

Operating Costs ◽

Fouling Control ◽

Dead End ◽

Cake Layer ◽

Flow Experiments

Membrane fouling in surface waters impacted by cyanobacteria is currently poorly controlled and results in high operating costs. A chemically enhanced backwash (CEB) is one possible strategy to mitigate cyanobacteria fouling. This research investigates the potential of using an ozone CEB to control the fouling caused by Microcystis aeruginosa in filtered surface water on a ceramic ultrafiltration membrane. Batch ozonation tests and dead-end, continuous flow experiments were conducted with ozone doses between 0 and 19 mg O3/mg carbon. In all tests, the ozone was shown to react more rapidly with the filtered surface water foulants than with cyanobacteria. In addition, the ozone CEB demonstrated an improved mitigation of irreversible fouling over 2 cycles versus a single CEB cycle; indicating that the ozone CEB functioned better as the cake layer developed. Ozone likely weakens the compressible cake layer formed by cyanobacteria on the membrane surface during filtration, which then becomes more hydraulically reversible. In fact, the ozone CEB reduced the fouling resistance by 35% more than the hydraulic backwash when the cake was more compressed.

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Membrane Fouling in Algal Separation Processes: A Review of Influencing Factors and Mechanisms

Frontiers in Chemical Engineering ◽

10.3389/fceng.2021.687422 ◽

2021 ◽

Vol 3 ◽

Author(s):

Andres Felipe Novoa ◽

Johannes S. Vrouwenvelder ◽

Luca Fortunato

Keyword(s):

Membrane Fouling ◽

Control Strategies ◽

Membrane Surface ◽

Cost Effective ◽

Dynamic Responses ◽

Feed Water ◽

Operational Conditions ◽

Term Operation ◽

Fouling Control ◽

And Control

The use of algal biotechnologies in the production of biofuels, food, and valuable products has gained momentum in recent years, owing to its distinctive rapid growth and compatibility to be coupled to wastewater treatment in membrane photobioreactors. However, membrane fouling is considered a main drawback that offsets the benefits of algal applications by heavily impacting the operation cost. Several fouling control strategies have been proposed, addressing aspects related to characteristics in the feed water and membranes, operational conditions, and biomass properties. However, the lack of understanding of the mechanisms behind algal biofouling and control challenges the development of cost-effective strategies needed for the long-term operation of membrane photobioreactors. This paper reviews the progress on algal membrane fouling and control strategies. Herein, we summarize information in the composition and characteristics of algal foulants, namely algal organic matter, cells, and transparent exopolymer particles; and review their dynamic responses to modifications in the feedwater, membrane surface, hydrodynamics, and cleaning methods. This review comparatively analyzes (i) efficiency in fouling control or mitigation, (ii) advantages and drawbacks, (iii) technological performance, and (iv) challenges and knowledge gaps. Ultimately, the article provides a primary reference of algal biofouling in membrane-based applications.

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Mechanism of Membrane Fouling Control by HMBR: Effect of Microbial Community on EPS

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17051681 ◽

2020 ◽

Vol 17 (5) ◽

pp. 1681

Author(s):

Qiang Liu ◽

Ying Yao ◽

Delan Xu

Keyword(s):

Microbial Community ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Extracellular Polymeric Substances ◽

Microbial Community Composition ◽

Domestic Wastewater ◽

Control Group ◽

Transmembrane Pressure ◽

Fouling Control ◽

Cake Layer

A hybrid membrane bioreactor (HMBR) employing activated sludge and biofilm simultaneously is proved to represent a good performance on membrane fouling control compared to conventional membrane bioreactor (CMBR) by reducing extracellular polymeric substances (EPS), especially bound EPS (B-EPS). In order to better understand the mechanism of membrane fouling control by the HMBR in regard of microbial community composition, a pilot scale HMBR operated to treat domestic wastewater for six months, and a CMBR operated at the same time as control group. Results showed that HMBR can effectively control membrane fouling. When transmembrane pressure reached 0.1 MPa, the membrane module in the HMBR operated for about 26.7% longer than that in the CMBR. In the HMBR, the quantity of EPS was significantly lower than that in the CMBR. In this paper, soluble EPS was also found to have a close relationship with cake layer resistance. The species richness and diversity in the HMBR were higher than those in the CMBR, and a certain difference between the compositions of microbial communities in the two reactors was confirmed. Therefore, the difference in microbial community compositions may be the direct reason why EPS in the HMBR was lower than that in the CMBR.

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Investigation of membrane fouling mechanism of intracellular organic matter during ultrafiltration

Scientific Reports ◽

10.1038/s41598-020-79272-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Weiwei Huang ◽

Yuanhong Zhu ◽

Bingzhi Dong ◽

Weiwei Lv ◽

Quan Yuan ◽

...

Keyword(s):

Organic Matter ◽

Chlorella Vulgaris ◽

Membrane Fouling ◽

Membrane Surface ◽

Layer Formation ◽

Fouling Control ◽

Fouling Mechanism ◽

Cake Layer ◽

Severe Degree ◽

Filtration Flux

AbstractThis study investigated the ultrafiltration (UF) membrane fouling mechanism of intracellular organic matter (IOM) from Chlorella vulgaris (CV) and Microcystis aeruginosa (MA). Both CV- and MA-IOM caused severe membrane fouling during UF; however, there were significant differences in the membrane fouling by these two materials. Neutral hydrophilic (N-HPI) compounds were the organics that caused the most severe membrane fouling during CV-IOM filtration, whereas the MA-IOM membrane fouling was induced by mainly hydrophobic (HPO) organics. From an analysis based on Derjaguin–Landau–Verwey–Overbeek theory, it was found that the interaction energy between the membrane and foulants in the later stage of filtration was the major factor determining the efficiency of filtration for both CV-IOM and MA-IOM. The TPI organics in CV-IOM fouled the membrane to a more severe degree during the initial filtration flux; however, when the membrane surface was covered with CV-IOM foulants, the N-HPI fraction of CV-IOM caused the most severe membrane fouling because its attractive energy with the membrane was the highest. For MA-IOM, regardless of the initial filtration flux or the late stage of filtration, the HPO organics fouled the membrane to the greatest extent. An analysis of modified filtration models revealed that cake layer formation played a more important role than other fouling mechanisms during the filtration of CV-IOM and MA-IOM. This study provides a significant understanding of the membrane fouling mechanism of IOM and is beneficial for developing some strategies for membrane fouling control when treating MA and CV algae-laden waters.

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Membrane Fouling Control in an Anaerobic Membrane Bioreactor Coupled with Online Ultrasound Equipment for Digestion of Waste Activated Sludge

Separation Science and Technology ◽

10.1080/01496391003659903 ◽

2010 ◽

Vol 45 (7) ◽

pp. 941-947 ◽

Cited By ~ 22

Author(s):

Meilan Xu ◽

Xianghua Wen ◽

Xia Huang ◽

Yushan Li

Keyword(s):

Activated Sludge ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Waste Activated Sludge ◽

Anaerobic Membrane Bioreactor ◽

Fouling Control

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Patterned Membrane in an Energy-Efficient Tilted Panel Filtration System for Fouling Control in Activated Sludge Filtration

Polymers ◽

10.3390/polym12020432 ◽

2020 ◽

Vol 12 (2) ◽

pp. 432 ◽

Cited By ~ 7

Author(s):

Aisyah Osman ◽

Normi Izati Mat Nawi ◽

Shafirah Samsuri ◽

Muhammad Roil Bilad ◽

Norazanita Shamsuddin ◽

...

Keyword(s):

Activated Sludge ◽

Membrane Fouling ◽

Membrane Surface ◽

Aeration Rate ◽

Membrane Bioreactors ◽

Widespread Application ◽

Membrane Area ◽

Surface Corrugation ◽

Fouling Control ◽

The Impact

A membrane bioreactor enhances the overall biological performance of a conventional activated sludge system for wastewater treatment by producing high-quality effluent suitable for reuse. However, membrane fouling hinders the widespread application of membrane bioreactors by reducing the hydraulic performance, shortening membrane lifespan, and increasing the operational costs for membrane fouling management. This study assesses the combined effect of membrane surface corrugation and a tilted panel in enhancing the impact of air bubbling for membrane fouling control in activated sludge filtration, applicable for membrane bioreactors. The filterability performance of such a system was further tested under variable parameters: Filtration cycle, aeration rate, and intermittent aeration. Results show that a combination of surface corrugation and panel tilting enhances the impact of aeration and leads to 87% permeance increment. The results of the parametric study shows that the highest permeance was achieved under short filtration–relaxation cycle of 5 min, high aeration rate of 1.5 L/min, and short switching period of 2.5 min, to yield the permeances of 465 ± 18, 447 ± 2, and 369 ± 9 L/(m2h bar), respectively. The high permeances lead to higher operational flux that helps to lower the membrane area as well as energy consumption. Initial estimation of the fully aerated system yields the energy input of 0.152 kWh/m3, much lower than data from the full-scale references of <0.4 kWh/m3. Further energy savings and a lower system footprint can still be achieved by applying the two-sided panel with a switching system, which will be addressed in the future.

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Application of air backflushing technique in membrane bioreactor

Water Science & Technology ◽

10.2166/wst.1997.0455 ◽

1997 ◽

Vol 36 (12) ◽

pp. 259-266 ◽

Cited By ~ 15

Author(s):

C. Visvanathan ◽

Byung-Soo Yang ◽

S. Muttamara ◽

R. Maythanukhraw

Keyword(s):

Activated Sludge ◽

Membrane Bioreactor ◽

Hollow Fiber Membrane ◽

Membrane Surface ◽

Operation Time ◽

Transmembrane Pressure ◽

Stable Operation ◽

Aeration Tank ◽

Permeate Flux ◽

Cake Layer

The optimum air backflushing and filtration cycle was investigated for a 0.1 μm hollow fiber membrane module immersed in an activated sludge aeration tank. It was found that 15 minutes filtration and 15 minutes air backflushing gave the best result both in terms of flux stability and net cumulative permeate volume. Although this cyclic operation could not completely remove the clogging, this process improved the flux by up to 371% compared to the continuous operation. During the long term runs, three different hydraulic retention times (HRT) of 12, 6 and 3 hours, corresponding to 0.16, 0.32 and 0.64 m3/m2.d of permeate flux respectively, were investigated. Stable operation was obtained at the HRT of 12 hours. Decrease in HRT led to rapid formation of a compact cake layer on the membrane surface thus increasing the transmembrane pressure. It was also noted that filtration pressure increases with increase in bioreactor MLSS concentration. With operation time, the MLVSS/MLSS value decreased without significant effect on the process performance, indicating that inorganic mass constantly accumulated in the bioreactor. All the experimental runs produced more than 90% removal of COD, and TKN. In terms of physical, chemical, biological and bacteriological parameters, the membrane bioreactor effluent was superior to the conventional activated sludge process.

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Effect of a suspended carrier on membrane fouling in a submerged membrane bioreactor

Water Science & Technology ◽

10.2166/wst.2006.199 ◽

2006 ◽

Vol 53 (6) ◽

pp. 211-220 ◽

Cited By ~ 22

Author(s):

Chun-Hai Wei ◽

Xia Huang ◽

Cheng-Wen Wang ◽

Xiang-Hua Wen

Keyword(s):

Membrane Fouling ◽

Membrane Bioreactor ◽

Membrane Surface ◽

Transmembrane Pressure ◽

Fouling Control ◽

Submerged Membrane Bioreactor ◽

Negative Effect ◽

Sludge Particle ◽

Carrier Volume ◽

Suspended Carrier

In an attempt at membrane fouling control, a kind of cylindrical plastic suspended carrier was added in a submerged membrane bioreactor (SMBR) and its effect was investigated in this study. According to the transmembrane pressure (TMP) profiles and the sludge characteristics in comparative runs with and without suspended carriers, it was found that the suspended carriers added in SMBR had two effects on membrane fouling: one was the positive effect of mechanically scouring the membrane surface and the other was the negative effect of breaking up sludge flocs. Sludge particle size distribution change was mainly responsible. It was suggested to apply the suspended carrier at higher MLSS concentration and lower carrier dose based on the consideration for retarding sludge breakage caused by the carrier. The experiment was conducted under higher MLSS (8 g L−1) and lower carrier dose (carrier volume/total volume = 1%). The TMP increase was effectively retarded by added suspended carriers compared to the system without addition of the carriers. The effect of suspended carriers on membrane fouling at high MLSS concentration was verified.

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Carbon Nanotubes-Sponge Modified Electro Membrane Bioreactor (EMBR) and Their Prospects for Wastewater Treatment Applications

Membranes ◽

10.3390/membranes10120433 ◽

2020 ◽

Vol 10 (12) ◽

pp. 433

Author(s):

Ali M. Almusawy ◽

Riyad H. Al-Anbari ◽

Qusay F. Alsalhy ◽

Arshed Imad Al-Najar

Keyword(s):

Carbon Nanotubes ◽

Activated Sludge ◽

Pore Size ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Membrane Surface ◽

Testing Procedure ◽

Nanocomposite Membrane ◽

Nitrogen And Phosphorus ◽

Electrical Field

A novel membrane bioreactor system utilizes Multi-Walled Carbon Nanotubes (MWCNTs) coated polyurethane sponge (PUs), an electrical field, and a nanocomposite membrane has been successfully designed to diminish membrane with fouling caused by activated sludge. The classical phase inversion was harnessed to prepare Zinc Oxide/Polyphenylsulfone (ZnO/PPSU) nanocomposite membranes using 1.5 g of ZnO nanoparticles (NPs). The prepared nanocomposite membrane surface was fully characterized by a series of experimental tools, e.g., Scanning electron microscope (SEM), Atomic force microscopy (AFM), contact angle (CA), pore size, and pore size distribution. The testing procedure was performed through an Activated Sludge-Membrane Bioreactor (ASMBR) as a reference and results were compared with those obtained with nanotubes coated sponge–MBR (NSMBR) and nanotubes coated sponge-MBR in the presence of an electrical field (ENSMBR) system. Observed fouling reduction of the membrane has improved significantly and, thus, the overall long-term was increased by 190% compared with the control ASMBR configuration. The experimental results showcased that sponge-carbon nanotubes (CNTs) were capable of adsorbing activated sludge and other contaminants to minimize the membrane fouling. At a dosage of 0.3 mg/mL CNT and 2 mg/mL of SDBS, the sponge-CNT was capable of eliminating nitrogen and phosphorus by 81% and >90%, respectively.

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