scholarly journals In-line coagulation assessment for ultrafiltration fouling reduction to treat secondary effluent for water reuse

2020 ◽  
Author(s):  
Samia A. Aly ◽  
William B. Anderson ◽  
Peter M. Huck
Keyword(s):  
Membrane Fouling ◽  
Water Reuse ◽  
Hollow Fiber Membrane ◽  
Secondary Effluent ◽  
Membrane Performance ◽  
Coagulant Dosage ◽  
Pre Treatment ◽  
Uf Membranes ◽  
Fouling Reduction ◽  
The Impact

Abstract Low pressure membranes are attracting attention for their potential to improve secondary effluent quality, but membrane fouling can limit their widespread applicability. In this study, in-line coagulation as pre-treatment to ultrafiltration (UF) was investigated using a bench-scale hollow fiber membrane at a constant flux of 33 L/m2 h. Membrane fouling was monitored by observing change in trans-membrane pressure when the membrane was fed with secondary effluent and in-line coagulated secondary effluent over a 24-h period. The impact of four coagulants at different dosages on reversible and irreversible membrane fouling and permeate quality was studied. It was found that in-line coagulation improved UF performance to varying degrees depending on coagulant type and dosage. Generally, higher reduction of fouling was achieved by increasing coagulant dosage within the 0.5–5.0 mg/L range investigated. Ferric-based coagulants were better than aluminum-based coagulants with respect to improving membrane performance for the secondary effluent investigated, even at low dosages (0.5 mg/L). Further investigations are required to determine how in-line coagulation affects removal of organic compounds through UF membranes.

scholarly journals Biological filtration with and without prior in-line coagulation to reduce UF fouling by secondary effluent

2017 ◽  
Vol 8 (2) ◽  
pp. 176-191 ◽  
Author(s):  
Samia A. Aly ◽  
William B. Anderson ◽  
Peter M. Huck
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Membrane Fouling ◽  
Loading Rate ◽  
Pilot Scale ◽  
Secondary Effluent ◽  
Biological Filtration ◽  
Treatment Processes ◽  
Pre Treatment ◽  
Fouling Reduction

Abstract The objectives of this research were to investigate biofiltration prior to ultrafiltration (UF) for treatment of secondary effluent. Biofiltration with and without prior in-line coagulation was assessed for UF membrane fouling reduction. Two parallel pilot-scale biofilters, each with different media (sand vs. anthracite), were operated under identical conditions at a hydraulic loading rate of 0.75 m/h. A component of this investigation included the in-line application of a 1.0 mg/L dose of ferric sulfate prior to an anthracite biofilter. All UF membrane fouling experiments were conducted at bench-scale at a constant flux of 32 L/m2h (LMH). The sand (BF1) and anthracite biofilters (BF2) removed on average 25 and 20%, respectively, of the biopolymer fraction of the effluent organic matter. Humic substances were less well removed at about 10%, while biofilter influent turbidity was reduced by 75 and 70% through BF1 and BF2, respectively. Feeding the UF membrane with biofilter effluent (no prior coagulant addition) substantially reduced both hydraulically reversible and irreversible membrane fouling by up to 60 and 80%, respectively. Hydraulically reversible and irreversible fouling were further reduced (up to 69 and 87%, respectively) by the integration of the in-line coagulation/biofiltration pre-treatment processes compared to biofiltration alone.

Low-pressure membrane filtration of secondary effluent in water reuse: Pre-treatment for fouling reduction

2008 ◽  
Vol 320 (1-2) ◽  
pp. 135-142 ◽  
Author(s):  
Linhua Fan ◽  
Thang Nguyen ◽  
Felicity A. Roddick ◽  
John L. Harris
Keyword(s):  
Water Reuse ◽  
Membrane Filtration ◽  
Low Pressure ◽  
Secondary Effluent ◽  
Pre Treatment ◽  
Fouling Reduction

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 Recycling of Reverse Osmosis Concentrates to the Membrane Bioreactor in the MBR-RO Process for Water Reuse: effect on mbr performances

2017 ◽  
Vol 30 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Thi Thu Nga Vu ◽  
Manon Montaner ◽  
Christelle Guigui
Keyword(s):  
Organic Matter ◽  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Water Reuse ◽  
High Performance ◽  
Membrane Bioreactor ◽  
Membrane System ◽  
Size Exclusion ◽  
Ro Concentrate ◽  
The Impact

Wastewater effluents can be treated by an integrated membrane system combining membrane bioreactor (MBR) and reverse osmosis (RO) for effective removal of micropollutants in the field of high-quality water reuse. However, discharging the RO concentrate waste stream directly into the natural environment could lead to serious problems due to the toxic components contained in the concentrates (micropollutants, salts, organic matter). A possible solution could be the recirculation of RO concentrate waste to the MBR. However, such an operation should be studied in detail since the recirculation of non-biodegradable organic matter or high concentrations of salts and micropollutants could directly or indirectly contribute to MBR membrane fouling and modification of the biodegradation activity. In this context, the work reported here focused on the recirculation of such concentrates in an MBR, paying specific attention to MBR membrane fouling. Lab-scale experiments were performed on a continuous MBR-RO treatment line with RO concentrate recirculation. The main goal was to determine the recovery of the RO unit and of the global process that maintained good process performance in terms of biodegradation and MBR fouling. The results demonstrate that the impact of the toxic flow on activated sludge depends on the recovery of the RO step but the same trends were observed regardless of the organic matter and salt contents of the concentrates: the concentration of proteins increased slightly. Size-exclusion high performance liquid chromatography (HPLC-SEC) was employed to study the effects of RO concentrate on the production of protein-like soluble microbial products (SMPs) and demonstrated a significant peak of protein-like substances corresponding to 10-100 kDa and 100-1 000 kDa molecules in the supernatant. Thus a significant increase in the propensity for sludge fouling was observed, which could be attributed to the increased quantity of protein-like substances. Finally, the effect of the concentrate on sludge activity was studied and no significant effect was observed on biodegradation, indicating that the return of the concentrate to the MBR could be a good alternative.

Reducing the effect of cyanobacteria in the microfiltration of secondary effluent

2010 ◽  
Vol 62 (7) ◽  
pp. 1682-1688 ◽  
Author(s):  
Y. T. Goh ◽  
J. L. Harris ◽  
F. A. Roddick
Keyword(s):  
Organic Matter ◽  
Sewage Treatment ◽  
Cyanobacterial Blooms ◽  
Secondary Effluent ◽  
Dissolved Air Flotation ◽  
Algal Organic Matter ◽  
Alum Coagulation ◽  
Pre Treatment ◽  
The Impact ◽  
Dissolved Air

Cyanobacterial blooms in the lagoons of sewage treatment plants can severely impact the performance of membrane plants treating the effluent. This paper investigates the impact of Microcystis aeruginosa in a secondary effluent on the microfiltration filterability and cleaning of the membrane. Alum coagulation and dissolved air flotation (DAF) were investigated to remove the algae and so enhance the volume of effluent processed, and their influence on reversible and irreversible fouling. Degree of fouling due to the algal components was found to be in decreasing order of algal cells, algal organic matter and extracellular organic matter. Alum coagulation with 5 mg L−1 as Al3 +  led to a substantial increase in permeate volume, an increase in dissolved organic carbon removal, and a foulant layer which protected the membrane from internal fouling but which was hydraulically removable resulting in full flux recovery. Pre-treatment by DAF or 1.5 μm filtration following alum coagulation enhanced the flux rate and permeate volume but exposed the membrane to internal irreversible fouling.

scholarly journals Biologically active ion exchange (BIEX) for NOM removal and membrane fouling prevention

2017 ◽  
Vol 17 (4) ◽  
pp. 1178-1184 ◽  
Author(s):  
M. Schulz ◽  
J. Winter ◽  
H. Wray ◽  
B. Barbeau ◽  
P. Bérubé
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Ion Exchange ◽  
Membrane Fouling ◽  
Building Blocks ◽  
Biologically Active ◽  
Low Molecular Weight ◽  
Effective Removal ◽  
Pre Treatment ◽  
The Impact

The natural organic matter (NOM) removal efficiency and regeneration behavior of ion-exchange filters with promoted biological activity (BIEX) was compared to operation where biological activity was suppressed (i.e. abiotic conditions). The impact of BIEX pre-treatment on fouling in subsequent ultrafiltration was also investigated. Biological operation enhanced NOM removal by approximately 50% due to an additional degradation of smaller humic substances, building blocks and low molecular weight acids. Promotion of biological activity significantly increased the time to breakthrough of the filters and, therefore, is expected to lower the regeneration frequency as well as the amount of regenerate of which to dispose. Pre-treatment using BIEX filters resulted in a significant decrease in total and irreversible fouling during subsequent ultrafiltration. The decrease was attributed to the effective removal of medium and low molecular weight NOM fractions. The results indicate that BIEX filtration is a robust, affordable and easy-to-operate pre-treatment approach to minimize fouling in ultrafiltration systems and enhance the quality of the produced permeate.

scholarly journals Advances in Antifouling Strategies in Membrane Ultrafiltration: A Brief Review

2021 ◽  
Vol 76 (1) ◽  
pp. 10-16
Author(s):  
Amina Tahreen ◽  
Mohammed Saedi Jami
Keyword(s):  
Membrane Fouling ◽  
Separation Efficiency ◽  
Membrane Integrity ◽  
Graphene Oxide Nanosheets ◽  
Membrane Pore ◽  
Pore Blockage ◽  
As Adsorption ◽  
Pre Treatment ◽  
The Impact

This study briefly reviews the recent advances in membrane and separation technology for antifouling strategies for membrane ultrafiltration. Membrane fouling is inevitable in ultrafiltration due to the eventual membrane pore blockage with foulants. Consequently, flux declines and affects the membrane integrity over time along with elevation in processing time and thereby complicating the overall membrane maintenance. To combat this issue, several studies had been undertaken such as grafting of TiO2 nanotubes (TNTs), graphene oxide nanosheets, zwitterions or polymers in the membrane and also by applying direct current. Moreover, many researchers emphasized on the integration of an enhanced pre-treatment process such as adsorption, coagulation, electrocoagulation and so on. By critically analysing and comparing the existing studies, the impact, suitability, efficiency and sustainability of the antifouling strategies will be discussed in this review. This refined approach of observing the progress in membrane technology will enable the determination of the existing gaps in the studies and will help to expand and propel the field further in separation efficiency.

Use of fouling resistant nanofiltration and reverse osmosis membranes for dyeing wastewater effluent treatment

2005 ◽  
Vol 51 (6-7) ◽  
pp. 159-164 ◽  
Author(s):  
S.-W. Myung ◽  
I.-H. Choi ◽  
S.-H. Lee ◽  
I.-C. Kim ◽  
K.-H. Lee
Keyword(s):  
Surface Roughness ◽  
Surface Charge ◽  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Water Reuse ◽  
Effluent Treatment ◽  
Poly Vinyl Alcohol ◽  
Dyeing Wastewater ◽  
Pre Treatment

Dyeing wastewater was post-treated by using nanofiltration (NF) and reverse osmosis (RO) membranes. To reduce membrane fouling, poly (vinyl alcohol) (PVA) with a neutral charge was coated on NF and RO membranes. The effect of surface charge and surface roughness on membrane fouling was investigated. Dyeing wastewater was pre-treated by using coagulation, activated sludge process, and MF process to investigate the effect of the pre-treatment on the membrane fouling. It is demonstrated that the extent of fouling is significantly influenced by the surface roughness and the surface charge on the NF and RO membranes. A membrane with a smooth and neutral surface was fouled less. The pre-treatment was essential for avoiding NF and RO membranes fouling. The quality of the final permeate was acceptable for water reuse.

scholarly journals Hydraulic Resistance and Protein Fouling Resistance of a Zirconia Membrane with a Tethered PVP Layer

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 951
Author(s):  
Yian Chen ◽  
Montserrat Rovira-Bru ◽  
Francesc Giralt ◽  
Yoram Cohen
Keyword(s):  
Ionic Strength ◽  
Hydraulic Resistance ◽  
Membrane Fouling ◽  
Vinyl Pyrrolidone ◽  
Fouling Resistance ◽  
Model Protein ◽  
Poly Vinyl Pyrrolidone ◽  
Ph Range ◽  
Fouling Reduction ◽  
The Impact

The influence of surface modification of zirconia (ZrO2) membrane with tethered poly(vinyl pyrrolidone) (PVP) chains was evaluated with respect to the impact of pH and ionic strength on hydraulic resistance and fouling resistance in the filtration of bovine serum albumin (BSA) and lysozyme (Lys) as model protein foulants. The tethered PVP surface layer led to membrane permeability and fouling propensity that were responsive to both pH and ionic strength. The PVP-modified membrane (PVP-ZrO2) hydraulic resistance increased by up to ~48% over a pH range of 6–11, but with no discernible impact at lower pH. Membrane hydraulic resistance was virtually unaffected by ionic strength over the 0.001–1 M range. However, reversible foulant cake resistance in BSA and Lys solution filtration increased with elevated ionic strength, owing in part to the weakening of protein–protein repulsion. Irreversible BSA and Lys fouling was affected by the operational pH relative to the protein isoelectric point (IEP) and reduced under conditions of chain swelling. Irreversible membrane fouling resistance for both proteins was significantly lower, by ~11–49% and 18–74%, respectively, for the PVP-ZrO2 membrane relative to the unmodified ZrO2 membrane. The present results suggest the merit of further exploration of fouling reduction and improvement of membrane cleaning effectiveness via tuning pH and ionic strength triggered conformational responsiveness of the tethered target polymer layer.

scholarly journals Evaluation of fouling and RO performance for MBR treated fruit wastewater

2020 ◽  
Vol 82 (11) ◽  
pp. 2282-2295
Author(s):  
A. T. Jamal-Uddin ◽  
R. G. Zytner
Keyword(s):  
Best Management Practices ◽  
Membrane Fouling ◽  
Water Reuse ◽  
Management Practices ◽  
Membrane Surface ◽  
Good Alternative ◽  
Sorption Process ◽  
Fruit Processing ◽  
Ro Membrane ◽  
The Impact

Abstract Fruit processing facilities are looking for ways to reduce water consumption to counter the impact of climate change. A good alternative is an MBR system to treat the processing wastewater, followed by tertiary treatment using a reverse osmosis (RO) unit to enable water reuse. However, fouling of the RO membrane causes operational challenges. As a result, experiments were completed on treated fruit processing wastewater to identify the causes of fouling that originated from the MBR effluent and develop best management practices (BMPs) to minimize fouling of the RO membrane. Physical and chemical analyses along with visual inspection of the membrane surface using scanning electron microscopy (SEM), energy diffusive X-ray (EDX) and Fourier transform infrared (FTIR) spectroscopy were completed. The issue of RO membrane fouling and subsequent flux decline was directly related to the presence of soluble microbial products, specifically dissolved organic matter (DOM) in the MBR effluent. The developed BMPs show that the previously completed enhanced coagulation-GAC sorption process, when combined with an online non-chemical flushing regimen and proper membrane preservation, keeps the flux readings high, resolving frequent fouling and cleaning problems of the RO membrane.

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