Cross-flow ultrafiltration for surface water treatment in North Thailand

2000 ◽  
Vol 41 (10-11) ◽  
pp. 69-76
Author(s):  
S. Takizawa ◽  
S. Babel ◽  
N. Pradhan ◽  
T. Prathomrungsiyunkul ◽  
K. Suwannarit ◽  
...  
Keyword(s):  
Surface Water ◽  
Membrane Fouling ◽  
Experimental Studies ◽  
Cross Flow ◽  
Variable Cross ◽  
Chemical Cleaning ◽  
Filtration Resistance ◽  
Cake Layer ◽  
The Cross ◽  
North Thailand

Experimental studies on cross-flow ultrafiltration were carried out to evaluate the applicability to treat surface water in North Thailand. Hollow-fiber UF modules (polyacrylonitrile, MWCO 13,000 daltons, I.D. 0.8 mm, and module length 1126 mm) were used in the experiments. While the permeation flux was controlled at 1.0 m/d, the cross-flow velocity was either fixed at 0.1 m/s or varied as the membrane fouling proceeded. The comparative study on fixed and variable cross-flow velocities revealed that the variable velocity operation was superior to achieve a longer operational period before chemical cleaning. Intensive backwashing was performed when the filtration resistance rose over 1013 m–1, which revealed that more than 80% of the resistance was caused by cake-layer that can be removed by the intensive backwashing. However, the operational period was only 54% of the one for the new membranes, which suggested that the percentage reduction of the filtration resistance should not be used as an index of the efficiency of chemical or physical membrane cleaning. Despite shortened operational periods, the intensive backwashing was proposed to be an easy and rapid method to recover the permeability of fouled membranes without chemical use. The cross-flow UF system used in this study was found to be easy to operate even in small water systems in developing countries.

scholarly journals Evaluation of the importance of various operating and sludge property parameters to the fouling of membrane bioreactors

2011 ◽  
Vol 64 (6) ◽  
pp. 1340-1346 ◽  
Author(s):  
F. Y. Sun ◽  
X. Y. Li
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Extracellular Polymeric Substances ◽  
Membrane Surface ◽  
Cross Flow ◽  
Correlation Coefficients ◽  
Single Fibre ◽  
Cake Layer ◽  
The Cross ◽  
Filtration Flux

A single-fibre microfiltration system was employed to investigate the importance of various operating and sludge property parameters to the membrane fouling during sludge filtration. The sludge was obtained from a submerged membrane bioreactor (SMBR). A series of comparative and correlative filtration and fouling tests were conducted on the influence of the operating variables, sludge properties and the liquid-phase organic substances on the membrane fouling development. The test results were analysed statistically with Pearson's correlation coefficients and the stepwise multi-variable linear regression. According to the statistical evaluation, the membrane fouling rate has a positive correlation with the biopolymer cluster (BPC) concentration, sludge concentration (mixed liquor suspended solids, MLSS), filtration flux and viscosity, a negative correlation with the cross-flow velocity, and a weak correlation with the extracellular polymeric substances and soluble microbial products. BPC appear to be the most important factor to membrane fouling development during the sludge filtration, followed by the filtration flux and MLSS concentration. The cross-flow rate also is important to the fouling control. It is argued that, during membrane filtration of SMBR sludge, BPC interact with sludge flocs at the membrane surface to facilitate the deposition of the sludge cake layer, leading to serious membrane fouling.

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.

scholarly journals Membrane Fouling Mechanisms in Combined Microfiltration-Coagulation of Algal Rich Water Applying Ceramic Membranes

Membranes ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 33 ◽  
Author(s):  
Kitae Park ◽  
Pooreum Kim ◽  
Hyoung Gun Kim ◽  
JiHoon Kim
Keyword(s):  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Ceramic Membranes ◽  
Constant Flow ◽  
Filtration Resistance ◽  
Fouling Mechanism ◽  
Coagulant Dosage ◽  
Cake Layer ◽  
Specific Cake Resistance ◽  
Resistance Value

In this paper, we investigated the membrane fouling mechanism according to the coagulant dosage in algal rich water using a ceramic membrane. The algae that were used in this experiment were Microcystis sp. of cyanobacteria, and the fouling mechanism was analyzed through irrigation and filtration resistance through a constant flow operation. The experimental results showed that the filtration resistance decreased as the coagulant dosage increased, but the irreversibility at above optimum coagulant dosage increased. Additionally, as the coagulant dosage increased, the resistance value due to cake and adsorption contamination decreased, and membrane fouling by adsorption was dominant in comparison with cake fouling and adsorption fouling. The specific cake resistance was decreased as the coagulant dosage increased. The characteristics of the cake layer according to the coagulant dosage were found to loosely form the cake layer by increasing micro-size algae as the coagulant dosage increased. The results of this experiment confirmed the membrane fouling mechanism according to coagulant dosage when the ceramic membrane filtered algal rich water.

scholarly journals Fouling Mechanisms Analysis via Combined Fouling Models for Surface Water Ultrafiltration Process

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 149 ◽  
Author(s):  
Bin Huang ◽  
Hangkun Gu ◽  
Kang Xiao ◽  
Fangshu Qu ◽  
Huarong Yu ◽  
...  
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Membrane Fouling ◽  
Mechanism Analysis ◽  
Surface Water Treatment ◽  
Dead End ◽  
Cake Layer ◽  
Significant Difference ◽  
Combined Models ◽  
And Control

Membrane fouling is still the bottleneck affecting the technical and economic performance of the ultrafiltration (UF) process for the surface water treatment. It is very important to accurately understand fouling mechanisms to effectively prevent and control UF fouling. The rejection performance and fouling mechanisms of the UF membrane for raw and coagulated surface water treatment were investigated under the cycle operation of constant-pressure dead-end filtration and backwash. There was no significant difference in the UF permeate quality of raw and coagulated surface water. Coagulation mainly removed substances causing turbidity in raw surface water (including most suspended particles and a few organic colloids) and thus mitigated UF fouling effectively. Backwash showed limited fouling removal. For the UF process of both raw and coagulated surface water, the fittings using single models showed good linearity for multiple models mainly due to statistical illusions, while the fittings using combined models showed that only the combined complete blocking and cake layer model fitted well. The quantitative calculations showed that complete blocking was the main reason causing flux decline. Membrane fouling mechanism analysis based on combined models could provide theoretical supports to prevent and control UF fouling for surface water treatment.

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

Membranes ◽  
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.

scholarly journals Experimental Studies of Heat Transfer Characteristics and Properties of the Cross-Flow Pipe Flow Melt Lead

2014 ◽  
Vol 04 (04) ◽  
pp. 54-65 ◽  
Author(s):  
Alexandr Viktorovich Beznosov ◽  
Mikhail Vladimirovich Yarmonov ◽  
Artyom Dmitrievich Zudin ◽  
Alexey Sergeevich Chernysh ◽  
Olga Olegovna Novogilova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pipe Flow ◽  
Experimental Studies ◽  
Cross Flow ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
The Cross

scholarly journals Tertiary Treatment for Safely Treated Wastewater Reuse

2021 ◽  
Author(s):  
Nebil Belaid
Keyword(s):  
Membrane Fouling ◽  
Large Scale ◽  
Wastewater Reuse ◽  
Experimental Studies ◽  
Cross Flow ◽  
Treated Wastewater ◽  
Transmembrane Pressure ◽  
Tertiary Treatment ◽  
Quality Of Water ◽  
Total Process

The tertiary treatment of resulting water from a conventional biological treatment process is envisaged in the aim to obtain a high quality of water that can be reused for different purposes. This treatment is based on the integration of the membrane-based technologies in the total process of wastewater treatment. The experimental studies are carried out on a small pilot, equipped with different mineral membranes of micro and ultrafiltration. These membranes are used for the different tested processes (MF, MF-UF and cogulation-MF). The results obtained make it possible to attend a complete elimination of the total flora and an additional reduction of the other parameters such as turbidity, suspended matter, COD and BOD. Tests on a large scale are then carried out on a semi-industrial pilot, equipped with the same type of membranes. The optimization of the operating conditions made allow the obtaining under the conditions of transmembrane pressure 0.85 bar, a cross flow velocity of 2.25m/s and with ambient temperature a filtrate flux of about 200 L/hm 2. The coupling of a stage of coagulation in the membrane process allows the reduction of the effect of the membrane fouling and an improvement of 36% of the filtrate flux.

scholarly journals Membrane surface properties and their effects on real waste oil-in-water emulsion ultrafiltration

Water SA ◽  
2019 ◽  
Vol 45 (3 July) ◽  
Author(s):  
Marjana Simonič
Keyword(s):  
Surface Properties ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Cross Flow ◽  
Influential Factors ◽  
Permeate Flux ◽  
Chemical Cleaning ◽  
Water Emulsion ◽  
Oil In Water ◽  
Oil In Water Emulsion

Membrane surface properties and their effect on the efficiency of ultrafiltration (UF) of real waste oily emulsions was studied. Experiments were performed in cross-flow operation at total recycle condition in a lab-scale system. The ceramic UF membrane in the tubular type module was employed. During the experiments permeate flux was measured. The most important influential factors, such as temperature, TMP, and pH, were considered during the experiments. Zeta potential was measured in order to explain the phenomena on the membrane surface. The isoelectric point of the fouled membrane was shifted to the alkaline range. COD removal efficiency reached 89%. Gas chromatography measurements were performed in order to determine the composition of waste emulsions. SEM micrographs showed the formation of calcite on the membrane, which contributed to membrane fouling. Chemical cleaning was examined using alkaline and acid solutions, and a cleaning strategy was determined.

Pilot-plant study of a high recovery membrane filtration process for drinking water treatment

2000 ◽  
Vol 41 (10-11) ◽  
pp. 77-84 ◽  
Author(s):  
J.Y. Huang ◽  
S. Takizawa ◽  
K. Fujita
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Cross Flow ◽  
Drinking Water Treatment ◽  
Pilot Scale ◽  
Raw Water ◽  
Circulation Flow ◽  
High Recovery ◽  
Chemical Cleaning ◽  
Cross Flow Filtration

Successful application of energy efficient dead-end micro-filtration (MF), which does not require recirculation like cross-flow filtration, depends on achieving high recovery rates. In this study, two different types of pilot scale membrane systems (horizontally and vertically stretched membrane filters) were evaluated based on the effects of pre-chlorination, intermittent chlorination and circulation flow by air-scrubbing. Additionally, the effects of operating factors including physical cleaning and chemical cleaning on membrane fouling were examined. The vertically stretched membranes showed better performance than horizontally stretched membranes at filtration fluxes of either 0.55 m/day or 0.78 m/day even under 2.6 to 27.5°C and raw water turbidity higher than 300 units, as long as intermittent chlorination (10 mg/l once a week) along with the circulation flow by air-scrubbing (once in 30 minutes) in the housing were employed. It was demonstrated that the vertically stretched membranes have been operated for one year without chemical cleaning of the membranes, wherein the recovery of raw water as a filtrate was 97.0% or 98.9%.

Ultrafiltration of activated sludge with ceramic membranes in a cross-flow membrane bioreactor process

2000 ◽  
Vol 41 (10-11) ◽  
pp. 243-250 ◽  
Author(s):  
X-j. Fan ◽  
V. Urbain ◽  
Y. Qian ◽  
J. Manem
Keyword(s):  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Ceramic Membrane ◽  
Treatment Plant ◽  
Cross Flow ◽  
Ceramic Membranes ◽  
Permeate Flux ◽  
Chemical Cleaning

A cross-flow membrane bioreactor (MBR) for raw municipal wastewater treatment, consisting of a suspended growth bioreactor and a ceramic membrane ultrafiltration unit, was run over a period of more than 300 days in a wastewater treatment plant (WWTP). Sludge Retention Times (SRT) of 20, 10 and 5 days, respectively, and Hydraulic Retention Times (HRT) of 15 and 7.5 hours were tested. Membrane fouling was found to be a function of SRT and permeate flux. Under an SRT of 20 days and flux of 71 l/m2\ · h at 30°C, the MBR was successfully run over 70 days without the need for chemical cleaning. However chemical cleaning had to be undertaken every 3–5 days at shorter sludge retention times (typically an SRT of five days and a flux of 143 l/m2\ · h at 30°C). In this study, fouling materials were removed efficiently through chemical cleaning, with an average permeablity recovery of 87±11%.

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