scholarly journals Seawater reverse osmosis membrane fouling causes in a full scale desalination plant; through the analysis of environmental issues: raw water quality

2020 ◽  
Vol 7 (2) ◽  
pp. 119-126
Author(s):  
Leila Rezaei ◽  
Mohsen Dehghani ◽  
Amir Hesam Hassani ◽  
Vali Alipour
Keyword(s):  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Field Analysis ◽  
Residual Chlorine ◽  
Stress Tests ◽  
Visual Evaluation ◽  
Desalination Plant ◽  
Improper Use ◽  
Metallic Compounds

Background: Membrane clogging is one of the most important problem for desalination plant operators in Iran, therefore, this study was conducted to investigate the main causes of this problem using field analysis. Methods: In this study, six continuous membranes in a reverse osmosis (RO) pressure vessel under the 33-month service period (April 2017 to November 2019) were selected. The membranes were analyzed through visual evaluation of the outer and inner membrane surface, analyzing the damages and physical harms, oxidative stress tests, iron spot test, fouling chemical analysis using loss on ignition (LOI) tests, X-ray fluorescence (XRF), and Fourier-transform infrared (FTIR) spectroscopy. Results: Particle size distribution in raw seawater (EC = 55 000 µs/cm, turbidity = 11 NTU) was 66.4% smaller than 1 µ and 28.3% between 1 to 1.9 µm. Physical damages were not seen on the membranes but telescopic damages were observed which was due to membrane fouling. Removal efficiencies of turbidity and silt density index (SDI) were 84% and 18%, respectively. Membrane oxidation was also seen. Most of the sediments compositions on the membranes were SiO2 , Al2 O3 , MgO, and Fe2 O3 . Biological fouling was detected on the membranes surface. Conclusion: Inaccurate use of chlorine neutralizer caused the residual chlorine to be present in the membrane entering water, which damaged the membrane. Accumulation of clogging agents on membrane surface showed malfunction of pretreatment function, therefore, revision of design and operation of units is necessary. Biological fouling is due to non-effective pre-chlorination of drinking water. Metallic compounds sedimentation on the membrane is due to improper use of anti-fouling chemicals. High SDI in the influent shows the need to change the cartridge filters.

scholarly journals Silica scale formation and effect of sodium and aluminium ions -29Si NMR study

2016 ◽  
Vol 2 (1) ◽  
pp. 174-185 ◽  
Author(s):  
L. Lunevich ◽  
P. Sanciolo ◽  
A. Smallridge ◽  
S. R. Gray
Keyword(s):  
Reverse Osmosis ◽  
Membrane Surface ◽  
Scale Formation ◽  
Significant Problem ◽  
29Si Nmr ◽  
High Recovery ◽  
Desalination Plant ◽  
Nmr Study ◽  
Silica Scale ◽  
Ro Membrane

Silica scale formation on reverse osmosis (RO) membrane surface is a significant problem for operation of high recovery RO desalination plant.

Advanced Treatment of Chemical Wastewater by Using a Combination of Ultrafiltration and Reverse Osmosis System

2012 ◽  
Vol 610-613 ◽  
pp. 1309-1314
Author(s):  
Jian Ding Zhou ◽  
Ping Yang ◽  
Chang Jun Yang ◽  
Bo Lai ◽  
Yun Hong Zhang
Keyword(s):  
Reverse Osmosis ◽  
Removal Efficiency ◽  
Membrane Fouling ◽  
Cooling Water ◽  
Advanced Treatment ◽  
Residual Chlorine ◽  
Scale Inhibitor ◽  
Average Value ◽  
Set Up ◽  
Full Scale Tests

The purpose of this paper was to investigate the application of ultrafiltration/reverse osmosis (UF/RO) for advanced wastewater treatment. Full-scale tests were set up for investigation in Yuntianhua Co.Ltd, Yunnan, China. The performances of turbidity, residual chlorine, conductivity and various ions were studied. The results suggested that the removal efficiency of turbidity was above 98.20%. Additionally, the average value of Silting Density Index (SDI) and residual chlorine of effluent of UF process were less than 1.80 and 0.06mg/L, respectively. However, its removal efficiency was limited by membrane fouling. And this system needed to be backwashed periodically to maintain high removal efficiency. Hardness and scale-forming ions could be decreased effectively by RO. The RO membrane fouling could be avoided by adjusting pH (7.0-7.5) and dosing scale inhibitor (MDC150, 4.00-5.00mg/L). Finally, the effluent of the UF/RO system can be reused as the cooling water or supply water for low-pressure boiler equipment.

Design considerations for wastewater treatment by reverse osmosis

2005 ◽  
Vol 51 (6-7) ◽  
pp. 473-482 ◽  
Author(s):  
C.R. Bartels ◽  
M. Wilf ◽  
K. Andes ◽  
J. Iong
Keyword(s):  
Wastewater Treatment ◽  
Calcium Phosphate ◽  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Urban Areas ◽  
Large Scale ◽  
Membrane Surface ◽  
Feed Water ◽  
High Quality ◽  
Quality Water

Reverse Osmosis is finding increasing use for the treatment of municipal and industrial wastewaters due to the growing demand for high quality water in large urban areas. The growing success of membranes in this application is related to improved process designs and improved membrane products. Key factors which have been determined to result in successful operation of large-scale plants will be discussed. Factors which play a key role in the use of RO membranes include ultra or microfiltration pretreatment, low fouling membranes, flux rate, recovery and control of fouling and scaling. In particular, high flux rates can be used when UF or MF pretreatment is used. These technologies remove most of the suspended particles that would normally cause heavy fouling of lead elements. Typically, fluxes in the range of 17–21 lmh lead to cleaning frequencies in the range of 3–4 months. By combining the use of membrane pretreatment and chloramination of the feed water through chlorine addition, two of the primary sources of RO membrane fouling can be controlled. The use of chloramine has become a proven means to control biofouling in a membrane for wastewater applications. The other significant problems for RO membranes result from organics fouling by dissolved organics and scaling due to saturation of marginally soluble salts. The former can be a significant problem for membranes, due to the strong attraction forces. To some extent, these can be mitigated by making the membrane surface more hydrophilic or changing the charge of the membrane surface. To minimize fouling, many plants are turning to low fouling membranes. Extensive studies have demonstrated that the membrane surface is hydrophilic, neutrally charged over a broad pH range, and more resistant to organic adsorption. Also, an analysis of the potential scaling issues will be reviewed. In particular, calcium phosphate has been found to be one of the key scalants that will limit RO system recovery rate. Calcium phosphate concentrations can reach high values in many wastewaters, and scaling of this compound is not often modeled in most RO projection software. Various process options will be presented to evaluate the most economic means of avoiding phosphate scaling. Finally, data from major RO wastewater treatment plants will be presented to show how the RO membranes operate under actual conditions, utilizing many of these design features. Long term data from the 2.6 mgd Bedok demonstration Plant demonstrate that the RO membranes operate consistently on wastewater. Experiences from the 8.5 mgd (32,000 m3/day) Bedok and 10.5 mgd (40,000 m3/day) Kranji plants will also be presented. These large plants started operation in the fall of 2002 and have demonstrated an effective means to reclaim high quality water from difficult source waters, such as municipal wastewaters.

Antifouling, fouling release and antimicrobial materials for surface modification of reverse osmosis and nanofiltration membranes

2018 ◽  
Vol 6 (2) ◽  
pp. 313-333 ◽  
Author(s):  
Rikarani R. Choudhury ◽  
Jaydevsinh M. Gohil ◽  
Smita Mohanty ◽  
Sanjay K. Nayak
Keyword(s):  
Surface Modification ◽  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Membrane Technology ◽  
Nanofiltration Membranes ◽  
Nonspecific Interaction ◽  
Antimicrobial Materials ◽  
Fouling Release

Membrane fouling, which arises from the nonspecific interaction between the membrane surface and foulants, significantly impedes the efficient application of membrane technology.

scholarly journals Performance of integrated sequencing batch reactor (SBR) and reverse osmosis (RO) process for leachate treatment: effect of pH

2022 ◽  
Author(s):  
Izabela Anna Tałałaj
Keyword(s):  
Organic Matter ◽  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Removal Rate ◽  
Membrane Surface ◽  
Ammonia Nitrogen ◽  
Electrostatic Repulsion ◽  
Permeate Flux ◽  
Leachate Treatment ◽  
Good Efficiency

Abstract Purpose In this paper the performance and effectiveness of the reverse osmosis (RO) process for the biologically pretreated leachate was investigated. The RO process was carried out separately for two different pH: 8.0 and 9.3. Methods A general pollution parameters as well as organic and inorganic indicators were determined in raw, biologically pretreated and RO treated leachate. The performance characteristics of the reverse osmosis system were made on the basis of permeate flux, electroconductivity removal rate, concentration factor and efficiency in removal of analyzed parameters. Results The use of SBR pretreatment had very good efficiency in BOD (97.3%) and ammonia nitrogen (95.4%) removal. The lowest effectivity was observed for chloride (11.6%), boron (3.9%) and TDS (1.2%). Pretreated leachate was subjected to RO system. The normalized average flux was 0.53 (42.3 L/m2·h) for pH = 8.0 and 0.68 (33.5 L/m2·h) for pH = 9.3. The lower membrane fouling at higher pH can be explained by electrostatic repulsion between the negatively charged membrane surface and organic substances. Independently of the process pH, a two-step membrane fouling was observed. The greatest differences in removal rates were observed for boron, which had a higher retention rate at higher pH, and ammonia nitrogen, whose removal rate decreased at higher pH. The obtained permeate pH after RO process was lower than the feed pH in two analyzed value of pH. Conclusions The higher flux value at pH = 9.3 is result of high content of organic matter in leachate, which is better rejected at higher pH because of higher electrostatic repulsion between organic matter and membrane surface. This indicates that the organic matter content should be taken into account when determining the operating parameters (pH values) of the RO system.

scholarly journals Fouling behaviour of a reverse osmosis membrane by three types of surfactants

2012 ◽  
Vol 2 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Naoyuki Kishimoto ◽  
Honami Kimura
Keyword(s):  
Surface Charge ◽  
Reverse Osmosis ◽  
Anionic Surfactant ◽  
Membrane Fouling ◽  
Surfactant Concentration ◽  
Membrane Surface ◽  
Pure Water ◽  
Ionic Surfactants ◽  
Lauryl Sulfate ◽  
Ro Membrane

The fouling behaviour of a reverse osmosis (RO) membrane by three types of surfactants and a countermeasure to the fouling were studied. The filtration experiments showed that the permeability during filtration depended on the surfactant concentration and the charge of surfactant. Higher surfactant concentration deteriorated the permeability due to the concentration polarization. A negatively charged anionic surfactant, sodium lauryl sulfate (SLS), had less influence on the permeability than cationic and non-ionic surfactants. As the RO membrane used in this research had a hydrophilic and negatively charged membrane surface, adsorption of the anionic surfactant was prevented by the electrostatic force between the membrane surface and the hydrophilic group of the surfactant. To control the fouling by the cationic and non-ionic surfactants, addition of SLS to the surfactant solution was tested. Consequently, the addition of excess SLS changed the surface charge of aggregates into more negative value and the permeability during filtration was successfully improved. Furthermore, the drop in pure water permeability after filtration was not observed by the addition of excess SLS. Thus, the modification of charge of solutes to the same sign of the membrane surface charge was thought to be useful to control a membrane fouling by surfactants.

The Effect of Different Pretreatment Methods on the Membrane Fouling in the Process of Reverse Osmosis Seawater Desalination

2013 ◽  
Vol 821-822 ◽  
pp. 1102-1109 ◽  
Author(s):  
Jian Gao Cheng ◽  
Jing Huan Ma ◽  
Zhi Wen Lin ◽  
Wei Xing Li ◽  
Zhan Sheng Ma ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Reverse Osmosis Membrane ◽  
Seawater Desalination ◽  
Membrane Flux ◽  
Attenuation Rate ◽  
Ultra Filtration ◽  
The One

One new pretreatment method was developed for solving the formed fouling on the equipments in the process of reverse osmosis seawater desalination, and the effect of different pretreatment methods on the membrane fouling was investigated. The experiment results showed that the flux attenuation rate of reverse osmosis membrane used in hardness-removed seawater was slower than the one of direct ultrafiltration seawater, and the salt reject rate and conductivity of output water from reverse osmosis membrane were not obviously affected by these two different pretreatment methods respectively. By according to the characterization of SEM, EDX and IR, the rapid attenuation of membrane flux was caused by the piled inorganic crystals on the membrane surface in direct ultra-filtration process, and the hardness-removed pretreatment process can effectively decrease the membrane fouling.

Membrane Fouling Mechanism and its Control in the Treatment of Brackish Water with Reverse Osmosis Process

2013 ◽  
Vol 788 ◽  
pp. 268-274 ◽  
Author(s):  
Jian Bing Wang ◽  
Jun Yang Cheng ◽  
Ting Shi ◽  
Qing Huang ◽  
Xu Wen He
Keyword(s):  
Water Quality ◽  
Reverse Osmosis ◽  
Organic Compounds ◽  
Brackish Water ◽  
Membrane Fouling ◽  
Control Method ◽  
Membrane Surface ◽  
Development Stage ◽  
Fouling Mechanism

Brackish water was treated with reverse osmosis process. The fouling mechanism of RO and its control method was studied. In the treatment of brackish water, the salt removal efficiency was above 95% and the effluent quality was up to the standard for drinking water quality (GB5749-2006). The SDI of the influent of RO was less than 5 after the raw water was pretreated by the combination of coagulation and sedimentation process and filtration process, which met the demand of the water quality of the RO influent. If ultrafiltration was added, the water quality of the pre-treatment was better. Coagulation and precipitation was not very effective for the removal of dissolved organic compounds, especially for the removal of organic compounds with molecular amount ranging from 1000 to 10000. The formation of RO membrane fouling can be divided into five stages, which is membrane surface coarseness stage by inorganic substrate, organic compounds adsorption stage, organism adhesion stage, microbial film development stage, and irreversible membrane block stage. The membrane fouling was effectively alleviated by the strategy of first alkali solution cleaning and then acid solution cleaning.

scholarly journals Effect of heat treatment on fouling resistance and the rejection of small and neutral solutes by reverse osmosis membranes

2014 ◽  
Vol 15 (3) ◽  
pp. 510-516 ◽  
Author(s):  
Takahiro Fujioka ◽  
Nagayasu Oshima ◽  
Ryoichi Suzuki ◽  
Michael Higgins ◽  
William E. Price ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Reverse Osmosis ◽  
Free Volume ◽  
Membrane Fouling ◽  
Volume Fraction ◽  
Membrane Surface ◽  
Feed Solution ◽  
Membrane Properties ◽  
Permeate Flux ◽  
Fouling Resistance

The effects of heat treatment on membrane fouling resistance and the rejection of small and neutral solutes by reverse osmosis (RO) membranes were elucidated. RO membrane modification by heat treatment reduced fouling and improved boron rejection. However, heat treatment also caused a decrease in the water permeability of RO membranes. Significant improvement on fouling resistance by heat treatment was observed when RO concentrate was used to simulate a feed solution with high fouling propensity. The improved fouling resistance is likely to be due to changes in the hydrophobic interaction between the membrane surface and foulants. Boron rejection by the ESPA2 membrane was enhanced by heat treatment from 26 to 68% (when evaluated at the permeate flux of 20 L/m2 h). Positron annihilation lifetime spectroscopy revealed that heat treatment did not significantly influence the free-volume hole-radius of the membrane active skin layer. The results reported in this study suggested that changes in the other membrane properties such as free-volume fraction and thickness may be the main cause improving boron rejection.

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