RO Membrane Fouling Prevention

A method for desalinating produced water to produce high quality water suitable for reuse and disposal options beyond oil and gas applications. The method involves reducing the pH of produced water to 5-6 before desalination to convert carbonate ions into CO2 that can be stripped out. This reduces the saturation of calcium and magnesium carbonate, allowing desalination without scaling issues. It eliminates the need for expensive lime softening prior to desalination.

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An inorganic membrane with a hierarchical pore structure and patterned surface that enhances filtration flux and reduces fouling in water and wastewater treatment. The membrane has multiple layers with gradually decreasing pore sizes. The outer layers have larger pores and the inner layer closest to the feed has the smallest pores. This gradient structure prevents fine particles from the active layer clogging the substrate. The patterned surface on the active layer further improves flux and antifouling by creating extra surfaces and turbulence. The membrane is made by depositing layers with controlled pore sizes and then 3D printing or imprinting a pattern on the active layer.

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Membrane biofouling is one of the most persistent challenges faced by desalination plants, particularly those utilizing reverse osmosis (RO) technology. Addressing this issue crucial to reduce maintenance costs, improve efficiency, and extend lifespan membranes. This study introduces SpectroMarine, an advanced optical water quality sensor that provides real-time data on organic content biomass levels, enabling operators take proactive measures for key parameters such as chlorophyll, total carbon oxidization agent prevent biofouling. The combines fluorescence absorption spectroscopy with Internet Things (IoT) integration, offering immediate analytics actionable insights. Field tests demonstrated significant potential reducing operational energy consumption, optimizing chemical use according quality, ultimately enhancing plant performance. paper discusses sensor’s design, application, outcomes, providing a roadmap revolutionizing monitoring in plants.

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Filter structure design for water purifiers that improves cleaning efficiency and prevents adsorption between components. The filter has wound membranes, a spacer, and a seal assembly around them. The membranes are spaced apart along the radial direction when wound around the tube. This creates gaps between the membranes for cleaning fluid to flow through. The seal assembly has a harder material than the membranes to prevent adsorption. This allows reliable cleaning and prevents blocking. The spacer maintains space between membranes. An adapter connects the tube to the spaced membranes. The design improves cleaning efficiency, prevents adsorption, and simplifies manufacturing compared to prior art.

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Optimizing reverse osmosis water desalination systems using machine learning to reduce operating costs and improve performance by predicting when to clean the membranes. The system measures parameters like feed pressure, flow, salinity, temperature, etc. and uses a trained ML model to determine fouling levels and optimize flow rates through the stages. This allows reducing energy use while maintaining permeate production. By predicting when fouling will inflect and decline, cleaning can be timed to minimize energy vs waiting for a 10% flux drop. The ML model also balances flow across stages for energy savings.

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Biocide compositions and methods for maintaining, cleaning, and defouling reverse osmosis membranes using a stabilized hypochlorous acid solution containing a bromide ion source. The stabilized hypochlorous acid solution forms small amounts of bromine in situ that effectively control biofouling without harming sensitive membranes. The biocide composition can be used as an online biocide to prevent fouling in reverse osmosis systems, as well as for offline cleaning of fouled membranes.

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Reverse osmosis filter system that improves efficiency and longevity compared to conventional RO filters. The system uses additional components like pre-filters, turbines, and end cap filters to more effectively remove impurities and prevent clogging. The components are arranged inside the filter housing in a specific order. This configuration allows larger impurities to be trapped and separated out before reaching the RO membrane, reducing membrane fouling. The turbine component generates fluid flow to help flush out impurities. The end cap filter catches any remaining particles before exiting the system.

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Filtration membrane unit and holder configuration that improves membrane cleaning maintainability by balancing filtrate flow rates across the membrane. The membrane unit has a socket that extends laterally and has an end inserted into a recess. The socket has two discharge ports, one on each side of the center, instead of just one at the end. This balances the suction force and filtrate flow rates across the membrane, preventing clogging from uneven flow.

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Water treatment method and apparatus to prevent biofouling of reverse osmosis (RO) membranes without harming the membranes. The method involves intermittently adding biocides to the water feed to the RO membrane. The biocide dose and frequency are adjusted based on membrane fouling levels. This prevents excessive biocide concentrations that can harm the membrane. The biocide addition is tuned to keep oxidation potential below a threshold without exceeding it. This prevents biocide-induced membrane fouling while still providing adequate biocide dosing to prevent organic growth.

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ABSTRACT The lack of safe drinking water infrastructures in off-grid communities is a significant risk to sustainable development, especially for low- and middle-income countries (LMICs). Photovoltaic-powered reverse osmosis (PVRO) has emerged as promising method due its performance, scalability, consistency, the robust global supply chain components. However, reliability issues like biofouling can quickly reduce shorten membrane lifetime, hinder adoption settings. Ultraviolet light-emitting diodes (UV-LEDs) ranging from 200 285 nm wavelengths have been shown number microorganisms by damaging their DNA, but there are mixed results about use mitigating systems. Herein, we aim provide preliminary assessment challenges associated with using UV-LEDs pre-treatment measure PVRO systems whether it curb feedwater, thereby For experimental evaluation, bacterial feedwater was prepared Escherichia coli ATCC 11229. Batch experiments Petri dishes 275 UV-LED radiometer showed non-uniform illumination target region, indicating need optimizing reactor design consistent dosage. Optical density measur... Read More

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Osmotic membrane separation system with feed and draw recirculation loops in each module to improve efficiency and prevent fouling. The system has a series of osmosis modules where feed and draw solutions are circulated co-currently through each module. Feed recirculation loops connect feed inlet to outlet of each module. Draw recirculation loops connect draw inlet to outlet. This allows controlled flow rates, solute concentrations, and hydrostatic pressures in each loop. The bulk feed and draw streams flow counter-currently through the system as a whole. The recirculation loops prevent boundary layer buildup and fouling. They also allow mixing of partially concentrated streams to reduce driving force and enhance membrane efficiency.

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Filter leaf for reverse osmosis filters with raised features on the membrane surface that enhance filtration performance and cleaning efficiency. The raised features are formed directly on the membrane using printing or embossing techniques. The feature configuration optimizes flow characteristics during normal filtration and reverse flushing. During filtration, the features induce higher velocities to resist fouling. During flushing, they induce higher velocities for scouring. This eliminates the need for cleaning chemicals and allows using reverse flow for cleaning.

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Method and inhibitor for suppressing silica fouling in reverse osmosis membrane systems. The method involves adding an acrylic acid-based polymer and/or a maleic acid-based polymer, along with a combined chlorine-based oxidizing agent and/or a combined bromine-based oxidizing agent, to the water being treated. This combination helps prevent silica fouling on both the concentrate and feed sides of the membrane. The acrylic/maleic acid polymers inhibit scale formation, while the oxidizing agents clean the membrane surface.

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Composition and membrane coating for preventing biofouling and reducing membrane fouling in water filtration. The composition contains a polymer blend with one component having lower water solubility than the other. The blended polymer forms fibers via electrospinning. Anti-quorum sensing molecules like Urolithin A are associated with the fibers. The composition releases the anti-quorum sensing molecules over time. The coated membranes have reduced biofilm formation compared to uncoated membranes. The blended polymer enables controlled release of the anti-quorum sensing molecules from the fibers.

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A simple and effective reverse osmosis membrane cleaning method and agent that can clean and sterilize the membrane in a single step using a composite cleaning solution containing hydrochloric acid, citric acid, surfactant, and bactericide. The method involves circulating this cleaning solution through the membrane system at elevated temperature to remove inorganic scale, organic fouling, and bacteria. The citric acid complexes with ions to enhance scale removal, the hydrochloric acid provides initial cleaning, and the surfactant and bactericide prevent re-fouling. This one-step cleaning eliminates the need for multiple cleaning steps and allows rapid and effective membrane restoration.

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Real-time monitoring of reverse osmosis (RO) membrane fouling to enable early detection, characterization, and mitigation of fouling. The technique involves isolating the permeate of a lead or tail element in each stage of an RO system and measuring its flux and rejection directly. This provides much higher sensitivity and faster detection of fouling compared to monitoring the entire stage or system. By isolating the lead or tail element permeate and measuring its performance, fouling can be detected several times faster. This allows for more targeted and effective fouling management strategies.

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Cleaning method for reverse osmosis membranes fouled by proteins and polysaccharides to restore water production. The cleaning process involves four steps: (1) cleaning with citric acid and sulfamic acid, (2) cleaning with urea and surfactant, (3) cleaning with sodium tripolyphosphate and sodium citrate, and (4) repeating step 1. The cleaning steps use specific chemical solutions and pH ranges to effectively remove the protein and polysaccharide fouling from the reverse osmosis membranes.

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Cleaning nanofiltration membranes using microbubbles to improve cleaning effectiveness and reduce fouling compared to conventional cleaning methods. The method involves preparing cleaning water with microbubbles by dissolving gases into the cleaning solutions. The microbubbles are used to clean the membranes by rinsing, acid cleaning, alkaline cleaning, and repair agent cleaning steps. This microbubble cleaning process provides better fouling removal and membrane recovery compared to traditional cleaning methods.

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Reverse osmosis membrane cleaning device and method for online cleaning of RO membranes to improve performance and prolong membrane life. The device has a cleaning unit, production unit, dosing unit, bypass monitoring unit, and control unit. The method involves diagnosing membrane fouling based on factors like water quality changes, then triggering cleaning modes tailored to the fouling type. Cleaning mode 1 is for inorganic fouling with calcium, magnesium, carbonate, and chloride. Cleaning mode 2 is for fouling with sulfate, fluoride, and organic compounds. The cleaning solutions contain acids, alkali, salts, and biocides. The device automatically dispenses the optimized cleaning solutions based on the diagnosis.

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A reverse osmosis membrane cleaning agent for organic fouling that effectively removes organic matter, microorganisms, and dirt from membrane surfaces. The cleaning agent contains specific components in optimized proportions. These include: 1% anionic surfactant (like sodium dodecyl benzene sulfonate), 25-35% chelant (like EDTA), 8-10% antioxidant, 0.1-0.3% aprotic solvent (like N-methylpyrrolidone), 0.5-1% fungicide (like 2,2-diao-3-nitropropionamide), and pH adjuster as needed. The components are chosen for their synergistic fouling removal properties. The anionic surfactant helps strip biological slime, chelant removes

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