Membrane Fouling Cleaning in Reverse Osmosis

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 method for desalinated reverse osmosis membranes in water treatment systems to maintain membrane performance and prevent fouling. The cleaning involves specific steps based on the type of contamination. For organic fouling, alkaline cleaning is followed by acid cleaning. For inorganic scale fouling, acid cleaning is followed by alkaline cleaning. The cleaning steps include soaking the membranes in cleaning solutions, rinsing with water, and using high quality water without residual chlorine.

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Deep cleaning method for MBR membranes with poor offline chemical cleaning effect to thoroughly clean the internal fouling and blockage of the membrane filaments. The method involves circulating cleaning chemicals through the membrane instead of just soaking it. The steps are: 1. Remove membranes from the system for deep cleaning. 2. Rinse membranes with clean water. 3. Soak membranes in an acidic cleaning solution for 30 minutes. 4. Circulate the cleaning solution through the membranes for several hours. 5. Resume normal operation. This cyclic cleaning allows the chemicals to dissolve internal fouling and blockages.

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A two-step cleaning method for membrane modules used in water treatment applications that effectively removes fouling contaminants and improves membrane performance. The method involves sequentially cleaning the membrane modules with an acidic cleaning agent followed by an alkaline cleaning agent. The acidic cleaning agent contains citric acid, sodium dichloroisocyanurate, hydroxyethylidenebisphosphonic acid, and water. The alkaline cleaning agent contains sodium carbonate, ethylenediaminetetraacetic acid disodium salt, sodium dichloroisocyanurate, and water. This two-step cleaning process removes scale, microbial contamination, and other fouling agents from the membrane surface.

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A method for cleaning reverse osmosis membranes in water treatment systems to improve cleaning efficiency and prevent dirt transfer between stages. The method involves sequentially flushing and soaking each membrane section with acidic, neutral, and alkaline cleaning agents. The membranes are separated during cleaning to prevent dirt from front stages washing into later stages. This prevents excessive sediment buildup and maintains membrane performance.

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Acid cleaning agent and method for hollow fiber ultrafiltration membranes that effectively remove both inorganic and organic fouling without damaging the membrane. The cleaning agent contains a specific ratio of organic acid, oxidizing acid, and polyethylene glycol. The cleaning method involves soaking the membranes in the cleaning solution, heating to promote pollutant decomposition, rinsing, and cooling. This sequence removes pollutants, restores flux, and reduces membrane aging.

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Method to clean filter membranes used in industrial water treatment systems that reduces consumption, simplifies disassembly, and minimizes environmental impact compared to traditional methods. The cleaning method involves using acid and alkali solutions in a cyclic cleaning process. The steps are: 1) immerse the membrane in an acid solution to remove inorganic contaminants. 2) Rotate the membrane in an alkali solution to remove organic contaminants. 3) Circularly clean the membrane with the alkali solution. 4) Reverse flush the membrane with an acid solution to neutralize and rinse. This cyclic cleaning with acid and alkali solutions thoroughly cleans the membrane. The alkali solution forms a tangential flow on the membrane surface for cleaning. The acid is reversed flushed to neutralize and rinse. This ensures complete cleaning and minimizes environmental impact

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An improved method for chemically cleaning reverse osmosis membranes to prevent fouling buildup that can clog the membranes and reduce performance. The method involves circulating the cleaning solution from the back of the membrane array towards the front during chemical cleaning, instead of feeding from the front as in traditional cleaning. This prevents front-end fouling from blocking the back-end grid channels during cleaning. The cleaning solution is circulated using the membrane element's former pump to reverse the flow direction.

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Cleaning and regeneration method for reverse osmosis membranes to effectively remove fouling and restore membrane performance. The method involves a sequence of pickling, alkaline washing, secondary pickling, regeneration cleaning, and pure water rinsing steps. Pickling uses organic solvents and acids to dissolve and flush out fouling. Alkaline washing removes organic matter. Secondary pickling removes residual alkali. Regeneration cleaning uses high volatility organic solvents to dissolve and remove blocking organic matter in membrane pores.

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Cleaning agent, cleaning liquid, and method for effectively restoring performance of aromatic polyamide reverse osmosis membranes that have become contaminated and have reduced permeation flux and rejection rate. The cleaning agent contains a chelating agent, alkaline agent, and stabilized halogen like chloramine. The stabilized halogen is a compound like chloramine that has a weaker oxidizing effect than chlorine. It allows cleaning aromatic polyamide membranes without damaging them. The cleaning liquid is a diluted solution of this agent. The method involves contacting the contaminated membrane with the cleaning liquid to restore performance.

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Cleaning method for membrane filters used in wastewater treatment to prevent fouling and restore filter performance. The method involves sequential acid and base cleaning cycles. The acid cycle removes scale and organic fouling using a pickling solution. The base cycle removes oils and organic fouling using a caustic solution. The filter is heated during the base cycle to aid cleaning. An air compressor provides agitation during both cycles. This combined acid-base cleaning effectively restores filter performance compared to just acid or base cleaning.

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Cleaning reverse osmosis membranes using a method that combines physical and chemical cleaning. The method involves pumping an aphron-based cleaning fluid into the membranes. The aphron-based cleaning fluid contains aphrons, which are microscopic bubbles surrounded by a surfactant film. The aphrons generate forces that dislodge fouling from the membrane surface. Chemical agents dissolve the fouling. The combination of physical and chemical cleaning improves effectiveness compared to just water-based cleaning.

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Cleaning semi-permeable membranes used in reverse osmosis and forward osmosis processes by applying pulsed water strokes in the permeate or residual brine stream while inducing backward flow across the membranes. This mechanical shaking of the membranes along with oscillating gauge pressures allows more effective cleaning compared to just reversing the osmotic process. The pulsed water strokes can be generated by pumps, generators, or changes in flow rates. The gauge pressure oscillations can be synchronized with the membrane natural frequency for resonance.

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Method for cleaning a separation membrane in a water treatment system to optimize cleaning efficiency and membrane restoration. The cleaning time is determined based on the amount of membrane blocking substance eluted during cleaning. This is done by measuring the concentration of the blocking substance in the feed water, the cleaning solution, and the membrane before and after cleaning. The change in concentration over time during cleaning is used to determine the optimal cleaning time. This allows targeted and efficient cleaning based on the specific blocking substance.

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A reverse osmosis membrane cleaning agent specifically designed to remove calcium sulfate scale from membranes. The cleaning agent contains optimized concentrations of pH regulator, penetrant, dispersant, softener, chelating agent, and phase transfer catalyst. This composition helps dissolve the insoluble calcium sulfate scale more effectively compared to conventional cleaners, without causing secondary pollution or membrane damage.

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Cleaning method for reverse osmosis membrane systems used in treating printing and dyeing wastewater. The method involves sequential steps of flushing with system permeate, cyclic acid pickling, alkaline washing, and rinsing with permeate again. The cleaning uses the system's own product water for flushing, pickling, and rinsing, along with specific acid and alkaline solutions. The cleaning steps are repeated until fouling is removed and performance improves. The method aims to improve flux recovery after cleaning compared to traditional methods.

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Reverse osmosis membrane cleaning agent and method to effectively remove fouling from reverse osmosis membranes used in water treatment. The cleaning agent is a two-part system consisting of an alkaline cleaner and an acidic cleaner that are stored separately. The alkaline cleaner contains components like citric acid, ammonia, phosphoric acid, surfactant, and bacteriostatic agent. The acidic cleaner has components like ammonia, phosphoric acid, and bacteriostatic agent. The alkaline and acidic cleaners are used sequentially to remove different types of fouling. The alkaline cleaner removes organic fouling like humic acids, polyacrylamides, and microbial slime. The acidic cleaner removes inorganic fouling like carbonate scales and metal oxides.

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Cleaning method for reverse osmosis (RO) membranes that prevents membrane deterioration while effectively removing organic fouling and biofilm. The cleaning involves two steps. First, cleaning with a solution containing chelating agents, organic acids, and inorganic acids to remove heavy metal ions from the membrane surface. Second, cleaning with a solution containing oxidizing agents, heavy metal compounds, and chelating agents to suppress the Fenton reaction and prevent membrane degradation while removing organic fouling. This two-step approach allows thorough cleaning without membrane damage.

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Cleaning agent and method for removing polyacrylamide fouling from membranes used in water treatment processes. The cleaning involves using a pre-soak solution with a low concentration of a soluble anionic polymer like sodium alginate or sodium polyacrylate before membrane use. After use, a cleaning solution containing sodium hydroxide and the same anionic polymer is used to remove the fouling. The low concentration pre-soak helps prevent fouling, and the cleaning solution with higher concentrations of the anionic polymer and sodium hydroxide effectively removes the polyacrylamide fouling from the membrane surface.

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Method for cleaning reverse osmosis membrane modules that improves fouling removal and reduces chemical usage. The method involves a sequence of steps: pre-cleaning, microbubble cleaning, and post-cleaning. During microbubble cleaning, microscopic air bubbles are introduced into the module using a microbubble generator. This increases turbulence and separates fouling layers from the membrane. The cleaning solution can be alkaline or acidic. The method uses an activated carbon filter to prevent impurities from re-fouling the membrane. Recycling the cleaning solution by adjusting pH between cleanings further reduces chemical usage.

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