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 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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Chemical cleaning method for industrial wastewater reverse osmosis membranes that involves an alkaline washing step followed by an acid cleaning step. The alkaline washing uses an alkaline agent with a pH of 11-11.5, and the acid cleaning uses an acid with a pH of 2.5-3. The alkaline washing is done in two stages followed by one stage. This cleaning method is suitable for industrial wastewater reverse osmosis membranes that treat complex and highly polluted wastewater because the alkaline washing removes organic fouling and the acid cleaning removes inorganic fouling.

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A method for cleaning nanofiltration membranes that delays fouling, saves cleaning steps, and reduces costs by selecting optimized cleaning procedures based on the severity of membrane fouling. The method involves judging the fouling level by the amount of membrane specific flux attenuation. Mild fouling (<= 30% flux attenuation) is cleaned with citric acid, moderate fouling (30-50%) with citric acid followed by EDTAMa, and severe fouling (> 50%) with EDTAMa alone. This targeted cleaning approach avoids overcleaning that can damage the membrane or cause false high flux and sudden TMP spikes.

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Cleaning composition and method for water treatment membranes to effectively remove irreversible fouling like biofilms. The cleaning composition contains an ionic liquid like phosphates, sulfates, acetates, halides, etc. The composition can have 0.01-20% ionic liquid by weight. The cleaning method involves contacting the membrane with the composition to dissolve and remove fouling contaminants. The cleaning improves water permeability recovery compared to traditional cleaners.

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Chemical cleaning system and method for reverse osmosis membranes that reduces residual amines, discoloration, and improves membrane performance after cleaning. The cleaning system has multiple tanks filled with specific solutions. The membranes are sequentially rinsed in the tanks with hydrophilic additives/esters, water-soluble acid, oxidizing agent, glycerol/surfactant. The order of the tanks allows progressive cleaning and conditioning steps to remove residuals, oxidize amines, stabilize the membrane, and prevent discoloration.

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Cleaning process for reverse osmosis (RO) membranes used in water reuse applications in the electrolytic copper foil industry. The cleaning process involves sequentially cleaning the RO membrane with specific cleaning liquids to effectively remove organic colloids, bacteria, scaling, and other impurities. The cleaning combination formula includes alkaline cleaning solutions (first, second, third, and seventh) and acidic cleaning solutions (fourth, fifth, and sixth) that are used in a stepwise sequence. This sequential cleaning approach enables thorough pore dredging, restores normal water production, increases membrane life, and reduces costs by preventing frequent membrane replacements.

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Online cleaning method for filter membranes in water supply pipelines to extend membrane life without disassembly. The method involves cleaning the membrane in place using a series of steps: (1) Citric or acetic acid immersion, (2) Sulfuric acid immersion, (3) Disodium EDTA solution circulation, (4) Air-air flushing. The cleaning steps use circulating pumps and chemicals to clean the membrane surfaces without disassembly. The citric/acetic acid dissolves organic matter, sulfuric acid etches minerals, EDTA removes inorganics, and air flushing rinses. The online cleaning extends membrane life by removing fouling without disassembly.

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An online cleaning method for reverse osmosis membranes that effectively removes fouling caused by compound pollution like aluminum, organic matter, and microbial slime. The cleaning steps involve: (1) Sterilization and initial cleaning with a strong alkali solution, (2) Enhanced alkaline cleaning, (3) Enhanced acid cleaning, and (4) Neutralization rinsing. The cleaning solutions are formulated with specific agents like surfactants, stabilizers, and complexing agents to remove fouling without harming the membranes. The cleaning sequence and conditions are tailored for different fouling types.

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A special cleaning agent for reverse osmosis membranes that effectively removes fouling without causing degradation. The cleaning agent contains a specific mixture of organic acids, bactericides, complexing agents, inorganic salts, surfactants, and water. The cleaning agent can clean reverse osmosis membranes of carbonate fouling and metal oxide deposits at pH 2-3. The cleaning agent enables complete removal of pollutants without membrane damage, preventing recontamination and improving membrane performance.

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Method for cleaning and regenerating reverse osmosis membranes to improve flux and prolong membrane life. The method involves a two-step cleaning process. First, the membrane is ultrasonically cleaned to loosen contaminants. Then, it is cleaned with an alkaline solution followed by an acidic solution. The alkaline cleaner has sodium hydroxide and sodium dodecylbenzene sulfonate at low concentrations, while the acidic cleaner has citric acid and ammonia water at higher concentrations.

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A device and method for reversely cleaning hollow fiber nanofiltration membranes to prevent fouling and scaling. The device has separate water inlet and backwash lines with filters and storage tanks. It allows reversing the flow direction through the membranes using backwash water to clean them. This prevents fouling buildup inside hollow fiber membranes that can degrade performance. The device also has compaction mitigation features to prevent irreversible membrane attenuation from high pressure and temperature. The backwash water is dosed into the feed line and reverses the flow through the membranes to clean them.

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A process for cleaning polymer membranes used in filtration applications to restore permeability and prevent fouling. The process involves backwashing the membranes using a chemical solution made from the purified filtrate obtained by nanofiltration or ion exchange of the backwash water. This helps remove fouling deposits from the membrane without using harsh chemicals. The steps are: filtering feed water through the membrane, reducing metal ion concentration in the filtrate by nanofiltration/ion exchange, backwashing the membrane with this purified filtrate, then continuing filtration.

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A cleaning agent for removing sulfur fouling from membranes used in treating landfill leachate. The cleaning agent contains specific chemicals like polyphosphate, chelating agent, sodium hydroxide, sodium carbonate, sodium dodecylbenzene sulfonate, alcohol, and alcohol amine. The cleaning agent is used to clean membranes like nanofiltration, microfiltration, reverse osmosis, and super reverse osmosis membranes after filtering landfill leachate. The agent dissolves sulfur pollution that forms on the membranes during leachate treatment, preventing fouling and improving membrane performance.

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Cleaning agent for reverse osmosis membranes used in seawater desalination to effectively remove calcium sulfate scale buildup. The cleaning agent contains specific chemicals like ethylenediaminetetraacetic acid (EDTA), dodecylbenzene sulfonate, and carbonate. These ingredients complex with the calcium ions in the calcium sulfate scale to make it soluble and washable.

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Integrated reverse osmosis (RO) and membrane cleaning (MC) system for preventing fouling in desalination systems. The system uses short, periodic membrane cleanings to remove fouling before it accumulates and requires full clean-in-place (CIP) procedures. The MC system is integrated with the RO unit and provides a sequence of cleaning solutions to effectively remove fouling in steps. The cleanings are done at lower pressures to promote contact and fouling destruction. By performing short MC cleanings regularly, fouling is prevented and CIP is avoided.

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Cleaning method for filter membranes without disassembling them to reduce maintenance costs. The cleaning steps are: 1) Soaking the membrane in a weak acid solution to loosen dirt. 2) Immersing the membrane in a stronger acid solution and circulating it at high flow rate to clean the membrane surface. 3) Reversing the acid flow using a suction pump to clean the membrane in reverse direction. This allows cleaning without disassembly. By cleaning forward, tangentially, and reversely, it ensures complete membrane cleaning.

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Cleaning method for membrane modules used in water filtration that provides better fouling removal and maintains filtration performance. The method involves a second backwashing step after the initial backwash. The second backwash uses higher flow rate, longer time, and more water compared to the first backwash. This allows complete removal of contaminants and reduces differential pressure between the membranes. The second backwash is optimized to balance cleaning effectiveness with avoiding issues like buckling, breakage, or peeling of the membrane. The method is specifically for hydrophilic hollow fiber membranes with contact angles of 105-150 degrees.

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Cleaning method for membrane separation devices like water filtration systems that uses a cleaning solution containing an amphoteric surfactant to effectively remove turbidity and fouling from membrane surfaces. The cleaning step involves contacting the raw water chamber side membrane with the surfactant solution to clean the membrane. The surfactant solution contains an amphoteric surfactant like betaine, sulfate, or sulfonate compounds. It does not contain phosphorus or oxidizers. This cleaning method is particularly effective for internal pressure membrane modules where turbidity is difficult to remove.

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Cleaning method for turbidity contamination in membrane filtration devices like reverse osmosis systems that uses air drying followed by hydrophilization treatment to effectively remove turbidity buildup without damaging the membrane. The method involves drying the raw water chamber and then treating the membrane surface with a surfactant solution to restore hydrophilicity. This prevents membrane fouling and turbidity reduction during air drying while allowing effective cleaning after hydrophilization. The hydrophilization step can be done by passing a surfactant solution through the filtration system or circulating it in the raw water chamber. The surfactant helps lift turbidity from the membrane surface during cleaning.

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Cleaning method for reverse osmosis membranes fouled by high molecular weight organic polymers like scale inhibitors. The cleaning process involves multiple steps: 1) Rinsing the membranes with DI water for 30-60 minutes to remove loose fouling. 2) Soaking the membranes in a solution of 0.1-0.5 g/L sodium dodecylbenzene sulfonate (SDBS) surfactant for 15-30 minutes. 3) Rinsing the membranes with DI water for 15-30 minutes. 4) Soaking the membranes in a solution of 1-2 g/L sodium hexametaphosphate (SHMP) chelating agent for 15-30 minutes. 5) Rinsing the membranes with DI water for 15-3

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Chemically cleaning ceramic membranes in water treatment systems using hydrogen peroxide to remove organic fouling without secondary pollution. The method involves online backwashing the membranes with hydrogen peroxide when transmembrane pressure increases, and offline immersion cleaning in a tank. The hydrogen peroxide oxidizes and decomposes fouling organics. It also returns to the biological treatment tank for degradation, promoting material circulation. This reduces fouling, saves chemicals, and avoids secondary pollution compared to sodium hypochlorite.

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Cleaning method for removing pollutants from reverse osmosis systems used in water treatment plants. The method involves a sequential cleaning process with alkaline pre-cleaning, intensified cleaning, enhanced cleaning, and sterilization steps. The cleaning agents used include sodium hydroxide, sodium dodecyl sulfate (SDS), ethylenediaminetetraacetic acid (EDTA), and sodium tripolyphosphate. The sequential cleaning with varying agents and conditions effectively removes organic matter, microorganisms, and other pollutants from the reverse osmosis membranes. This improves membrane performance and reduces pressure differentials compared to conventional cleaning methods.

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Cleaning agent and method for reversed osmosis (RO) membranes used in treating landfill leachate. The cleaning agent contains thiosulfuric acid, sodium sulfite, sodium hydroxide, and a surfactant. The cleaning method involves injecting the cleaning agent into the RO membrane system, allowing it to circulate for a few hours, then flushing the membrane with water. This quickly removes sulfur and silica fouling from the RO membranes without prolonged acid or alkaline cleaning cycles.

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A more effective cleaning process for reverse osmosis membranes that improves the cleaning efficiency and thoroughness compared to conventional acid and alkali cleaning methods. The process involves using micro-nano bubbles in acidic and alkaline solutions to clean the membrane. The bubbles adsorb pollutants from the membrane surface and bring them into solution. The acids and bases neutralize and displace each other to form precipitates that remove fouling. Ultrasonic treatment is applied when the bubble concentration reaches a certain level. The ultrasonic vibration aids in membrane cleaning by enhancing bubble adsorption and dislodging fouling particles.

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Using formic acid generated on-site to clean membranes like reverse osmosis filters without damaging them. The formic acid composition is applied to the membranes to remove biofilms and mineral deposits that can reduce flow and performance. The formic acid is generated in situ by reacting water and carbon dioxide in the presence of a catalyst. This allows creating a membrane-compatible cleaning composition that doesn't require transporting pre-made formic acid solutions.

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Cleaning method for water treatment membranes to effectively remove biofilms formed by Pseudomonas aeruginosa bacteria. The method involves cleaning the membrane with a pH of 4.5 or less. The pH and contact time can be optimized based on the decay constant of Pseudomonas aeruginosa calculated by measuring its growth rate at pH 4.5 and sterile conditions. By using this pH and contact time, the cleaning efficiency can be maximized. Regularly evaluating the cleaning efficiency by comparing Pseudomonas aeruginosa levels before and after cleaning allows resetting the pH and contact time if needed.

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Cleaning method and system for reverse osmosis and nanofiltration membranes during preparation to reduce residual chemicals and improve membrane quality. The method involves cleaning steps using specific solutions followed by physical treatments like extrusion and vacuum adsorption. The system has devices for extrusion, vacuum, and stretching. This reduces residual monomers like amines on the membrane surface and pores.

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Continuous detergent for cleaning biofilms in reverse osmosis membranes that can keep the membranes clean without periodic cleaning. The detergent contains an organic chelator, a hybrid-biopolymer, and chlorosulfamate. It continuously removes biofilms during membrane operation. The organic chelator loosens the biofilm matrix, the hybrid-biopolymer disperses the biofilm, and chlorosulfamate kills the bacteria. The detergent is diluted and continuously injected into the membrane feed.

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Cleaning method for membranes used in filtration processes to restore permeability without requiring disassembly. The method involves filtering the feed solution through the membrane, then drying the membrane, washing with water or cleaning solution, and resuming filtration. This drying step removes some fouling deposits that can be challenging to fully remove during chemical cleaning. The process can be repeated as needed to maintain membrane performance.

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Online chemical cleaning method for reverse osmosis membranes to improve cleaning efficiency and reduce downtime compared to traditional offline cleaning. The method involves a stepwise cleaning process that includes sterilization, acid washing, descaling, and alkaline washing. The steps are designed to thoroughly clean the membrane, remove fouling, dissolve scales, and kill bacteria. The cleaning agent composition contains anionic surfactant, dispersant, and bactericide to enhance flotation, dispersion, and sterilization. Backwashing before each cleaning step removes physical impurities and prevents damage.

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Cleaning method for nanofiltration and reverse osmosis membranes used in wastewater treatment applications. The method involves stepwise cleaning cycles using pH adjusted solutions to effectively remove fouling without damaging the membranes. It involves three steps: 1) product water circulation cleaning using the permeate from the RO membrane to loosen fouling, 2) alkaline cleaning at low temperature with soaking to remove organic fouling, and 3) acidic cleaning at higher temperature to remove inorganic fouling. The pH and temperature are controlled to prevent membrane damage. The method improves fouling removal efficiency and extends membrane life compared to single-step cleaning.

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A chemical cleaning method for nanofiltration and reverse osmosis membranes used in landfill leachate treatment that provides simple, low-cost, high-efficiency cleaning with good membrane longevity. The cleaning involves a two-step process of acidic cleaning followed by alkaline cleaning. The acidic cleaning uses citric acid to remove organic contaminants and metal oxides, while the alkaline cleaning uses a non-oxidizing bactericide to remove inorganic scales and metal oxides. The cleaning solutions are adjusted to pH 2-3 during pickling. This targeted, pH-controlled cleaning removes contaminants without damaging the polyamide membranes.

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