Safeguarding Practices: Reverse Osmosis Preserve Membrane During Cleaning

Online cleaning system for micro-polluted nanofiltration membranes using forward osmosis. The system allows in-situ cleaning of nanofiltration membranes to remove fouling without shutting down the system. It uses a forward osmosis (FO) process where concentrated saline water is pumped into the FO feed solution tank. The FO system draws clean water from the feed and concentrates it into the draw solution tank. This allows bidirectional cleaning by reversing the feed and draw water flow through the membrane. The system also has temperature control to maintain optimal cleaning conditions.

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Cleaning method for hollow fiber membrane modules used in filtering raw water that reduces fouling and maintains filtration performance over time. The cleaning involves two steps: a first cleaning step to remove most of the water and suspended components from the module, followed by a second step to shake the membranes with air to remove the remaining fouling. This two-step process removes 50% or more of the module's original water volume in the first step, then shakes the membranes in the second step to dislodge any remaining fouling. This provides effective cleaning to prevent fouling buildup and deterioration of filtration performance in long-term use of the membrane modules.

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Method for cleaning membranes in filtration devices that adapt the cleaning process based on liquid temperature to optimize cleaning effectiveness and minimize costs. The cleaning involves periodic steps using increasing strength chemicals and longer times. The cleaning intervals are triggered when a performance metric (transmembrane pressure difference or permeability) exceeds a threshold. For each trigger, the cleaning strength is increased. The cleaning strength is adjusted based on the liquid temperature to optimize cleaning for that temperature. This prevents overcleaning at high temperatures and insufficient cleaning at low temperatures.

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Cleaning semi-permeable membranes used in desalination and filtration processes without stopping the operation or using harsh chemicals. The cleaning involves inducing mechanical shaking of the membranes while running the process in reverse osmosis mode. This is achieved by applying pulsed water strokes to the feed or permeate side while also injecting additional solution to create reverse flow. The pulsed water strokes cause membrane oscillation that helps detach fouling layers. The pulsed water strokes can be generated internally by valves or externally by pumps or pistons. The pulsing frequency is matched to the natural membrane vibration frequency for enhanced shaking.

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Cleaning and sanitizing membranes used in filtration systems like water treatment plants to remove biofilms and spores without damaging the membranes. The cleaning involves a two-step process: first an acid cleaning solution, then a boosted antimicrobial solution made by combining the acid cleaner with an oxidizer sanitizer. This synergistic cleaning removes bacteria, biofilms, and scales without harming the membranes. It allows effective cleaning and sanitization of membranes like UF, NF, RO, and MF used in food, beverage, pharmaceutical, and water applications.

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Using permeate (filtered fluid) to flush reverse osmosis filters in the same direction as when untreated fluid is filtered, instead of using high TDS untreated fluid for flushing. This improves filter life and efficiency by removing trapped solids that can't be flushed with untreated fluid. The method involves routing permeate through the filter, then stopping flow and immersing the filter in permeate for resorption. This allows permeate to dissolve trapped solids. Then the permeate pump is restarted to flush out the resorbed solids.

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Cleaning polymeric and ceramic microfiltration and ultrafiltration membranes using a reducing agent like ascorbic acid to effectively remove fouling contaminants like iron floc without damaging the membranes. The cleaning method involves contacting the fouled membranes with a solution of ascorbic acid in a compatible solvent. The reducing agent reduces the valence state of fouling contaminants like iron to a soluble form that can be removed during cleaning.

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Cleaning a polymer membrane used in filtration processes to restore permeability without using harsh chemicals. The cleaning steps are: 1. Filtering the feed water through the membrane. 2. Drying the membrane. 3. Washing the membrane with water or a chemical solution. 4. Continuing to filter the feed water through the cleaned membrane. This sequential process helps to remove foulants from the membrane without needing harsh chemicals. The drying step removes loose particles, followed by washing to dislodge stubborn fouling. The final step of filtering flushes out any remaining contaminants.

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Desalination system with intermittent cleaning of reverse osmosis membranes to reduce fouling. The system has a reverse osmosis desalination unit with membranes that feeds saline water at a pressure exceeding the osmotic pressure. Periodically, the permeate outlet is closed and the feed pressure reduced while the permeate is reversed through the membranes. This dislodges foulants into the feed water, allowing flushing. By varying feed pressure based on salinity and intermittently cleaning, fouling is reduced compared to constant high feed pressure.

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Water purifier with a storage chamber to improve initial purity when the purifier is not used for long periods. The purifier has a reversed osmosis membrane device with raw, purified, and waste water ports. A storage chamber can connect to either the raw or purified port. When the purifier is producing water, the chamber connects to the purified port to collect water. When the purifier is cleaning, the chamber connects to the raw port to flush the membrane with collected water. This ensures the membrane has purified water on both sides when not in use, preventing contamination during initial production.

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Filter device for purifying water that allows thorough cleaning of the reverse osmosis membrane to remove fouling. The device has a membrane housing, spacer, membrane element, first electrode in the feed chamber, and second electrode in the permeate chamber. It connects to a power supply to generate acid or alkaline water inside the feed chamber during cleaning. The acid/alkaline water contacts the membrane surface, dissolves foulants, and flows out during cleaning. It also has a closing mechanism for static washing. This allows complete coverage of the membrane surface for thorough fouling removal.

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Cleaning agents and liquids for efficiently removing foulants from reverse osmosis (RO) membranes, particularly aromatic polyamide RO membranes, that have become fouled during use. The cleaning agents and liquids contain amide compounds, such as nicotinamide, asparagine, and benzamide, that can effectively remove foulants like organic substances and microorganisms from RO membranes. The amide compounds can be used alone or with other cleaning agents like alkaline solutions, surfactants, and dispersants. The amide compounds should be soluble in water and have low molecular weights. The amide-containing cleaning agents and liquids can be used to restore RO membrane performance after fouling.

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Filtration system and method for improved backwashing of filter membranes to remove accumulated contaminants. The system has a feed line, concentrate return line, feed pump, and backwash supply. In the priming phase, valves block feed and concentrate outlets while permeate is pressurized to equalize membrane pressures. In the crossflow flush phase, feed and concentrate flow with higher permeate pressure to clean membrane. In the concentrate flush phase, only permeate cleans membrane. In the feed flush phase, only permeate cleans membrane. This sequence removes contaminants from both membrane sides.

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Cleaning method and apparatus for filter membranes used in water treatment systems to remove fouling and improve performance. The cleaning involves two steps using oxidizing agents in order of decreasing oxidizability. First, clean with a low oxidizability agent. Then, clean with a high oxidizability agent. This sequence allows efficient removal of both easily degradable and refractory fouling compounds from the membrane surface and pores. By using lower oxidizing power first, it prepares the membrane for better oxidative degradation of the harder-to-remove fouling compounds using the higher oxidizing power agent.

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Integrated reverse osmosis (RO) and membrane cleaning (MC) systems that prevent fouling in RO systems without needing periodic cleaning cycles. The integrated RO-MC system has brief MC sequences executed at predefined intervals to remove fouling deposits off membrane surfaces at their embryonic stage. This avoids accumulation and prevents the need for full cleaning cycles. The MC sequences involve exposing the membranes to cleaning solutions under modified osmotic conditions to facilitate fouling breakdown. The MC steps are done automatically in between normal RO operation to maintain membrane performance.

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A reverse osmosis system with multiple membrane banks that allows continuous operation while cleaning membranes. The system has a bypass line to divert water around a bank being cleaned and a chemical cleaning line to provide a cleaning solution to a bank being bypassed. This lets the system isolate, clean, and restart one bank at a time while the others produce water, and thereby, the reverse osmosis preserve membrane during cleaning.

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