Optimizing Performance by Reverse Osmosis pH Adjustment

A pure water production system that reduces boron concentration while maintaining energy efficiency and cost effectiveness. The system uses reverse osmosis followed by electric deionization. The reverse osmosis conditions are optimized to limit the electric deionization boron removal rate to a threshold value. This allows lower current and power consumption in electric deionization without compromising boron removal. The reverse osmosis conditions are adjusted to achieve the desired boron level in the electric deionization output water.

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An apparatus and method for removing boron from water using a specific pH adjustment before reverse osmosis. The method involves adjusting the pH of the water to be treated to a range of 9.0 before passing it through a low-pressure reverse osmosis membrane. This pre-treatment step greatly improves boron removal efficiency in the subsequent high-pressure reverse osmosis stage. The higher pH prevents boron inhibition on the membrane and allows more boron to be rejected. This enables boron levels to be reduced to very low concentrations.

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Reverse osmosis water treatment method that allows efficient processing of high pH, high ammonia, and high TOC water without excessive cleaning costs or membrane fouling. The method involves adjusting the pH of the feed water to 4-8, then passing it through a RO membrane. Intermittently, high pH water above 9.5 is brought into contact with the RO membrane. This periodic high pH exposure prevents fouling without constant disinfection. The high pH water can be the original feed water itself or preprocessed water. The intermittent high pH contact is done every 12 hours to once a month.

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A method to improve the quality of permeate water produced by a reverse osmosis (RO) system when treating decarboxylated water. The method involves adjusting the pH of the RO feed water in small increments based on the permeate water quality. By periodically changing the RO feed pH by a small amount and then monitoring the permeate quality, the optimal pH for the feed water can be found that results in consistently high quality permeate water.

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Reverse osmosis system with recirculation loop that overcomes limitations of prior art recirculating RO systems. The system uses a combined pump and energy recovery device with fixed recovery rate that avoids mixing between feed and return streams. This allows higher recovery rates and minimizes scaling on membranes compared to prior systems with separate energy recovery units. The fixed recovery rate structure enables automated pressure adjustment as salinity increases. A pressure switch actuates a valve to replenish feed water at predetermined salinity. The fixed recovery rate structure also allows using a fixed displacement pump instead of variable speed centrifugal pumps.

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Electrodialysis system for removing dissolved ions and silica from water. The system consists of multiple stages with separate electrodialysis devices. In stage 1, traditional electrodialysis removes dissolved ions from the water. In stage 2, bipolar membrane electrodialysis removes silica from the desalinated water. The pH of the water is maintained in stage 2 by routing it through the alkaline chamber of the bipolar device. This prevents pH decrease and allows silica removal. The brine from stage 1 goes to stage 2.

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A system and method for treating reverse osmosis (RO) concentrated water with high temporary hardness using calcium bicarbonate crystallization. The system has a crystallization reactor, a centrifugal dewatering machine, and a freezer bin. The method involves feeding RO concentrated water into the crystallization reactor, allowing calcium bicarbonate crystals to form, then transferring the slurry to the centrifugal dewatering machine to separate the crystals. The crystals are further dewatered in the freezer bin. By separating the crystals from the water, the temporary hardness is removed.

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A dialysis system that accurately controls dialysate pH and buffer concentration during hemodialysis to improve patient outcomes. The system infuses a predetermined amount of bicarbonate buffer into the dialysate loop to adjust the pH and buffer levels. This is done using a controller that calculates the required buffer based on urea levels measured in the dialysate. The infusion system can add bicarbonate bi-directionally to match flow rates. This allows precise pH and buffer control without using sorbents that change pH.

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Reducing membrane scaling in high recovery reverse osmosis systems by dynamically adjusting the volume of the system as recovery increases. At lower recoveries, the entire concentrate volume is cycled through the RO system. As recovery increases and concentrate becomes more concentrated with scaling constituents, part of the concentrate volume is isolated, reducing the overall system volume. This shorter concentrate cycle time through the smaller volume system prevents scaling by reducing exposure to supersaturated concentrate.

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Filtration system design that allows higher recovery rates compared to conventional continuous or batch reverse osmosis (RO) systems without the drawbacks of scaling or fouling. The system operates in a non-steady state between continuous and batch modes. It starts with continuous RO without antiscalant until near scaling, then adds antiscalant to extend operation before flushing. This allows recovery above continuous limits but below batch. It leverages higher pressure RO membranes and antiscalant to enable higher recovery without scaling.

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A parallel water filtration system increases reverse osmosis water filtration's flow rate and capacity by connecting multiple RO systems in parallel. This allows customization of RO capacity for commercial applications like restaurants. A water leakage sensing shutoff valve protects against flooding. The parallel connection also allows adding remineralization and pH adjustment filters to optimize output water quality.

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Reducing the risk of contact activation during blood dialysis by maintaining a physiological pH during priming and initial treatment phases. The blood treatment apparatus has an online preparation unit to make dialysate and priming solutions. The pH of these solutions is set close to blood pH (7.3-7.4) during priming and initial treatment. This prevents contact activation of blood components on the membrane surface. The pH can then be adjusted during subsequent treatment phases as needed.

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Managing operation of reverse osmosis membrane treatment systems to inhibit scaling without reverse osmosis pH adjustment or scale dispersants. The method involves measuring aluminum and iron ion concentrations in the feed and concentrate streams and using those values to determine optimal operation parameters.

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