pH Control in Reverse Osmosis Systems

Membrane fouling remains a persistent challenge in reverse osmosis (RO) systems. Devising effective strategies to mitigate membrane has become crucial for sustainable water treatment. Here, we propose titanium-based pre-coagulation strategy RO mitigation through regulation of the microbial habitat feed. The performance Ti(SO4)2 desulfurization wastewater and subsequent mechanism were systematically investigated. Our findings revealed that Ti induced an acidized environment, maintained balance between organic inorganic depositions, fostered beneficial community resisted rapid fouling. 20 day operations different scenarios (Ti, Al, Ctrl) showed group membranes highest normalized flux at 57.15%, outperforming Ctrl Al groups by 7.92% 15.16%, respectively. Microbial analyses, including taxonomic profiling metagenomic analysis, demonstrated Ti-based reduced dominance extracellular polymeric substance (EPS)-secreting genera, such as Sphingopyxis, while promoting Terrimonas Paenarthrobacter, with acid-tolerance traits EPS production. This shift mitigated biofouling enhancing limiting biofilm... Read More

Source

Nowadays, reverse osmosis (RO) desalination has become a highly effective and economical solution to address water scarcity worldwide. The membranes used in this type of separation are influenced by both pre-treatment operations feed quality, leading fouling, complex phenomenon responsible for reducing treatment performance shortening membrane lifespan. In study, an autopsy RO from the Boujdour plant was performed, fouling prediction tool based on transmembrane pressure (TMP) developed using MATLAB/Simulink (R2015a) with artificial neural network (ANN) model. impact also examined through one year monitoring. A detailed analysis fouled conducted SEM/EDS techniques characterize membranes surface cross-section. results revealed significant fractures surface, predominantly consisting organic deposits (characterized high oxygen concentration 39.69%) inorganic including Si (7.99%), Al (2.79%), Mg (1.56%), Fe (1.27%), smaller quantities K (0.87%), S (0.36%), Ca (0.12%). ANN model predicting successfully developed, achieving R2 value 92.077% low mean square error (MSE) 0.005657. This pred... Read More

Source

Reverse osmosis (RO) desalination technology offers a promising solution for mitigating water scarcity. However, one of the major challenges faced by RO membranes is biofouling, which significantly increases costs. Traditional simulation models often overlook environmental variability and do not incorporate effects membrane-surface modifications. This paper develops bacterial growth model prediction seawater performance, applicable to commercial membranes, can be either uncoated or coated with iron nanoparticles (FeNPs nZVI). FeNPs were selected due their known antimicrobial properties potential mitigate biofilm formation. The native bacterium Bacillus halotolerans MCC1 was used as biofouling bacterium. Growth kinetics determined at different temperatures (from 26 50 C) pH values 4 10) obtain parameters. Microbial on modeled using Monod equation. performance evaluated in terms hydraulic resistance permeate flux under clean biofouled conditions. validated data obtained laboratory scale. Bacteria grew faster 42 C 10. had more significant effect than temperature rate. FeNP-coated ex... Read More

Source

Treatment system for wastewater containing biomass, like stillage from ethanol plants, to recover water and biogas. The system uses anaerobic digestion followed by separation steps to remove ammonia, organics, and minerals from the digested water. This allows recycling a significant portion of the wastewater back into the digestion process to reduce freshwater requirements. The treated water can also be used in other plant processes. The digestion and separation steps involve pH adjustment, nanofiltration, reverse osmosis, and centrifugation.

Source

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.

Source

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 sensors design, application, outcomes, providing a roadmap revolutionizing monitoring in plants.

Source

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

Source

Wastewater concentration device and method that can stably perform wastewater concentration treatment by adjusting the pH of water supplied to an osmotic pressure-assisted reverse osmosis device. The device has an osmotic pressure-assisted reverse osmosis system with a primary chamber and secondary chamber separated by a membrane. A water supply system feeds water to the primary chamber. It has an ion exchange device to treat the water and adjust its pH. This allows concentrating wastewater with high or low pH using osmotic reverse osmosis, avoiding the need for high pressures. The ion exchange removes components that contribute to the high/low pH, then hydrogen/hydroxide ions are released through ion exchange. This reduces the pH of high pH wastewater and raises the pH of low pH wastewater, making it suitable for osmotic reverse osmosis concentration

Source

Cost-reducing and efficiency-increasing reverse osmosis pH adjustment method to reduce chemicals waste and energy consumption in reverse osmosis water filtration systems. The method involves dynamically adjusting the frequency of adding acid to the concentrated water stream based on pH measurements. This prevents over-addition of acid in later stages where scaling is lower, and under-addition in earlier stages where scaling is higher. By optimizing acid dosing based on the actual scaling risk, it reduces acid consumption and prevents pH overshoot.

Source

Device to maintain pH of reverse osmosis system effluent without dosing chemicals excessively. It uses floating balls in the secondary reverse osmosis production pool, filters on the overflow pipe and external water supply pipe, and a dosing pipe for the secondary reverse osmosis membrane group. The floating balls raise the water level to counteract pH drop from CO2 dissolution. Filters prevent CO2-rich air from entering the production pool. The dosing pipe allows adjusting pH by adding chemicals only to the secondary reverse osmosis feed.

Source

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.

Source

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.

Source

Multi-stage reverse osmosis water treatment system that reduces energy consumption while maintaining water quality. The system uses low-pressure reverse osmosis membranes with high flux per pressure in the first stages to remove impurities like boron and silica. The water pH is adjusted in the first stage to enhance removal. This allows fewer high-pressure stages compared to traditional RO systems, reducing energy. By optimizing the membrane selection and pH adjustment, the treated water quality can still meet requirements.

Source

A method for producing high quality permeate in reverse osmosis systems by dynamically adjusting the pH of the feed water based on the measured quality of the permeate. The method involves fluctuating the pH of the feed water by a small range, measuring the permeate quality after a short time, and then adjusting the feed pH again based on the average permeate quality during that time. This allows stabilizing the permeate quality even with fluctuating feed water quality by dynamically optimizing the feed pH.

Source

Lye addition system for adjusting pH of wastewater in a sewage treatment plant. The system has separate lye metering pumps to add alkali to the wastewater at two different points in the treatment process. One pump adds lye before softening to raise pH for better reverse osmosis membrane performance. The other pump adds lye after softening to adjust final effluent pH. This allows precise pH control at each step to meet specific process requirements.

Source

A reverse osmosis membrane treatment method to efficiently clean and prolong the life of reverse osmosis membranes in water treatment systems while reducing cleaning chemicals and costs. The method involves treating the feed water to a pH range of 4-8, then periodically bringing highly alkaline water with pH 9.5 or above into contact with the reverse osmosis membranes. This intermittent alkaline treatment helps suppress slime formation on the membranes between cleanings.

Source

Automatic pH adjustment system for secondary reverse osmosis EDI water purification to improve efficiency and quality. The system uses a mixing device with inner and outer stirring mechanisms that can rotate in different directions. The inner stirring mechanism mixes the water and reagent in the tank, while the outer stirring mechanism swirls the tank contents. This allows continuous switching between different mixing methods. The mixing device is controlled by a controller to optimize pH adjustment.

Source

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.

Source

Reducing the amount of pH adjuster used in a purified water production system while maintaining high water quality by dynamically adjusting the pH of the feed water to the reverse osmosis membrane. The adjustment involves increasing the pH range allowed for the feed water when the permeate quality meets a target range, and decreasing it when the permeate quality falls below the target range. This allows optimizing the pH without over-adjustment. The pH adjustment is done using acid addition before decarboxylation and alkali addition before RO.

Source

A reverse osmosis alkali addition control system for a power plant to maintain stable pH levels in reverse osmosis systems used in power plant water treatment. The system uses multiple pH sensors and dosing mixers between the primary and secondary reverse osmosis units. Alkali is added at the primary reverse osmosis stage to raise pH and remove carbon dioxide. The secondary reverse osmosis feed water pump has multiple pumps to provide redundancy. This allows precise pH control throughout the reverse osmosis process to prevent fluctuations.

Source