A system separates and in-situ analyzes a discrete sample of multiphase fluid. The system includes a separation vessel having a first inner chamber for separating a discrete sample of multiphase fluid into liquid phases including an aqueous liquid phase and a nonporous liquid phase, and a built-in water analysis unit. The built-in water analysis unit includes an analytical cell disposed inside the first inner chamber of the separation vessel, the analytical cell having a second inner chamber, and at least one probe having a sensing area disposed in the second inner chamber for in-situ analysis of a sample of the aqueous liquid phase that is separated from the discrete sample of multiphase fluid in the first inner chamber and that is channeled to the second inner chamber from the first inner chamber for the in-situ analysis. The second inner chamber is defined inside the first inner chamber.

Provided are hybrid electrochemical and membrane-based systems for removing silica from water stream to achieve ultra-pure water. The silica concentration of a feed water stream may dictate the most effective and economical variation of disclosed hybrid processes to use. For example, for a feed water stream having a silica concentration of 1-30 ppm, a hybrid system for treating the feed water includes an electrodialysis reversal unit, the electrodialysis reversal unit comprising an inlet stream and a product outlet stream; a reverse osmosis unit, the reverse osmosis unit comprising an inlet stream and a product outlet stream, wherein the inlet stream of the reverse osmosis unit comprises the product outlet stream of the electrodialysis reversal unit; and an electrodeionization unit, the electrodeionization unit comprising an inlet stream and a product outlet stream, wherein the inlet stream of the electrodeionization unit comprises the product outlet stream of the reverse osmosis unit.

A method of generating electrical power or hydrogen from thermal energy is disclosed. The method includes separating, by a selectively permeable membrane, a first saline solution from a second saline solution, receiving, by the first saline solution and/or the second saline solution, thermal energy from a heat source, and mixing the first saline solution and the second saline solution in a controlled manner, capturing at least some salinity-gradient energy as electrical power as the salinity difference between the first saline solution and the second saline solution decreases. The method further includes transferring, by a heat pump, thermal energy from the first saline solution to the second saline solution, causing the salinity difference between the first saline solution and the second saline solution to increase.

Provided are electrodialysis systems comprising a plurality of electrodialysis devices, wherein each electrodialysis device of the plurality of electrodialysis devices has a product inlet stream, a product outlet stream, a brine inlet stream, and a brine outlet stream. The product inlet stream for a first electrodialysis device comprises the brine outlet stream of a second electrodialysis device. Further, a first portion of a feed stream is the brine inlet stream for the first electrodialysis device and a second portion of the feed stream is the brine inlet stream for the second electrodialysis device or a third electrodialysis device.

A plasma activated water production system includes a plasma reactor and a membrane concentrator. The plasma reactor includes an internal cavity, at least one electrically-conductive inlet capillary and outlet capillary. A mixing chamber has a feed gas inlet, a liquid inlet, and a mixed gas and liquid outlet. A power source is provided. The plasma reactor propagates a plasma discharge between the inlet capillary and the outlet capillary. A membrane concentrator includes a water flow channel with a water inlet and a water outlet, a dry gas inlet and a humidified gas outlet. An ion selective membrane is provided, and water will pass through the membrane into the dry gas, and the water leaving the membrane concentrator will have increased concentrations of nitrates, nitrites and hydrogen peroxide. An electrodialysis embodiment and a method of generating plasma activated with increased concentration of nitrates, nitrites and hydrogen peroxide are also disclosed.

Methods of treating a waste stream containing perfluoroalkyl substances (PFAS) are disclosed. The methods include directing the waste stream to a dilution compartment of an electrochemical separation device, directing a treatment stream to a concentration compartment of the electrochemical separation device, and applying a voltage across the electrodes to produce a dilute stream substantially free of the PFAS and a concentrate stream. At least one of the waste stream and the treatment stream comprises a water miscible organic solvent. Methods of concentrating PFAS from a wastewater are also disclosed. PFAS concentration systems are also disclosed. The systems include a column comprising an ion exchange resin and an electrochemical separation device having a dilution compartment fluidly connected to an outlet of the column. Methods of facilitating treatment of a waste stream containing PFAS are also disclosed.

A switching system of an EDR water purifier has a first inlet end, a second inlet end, a first three-way solenoid valve, a second three-way solenoid valve, a third three-way solenoid valve, a fourth three-way solenoid valve, an EDR membrane stack, a first outlet end, and a second outlet end. The EDR membrane stack has a first inlet port, a second inlet port, a first outlet port, a second outlet port, a first electrode, and a second electrode. Each three-way solenoid valve has an inlet opening, a first outlet opening, and a second outlet opening. Each outlet opening of each three-way solenoid valve can be turned open or closed for switching two water routes passing the EDR membrane stack. Therefore, speed of forming limescale decreases, lifespan of the EDR membrane stack is prolonged, and water-purifying efficiency is improved.

A switching system has two inlet ends, two outlet ends, and an EDR membrane stack. Each inlet end and each outlet end are connected to both a primary branch and a secondary branch. Solenoid valves are mounted on each primary branch and each secondary branch to switch between opening and closing. The EDR membrane stack has two inlets, two outlets, and two electrodes. One inlet is connected to the primary branch of the two inlet ends while the other is connected to the secondary branch of the two inlet ends. One outlet is connected to the primary branch of the two outlet ends while the other is connected to the secondary branch of the two outlet ends. The polarity of the two electrodes is interchangeable to realize the reverse polarity of the electrodes. The two water flows that pass through the EDR membrane stack are interchangeable.

A switching system for an EDR water purifier has a first raw-water inlet end, a second raw-water inlet end, two four-way solenoid valves, an EDR membrane stack, a freshwater outlet end, and a wastewater outlet end. Each four-way solenoid valve has a first inlet end, a second inlet end, a first outlet end, and a second outlet end. The first inlet end of each four-way solenoid valve can communicate with one of the first outlet end and the second outlet end of the same four-way solenoid valve, and the second inlet end of the same four-way solenoid valve can communicate with the other one of the first outlet end and the second outlet end, to execute water-route switching. By switching two water routes passing through the EDR membrane stack, forming of limescale is alleviated, lifespan of the EDR membrane stack is extended, and water-purifying efficiency is improved.

A first stream of an aqueous solution flows through an upstream desalination or nanofiltration system. A second stream of the aqueous solution is mixed with the diluate output from the upstream desalination system or with the diluate or concentrate output from the upstream nanofiltration system with a flow ratio of the second stream of the aqueous solution to the feed stream of <0.47 or >0.63. A liquid composition flows into the concentrate channels of an electrically driven separation apparatus, while the feed stream flows into at least the diluate channels at a ratio of 0.3 to 0.81 to the flow of the liquid composition. An applied voltage selectively draws monovalent ions from the feed stream in the diluate channels through the monovalent-selective ion exchange membranes into the concentrate channels to produce a treated diluate having a sodium chloride ratio (SCR)<0.7.