A water treatment system 100 includes: a filtration device 16 that includes an RO membrane element 12 and an NF membrane element 14, and treats raw water containing sodium chloride by the RO membrane element 12 and the NF membrane element 14 to generate concentrated raw water; and an electrolytic device 18 that is disposed downstream of the filtration device 16 and electrolyzes the concentrated raw water to generate water containing sodium hypochlorite.

A method of concentrating lithium containing solutions includes inputting a feed brine solution to an initial separation stage, the feed brine solution including lithium sulfate and one or more of sodium sulfate, potassium sulfate, calcium sulfate, and sodium chloride dissolved in water. In the initial separation stage, the feed brine solution is introduced to a pre-treatment membrane at a pressure that is less than the osmotic pressure of the feed brine solution. An initial permeate that passes through the pre-treatment membrane becomes the feed to a final separation stage, and an initial retentate that does not pass through the pre-treatment membrane includes a precipitate of at least one of the salts other than lithium sulfate. In the final separation stage, the initial permeate is introduced to a nanofiltration membrane at a pressure that is less than the osmotic pressure of the initial permeate. A final retentate that does not pass through the nanofiltration membrane is combined with the initial retentate to obtain a product solution having a higher concentration of dissolved lithium sulfate than the feed brine solution.

Systems and methods for treating water may involve a first electrochemical separation module that includes at least one ion exchange membrane having a first set of performance characteristics, and a second electrochemical separation module that includes at least one ion exchange membrane having a second set of performance characteristics that is different than the first set of performance characteristics. Performance characteristics may relate to at least one of water loss, electrical resistance, and permselectivity. Staged treatment systems and methods may provide improved efficiency.

An automated modular filtration system, particularly for low volume tangential flow filtration processes, comprises a plurality of filtration modules formed as separate assemblies and at least one control unit for jointly controlling filtration processes of individual filtration units. Each filtration module contains at least one individual filtration unit for executing a filtration process independent of the other filtration units, first input ports for receiving a first type of fluids, second input ports for receiving a second type of fluids, and exit ports for outputting unused system fluids. First type fluids are process fluids are specific to the filtration processes executed in individual filtration units. Second type fluids are system fluids not specific to filtration processes executed in the individual filtration units. The second input and exit ports establish inter-module connections so system fluids can be forwarded from one filtration module to an adjacent filtration module of the filtration system.

A high salinity water purification system and process, including a forward osmosis system and a reverse osmosis or nanofiltration system. A concentrated brine of a zinc or iron complex combined with a salt or acid draws pure water across the FO membrane from the influent water. The diluted brine is pumped through a vessel holding an anionic adsorption media to remove the zinc or iron complex and the resultant brine is passed through the RO or nanofiltration system to obtain purified water and a concentrated brine stream. The adsorption media is regenerated by a rinse cycle using fresh water or water from the RO system, removing the zinc or iron complex adhered to the media. The resultant brine is stored and mixed with the output of the RO system. Charged membrane can be used as a standalone membrane in FO process or in combination with resin or resin embedded membrane.

A method of obtaining a compound may include adding a substrate to a medium in a reactor, and reacting the substrate in the reactor to form the compound. A first stream is separated from the reaction liquid through a first membrane. A second stream is separated from the reaction liquid through a second membrane. The first membrane is a filtration membrane and the second membrane is configured for liquid-gas or liquid-liquid extraction The first membrane and the second membrane are at least partially immersed in the medium and are moved relative to the reactor during the separation steps.

The present invention provides a multi-stage filter system suitable for the production of drinking water from a wide variety of contaminated water sources. The modular nature of the multi-stage filter system allows for the customization of filter combinations according to the remediation requirements. The multi-stage filter system comprises a coarse filter (S1); an ultrafiltration filter (S2); a graphene-based filter (S3); and a residual nanoparticle filter (S4). The graphene-based filter cartridge comprises few-layer graphene powder; a combination of few-layer graphene powder and pellets comprising a mixture of polyethersulfone, graphene oxide (GO), and dimethylformamide; a composite comprising chitosan, GO, sodium sulfate and ferric chloride; or a combination of few-layer graphene powder, granular activated carbon and a composite comprising chitosan, GO, sodium sulfate and ferric chloride.

A method of obtaining a compound may include adding a substrate to a medium in a reactor, and reacting the substrate in the reactor to form the compound. A first stream is separated from the reaction liquid through a first membrane. A second stream is separated from the reaction liquid through a second membrane. The first membrane is a filtration membrane and the second membrane is configured for liquid-gas or liquid-liquid extraction The first membrane and the second membrane are at least partially immersed in the medium and are moved relative to the reactor during the separation steps.

A method for desalination is provided. An electric potential difference is applied across a saline solution, where a salinity of the saline solution is in a range of 2.5 to 7.8 parts per thousand. The saline solution is separated, using electrodialysis, into a concentrated saline solution and a first diluate. The concentrated saline solution is transferred to a reverse osmosis chamber. The concentrated saline solution is pumped through a partially permeable membrane, thereby removing salt ions from the concentrated saline solution, and creating a second diluate and a brine solution. A pressure of the solution is then increased, using a pressure exchanger, by transferring water pressure from the brine solution to the concentrated saline solution. The first diluate and the second diluate are combined, where a first recovery ratio of the first diluate is greater than a second recovery ratio of the second diluate.

This specification describes membrane based filtration and softening systems and methods. A system has a microfiltration or ultrafiltration (MF/UF) membrane unit upstream of a nanofiltration or reverse osmosis (NF/RO) membrane unit, optionally with no intermediate tank. In some cases, the system and method may be used with feed water provided at municipal line pressure to the membranes. NF/RO permeate is collected in a tank and then pumped to a header. Treated water may be drawn from the header for use or recycled to the system, for example to backwash or flush one or both of the membrane units. In a combined process, NF/RO permeate flushes the feed side of the NF/RO unit and then backwashes the MF/UF unit. In another process, the MF/UF unit and NF/RO unit are filled with NF/RO permeate before being placed in a standby mode.