Embodiments described herein relate generally to systems, apparatus, and methods for using graphene oxide-containing membranes for separation and concentration processes. In some embodiments, a fluid component having a first concentration in a fluid mixture can be concentrated using a first distillation process to a second concentration. In some embodiments, the fluid component can be concentrated from the second concentration to a third concentration using a graphene oxide-containing membrane. In some embodiments, the fluid component can be concentrated from the third concentration to a fourth concentration using a second distillation process. In some embodiments, the fluid component can have an azeotropic concentration between the second concentration and the third concentration.

A system and method for producing from saline source water a product containing an increased ratio of multi-valent ions to mono-valent ions, which includes multiple nanofiltration units arranged to selectively remove mono-valent ions from the water fed into each nanofiltration stage in the nanofiltration permeate stream while retaining multi-valent ions in the nanofiltration reject stream. The rate at which the increase in the multi-valent ion- to mono-valent ion ratio is obtained may be enhanced by introduction of lower salinity water into the nanofiltration reject between stages, and by recirculating a portion of downstream nanofiltration reject flow into an upstream nanofiltration unit. The enhanced multi-valent ion product is suitable for multiple uses, including irrigation of plants and remineralization of desalinated water. The relative concentrations of the multi-valent ions in the product may be adjusted, for example by selection of nanofiltration membrane technologies which have higher or lower rejection for specific multi-valent ions.

A submersible reverse osmosis desalination apparatus uses low temperature concentrate or brine from the desalination apparatus to provide a high volume cold liquid stream to an Ocean Thermal Energy Conversion (OTEC) heat engine. The OTEC engine also employs a warm liquid stream and uses the cold and warm liquid streams to obtain electrical power from a closed-cycle or open-cycle heat exchange and generator system. Use of the concentrate or brine stream provides a much greater liquid volume and much greater cold thermal energy content than would be obtained by using cold desalinated product water from the desalination apparatus in the OTEC heat engine.

Disclosed is a continuous process for the purification of steviol glycosides such as Rebaudioside D and/or Rebaudioside M extracted from the dried stevia leaves or extracted from a fermentation broth using continuous simulated moving bed processes and nanofiltration without the addition of organic solvents to obtain a purified steviol product comprising sweet steviol glycosides. The sweet steviol glycosides can be used as substitutes for caloric sweeteners in beverages and in other food items.

The present disclosure provides a system for extracting long chain dicarboxylic acid, the system comprising: a primary membrane filtration unit, a first crystallization unit, a first separation unit, a first dissolution tank, a secondary membrane filtration unit, a second separation unit, a second crystallization unit and a third separation unit. By the system for extracting long chain dicarboxylic acid of an embodiment of the present invention, the resulted long chain dicarboxylic acid product has a high purity, very low and even no residual alkane residue, and organic solvent-free.

A system and method for producing minerals from divalent ion-containing brine stream includes rejecting sulfate from a divalent-ion rich reject stream in a first nanofiltration seawater reverse osmosis (NF-SWRO) unit, producing solid calcium sulfate dihydrate and a magnesium-rich brine stream in a first concentration unit, concentrating the magnesium-rich brine stream to a saturation point of sodium chloride in a second concentration unit, producing solid sodium chloride and a supernatant product stream in a first crystallizing unit, produce a concentrated magnesium-rich bittern stream from the supernatant product stream in a third concentration unit, and at least one of producing hydrated magnesium chloride from the concentrated magnesium-rich bittern stream in a second crystallizing unit and producing anhydrous magnesium chloride by prilling the concentrated magnesium-rich bitterns stream under a hydrogen chloride atmosphere in a dry air process unit.

The present application relates to a preparation method for recycling inorganic salt in printing and dyeing wastewater and comprises the following process steps: S1, performing impurity removal, softening, COD removal and decoloration on reverse osmosis (RO) membrane concentrated water to obtain pretreated wastewater; S2, performing two-stage electrodialysis on the wastewater obtained in step S1: returning fresh water obtained in a first-stage electrodialysis desalination chamber to a front end of the RO process, and taking saline water obtained in a concentration chamber as raw water of a second-stage electrodialysis desalination chamber and a second-stage electrodialysis concentration chamber; and returning the fresh water obtained by the second-stage electrodialysis desalination chamber to the first-stage electrodialysis concentration chamber; and S3, dealkalizing the concentrated saline water obtained in the step S2 and then adjusting the pH value to obtain concentrated saline water capable of being reused for cloth dyeing in a printing and dyeing mill.

Provided are water treatment systems for reducing hardness in water. The water treatment systems include an electrodialysis device comprising a brine inlet stream, a feed stream, a brine outlet stream, and a product outlet stream, and a template assisted crystallization (TAC) filter comprising a brine inlet stream and a brine outlet stream. The brine inlet stream comprises the brine outlet stream of the electrodialysis device and the brine inlet stream of the electrodialysis device comprises the brine outlet stream of the TAC filter. The system pressure is reduced by 30-60% when the brine stream goes through a TAC filter than a system without the filter. An acid supply and an acid feed stream may also be included, wherein the brine inlet stream of the electrodialysis device comprises the brine outlet stream of the TAC filter and the acid feed stream.

Water treatment systems including electrically-driven and pressure-driven separation apparatus configured to produce a first treated water suitable for use as irrigation water and a second treated water suitable for use as potable water from one of brackish water and saline water and methods of operation of same.

A submersible water desalination apparatus includes an array of generally parallel water separation membrane cartridges each having a water separation membrane, an impermeable cartridge wall surrounding the membrane, and a product water collection tube that collects from inside the cartridges at least partially desalinated product water passing through the membrane, and through which the at least partially desalinated water exits the cartridges and enters a product water collection manifold. The cartridges are mounted in a perforated divider plate. In embodiments, a) the manifold is adhesively bonded to a plurality of the collection tubes, orb) the divider plate is adhesively bonded to a plurality of the cartridge walls or ends, or both a) and b). The adhesive reduces the likelihood of leakage at the manifold or divider plate.