Systems and methods for removing a contaminant from a liquid are generally described. The liquid (e.g., water) containing the contaminant may be flowed across a semipermeable membrane (e.g., via forward osmosis) that is not permeable to the contaminant in order to remove the contaminant from the liquid. A concentration gradient across the semipermeable membrane may be provided and maintained by electrolysis of the liquid and can drive forward osmosis of the liquid through the semipermeable membrane.

A complete kit, including components to assemble a U-tube apparatus, materials, and methods of using thereof, for the purpose of osmosis pedagogy, is described. The self-contained kit makes possible hands-on osmosis experiments that may be conducted safely at home, and is well-suited for STEM (science, technology, engineering and mathematics) education. The kit supplies unmodified glycerin and unmodified dextran as solutes, and components to assemble a watertight U-tube apparatus capable of accurate, repeatable quantitative measurements and bidirectional osmosis. One method describes osmotic rate measurements using glycerin as solute under varying parameters of solute concentration, temperature, and osmosis direction. Another method describes the comparison of experimental measurement of osmotic pressure at equilibrium to theoretical prediction using dextran as solute.

Systems and processes for purifying and concentrating a liquid feed stream are disclosed. In the systems, the concentrated liquid output from the high pressure side of a reverse osmosis stage is used as the draw solution in the low pressure side of the reverse osmosis stage in a configuration called osmotically assisted reverse osmosis. This reduces the osmotic pressure differential across the membrane, permitting high solute concentrations to be obtained, hastening the purification of the liquid. Reduced system pressures are also obtained by arranging multiple osmotically assisted reverse osmosis stages in a cross-current arrangement. Overall system energy consumption is reduced compared to conventional thermal processes for high concentration streams.

The present disclosure relates to osmotic power plants and method for their operation. For example, a method for operating an osmotic power plant may include: supplying a starting solution containing a first substance to the thermal separating facility; evaporating the starting solution in an evaporator; discharging the substance out of the evaporator with a gaseous medium flowing through the evaporator; converting the discharged substance to a liquid phase in a condenser and thereby generating the first solution; wherein the substance is more easily converted to a gas phase than the solvent of the starting solution. The first solution has a first concentration the substance dissolved in a solvent. A second solution has a second, lesser concentration of the substance. The first solution is provided by a thermal separating facility.

An apparatus for reducing the total dissolved solids of a solution includes a unit having at least two chambers; a respective semi-permeable membrane arrangement disposed between each of the at least two chambers; a device for introducing respective solutions into, and withdrawing solutions from, the chambers; and at least one paddle disposed in each of said chambers. The paddles are configured to sweep opposite sides of each of the semi-permeable membrane arrangements. A device provides relative movement between the paddles and the semi-permeable arrangements.

Separation processes using forward osmosis are disclosed generally involving the extraction of a solvent from a first solution to concentrate a solute therein by using a second concentrated solution to draw the solvent from the first solution across a semi-permeable membrane. One or both of the solute and solvent may be a desired product. By manipulating the equilibrium of the soluble and insoluble species of solute within the second solution, a saturated second solution can be used to generate osmotic pressure on the first solution. The various species of solute within the second solution can be recovered and recycled through the process to affect the changes in equilibrium and eliminate waste products. Enhanced efficiency may result from using low grade waste heat from industrial or commercial sources.

A system for treatment of a brine feed, the system including a hybrid reactor, the reactor having a plurality of forward osmosis membranes configured to permit the passage of a draw solution solute through the middle of the membrane to draw water across the membrane wall from the brine feed so as to generate diluted solute, and a plurality of membrane electrode assemblies configured to separate ions of the salt in the brine feed to concentrate the salt ions, each membrane electrode assembly having an anion exchange membrane and a cation exchange membrane; whereby each membrane electrode assembly houses a plurality of forward osmosis membranes therewithin.

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.

Embodiments described herein relate to methods and systems for dewatering solutions via forward osmosis.

A desalination system (100) having an intake unit (110) providing seawater to a pre-treatment unit (120) connected to a reverse osmosis (RO) desalination unit (130) and a post treatment unit (150). The desalination system (100) is configured to operate without any external addition of chemicals to simplify logistics and regulation concerns. The units of the system are configured to prevent biofouling, scaling and corrosion by mechanical and biological means including high flow speeds, biological flocculation of colloids, and making the water entering the RO units inhospitable to bacteria and other organisms that cause biofouling, hence preventing their settlement and removing them with the brine. Recovery rate is lowered and energy is recovered to increase the energetic efficiency and minerals that are added to the product water are taken from the brine.