Provided are a cleaning agent and a cleaning liquid that prevent a reduction in the rejection rate of an RO membrane which may occur when the RO membrane is cleaned and a method for cleaning an RO membrane with the cleaning liquid. The agent for cleaning an RO membrane includes a urea derivative. The urea derivative preferably includes urea (H.sub.2N—CO—NH.sub.2) and/or biuret (H.sub.2N—CO—NH—CO—NH.sub.2). The cleaning liquid is an aqueous solution produced by diluting the cleaning agent. The method for cleaning an RO membrane uses the cleaning liquid. Urea and biuret have a structure analogous to amide bonds included in aromatic polyamide RO membranes, and have a strong affinity for amide bond portions. Urea and biuret adsorb onto the amide bond portions, and prevent the amide bonds from being broken by the cleaning liquid.

Systems and methods for the desalination of water are disclosed. A system includes a concentrated solar power (CSP) system, the CSP system operable to concentrate solar energy to increase temperature and pressure of a heat transfer fluid and operable to produce steam utilizing heat from the heat transfer fluid; a photovoltaic (PV) system, the PV system operable to collect solar energy to produce electricity; a desalination system in fluid communication with the CSP system and in electrical communication with the PV system, the desalination system operable to produce desalinated water from a salt water source utilizing the steam from the CSP system and electricity from the PV system; and a pump station in fluid communication with the CSP system and the desalination system, and in electrical communication with the PV system, the pump station operable to transmit the desalinated water to consumers for use.

A forward osmosis system is provided. The system includes forward osmosis container having a semipermeable membrane dividing the forward osmosis chamber into a first chamber and a second chamber, a draw solution water removal unit including a quantity of draw solution solvent and water, wherein the draw solution solvent includes a nonaqueous liquid and a condenser configured to receive either water vapor or draw solution solvent vapor from the draw solution water removal unit and provide condensed draw solution solvent to the second chamber. The second chamber provides a water diluted draw solution solvent to the draw solution water removal unit. The first chamber takes in received water including a dissolved solute at an input mass per unit of volume and provides a fluid output having an output mass per unit of volume greater than the input mass per unit of volume.

A system for production of desalinated water includes a wave energy convertor for conversion of mechanical energy from ocean waves into electricity and mechanical energy in the form of a salt-water stream. The system further includes a desalination unit coupled to the wave energy convertor. The system further includes an electrical connection from the wave energy convertor to the desalination unit, configured to supply the electricity to the desalination unit. The system further includes a conduit to supply the salt-water stream produced by the wave energy convertor to the desalination unit, wherein the desalination unit is configured to produce desalinated water.

A water treatment assembly (10) and method for its operation, comprising a spiral wound hyperfiltration membrane module (12) connected to: i) a feed line (14) adapted for connection to a source of pressurized feed water, ii) a permeate line (16) adapted for connection to a dispenser of treated water and iii) a concentrate line (18) adapted for connection with a drain; wherein the assembly includes a pressurizable reservoir (22) containing weak acid cation exchange resin (25) and further includes at least one valve for selectively diverting flow of pressurized feed water along the feed line (14), through the reservoir (22) and returning to the feed line (14) prior to passing through the hyperfiltration membrane module (12).

Poly(amino acids) having hydrophilic side groups may be grafted onto active surfaces of polyamide composite membranes so as to confer fouling resistance. Polylysine, polyhistidine, polyarginine and their blends with polyglutamic acid may be grafted to membrane surfaces via amide linkages or via peroxide-induces bonding, modifying membrane surfaces behavior towards foulants.

Reverse osmosis membranes made by interfacial polymerization of a monomer in a nonpolar (e.g. organic) phase together with a monomer in a polar (e.g. aqueous) phase on a porous support membrane. Interfacial polymerization process is disclosed for preparing a highly permeable RO membrane, comprising: contacting on a porous support membrane, a) a first solution containing 1,3-diaminobenzene, and b) a second solution containing trimesoyl chloride, wherein at least one of solutions a) and b) contains nanoparticles when said solutions are first contacted, and recovering a highly permeable RO membrane.

A system and a method for reusing waste water from a Reverse Osmosis (RO) filtering process are described, said system including: a Reverse Osmosis (RO) filtration system, from which a flow of highly alkaline waste water results; two tanks intended to receive waste water and able to alternately determine the physical and chemical properties of waste water through sensors or, and perform homogenization, chlorination and chemical treatments of said waste water; an output line which comprises a pump and connects the tanks to a reservoir; and said reservoir being able to blend the water treated by the tanks with treated chlorinated drinking water, depending on the physical and chemical properties of these volumes of water; the chlorination and chemical treatment includes addition of a hypochlorite compound, which reaction releases chlorine in the waste water and causes evaporation of at least O.sub.2 and H.sub.2 gases, reducing the alkaline pH of said waste water.

Provided are an inexpensive, high-quality, permeation-side flow path material that is suitable for use in spiral membrane elements and enables the improvement of productivity, a method for producing such a permeation-side flow path material, and a membrane element having such a permeation-side flow path material. Provided are (a) a permeation-side flow path material for use in a spiral membrane element, the permeation-side flow path material comprising a resin sheet comprising a plurality of ridge portions 31 formed parallel to one another; and a plurality of openings 32 formed between each pair of the ridge portions 31, (b) a method for producing such a permeation-side flow path material, and (c) a membrane element having such a permeation-side flow path material.

A feed of at least one of (a) a source liquid including a solvent with a dissolved impurity and (b) a retentate of the source liquid is pumped in a substantially closed loop through a liquid-separation module. The liquid-separation module includes a membrane that passes at least partially purified solvent to a permeate side of the membrane while diverting the impurity in a retentate on the retentate side of the membrane. The purified solvent is extracted from the permeate side of the membrane; and the retentate from the liquid-separation module is pumped to or through a pressurized reservoir with a variable volume for the feed component and recirculated as a component of the feed. Over time, the volume for the feed is reduced and the pressure applied to the feed in the reservoir is increased to balance against an increasing difference in osmotic pressure across the membrane.