A system for desalinating water is disclosed. The system comprises a subsea reverse osmosis unit located beneath the surface of a body of water, a first liquid column comprising seawater, a second liquid column comprising desalinated water with a salinity less than seawater, and a brine discharge outlet. Due to the difference in density between the seawater and the desalinated water, the gravitational hydrostatic pressure of the first liquid column may be greater than the gravitational hydrostatic pressure of the second liquid column. At least a portion of the pressure difference for reverse osmosis desalination may be provided by the difference in gravitational hydrostatic pressure between the first liquid column and the second liquid column. A significant reduction in desalination energy consumption may be enabled by discharging the brine at an elevation lower than the maximum elevation of the first liquid column or the second liquid column.

A device for easy and rapid removal of pollutants from drinking water and other liquids. A method for removing a pollutant from a drink by immersing the device into the drink. A method for constructing the device using polypropylene (PP) membrane sheet and an adsorbent.

A desalination brine dispersal apparatus and method employ airlift to remove, oxygenate and disperse brine from a desalination apparatus. The apparatus includes a brine removal conduit having a brine inlet that receives brine from the desalination apparatus, a plurality of brine outlets submerged in seawater and one or more air introduction points located at depths below the brine outlets. The supplied air oxygenates and moves brine through the brine removal conduit and outlets via airlift and disperses the brine into seawater away from the brine removal conduit. The apparatus avoids the formation of concentrated, high shear brine plumes and can disperse brine into seawater over a wide area well away from the brine removal conduit.

The reverse osmosis system with at least one high pressure pump, which supplies untreated water to at least one module pipe, in which a membrane with a permeate collecting pipe is arranged, includes a permeate outlet of the at least one module pipe that is connected by means of a first conduit to a permeate tank, which is in communication by means of a further conduit, connected into which there is a permeate supply pump, with a loop feed line, to which a plurality of dialysis devices are connected and that branching off from the first conduit there is a bypass conduit, which discharges into the further conduit downstream of the permeate tank and the permeate supply pump.

A submersible reverse osmosis desalination apparatus and method employs airlift to remove desalinated water from the apparatus via as annular flow regime over a substantial portion of the product water discharge conduit. Use of a high air fraction for airlift operation and an annular flow regime significantly lowers the weight of the product water column, as well as the backpressure on the downstream side of the osmotic membranes and at the bottom of the discharge water conduit. This permits deployment of the apparatus at reduced depths and in many eases closer to shore. In preferred embodiments the apparatus relies wholly upon hydrostatic pressure to drive seawater through the osmotic membranes, and continuously desalinates seawater and delivers pure water to the discharge water conduit without using any submerged moving parts subject to wear or breakage.

A water treatment system for brackish water is disclosed. The water treatment system includes a first electrochemical separation stage fluidly connected to a second, downstream electrochemical separation stage, with the concentrate outlet of the second electrochemical separation stage fluidly connectable to the concentration compartment of the first electrochemical separation stage and a control system configured to regulate feed directed to the concentration compartments of the first and the second electrochemical separation stages. Methods of treating brackish water to produce potable water and methods of treating brackish water using systems of the invention are disclosed. The Donnan potential difference and osmotic water losses are lessened by controlling a source and a flowrate of a make-up feed water directed to concentration compartments of first and the second electrochemical separation stages of the systems.

A method of providing water suitable for irrigation use includes feeding pre-treated water to an electrodialysis apparatus, treating the pre-treated water in the electrodialysis apparatus by selectively removing either one or both of monovalent anionic and monovalent cationic species from the pre-treated water while retaining either one or both of multivalent anionic and multivalent cationic species to produce a treated water stream having a lower ratio of monovalent ions to multivalent ions than the pre-treated water, and directing the treated water into an irrigation water distribution system.

The reverse osmosis system with at least one high pressure pump, which supplies untreated water to at least one module pipe, in which a membrane with a permeate collecting pipe is arranged, includes a permeate outlet of the at least one module pipe that is connected by means of a first conduit to a permeate tank, which is in communication by means of a further conduit, connected into which there is a permeate supply pump, with a loop feed line, to which a plurality of dialysis devices are connected and that branching off from the first conduit there is a bypass conduit, which discharges into the further conduit downstream of the permeate tank and the permeate supply pump.

A desalination brine dispersal apparatus and method employ airlift to remove, oxygenate and disperse brine from a desalination apparatus. The apparatus includes a brine removal conduit having a brine inlet that receives brine from the desalination apparatus, a plurality of brine outlets submerged in seawater and one or more air introduction points located at depths below the brine outlets. The supplied air oxygenates and moves brine through the brine removal conduit and outlets via airlift and disperses the brine into seawater away from the brine removal conduit. The apparatus avoids the formation of concentrated, high shear brine plumes and can disperse brine into seawater over a wide area well away from the brine removal conduit.

A desalination brine dispersal apparatus and method employ airlift to remove, oxygenate and disperse brine from a desalination apparatus. The apparatus includes a brine removal conduit having a brine inlet that receives brine from the desalination apparatus, a plurality of brine outlets submerged in seawater and one or more air introduction points located at depths below the brine outlets. The supplied air oxygenates and moves brine through the brine removal conduit and outlets via airlift and disperses the brine into seawater away from the brine removal conduit. The apparatus avoids the formation of concentrated, high shear brine plumes and can disperse brine into seawater over a wide area well away from the brine removal conduit.