A submersible water desalination apparatus includes an array of hot-swappable water separation membrane modules arrayed in an approximately polygonal configuration around a product water collection conduit that represents or is proximate to and generally aligned with a central axis of the array; a plurality of hot-swap product water valves connected to the conduit and detachably connected to generally radially-extending product water collection manifolds in fluid communication with a plurality of water separation membrane cartridges within the modules; the modules having in cross-section generally tapered module sides that converge towards the conduit and assist in underwater docking and attachment of a replacement module to a hot-swap product water valve.

A submersible water desalination apparatus includes a plurality of water separation membrane elements that when supplied with salinated water under pressure at a first depth will produce at least partially desalinated product water and concentrate or brine; a product water collector that receives product water from the membrane elements; and a permeate conduit that transports product water from the collector downwardly to a motorized submersible pump remotely located from the membrane elements and collector at a second depth greater than the first depth. The second depth is sufficiently greater than the first depth so that the height of a standing column of product water in the product water collector and permeate conduit between the membrane elements and the suction side of the pump maintains a net positive suction head that prevents inlet side cavitation during pump startup and operation.

A system for an electrochemical process includes an electrochemical reactor, a converter bridge for supplying direct current to electrodes of the electrochemical reactor, and serial inductors connected to alternating voltage terminals of the converter bridge. The converter bridge includes bi-directional controllable switches between the alternating voltage terminals and direct voltage terminals of the converter bridge. Forced commutation of the bi-directional controllable switches enables reduction of current ripple in the direct current supplied to the electrochemical reactor. The forced commutation enables also to control a power factor of an alternating voltage supply of the system.

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.

A submersible water desalination apparatus includes a plurality of water separation membrane elements, a product water collector that receives product water from the membrane elements, and a variable output motorized submersible pump having a suction side that receives product water from the product water collector and a discharge side that pumps product water away from the apparatus through a product water conduit for surface or subsurface use. An automatic control or coupling is employed to reduce the pump output upon the occurrence or onset of suction side cavitation, and discourage or prevent cavitation over a range of product water flow rates from the membrane elements.

A submersible water desalination apparatus includes a plurality of water separation membrane elements, a product water collector that receives product water from the membrane elements, and a variable output motorized submersible pump having a suction side that receives product water from the product water collector and a discharge side that pumps product water away from the apparatus through a product water conduit for surface or subsurface use. At least a portion of the product water is used to lubricate and optionally also cool at least a portion of the pump, motor or both the pump and motor.

Electrodialysis cell systems for water deionization is provided. Also provided are methods for using the electrodialysis cell systems. The cells use the forward and reverse reactions of a redox mediator and the combined operations of a deionization cell and an ion-accumulation cell to enable sustainable deionization with a significantly decreased operating voltage, relative to conventional deionization cells. The cells have applications in seawater desalination, water purification, and wastewater treatment.

An apparatus and a method for producing carbon, oxygen and optionally nitrogen from treated flue gases are provided. The apparatus provides a thermo-dielectric-electric field that splits molecules of carbon dioxide and carbon monoxide into carbon and oxygen and nitrogen oxides into nitrogen and oxygen. The carbon is recovered in a variety of solid forms, and oxygen and nitrogen are recovered as gases.

A device for the electrodeionization of a sample liquid. The device has an anode chamber having two openings and an anode, a cathode chamber having two openings and a cathode, and a treatment chamber, that is arranged between the anode chamber and the cathode chamber and has two openings and ion exchanger. The anode chamber and the cathode chamber are separated from the treatment chamber in each case by a permselective membrane and an energy source is operatively connected to the anode and the cathode. In addition, a method for the electrodeionization of a sample liquid is provided.

A wave-actuated system for desalination of water by reverse osmosis (RO) having a wave energy converter (WEC) subsystem and a RO desalination subsystem is disclosed. The WEC subsystem has a float, a reaction member, and a hydraulic cylinder connected between the float and the reaction member and defining first and second variable volume chambers The RO desalination subsystem has a RO cell containing a RO membrane and a flow smoothing device (FSD). During a first stroke of the WEC subsystem: the float moves in a first direction; and seawater is supplied from the first variable volume chamber to the RO cell and to the FSD. During a second stroke of the WEC subsystem: the float moves in a second direction; seawater is supplied from a seawater intake to the first variable volume chamber; and seawater is supplied from the FSD to the RO cell.