Abstract: There is described a method of treating potable mains feed water to provide a purified water stream of conductivity <20 ?S/cm, comprising at least the steps of: (a) providing the potable mains feed water into a first storage tank; (b) circulating the feed water in the first storage tank one or more times through a first purification re-circulation loop including a first capacitive deionisation module in a charging mode to provide a first purified water stream having a conductivity less than the feed water; (c) circulating the first purified water stream one or more times through a second purification re-circulation loop including a second capacitive deionisation module in a charging mode to provide a second purified water stream having a conductivity less than the first purified water stream.

Abstract: A method of providing a dispense purified water stream from a water purification apparatus involving passing a water inlet stream through a first water purification station to provide a first internal purified water stream, passing the first internal purified water stream to an internal reservoir, and providing a second internal purified water stream from the reservoir, passing the second internal purified water stream into a recirculation loop, measuring the conductivity of the second internal purified water stream; passing the second internal purified water stream to a second water purification station to provide a third internal purified water stream passing the recirculated water return stream into the internal reservoir; calculating the purity of the first internal purified water stream using the measurement of the conductivity of the second internal purified water stream.

Abstract: A water purification apparatus including a first water purification station for a first internal purified water stream. A valve selects either a first dispense purified water stream or a first continuing water stream or both. An internal reservoir receives the first continuing water stream to hold a volume of second purified water, and provides a second internal purified water stream. A second valve able dispenses the second dispense purified water stream. A second water purification station receives the second internal purified water and provides a third internal purified water stream. A third valve selects from the third internal purified water stream either a third dispense purified water stream, or a third continuing water stream, or both. A recirculation loop returns the third continuing water stream into the internal reservoir. A pump pumps the second internal purified water stream from the internal reservoir around the recirculation loop.

Abstract: A hand-holdable portable water purifying and dispensing unit is described comprising at least a housing, a purified water inlet, a further-purified water dispense outlet, a dispense operator, a reservoir, one or more water further-purification devices, and an internal water recirculation pump and pathway, said pathway including the reservoir and the one or more water further-purification devices. Optionally, the reservoir has a volume in the range 100 ml to 2000 ml, preferably in the range 200 ml and 1000 ml.

Abstract: A method of providing ultrapure water from feed water containing hardness forming ions, comprising at least the steps of passing the feed water successively through: (i) providing a feed water stream containing hardness forming ions: (ii) passing the feed water stream through a reverse osmosis (RO) unit to remove at least some ionic contamination to provide a RO permeate water stream: (iii) passing the RO permeate water stream though a capacitive de-ionisation (CDI) unit to remove at least some of the ions to provide a post-CDI stream: and (iv) passing the post-CDI stream through an electrodeionisation (EDI) unit to remove at least some of the ions and carbon dioxide and to provide an ultrapure water stream for dispense or storage. In this way, the capacitive deionisation provides a wholly or substantially continuous process for removing a proportion of unwanted ions, especially the hardness forming ions, from the feed water prior to the use of electrodeionisation.

Abstract: A method of providing ultrapure water from feed water containing hardness forming ions, comprising at least the steps of passing the feed water successively through: (i) providing a feed water stream containing hardness forming ions: (ii) passing the feed water stream through a reverse osmosis (RO) unit to remove at least some ionic contamination to provide a RO permeate water stream: (iii) passing the RO permeate water stream though a capacitive de-ionisation (CDI) unit to remove at least some of the ions to provide a post-CDI stream: and (iv) passing the post-CDI stream through an electrodeionisation (EDI) unit to remove at least some of the ions and carbon dioxide and to provide an ultrapure water stream for dispense or storage. In this way, the capacitive deionisation provides a wholly or substantially continuous process for removing a proportion of unwanted ions, especially the hardness forming ions, from the feed water prior to the use of electrodeionisation.

Abstract: An electrodeionisation apparatus comprising a first deionising flow path and an integral second deionising flow path is described. The outflow from the first path is held in a holding tank prior to passage through the second flow path, and the outflow from the second path is available for use. Optionally, the second path outflow is partly or fully returned to the holding tank. Me recirculation of the already purified water in the holding tank maintains the water in the holding tank at a higher standard than otherwise “standing” purified water. The water in the holding tank could be separately made available for use. The apparatus requires the use of only a single pair of electrodes and hence one power supply. Moreover, the ion exchange materials in the first deionising flow path can be regenerated when water is not flowing through them such that they have a greater capacity for deionisation when required.

Abstract: An electrodialysis apparatus and method for purifying water. An electrodialysis apparatus including an anode and anode chamber, a cathode and cathode chamber, and a desalting stream flow path comprising a first portion juxtaposed to the anode and a second portion juxtaposed to the cathode is described. By passing water through the apparatus, purified water is produced.