The invention relates to a method and a system for purifying water
whereby: the water to be purified is pressurized; a pressurized flow of
said water is directed onto at least one selective permeability membrane
to divide (11) the flow of pressurized water into a permeate flow and a
retentate flow; the permeate flow is electrodeionized (12) to produce a
flow of purified water consisting of the electrodeionized permeate flow;
the flowrate of the retentate flow (19) is reduced; a substantially
constant predetermined pressure (21) is maintained on the selective
permeability membrane(s); and a substantially constant predetermined
permeate flowrate is maintained and also relates to a suitable tangential
filtration module system.