| 摘要 |
PROBLEM TO BE SOLVED: To provide a pure water producing apparatus capable of recovering the water quality of pure water immediately after starting the operation of the apparatus.SOLUTION: There is provided a pure water producing apparatus which comprises: a first reverse osmosis membrane module 11; a second reverse osmosis membrane module 12; an electric deionization stack 20; sending means 63 executable to send desalted water W6; and a control part 30 for controlling the sending means 63 so that in starting the apparatus, the supply of the desalted water W6 to a demand place is started after performing a first step of returning first permeated water W2 separated by the first reverse osmosis membrane module 11 to the upstream side of the first reverse osmosis membrane module 11 through a first circulation water line L5, a second step of returning second permeated water W4 separated by the second reverse osmosis membrane module 12 to a first permeated water line L2 through a second circulation water line L7, and after the first step and the second step, a third step of returning the desalted water W6 obtained by the electric deionization stack 20 to the first permeated water line L2 through a third circulation water line L9. |
