PURE WATER PRODUCING APPARATUS

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: reverse osmosis membrane modules 11 and 12; an electric deionization stack 20; a permeated water line L3 for circulating permeated water W4 separated by the reverse osmosis membrane modules 11 and 12 to the electric deionization stack 20; a desalted water line L8 for sending desalted water W6 to a demand place; sending means 63 executable to send the 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 sending the desalted water W4 separated by the reverse osmosis membrane module 12 to the upstream side of the reverse osmosis membrane modules 11 and 12 through a first circulation water line L7 and after performing the first step, a second step of sending the desalted water W6 obtained by the electric deionization stack 20 to the upstream side of the reverse osmosis membrane module 12 through a second circulation water line L9 .