WATER TREATMENT SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a water treatment system which can keep the film performance of specified biofilm reliably until the operation of a biofilm treatment apparatus is resumed even when a some-extent long time elapses from the stop of take-in of fresh water to be treated.SOLUTION: A water treatment system A is provided with a reverse osmosis membrane apparatus 2 for separating to-be-treated water 3 (target water 3) into concentrated water 12 of a high solute concentration and plain water 13 and includes a biofilm treatment apparatus 4 which is provided with a support having biofilm on the surface and treats the target water 3 before passing through the reverse osmosis membrane apparatus 2 and target water stopping-time circulation means 7 which operates at the time of stopping take-in of fresh target water 3 and supplies the target water 3 from the target water discharge port 4a side to the target water supply port 4b side or from the target water supply port 4b side to the target water discharge port 4a side of the biofilm treatment apparatus 4 so as to circulate the target water 3 and/or target water stopping-time supply means 8 of supplying fresh target water 3 to the biofilm treatment apparatus 4.