To prevent a very small amount of an ionic metal component such as manganese, iron or the like contained in raw water from being precipitated in treated water as a minute precipitate.
In this modifying method for membrane-treated water, the following filtering operation (1) and backwashing operation (2) are performed. In the filtering operation (1): raw water is sent to the primary side 31 of a membrane filter apparatus 3 from a raw water tank 21 to be filtered and the remainder thereof is circulated and supplied so as to be returned to the raw water tank 21 but an oxidizing agent added heretofore is not used at all and, in the backwashing operation (2): the filtering operation is stopped and primary washing water, to which the oxidizing agent in an oxidizing agent supply tank 22 is added, is supplied to the primary side 31 of a filter membrane 30 to wash the interior of the primary side 31 and a laminated cake layer to sterilize them. Subsequently, backwashing water, to which no oxidizing agent is added, is supplied to the secondary side 32 to backwash the filter membrane 30.
NOGUCHI MOTOHARU
| JPH09122460A | 1997-05-13 | |||
| JP2001191086A | 2001-07-17 | |||
| JP2000185222A | 2000-07-04 | |||
| JP2002028456A | 2002-01-29 | |||
| JPH10230142A | 1998-09-02 |
Akio Najima
Fumio Yamamoto