| 摘要 |
PROBLEM TO BE SOLVED: To accomplish automatic washing of a strainer using raw water having a more excellent washing ability as compared with conventional one and to accomplish enhancement of a filtration performance of a water treatment apparatus by membrane filtration. SOLUTION: The strainer 25 is arranged between a raw water pump 23 and a membrane module 26, an opening/closing valve (strainer outlet valve) 31 is provided between a secondary side water outlet of the strainer and the membrane module, and an opening/closing valve (washing water-discharge valve) 32 and a throttling means (orifice 33) are provided on a washing water-discharge line of the strainer. Before or after the membrane filtration step under the operation state of the raw water pump 23, in the state that the strainer outlet valve 31 is closed, the washing water-discharge valve 32 is opened, and raw water is passed through the washing water-discharge line from a primary side or a secondary side of the strainer by at least a predetermined pump pressure required for strainer washing to wash the strainer. COPYRIGHT: (C)2007,JPO&INPIT
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