| 摘要 |
In order to prevent oxidation degradation of a semipermeable membrane and biofouling growth and avoid an increase in cost due to chemicals and the like, the present invention provides a fresh water production method including membrane-filtering raw water with a microfiltration/ultrafiltration membrane module, followed by performing membrane filtration with a semipermeable membrane unit, in which the membrane filtration in the microfiltration/ultrafiltration membrane module is temporarily interrupted, chlorine agent-containing water is fed from a secondary side of the microfiltration/ultrafiltration membrane module to perform back-pressure washing of the microfiltration/ultrafiltration membrane module, thereafter, an ammoniacal compound and/or an amino group-containing compound are added to a primary side of the microfiltration/ultrafiltration membrane module, and the membrane filtration in the microfiltration/ultrafiltration membrane module is resumed. |
