FRESH WATER GENERATION METHOD AND FRESH WATER GENERATION DEVICE

摘要

To prevent an oxidation degradation of a semipermeable membrane and an increase in bio-fouling therein and avoid a cost increase due to chemicals or the like, in a fresh water generation method in which raw water is subjected to a membrane filtration with a microfiltration/ultrafiltration membrane module and then subjected to a membrane filtration with a semipermeable membrane unit, the membrane filtration in the microfiltration/ultrafiltration membrane module is temporarily stopped, chlorine agent containing water is supplied from a secondary side of the microfiltration/ultrafiltration membrane module to perform counter pressure cleaning of the microfiltration/ultrafiltration membrane module, and thereafter an ammonia compound and/or an amino compound is added to a primary side of the microfiltration/ultrafiltration membrane module to restart the membrane filtration in the microfiltration/ultrafiltration membrane module.