| abstract |
In order to provide a water treatment method and a water treatment device that treat the backwash drainage, wash drainage, circulating water or concentrated water of the membrane separation device and use it as cooling water for cooling towers. After filtering the discharged water from the cooling tower (1) through the filter (30), it is treated by a pretreatment membrane device (33) such as MF membrane, and then treated by an RO membrane device (reverse osmosis membrane device) (38), Return the RO treated water to the cooling tower (1). The concentrated water, backwash drainage, and washing drainage of the pretreatment membrane device (33) and the RO membrane device (38) are sent back to the water supply piping (11) leading to the side filter (14). |