| abstract |
A water treatment method for treating backwash waste water, wash waste water, circulating water or concentrated water of a membrane separator and using it as cooling water for a cooling tower and a water treatment device therefor are provided. SOLUTION: The blow water of the cooling tower 1 is filtered by a filter 30 and then treated by a pretreatment membrane device 33 such as an MF membrane, and then treated by an RO device (reverse osmosis membrane device) 38. Return to cooling tower 1. The concentrated water, backwash waste water, and wash waste water from the pretreatment membrane device 33 and the RO device 38 are returned to the water supply pipe 11 to the side filter 14. [Selection] Figure 1 |