| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultra-pure water producing apparatus that can switch the return destination of waste water from a use point corresponding to the waste water quality from the use point to reduce ultra-pure water producing cost.SOLUTION: An ultra-pure water producing apparatus includes a pipe 21 for delivering waste water from a use point 12 to a desalted water tank 4 as it is, a pipe 22 for delivering the water to a water collecting tank 17; and a pipe 23 for delivering the water to a primary pure water tank 7. At the use point 12, switching is performed through which pipes 13, 20 to 22 the waste water is delivered, in accordance with the quality of cleaned waste water or with the operation mode of the use point 12. |
