| 摘要 |
Technical Field: pure water or ultrapure water of a reduced boron concentration used suitably for the production of a semiconductor device. Means for solving the problems: the apparatus comprises a primary pure water treatment system provided with a membrane treatment means and adapted to obtain pure water from treated water in a pretreatment unit (1), a tank (9) for storing this primary pure water, and a secondary pure water treatment system provided with an ion exchange means and a membrane treatment means and adapted to obtain ultrapure water from the primary pure water supplied via the tank (9). A boron selective ion exchange resin is provided in a K tower in a two-bed 3-tower type ion exchange unit (3) in the primary pure water treatment system so that this ion exchange resin is laminated on the upstream side of a strong acid ion exchange resin. Owing to the existence of the boron selective ion exchange resin, the boron concentration in the treated water can be reduced stably for a long period of time. <IMAGE>
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