| 摘要 |
PROBLEM TO BE SOLVED: To provide an operation method of an ultrapure water making apparatus satisfying ultrapure water quality more enhanced in purity, that is, TOC of 0.5 ppb or less. SOLUTION: In a method for operating an ultrapure water making apparatus having a catalyst packed deoxygenating apparatus supplying hydrogen to water to be treated to bring the same into contact with a noble metal catalyst to remove dissolved oxygen in water to be treated and an UV oxidizing device provided on the downstream side thereof along with a desalting device, the amt. of hydrogen supplied to the catalyst packed deoxygenating apparatus is regulated so that the concn. of dissolved oxygen in water to be treated flowing in the UV oxidizing device becomes 15 ppb or less. |
