| 摘要 |
PROBLEM TO BE SOLVED: To sterilize a subsystem of an ultrapure water production and feed device and a terminal piping system without stopping the device. SOLUTION: In this sterilizing method of the ultrapure water production and feed device, ultrapure water being <=50 μg/L in dissolved oxygen concentration, dissolving gaseous hydrogen and showing negative value in oxidation reduction potential is conducted into a water passage of the ultrapure water production and feed device, and a gaseous hydrogen feed device 10 is connected with the ultrapure water production and feed device and with water passages at optional positions of an ultrapure feed piping 6A from the ultrapure water production device to a use point and of an ultrapure water return piping 6B from a use point. |
