Ultrapure water production equipment and its water quality management method

摘要

PROBLEM TO BE SOLVED: To provide a water quality management method for an ultrapure water production apparatus, which makes it easy to identify a location where an abnormality occurs when the metal concentration of ultrapure water does not satisfy the required specifications at a point of use. .. An ultrapure water supply line connected to a primary pure water tank, an ion exchange device, an ultrafiltration membrane device, and the ultrafiltration membrane device to supply ultrapure water toward a point of use. It is a water quality control method of an ultrapure water production apparatus including a return line that branches from an ultrapure water supply line and returns a part of ultrapure water to a primary pure water tank, and is an outlet of the ion exchange apparatus. The metal concentrations of water, water flowing downstream of the ultrafiltration membrane device and upstream of the branch point of the return line of the ultrapure water supply line, and water flowing through the return line are concentrated by a concentration method. Includes an analysis process for analysis. [Selection diagram] Fig. 1