| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To produce ultrapure water of high purity which is extremely low in TOC (Total Organic Carbon) concentration, by efficiently decomposing urea in raw water by biological activated carbon treatment even in raw water containing ammonia nitrogen. <P>SOLUTION: The method of producing ultrapure water by treating raw water with a primary pure water system followed by subsystem treatment, includes a process of adding a chlorine-based oxidizer to treating water, and then treating by the biological treating means provided as a preceding step to the subsystem. The chlorine-based oxidizer is added to be five times or more in terms of Cl<SB>2</SB>in relation to the ammonia nitrogen in the treating water treated by the biological treatment means. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
