Patent ID: 11958019
Assignee: KURITA WATER INDUSTRIES LTD.
Field: Chemical engineering (Chemistry)
Classification: CPC B  C  Y | IPC B  C

Claim 3:
4. The membrane treatment method according to claim 2, which the membrane separation treatment is a reverse osmosis membrane treatment, wherein concentrated water obtained by the reverse osmosis membrane treatment satisfies the following condition (A) and/or (B), and the following condition (C):
(A) as for filtered water obtained by filtering the concentrated water with a filter having a hole diameter of 0.45 μm, absorbance at a wavelength of 260 nm measured in a cell of 50 mm (abs (50 mm cell)) by using an ultraviolet visible light spectrophotometer is 0.01 to 5.0;
(B) the concentration of total organic carbon (TOC) or non-purgeable organic carbon (NPOC) in the concentrated water is 0.01 to 100 mg/L;
(C) the concentration of polyvalent metal cation in the concentrated water is 1 mg/L or more.