Patent ID: 8845888
Filing Date: 2014-09-30
Classification: C02F

Abstract:
1. A water treatment system, comprising: a water softening device configured to produce soft water having a hardness of equal to or lower than 0.8 mg CaCO a membrane separation device configured to produce permeate water from the soft water, wherein: the water softening device comprises a pressure tank including a top portion screen, an intermediate portion screen, and a bottom portion screen, the pressure tank having: a valve unit configured to switch between a softening process in which the soft water is obtained by passing the raw water through the cation exchange resin bed downward while supplying the raw water from the top portion screen, and the obtained water is filtered through the supporting bed and collected from the bottom portion screen, and a regeneration process in which the cation exchange resin bed is regenerated by generating an opposite flow of the regenerant by supplying a first portion of the regenerant from the top screen portion and a second portion of the regenerant from the bottom screen portion while filtering with the supporting bed and collecting a liquid at the intermediate portion, and a regenerant supply unit configured to supply the regenerant in a volume which gives a regeneration level of 1 to 6 eq/L-R, with respect to the cation exchange resin bed, in the regeneration process; and the membrane separation device comprises: a bottom portion of the cation exchange resin bed is regenerated in the regeneration process, the bottom portion having a depth D the reverse osmosis membrane module includes a reverse osmosis membrane on a surface of which a skin layer of a negative electric characteristic made of a bridged wholly aromatic polyamide is formed, the reverse osmosis membrane having a water permeability coefficient of 1.5×10