Patent ID: 10160671

Abstract:
A water treatment system includes a first demineralizing section that separates water to be treated including Ca ions, SO4 ions, and carbonate ions into concentrated water and treated water; a crystallizing section including a first crystallizing tank 21 that crystallizes gypsum from the concentrated water and a first seed crystal supplying section 22 that supplies seed crystals of gypsum to the first crystallizing tank 21; a first pH measuring section 543 that measures the pH of the first concentrated water in the first crystallizing tank 21; and a first controlling section that reduces the amount of the seed crystals of the gypsum to be supplied when the measured pH falls within a pH range in which a scale inhibition function of the calcium scale inhibitor is reduced, and increases the amount of the seed crystals of the gypsum to be supplied when the measured pH is beyond the pH range.