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Water treatment process and water treatment system

  • US 9,969,629 B2
  • Filed: 03/30/2015
  • Issued: 05/15/2018
  • Est. Priority Date: 07/05/2013
  • Status: Expired due to Fees
First Claim
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1. A water treatment process comprising:

  • a scale inhibitor supplying step of supplying a calcium scale inhibitor which is a scale inhibitor for inhibiting the deposition of a scale containing calcium to water containing Ca2+ ions SO42−

    ions and carbonate ions;

    a first pH adjusting step of adjusting the water to a pH which is 10 or more;

    a demineralizing step of separating the water in which a pH is 10 or more into concentrated water in which the Ca2+ ions, the SO42−

    ions, and the carbonate ions are concentrated and treated water after the first pH adjusting step;

    a second pH adjusting step of adjusting the concentrated water to a pH which is 6 or less after the demineralizing step;

    a crystallizing step of supplying seed crystals of gypsum to the concentrated water in which a pH is 6 or less containing the calcium scale inhibitor so that gypsum is crystallized from the concentrated water; and

    a separating step of separating the gypsum from the concentrated water after the crystallizing step.

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