Water treatment device and water treatment method

Patent metadata

Field	Value
Publication number	US-2016176739-A1
Application number	US-201414894284-A
Country	US
Kind code	A1
Filing date	Sep 12, 2014
Priority date	May 26, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A water treatment device 1 includes: a soluble silica deposition section 13 that deposits soluble silica dissolved in water to be treated W 1, the water to be treated W 1 having a concentration of aluminate ion represented by general formula (1) below and a pH that are in predetermined ranges; a solid-liquid separating section 14 that separates the deposited soluble silica from the water to be treated W 1 to obtain water to be treated W 1 in which the soluble silica has been removed from the water to be treated W 1; and a reverse osmosis membrane filtration section 30 that filtrates, by using a reverse osmosis membrane 30 a, the water to be treated W 1 in which the soluble silica has been removed in the solid-liquid separating section 14.
[Al(OH) 4 ] −   Formula (1)

First claim

1 . A water treatment device comprising:
a soluble silica deposition section that deposits soluble silica dissolved in water to be treated, the water to be treated having a concentration of aluminate ion represented by general formula (1) below and a pH that are in predetermined ranges; a solid-liquid separating section that separates the deposited soluble silica from the water to be treated to obtain water to be treated in which the soluble silica has been removed from the water to be treated; and a reverse osmosis membrane filtration section that filtrates, by using a reverse osmosis membrane, the water to be treated in which the soluble silica has been removed in the solid-liquid separating section:
[Al(OH) 4 ] −   Formula (1).

2 . The water treatment device according to claim 1 , further comprising an aluminate ion adding section by which an aluminate ion additive is added to the water to be treated.

3 . The water treatment device according to claim 2 , wherein the aluminate ion additive is sodium aluminate.

4 . The water treatment device according to claim 1 , further comprising a pH adjusting agent adding section by which the pH of the water to be treated is adjusted to a pH of 5.5 or higher by adding a pH adjusting agent to the water to be treated.

5 . The water treatment device according to claim 1 , further comprising a seed material adding section by which soluble silica that is deposited in advance and that is contained in the water to be treated is added, as a seed material, to the water to be treated.

6 . The water treatment device according to claim 1 , further comprising a magnesium ion adding section by which a magnesium ion additive is added to the water to be treated.

7 . The water treatment device according to claim 1 , further comprising an electrolysis apparatus by which aluminate ion-containing water generated by electrolyzing a part of the water to be treated is added, as the aluminate ion additive, to the water to be treated.

8 . The water treatment device according to claim 1 , further comprising an aluminum ion treating section by which aluminum ion contained in the treated water to be supplied to the reverse osmosis membrane filtration section is removed.

9 . The water treatment device according to claim 8 , wherein the aluminum ion is removed by an ion exchange resin provided in the aluminum ion treating section.

10 . The water treatment device according to claim 8 , wherein the aluminum ion is removed by adding a chelating agent to the water to be treated in the aluminum ion treating section.

11 . The water treatment device according to claim 1 , further comprising:
an aluminum ion concentration measurement device that measures an aluminum ion concentration of the water to be treated that is introduced to the reverse osmosis membrane filtration section; and a controlling device that controls at least one of: the aluminate ion concentration, pH of the water to be treated, an added amount of the chelating agent that is added to the aluminum ion treating section, and treatment of the ion exchange resin, based on the aluminum ion concentration that is measured by the aluminum ion concentration measurement device.

12 . A water treatment method comprising:
a deposition step of depositing soluble silica dissolved in water to be treated, the water to be treated having a concentration of aluminate ion represented by general formula (1) below and a pH that are in predetermined ranges; a solid-liquid separating step of solid-liquid separating the deposited soluble silica from the water to be treated to obtain water to be treated in which the soluble silica has been removed from the water to be treated; and a filtration step of filtrating, by using a reverse osmosis membrane filtration section, the water to be treated in which the soluble silica has been removed by the solid-liquid separation:
[Al(OH) 4 ] −   Formula (1).

13 . The water treatment method according to claim 12 , wherein an aluminate ion additive is added to the water to be treated.

14 . The water treatment method according to claim 13 , wherein the aluminate ion additive is sodium aluminate.

15 . The water treatment method according to claim 12 , wherein the pH of the water to be treated is adjusted to a pH of 5.5 or higher by adding a pH adjusting agent to the water to be treated.

16 . The water treatment method according to claim 12 , wherein soluble silica that is deposited in advance and that is contained in the water to be treated is added, as a seed material, to the water to be treated.

17 . The water treatment method according to claim 12 , wherein a magnesium ion additive is added to the water to be treated.

18 . The water treatment method according to claim 12 , wherein aluminate ion-containing water generated by electrolyzing a part of the water to be treated is added, as the aluminate ion additive, to the water to be treated.

19 . The water treatment method according to claim 12 , wherein the aluminum ion contained in the treated water to be supplied to the reverse osmosis membrane filtration section is removed by an aluminum ion treating section.

20 . The water treatment method according to claim 12 , the method further comprising: measuring an aluminum ion concentration in the water to be treated that is introduced to the purifying section of the water to be treated which is used in the filtration step, and controlling at least one of: the aluminate ion concentration, pH of the water to be treated, an added amount of a chelating agent that is added to the aluminum ion treating section, and treatment of the ion exchange resin, based on the measured aluminum ion concentration.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Ukai Nobuyuki
• Okino Susumu
• Suzuki Hideo
• Nakashoji Hiroshi
• Yoshioka Shigeru
• Komatsu Tomomi

Classifications

• B01D2311/06

  Specific process operations in the permeate stream · CPC title

• B01D61/025

  Reverse osmosis; Hyperfiltration · CPC title

• C02F2103/346

  from semiconductor processing, e.g. waste water from polishing of wafers · CPC title

• C02F1/441

  by reverse osmosis · CPC title

• C02F2303/22

  Eliminating or preventing deposits, scale removal, scale prevention (C02F1/042, C02F1/4602, C02F5/00 take precedence) · CPC title