Post treatment for desalinated and soft water for balanced water composition supply

A salt water and seawater technology, applied in water/sewage treatment, neutralized water/sewage treatment, multi-stage water/sewage treatment, etc., can solve the problems of not being able to provide naturally, not meeting the proportion requirements, not being provided in water, etc.

CN101631750AInactive Publication Date: 2010-01-20TECHNION RES & DEV FOUND LTD
0 Cites 2 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2010-01-20
Estimated Expiration
Not applicable · inactive patent

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

An H2S04-based calcite dissolution post-treatment process and apparatii for desalinated water are provided. The process comprises separating cations from seawater by ion exchange resin (s) (12) onto which the ions are loaded, contacting the ion exchange resin (s) (12) loaded with the cations with an effluent (1) of a calcite dissolution reactor (10) wherein the cations are exchanged with Ca2+ from this effluent. The Ca2+ concentration of the resulting desalinated water (6) decreases while the cations concentration increases to comply with required quality criteria. Batch type and continuous apparatii by which the process can be carried out are described.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The present invention relates to demineralized and softened water. More specifically, the present invention relates to post-treatment of demineralized and demineralized water for providing a balanced water composition. Background technique

[0002] Desalination of seawater and brackish water is gaining increasing attention worldwide. It is expected that the proportion of desalinated water in total water consumption in many countries will increase significantly in the near future. There are two types of desalination methods in the industry: reverse osmosis (RO) technology and electrodialysis technology. Both types of methods produce water with very low dissolved solids content. Many places also have naturally soft water. In order to improve the quality of these water resources, they need to be treated (demineralized water is treated after the membrane separation step, and the technical term is called "post-treatment"). Water low in dissolved substa...

Examples

Embodiment 1

Embodiment 1 (operation under continuous mode)

[0057] Water quality requirements for post-treatment process outlets

Alkalinity>90mg / L CaCO 3

120>[Ca 2+ ]≥80mg / L CaCO 3

[Mg 2+ ]=24.3mg / L Mg 2+

CCPP≥3.0mg / L CaCO 3

pH=<8.5

General design

[0058] The chemicals that need to be added to the water as it passes through the calcite reactor are (assuming only 25% of the water passes through the calcite reactor, the chemical added per cubic meter of water represents 25% of these values):

h 2 SO 4 (100%)=487mg / L (pH reaches 2.06)

CaCO 3(s) =760mg / L

[0059] According to the existing calcite dissolution method, this water flow should be combined with 75% untreated water and added NaOH to obtain a pH value of about 7.8 to obtain the following results: Alkalinity = 92.5mg / L CaCO 3 , [Ca 2+ ]=190mg / L CaCO 3 , CCPP=3.2mg / L CaCO 3 (NaOH required in this hypothetical case is 21.4 mg / L).

[0060] In the method that the present invention proposes, the water quality...

Embodiment 2

Embodiment 2 (multi-column operation)

[0066] Water quality requirements for post-treatment process outlets

Alkalinity≥65mg / L CaCO 3

120>[Ca 2+ ]≥80mg / L CaCO 3

[Mg 2+ ]=12.15mg / L

CCPP≥2.0mg / L CaCO 3

pH<8.5

General design

[0067] The chemicals that need to be added to the water as it passes through the calcite reactor are (assuming only 25% of the water passes through the calcite reactor, the chemical added to the entire water flow represents a quarter of the dosage stated in this article):

h 2 SO 4 (100%)=316mg / L (pH reaches 2.24)

CaCO 3(s) =525mg / L

[0068] According to the existing calcite dissolution method, this water flow should be combined with 75% untreated water and added NaOH to obtain a pH value of about 8.2 to obtain the following results: Alkalinity = 66mg / L CaCO 3 , [Ca 2+ ]=132mg / L CaCO 3 , CCPP=3.0mg / L CaCO 3 (NaOH dosage required in this case is 12.3 mg / L).

[0069] In the method that the present invention proposes, the water (its...