Drainage disposal method and device

A drainage treatment device and drainage treatment technology, applied in the field of drainage treatment, can solve problems such as selective recovery of phosphate ions, low treatment efficiency, difficulty in selective recovery of phosphoric acid, etc.

Inactive Publication Date: 2008-05-21
KOBELCO ECO-SOLUTIONS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, in the method described in Patent Document 1, it is necessary to adjust the amount of iron ions or aluminum ions generated according to changes in the concentration of ions contained in the wastewater, and the treatment becomes complicated.
[0007] Furthermore, because the electric field is used to generate iron ions or aluminum ions, high energy costs are required, and it is particularly difficult to make the concentration of phosphate ions reach the solubility of iron phosphate or aluminum phosphate or below, so the lower the concentration of phosphoric acid, the treatment The lower the efficiency, it is practically difficult to adopt low-concentration drainage such as phosphate ion concentration of 1% or less.
[0008] In addition, the precipitate obtained in this way may contain iron or aluminum salts other than phosphate, and it cannot be said that phosphate ions are selectively recovered
[0009] In addition, in order to recover phosphate ions, it is also conceivable to perform ion exchange using an anion exchange resin, etc., but it is known that generally, anions such as nitrate ions, sulfate ions, and iodide ions are easily ion exchanged with anion exchange resins like phosphoric acid ions. Therefore, it is not possible to use anion exchange resin to ion-exchange the drainage to recover phosphate ions
[0010] Like this, there is the problem that it is difficult to selectively recover phosphoric acid in the wastewater treatment of the prior art
[0011] In addition, this problem exists not only in the wastewater treatment that selectively recovers phosphate ions from wastewater containing low-concentration phosphate ions, such as wastewater that has washed liquid crystal substrates, but also in wastewater containing nitrate ions, sulfate ions, and iodide ions. In the wastewater treatment of selective recovery of phosphate ions in the wastewater of equal ions and phosphate ions

Method used

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  • Drainage disposal method and device
  • Drainage disposal method and device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0114]

[0115] In the first and second anion exchange towers, "Rebachitto MP62WS" of Bayer Chemical Co., Ltd. is respectively arranged as an anion exchange resin, and the respective superficial velocity SV=(treatment amount / resin amount)=10[1 / h], as For the wastewater to be treated, make the acidic wastewater containing 300ppm phosphate ions, 25ppm acetate ions, and 8ppm nitrate ions pass through the first and second anion exchange towers continuously at a flow rate of 3L / min, then wash with pure water, and then use 2 times the equivalent The 10wt% sodium hydroxide aqueous solution is regenerated to obtain the sodium phosphate aqueous solution.

[0116]

[0117] Through the above recovery, 80% or more of the phosphate ions in the wastewater can be recovered in the form of an 8 wt% sodium phosphate salt solution. In addition, the above-mentioned sodium phosphate salt was analyzed by ion chromatography, and the molar ratio of phosphorus to sodium was measured, and the resul...

Embodiment 2

[0120]

[0121] Wastewater treatment and recovery of sodium phosphate were performed in the same manner as in Example 1 except that the aqueous sodium hydroxide solution used for regeneration was 25 wt %.

[0122]

[0123] Through the above recovery, 80% or more of the phosphate ions in the wastewater can be recovered in the form of a 15 wt% sodium phosphate salt solution.

[0124] In addition, in the same manner as above, the regenerated solution was contacted with the cation exchange resin to form a sodium phosphate salt with a pH of 4.5, which was analyzed by ion chromatography, and the molar ratio of phosphorus to sodium was measured. The result was basically 1, thus confirming that the recovered Sodium phosphate is sodium dihydrogen phosphate.

Embodiment 3

[0126]

[0127] Wastewater treatment and recovery of sodium phosphate were performed in the same manner as in Example 1 except that the aqueous sodium hydroxide solution used for regeneration was 40 wt %.

[0128]

[0129] By the recovery described above, the phosphate ions in the waste water can be recovered as a 17 wt % sodium phosphate salt solution.

[0130] However, it was observed that the ion exchange resin reached 70 to 80° C. due to the heat generation when adding sodium hydroxide, and disodium hydrogen phosphate was very easily precipitated.

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Abstract

The present invention provides a method for treating waste water, by which a phosphate ion can easily be recovered selectively from the waste water containing the phosphate ion and other ions such as a nitrate ion, a sulfate ion and an iodide ion. In the waste water treating method for recovering the phosphate ion from the waste water containing the phosphate ion and at least one ion selected from the nitrate ion, the sulfate ion and the iodide ion, the waste water is brought into contact with an anion exchange resin on condition of acidity so as to exchange the ion contained in the waste water from among the nitrate ion, the sulfate ion and the iodide ion, and after that, the ion-changed waste water is brought with the anion exchange resin again so as to allow the anion exchange resin to exchange the phosphate ion in order to recover the phosphate ion. The invention also provides an apparatus used in the method for treating waste water.

Description

technical field [0001] The present invention relates to a wastewater treatment method, in particular to a treatment method and a treatment device for acidic wastewater containing phosphate ions. Background technique [0002] As a substrate of a liquid crystal display panel or the like, a substrate in which a single layer of aluminum or a pattern of a conductive layer formed of two layers of aluminum and molybdenum is formed on an insulating material is used. [0003] When forming the pattern of this conductive layer, a method of etching with an etchant composed of a mixture of nitric acid, phosphoric acid, and acetic acid has been conventionally used. [0004] When producing substrates such as such a liquid crystal display panel, the waste liquid concentration of the etchant produced is high and easy to circulate, so it is easy to divert to other uses. On the other hand, the effluent of the etched liquid crystal substrate has a lower concentration of phosphate ions than the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/42
Inventor 三宅明子
Owner KOBELCO ECO-SOLUTIONS CO LTD
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