Treatment method of selenium-containing wastewater

A treatment method and wastewater technology, applied in water/sewage multi-stage treatment, water/sludge/sewage treatment, chemical instruments and methods, etc., can solve the problem of inability to treat selenium-containing wastewater for a long time, limited anaerobic biological tolerance, Groundwater pollution and safety issues, to ensure long-term stable operation, improve environmental and economic benefits, and reduce selenium content

Active Publication Date: 2018-04-10
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method uses selenium-containing wastewater directly into the anaerobic reaction without pretreatment. Due to the limited tolerance of anaerobic organisms, it cannot treat high-concentration selenium-containing wastewater for a long time.
In addition, when the selenium concentration in the wastewater is too high or the selenium concentration is constantly changing, the anaerobic reaction may be affected. If the hexavalent selenium is not completely reduced to tetravalent selenium and exists in the anaerobic effluent, it will affect the subsequent flocculation reaction. Potion selection brings trouble
[0008] In addition, the sewage treatment plant produces a large amount of excess activated sludge every day (about 0.2-0.4 kg of activated sludge is generated for every kg of COD degraded). If it is incinerated, due to the low calorific value, additional fuel needs to be added. If it is landfilled, there may be groundwater pollution or safety problems due to the generation of biogas, and it will take up a lot of land

Method used

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  • Treatment method of selenium-containing wastewater
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  • Treatment method of selenium-containing wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The selenium-containing wastewater is treated by the technological process of the invention. Wastewater quality: pH was 7.3, and the selenate ion (SeO) was determined by single-column ion chromatography. 4 2- ) was 326.3 μg / L, and the selenite ion (SeO 3 2- ) was 269.7 μg / L, COD (Cr method, the same below) was 483 mg / L, and ammonia nitrogen was 53.1 mg / L. The main test equipment composition, operating conditions and treatment effects of each treatment unit are shown in Table 1.

[0028] Table 1 The main processing unit structure and processing effect of Example 1

[0029]

[0030] As can be seen from Table 1, using the treatment process of the present invention, the removal rate of selenium reaches 98.3%, the removal rate of COD is 90.9%, and the removal rate of ammonia nitrogen is 90.4%, and the effluent meets the discharge requirements. The same selenium-containing wastewater was treated with the same operating conditions. After five batches of aerobic biologi...

Embodiment 2

[0032] The selenium-containing wastewater is treated by the method of the invention. Wastewater quality: pH was 6.9, and the selenate ion (SeO) was determined by single-column ion chromatography. 4 2- ) was 1228.3 μg / L, and the selenite ion (SeO 3 2- ) concentration was 1757.7 μg / L, COD: 637 mg / L, ammonia nitrogen: 75.1 mg / L. The main test equipment composition, operating conditions and treatment effects of each treatment unit are shown in Table 2.

[0033] Table 2 The main processing unit structure and processing effect of Example 2

[0034]

[0035] As can be seen from Table 2, using the treatment process of the present invention, the removal rate of selenium reaches 96.8%, the removal rate of COD is 89.9%, and the removal rate of ammonia nitrogen is 90.7%, and the effluent meets the discharge requirements. The same selenium-containing wastewater was treated with the same operating conditions. After five batches of aerobic biological treatment, the sludge concentrati...

Embodiment 3

[0037] The selenium-containing wastewater is treated by the method of the invention. Wastewater quality: pH was 6.9, and the selenate ion (SeO) was determined by single-column ion chromatography. 4 2- ) was 1228.3 μg / L, and the selenite ion (SeO 3 2- ) concentration was 1757.7 μg / L, COD: 637 mg / L, ammonia nitrogen: 75.1 mg / L. The main test equipment composition, operating conditions and treatment effects of each treatment unit are shown in Table 3.

[0038] Table 3 The main processing unit structure and processing effect of Example 3

[0039]

[0040] It can be seen from Table 3 that using the treatment process of the present invention, the removal rate of selenium reaches 98.7%, the removal rate of COD is 92.8%, the removal rate of ammonia nitrogen is 91.6%, and the effluent meets the discharge requirements. The same selenium-containing wastewater was treated with the same operating conditions. After five batches of aerobic biological treatment, the sludge concentrati...

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Abstract

The invention discloses a treatment method for selenium-containing wastewater, comprising: (1) adjusting the pH of the selenium-containing wastewater to 2-4 by using concentrated sulfuric acid, adding cross-linked chitosan to absorb SeO42-in the wastewater; Step (1) Ferric sulfate or ferrous sulfate is added to the effluent to precipitate and remove SeO32‑ in the wastewater; (3) The effluent from step (2) is subjected to aerobic biological treatment. The method of the invention has a high removal rate of total selenium, and can efficiently remove COD and ammonia nitrogen in the wastewater, thereby realizing the up-to-standard treatment of the selenium-containing wastewater.

Description

technical field [0001] The invention belongs to the technical field of environmental protection wastewater treatment, and in particular relates to a treatment method of selenium-containing wastewater. Background technique [0002] With the development of industry and agriculture, the situation of selenium pollution in water is more and more serious, and the phenomenon of excessive selenium in water is becoming more and more common. Selenium-containing industrial wastewater mainly comes from industries that produce and apply selenium, such as smelting metal ores containing selenium, oil refining, thermal power generation, manufacturing sulfuric acid, pigments and special glass. The selenium concentration in coal mining wastewater is generally 3-330 μg / L, the selenium concentration in gold mining wastewater is generally 200-33000 μg / L, and the selenium concentration in oil refining wastewater is generally 170-4900 μg / L. Concentrations can also be as high as 300 μg / L. Accordi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/14
Inventor 许莹周彤郭宏山
Owner CHINA PETROLEUM & CHEM CORP
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