Wastewater treatment method for synchronously removing uranium, manganese and ammonia nitrogen through oxidation method

Abstract

According to the wastewater treatment device for synchronously removing uranium, manganese and ammonia nitrogen through the oxidation method and the using method, a novel pipeline mixer is adopted as a reaction device, compared with a traditional technology, a stirring device is omitted, the whole technological process is closed, no leakage risk exists, and the cost is low. An oxidizing agent hypohalite solution is added into the wastewater through a pipeline dosing port, and precipitates are removed after full reaction, so that the content of uranium, manganese and ammonia nitrogen in the wastewater can be greatly reduced. The method has the advantages of few types of chemicals, no need of special process, easiness in large-scale implementation, small occupied area and suitability for batch wastewater treatment of uranium tailings ponds and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of radioactive wastewater treatment, and in particular relates to a wastewater treatment method for simultaneously removing uranium, manganese, ammonia and nitrogen by an oxidation method and a device used therein. Background Art

[0002] Uranium mining and industrial production processes generate large quantities of wastewater, characterized by high volumes of water, radioactivity, high concentrations of uranium, manganese, ammonia nitrogen, and salinity. If uranium-containing wastewater enters water bodies directly, it could pose adverse impacts to human health and the ecological environment, requiring treatment to meet standards before discharge. Currently, common uranium removal methods, including adsorption, ion exchange, chemical precipitation, and solvent extraction, are insufficient for practical treatment. Extraction methods also introduce organic matter and other issues.

[0003] In addition, excessive manganese can cause hyperthyroidism and damage important organs, and ammonia nitrogen can lead to eutrophication of water bodies. Excessive ammonia nitrogen is an important factor leading to abnormal proliferation of algae and microorganisms in water bodies.

[0004] It can be seen that during the process of tailings pond beach treatment, excessive seepage and drainage are generated, which need to be treated to meet the standards before being discharged. Therefore, a new method for removing uranium, manganese, and ammonia nitrogen is urgently needed. Summary of the Invention

[0005] To address these issues, the present invention provides a wastewater treatment method for the simultaneous removal of uranium, manganese, ammonia, and nitrogen by oxidation. By adding a hypohalite to the wastewater, allowing for a full reaction and then removing the precipitate, the wastewater can significantly reduce the uranium, manganese, and ammonia nitrogen contents. This method utilizes a limited number of reagents, offers simple operation and easy control, and delivers excellent removal results, reducing uranium concentrations to below 0.08 mg / L, manganese concentrations to below 0.02 mg / L, and ammonia nitrogen concentrations to below 12.4 mg / L.

[0006] The object of the present invention is to provide a wastewater treatment method for simultaneously removing uranium, manganese, ammonia and nitrogen by oxidation. The method comprises adding hypohalite to wastewater containing uranium, manganese and ammonia, nitrogen, reacting the wastewater, removing precipitates and obtaining treated wastewater.

[0007] The hypohalite is selected from one or more of hypochlorite and hypobromite, preferably one or more of water-soluble hypochlorites, more preferably calcium hypochlorite and / or sodium hypochlorite.

[0008] After the reaction is completed, the mixture is allowed to stand and settle, and the precipitate is separated to obtain a filtrate, and the pH value is adjusted to 9-10 to obtain treated wastewater.

[0009] The present invention has the following beneficial effects:

[0010] (1) In the present invention, uranium, manganese and ammonia nitrogen in wastewater can be removed by only using hypohalite oxidation. After treatment, the uranium concentration in the wastewater is reduced to below 0.08 mg / L, the manganese concentration is reduced to below 0.02 mg / L, and the ammonia nitrogen concentration is reduced to below 12.4 mg / L.

[0011] (2) The wastewater treatment method for simultaneously removing uranium, manganese, ammonia and nitrogen by oxidation method of the present invention does not need to use a variety of complex reagents. The reagents are simple and easy to implement, avoiding environmental pollution caused by the use of toxic reagents.

[0012] (3) No agitator is required, and the reaction is carried out in a pipeline. The device used is a pipeline mixer. The entire device is a closed device, with no risk of leakage and a small footprint.

[0013] (4) The wastewater treatment method of the present invention has mild process conditions, simple equipment, and is easy to control. It can significantly reduce the concentrations of uranium, manganese, and ammonia nitrogen in wastewater and is suitable for promotion and application in large-scale wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic structural diagram of a pipeline mixer used in a preferred embodiment of the present invention is shown. DETAILED DESCRIPTION

[0015] The present invention will be described in detail below through specific embodiments, and the features and advantages of the present invention will become clearer and more distinct with these descriptions.

[0016] The present invention provides a wastewater treatment method for the simultaneous removal of uranium, manganese, ammonia, and nitrogen by oxidation. By adding hypohalite to the wastewater, allowing for a full reaction and removing the precipitate, the uranium, manganese, and ammonia nitrogen contents in the wastewater can be significantly reduced. This method, which requires no special processes or equipment, is easily scalable and suitable for treating bulk wastewater from uranium tailings ponds and other locations.

[0017] The present invention uses a pipeline mixer as the reaction device. Compared with traditional processes, it eliminates the need for a stirring device. The entire process is closed, eliminating the risk of leakage and occupying a small area. The pipeline mixer is not particularly limited and can be a known pipeline mixer, preferably a pipeline mixer with the structure shown in the figure.

[0018] The method comprises adding hypohalite to wastewater containing uranium, manganese and ammonia nitrogen, reacting the wastewater, removing precipitates and obtaining treated wastewater.

[0019] The hypohalite is selected from one or more of hypochlorite and hypobromite, preferably one or more of water-soluble hypochlorites, more preferably calcium hypochlorite and / or sodium hypochlorite.

[0020] The ratio of the molar amount of the hypohalite to the total molar amount of uranium, manganese and ammonia nitrogen in the wastewater is 2:1-10:1, preferably 3:1-8:1.

[0021] The reaction temperature is 10-60° C., preferably 15-50° C., and more preferably 20-40° C. In the present invention, the use of hypohalite to treat wastewater containing uranium, manganese, and ammonia nitrogen does not require special heating or cooling, and the reaction treatment can be carried out at the above-mentioned ambient temperature. The treatment conditions are mild, which is conducive to batch treatment of wastewater, saves energy, and achieves low-cost treatment.

[0022] The reaction time is 0.5-2 h, preferably 0.5-1.5 h, more preferably 0.5-1 h.

[0023] After the reaction is completed, the precipitate is separated to obtain a filtrate, and the pH value is adjusted to 8-9 with acid to obtain qualified wastewater.

[0024] The method separates the supernatant by filtration, static sedimentation, centrifugation, etc.

[0025] After treatment, the uranium concentration in the wastewater was reduced to below 0.08 mg / L, the manganese concentration was reduced to below 0.02 mg / L, and the ammonia nitrogen concentration was reduced to below 12.4 mg / L.

[0026] Example

[0027] Example 1

[0028] The wastewater from a uranium tailings pond was analyzed and found to have a uranium concentration of 0.8 mg / L, a manganese ion concentration of 25.7 mg / L, and an inorganic ammonia nitrogen concentration of 260 mg / L.

[0029] Take 5000mL of metal-containing, ammonia-containing and radioactive wastewater, add the wastewater and 0.5L of calcium hypochlorite solution (1.25mol / L, effective chlorine content 30%) into the Figure 1 In the pipeline mixer shown, the molar ratio of calcium hypochlorite to ammonia nitrogen is 8:1. At room temperature, the mixture of wastewater and calcium hypochlorite solution flows through the entire reaction pipeline mixer for 0.5 hours. The collected liquid is allowed to stand for 0.5 hours to allow the precipitate to settle, and then filtered and separated to obtain a filtrate.

[0030] Sulfuric acid was added to the filtrate to adjust the value to 8.3 to obtain treated wastewater.

[0031] The uranium content, manganese ion content, and ammonia nitrogen content of the treated wastewater were tested, and the test results are shown in Table 1.

[0032] Table 1:

[0033]

[0034] Example 2

[0035] Metal- and ammonia-nitrogen-containing radioactive wastewater was treated according to the method described in Example 1, with the following difference: 0.5 L of calcium hypochlorite solution (1 mol / L, 30% available chlorine) was added, with a molar ratio of calcium hypochlorite to ammonia nitrogen of 7:1. The pH of the filtrate was adjusted to 9.5. The uranium, manganese ion, and ammonia nitrogen contents of the treated wastewater were measured. The results are shown in Table 2.

[0036] Table 2:

[0037]

[0038] Example 3

[0039] Metal- and ammonia-nitrogen-containing radioactive wastewater was treated according to the method described in Example 1, with the following difference: 0.5 L of calcium hypochlorite solution (0.84 mol / L, 30% available chlorine) was added, with a molar ratio of calcium hypochlorite to ammonia nitrogen of 6:1. The pH of the filtrate was adjusted to 8.9. The uranium, manganese ion, and ammonia nitrogen contents of the treated wastewater were tested. The test results are shown in Table 3.

[0040] Table 3:

[0041]

[0042] Example 4

[0043] Metal- and ammonia-nitrogen-containing radioactive wastewater was treated according to the method described in Example 1, with the following differences: 0.25 L of sodium hypochlorite solution (1.25 mol / L, 30% available chlorine) was added, and the molar ratio of calcium hypochlorite to ammonia nitrogen was 8:1. The pH of the filtrate was adjusted to 8.7. The treated wastewater was tested for uranium, manganese ion, and ammonia nitrogen contents. The results are shown in Table 4.

[0044] Table 4:

[0045]

[0046] The present invention has been described in detail above with reference to specific embodiments and / or exemplary examples and the accompanying drawings. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A wastewater treatment method for simultaneously removing uranium, manganese, ammonia and nitrogen by oxidation, wherein hypohalite is added to wastewater containing uranium, manganese and ammonia and nitrogen, reacted, and precipitates are removed to obtain treated wastewater.

2. The method according to claim 1, characterized in that The hypohalite is selected from one or more of hypochlorite and hypobromite, and is preferably one or more of water-soluble hypochlorites.

3. The method according to claim 2, characterized in that The hypohalite is calcium hypochlorite and / or sodium hypochlorite.

4. The method according to claim 1, wherein The ratio of the molar amount of the hypohalite to the total molar amount of uranium, manganese and ammonia nitrogen in the wastewater is 2:1-10:1, preferably 3:1-8:

1.

5. The method according to claim 1, wherein The reaction temperature is 10-60°C, and the reaction time is 0.5-2h.

6. The method according to claim 1, characterized in that The reaction temperature is 15-50°C, and the reaction time is 0.5-1.5h.

7. The method according to claim 1, characterized in that After the reaction is completed, the precipitate is separated to obtain a filtrate, and the pH value is adjusted to 9-10 with acid to obtain qualified wastewater.

8. The method according to claim 1, characterized in that After treatment, the uranium concentration in the wastewater was reduced to below 0.08 mg / L, the manganese concentration was reduced to below 0.02 mg / L, and the ammonia nitrogen concentration was reduced to below 12.4 mg / L.

9. The method according to claim 1, characterized in that The reaction is carried out in a pipeline mixer, and the pipeline mixer device is a closed device.

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