Method for removing COD (Chemical Oxygen Demand) and ammonia nitrogen in ammonium rhenate production wastewater in short process

Abstract

The invention relates to the technical field of wastewater treatment, and particularly discloses a method for removing COD (Chemical Oxygen Demand) and ammonia nitrogen in ammonium rhenate production wastewater in a short process, which comprises the following steps: pumping pretreated wastewater into an advanced oxidation reaction tank, turning on a circulating pump, pumping the wastewater into an ultra-fine bubble generator from the advanced oxidation reaction tank to form ultra-fine bubbles, and then removing ammonia nitrogen in the ultra-fine bubbles; hydroxyl radicals are generated in the waste liquid, the hydroxyl radicals perform chain scission on organic macromolecular pollutants in the waste liquid to form small-molecular organic matters, part of the small-molecular organic matters continue to react with the hydroxyl radicals and are decomposed and mineralized into carbon dioxide and water, and meanwhile, the hydroxyl radicals can perform deep oxidation on ammonia water or ammonium ions; the method comprises the following steps: dissolving ammonium rhenate into ultra-fine bubbles, converting the ultra-fine bubbles into nitrogen and water, directly overflowing the nitrogen from the solution, reacting for 18-36 hours at the temperature of 25-45 DEG C, determining whether to discharge the wastewater according to a monitoring result, and completely degrading COD and ammonia nitrogen in the ammonium rhenate production wastewater in one step by using the ultra-fine bubbles, thereby shortening the process flow and saving the production cost.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process. Background Art

[0002] Ammonia nitrogen is one of the most important pollutants discharged into natural water bodies. It is easily oxidized by microorganisms into nitrate nitrogen and nitrite nitrogen, causing eutrophication of surface water, ultimately leading to acute poisoning of fish and threatening human health. Therefore, converting ammonia nitrogen into gaseous nitrogen has attracted widespread attention.

[0003] Chemical oxygen demand (COD) is a chemical method to measure the amount of reducing substances that need to be oxidized in water samples. It reflects the degree of pollution by reducing substances in water and is also one of the comprehensive indicators of the relative content of organic matter. At present, the method of removing COD and ammonia nitrogen from ammonium rhenate production wastewater is usually to use biological treatment or chemical oxidation method for removal. Among them, the biological treatment method is to convert organic matter in wastewater into harmless substances through the metabolism of microorganisms, such as aerobic treatment and anaerobic treatment; the chemical oxidation method is to oxidize and decompose organic matter in wastewater by adding chemical gasification agents, such as ozone, hydrogen peroxide, etc.

[0004] However, due to the large variety and high concentration of pollutants in the wastewater, multiple treatment methods need to be used in combination, resulting in a complex treatment process and a long time. In addition, there may be some difficult-to-degrade organic substances in the wastewater, which are difficult to be decomposed by microorganisms and difficult to be oxidized by chemical oxidants, resulting in low treatment efficiency of COD and ammonia nitrogen. Therefore, we need to propose a short-process method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater to solve the above-mentioned problems, so that it can completely degrade COD and ammonia nitrogen in ammonium rhenate production wastewater, shorten the process flow, and save production costs. Summary of the invention

[0005] The object of the present invention is to provide a method for removing COD and ammonia nitrogen in ammonium rhenate production wastewater in a short process, which can completely degrade COD and ammonia nitrogen in ammonium rhenate production wastewater, shorten the process flow, save production costs, and solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process comprises the following steps:

[0008] S1. Pre-treating ammonium rhenate production wastewater to remove large particle impurities and adjust the pH value;

[0009] S2, pumping the pretreated wastewater into an advanced oxidation reaction tank;

[0010] S3, connecting the inlet of the ultrafine bubble generator to the circulation pump, so that the outlet of the ultrafine bubble generator is open in the waste liquid, and at the same time ensuring that the air inlet is connected to the atmosphere;

[0011] S4, turning on the circulation pump, the waste liquid is pumped from the advanced oxidation reaction tank into the ultrafine bubble generator to form ultrafine bubbles;

[0012] S5, the ultrafine bubbles enter the advanced oxidation reaction tank from the outlet of the ultrafine bubble generator, and generate hydroxyl radicals in the waste liquid, and the hydroxyl radicals break the chain of the organic macromolecular pollutants in the waste liquid to form small molecular organic matter;

[0013] S6. Some small molecular organic matter continues to react with hydroxyl radicals, decomposing and mineralizing into carbon dioxide and water. At the same time, hydroxyl radicals will also deeply oxidize ammonia water or ammonium ions, converting them into nitrogen and water, and nitrogen will directly overflow from the solution;

[0014] S7. React at a temperature of 25-45°C for 18-36 hours, monitor the treated water, and determine whether to discharge the wastewater based on the monitoring results.

[0015] Preferably, the pretreatment of the ammonium rhenate production wastewater comprises the following steps:

[0016] A1. Remove large particles of impurities from wastewater through screens or filters. Large particles of impurities include suspended solids and sediments.

[0017] A2. Use acidic or alkaline chemicals to adjust the pH value of wastewater to an appropriate range;

[0018] A3. If the composition of wastewater changes greatly over time, homogenization treatment is required to ensure that the composition of wastewater entering the subsequent treatment stage is relatively stable;

[0019] A4. Promote the aggregation and precipitation of tiny particles by adding flocculants or coagulants;

[0020] A5. If the wastewater contains oily substances, oil-water separation is required.

[0021] Preferably, in step A2, the pH value adjustment range depends on the specific oxidant and catalyst used in the advanced oxidation reaction tank. Different oxidants and catalysts have different pH ranges. There are the following three situations:

[0022] 1) When the oxidant is ozone, the catalyst needs to use activated carbon or metal oxide, and the pH value of the wastewater is adjusted to between 7 and 8;

[0023] 2) When the oxidant is hydrogen peroxide, the catalyst needs to use ferrous ions, and the pH value of the wastewater is adjusted to between 3-5:

[0024] 3) When the oxidant is oxygen or air, the catalyst uses a semiconductor photocatalyst and the pH value of the wastewater is adjusted to be between 5 and 9.

[0025] Preferably, the oxidation reaction occurring in the advanced oxidation reaction tank is set to be one of the Fenton reaction, the photocatalytic oxidation reaction and the ozone oxidation reaction, wherein the reaction process of the Fenton reaction is: pumping the pretreated wastewater into the advanced oxidation reaction tank, adjusting the pH value of the wastewater to 3-5, then adding hydrogen peroxide and ferrous ions to the wastewater to react, generating hydroxyl radicals to attack organic matter, oxidizing the organic matter into small molecules or mineralizing it into carbon dioxide and water, adjusting the pH value after the reaction is completed to precipitate iron mud, and finally performing solid-liquid separation;

[0026] The reaction process of photocatalytic oxidation reaction is as follows: the pretreated wastewater is pumped into the advanced oxidation reaction tank containing the photocatalyst, and the reactor is irradiated with ultraviolet light or sunlight to excite the photocatalyst to generate electron-hole pairs, which react with water molecules or OH - Ions react to generate hydroxyl radicals, and electrons react with oxygen to generate superoxide anions, which further react to generate other reactive oxygen species that participate in the oxidation and mineralization of organic matter;

[0027] The reaction process of ozone oxidation reaction is: pump the pretreated wastewater into the advanced oxidation reaction tank containing ozone, inject ozone gas into the wastewater, ozone directly oxidizes organic matter or indirectly oxidizes organic matter by generating hydroxyl radicals, and the remaining ozone after the reaction needs to be degassed or further treated to meet emission standards.

[0028] Preferably, the ultrafine bubble generator includes a microporous material for generating ultrafine bubbles and a generator body for supporting the microporous material, the generator body is provided with a chamber for liquid to flow through the microporous material inside the generator body, one end of the generator body is provided with a liquid inlet for waste liquid to enter, the generator body is also provided with an air inlet for allowing atmospheric gas to enter the interior thereof and a liquid outlet for discharging waste liquid containing ultrafine bubbles.

[0029] Preferably, the diameter of the ultrafine bubbles generated by the ultrafine bubble generator is less than 50 microns. The waste liquid is pressurized by a circulating pump and then sent into the generator. Inside the ultrafine bubble generator, the waste liquid passes through a large number of microporous materials. When the waste liquid passes through the microporous materials, due to the change in pressure, the gas dissolved in the waste liquid is released to form tiny bubbles. At the same time, if the air inlet is connected to the atmosphere, the gas in the atmosphere is sucked in, increasing the generation of bubbles. The generated bubbles flow out of the ultrafine bubble generator with the waste liquid and enter the advanced oxidation reaction tank.

[0030] Preferably, in step S5, the organic macromolecular pollutants in the waste liquid are mainly one or more of organic amines, lower alcohols and oils.

[0031] Preferably, the ultrafine bubbles can be suspended in water for a long time. During the rising process of the ultrafine bubbles in the waste liquid, hydroxyl radicals are generated due to pressure changes. Hydroxyl radicals are strong oxidants and can attack organic molecules. Hydroxyl radicals react with organic macromolecular pollutants in the waste liquid and convert the pollutants into small molecular organic matter through oxidative chain scission. Hydroxyl radicals will continue to attack organic matter until it is completely mineralized into carbon dioxide and water. As the reaction proceeds, the hydroxyl radicals are gradually consumed, and finally harmless substances are generated.

[0032] Preferably, in step S6, when some small molecular organic matter continues to react with hydroxyl radicals, an oxidant and a catalyst need to be added to make the pH value of the wastewater during the reaction between 2.5 and 4.5.

[0033] Preferably, in step S7, the standard for wastewater discharge is to discharge when the monitored value meets the national environmental protection standard. When the monitored value does not meet the national environmental protection standard, S1-S7 are repeated, and the contents monitored for the treated water include COD, ammonia nitrogen content and BOD.

[0034] The short-process method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater proposed by the present invention has the following advantages compared with the prior art:

[0035] 1. The present invention pumps the pretreated wastewater into an advanced oxidation reaction tank, connects the inlet of the ultrafine bubble generator to a circulation pump, opens the outlet of the ultrafine bubble generator in the waste liquid, ensures that the air inlet is connected to the atmosphere, turns on the circulation pump, and the waste liquid is pumped from the advanced oxidation reaction tank into the ultrafine bubble generator to form ultrafine bubbles, which enter the advanced oxidation reaction tank from the outlet of the ultrafine bubble generator to generate hydroxyl free radicals in the waste liquid, which break the chains of organic macromolecular pollutants in the waste liquid to form small molecules. The organic matter and some small molecule organic matter continue to react with hydroxyl radicals, decompose and mineralize into carbon dioxide and water. At the same time, hydroxyl radicals will also deeply oxidize ammonia water or ammonium ions, converting them into nitrogen and water. Nitrogen overflows directly from the solution and reacts at a temperature of 25-45°C for 18-36h. The treated water is monitored and whether to discharge the wastewater is determined based on the monitoring results. The use of ultra-fine bubbles can degrade all COD and ammonia nitrogen in the wastewater of ammonium rhenate production in one step, shortening the process and saving production costs.

[0036] 2. The present invention generates a large number of hydroxyl free radicals by introducing ultrafine bubbles, converting organic macromolecular pollutants into non-toxic and harmless carbon dioxide and water, and oxidizing ammonia water or ammonium ions into nitrogen and water, completely degrading COD and ammonia nitrogen without generating new waste, thus completely solving the problem of secondary pollution.

[0037] 3. The operation method of the present invention is simple, the process is simple and reliable, no reagents need to be added, it is easy to industrialize and automate, and has important economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a flowchart of the present invention;

[0039] Figure 2 The present invention is a flowchart of the pretreatment process of ammonium rhenate production wastewater. DETAILED DESCRIPTION

[0040] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] The present invention provides Figure 1-2 A short-process method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater includes the following steps:

[0042] S1. Pre-treating ammonium rhenate production wastewater to remove large particle impurities and adjust the pH value;

[0043] The ammonium rhenate production wastewater is pretreated, comprising the following steps:

[0044] A1. Remove large particles of impurities from wastewater through screens or filters. Large particles of impurities include suspended solids and sediments.

[0045] A2. Use acidic or alkaline chemicals to adjust the pH value of wastewater to an appropriate range;

[0046] In step A2, the pH value adjustment range depends on the specific oxidant and catalyst used in the advanced oxidation reaction tank. Different oxidants and catalysts have different pH ranges. There are the following three situations:

[0047] 1) When the oxidant is ozone, the catalyst needs to use activated carbon or metal oxide, and the pH value of the wastewater is adjusted to between 7 and 8;

[0048] 2) When the oxidant is hydrogen peroxide, the catalyst needs to use ferrous ions, and the pH value of the wastewater is adjusted to between 3-5:

[0049] 3) When the oxidant is oxygen or air, the catalyst uses a semiconductor photocatalyst and the pH value of the wastewater is adjusted to be between 5 and 9.

[0050] A3. If the composition of wastewater changes greatly over time, homogenization treatment is required to ensure that the composition of wastewater entering the subsequent treatment stage is relatively stable;

[0051] A4. Promote the aggregation and precipitation of tiny particles by adding flocculants or coagulants;

[0052] A5. If the wastewater contains oily substances, oil-water separation is required.

[0053] S2, pumping the pretreated wastewater into an advanced oxidation reaction tank;

[0054] The oxidation reaction occurring in the advanced oxidation reaction tank is set to be one of the Fenton reaction, the photocatalytic oxidation reaction and the ozone oxidation reaction, wherein the reaction process of the Fenton reaction is: pumping the pretreated wastewater into the advanced oxidation reaction tank, adjusting the pH value of the wastewater to 3-5, then adding hydrogen peroxide and ferrous ions to the wastewater to react, generating hydroxyl radicals to attack organic matter, oxidizing the organic matter into small molecules or mineralizing it into carbon dioxide and water, adjusting the pH value after the reaction is completed to precipitate iron mud, and finally performing solid-liquid separation;

[0055] The reaction process of photocatalytic oxidation reaction is as follows: the pretreated wastewater is pumped into the advanced oxidation reaction tank containing the photocatalyst, and the reactor is irradiated with ultraviolet light or sunlight to excite the photocatalyst to generate electron-hole pairs, which react with water molecules or OH - Ions react to generate hydroxyl radicals, and electrons react with oxygen to generate superoxide anions, which further react to generate other reactive oxygen species that participate in the oxidation and mineralization of organic matter;

[0056] The reaction process of ozone oxidation reaction is: pump the pretreated wastewater into the advanced oxidation reaction tank containing ozone, inject ozone gas into the wastewater, ozone directly oxidizes organic matter or indirectly oxidizes organic matter by generating hydroxyl radicals, and the remaining ozone after the reaction needs to be degassed or further treated to meet emission standards.

[0057] S3, connecting the inlet of the ultrafine bubble generator to the circulation pump, so that the outlet of the ultrafine bubble generator is open in the waste liquid, and at the same time ensuring that the air inlet is connected to the atmosphere;

[0058] The ultrafine bubble generator includes a microporous material for generating ultrafine bubbles and a generator body for supporting the microporous material. The generator body is provided with a chamber for liquid to flow through the microporous material inside the generator body. One end of the generator body is provided with a liquid inlet for waste liquid to enter. The generator body is also provided with an air inlet for allowing atmospheric gas to enter the interior thereof and a liquid outlet for the waste liquid containing ultrafine bubbles to flow out.

[0059] S4, turning on the circulation pump, the waste liquid is pumped from the advanced oxidation reaction tank into the ultrafine bubble generator to form ultrafine bubbles;

[0060] The diameter of the raw ultrafine bubbles generated by the ultrafine bubble generator is less than 50 microns. The waste liquid is pressurized by a circulating pump and then sent into the generator. Inside the ultrafine bubble generator, the waste liquid passes through a large number of microporous materials. When the waste liquid passes through the microporous materials, due to the change in pressure, the gas dissolved in the waste liquid is released to form tiny bubbles. At the same time, if the air inlet is connected to the atmosphere, the gas in the atmosphere is sucked in, increasing the generation of bubbles. The generated bubbles flow out of the ultrafine bubble generator with the waste liquid and enter the advanced oxidation reaction tank. Since the bubbles are very small, they can be suspended in the water for a long time instead of rising quickly to the water surface.

[0061] S5. Ultrafine bubbles enter the advanced oxidation reaction tank from the outlet of the ultrafine bubble generator, and generate hydroxyl radicals in the waste liquid. The hydroxyl radicals break the chains of the organic macromolecular pollutants in the waste liquid to form small molecular organic matter; the organic macromolecular pollutants in the waste liquid are mainly one or more of organic amines, low-level alcohols and oils.

[0062] The ultrafine bubbles can be suspended in water for a long time. During the rising process of the ultrafine bubbles in the waste liquid, hydroxyl radicals are generated due to pressure changes. The hydroxyl radicals are strong oxidants and can attack organic molecules. The hydroxyl radicals react with organic macromolecular pollutants in the waste liquid and convert the pollutants into small molecular organic matter through oxidation chain scission. The hydroxyl radicals will continue to attack the organic matter until it is completely mineralized into carbon dioxide and water. As the reaction proceeds, the hydroxyl radicals are gradually consumed and finally generate harmless substances. These harmless substances are further removed through steps such as precipitation, adsorption or membrane filtration to meet emission standards or reuse requirements.

[0063] S6. Some small molecular organic matter continues to react with hydroxyl free radicals, decomposing and mineralizing into carbon dioxide and water. At the same time, hydroxyl free radicals will also deeply oxidize ammonia water or ammonium ions, converting them into nitrogen and water, and nitrogen will directly overflow from the solution. When some small molecular organic matter continues to react with hydroxyl free radicals, oxidants and catalysts need to be added to make the pH value of the wastewater during the reaction between 2.5-4.5.

[0064] S7. React at a temperature of 25-45°C for 18-36 hours, monitor the treated water, and determine whether to discharge the wastewater based on the monitoring results.

[0065] In step S7, the standard for wastewater discharge is to discharge when the monitored value meets the national environmental protection standard. When the monitored value does not meet the national environmental protection standard, S1-S7 are repeated, and the contents monitored for the treated water include COD, ammonia nitrogen content and BOD.

[0066] Based on the method described above, the present invention actually carried out COD and ammonia nitrogen removal verification experiments on ammonium rhenate production wastewater to confirm the COD and ammonia nitrogen removal effects. The results are as follows:

[0067] Experiment 1:

[0068] 100L of ammonium rhenate production wastewater was taken and analyzed, the COD content was 1876.8mg / L, and the ammonia nitrogen content was 67.7mg / L. The inlet of the ultrafine bubble generator was connected to the circulation pump, the outlet of the ultrafine bubble generator was open in the waste liquid, and the air inlet of the ultrafine bubble generator was connected to the atmosphere; the circulation pump was turned on, the waste liquid was pumped into the ultrafine bubble generator from the advanced oxidation reaction tank, and the air was sucked into the ultrafine bubble generator to form ultrafine bubbles. The ultrafine bubbles entered the advanced oxidation reaction tank from the outlet of the ultrafine bubble generator. The reaction temperature was 25°C and the reaction time was 18h.

[0069] After the method of the present invention is used to remove COD and ammonia nitrogen from ammonium rhenate production wastewater, the COD is 50.4 mg / L and the ammonia nitrogen content is 7.4 mg / L.

[0070] Experiment 2:

[0071] 100L of ammonium rhenate production wastewater was taken and analyzed. The COD content was 2131.6mg / L and the ammonia nitrogen content was 61.8mg / L. The inlet of the ultrafine bubble generator was connected to the circulation pump, the outlet of the ultrafine bubble generator was open in the waste liquid, and the air inlet of the ultrafine bubble generator was connected to the atmosphere; the circulation pump was turned on, the waste liquid was pumped into the ultrafine bubble generator from the advanced oxidation reaction tank, and the air was sucked into the ultrafine bubble generator to form ultrafine bubbles. The ultrafine bubbles entered the advanced oxidation reaction tank from the outlet of the ultrafine bubble generator. The reaction temperature was 35°C and the reaction time was 24h.

[0072] After the method of the present invention is used to remove COD and ammonia nitrogen from ammonium rhenate production wastewater, the COD is 55.7 mg / L and the ammonia nitrogen content is 6.9 mg / L.

[0073] Experiment 3:

[0074] 100L of ammonium rhenate production wastewater was taken and analyzed, the COD content was 2468.9mg / L, and the ammonia nitrogen content was 65.1mg / L. The inlet of the ultrafine bubble generator was connected to the circulation pump, the outlet of the ultrafine bubble generator was open in the waste liquid, and the air inlet of the ultrafine bubble generator was connected to the atmosphere; the circulation pump was turned on, the waste liquid was pumped into the ultrafine bubble generator from the advanced oxidation reaction tank, and the air was sucked into the ultrafine bubble generator to form ultrafine bubbles, and the ultrafine bubbles entered the advanced oxidation reaction tank from the outlet of the ultrafine bubble generator. The reaction temperature was 45°C and the reaction time was 36h.

[0075] After the method of the present invention is used to remove COD and ammonia nitrogen from ammonium rhenate production wastewater, the COD is 58.6 mg / L and the ammonia nitrogen content is 7.8 mg / L.

[0076] In summary, the method provided by the present invention can utilize the introduction of ultrafine bubbles to completely degrade COD and ammonia nitrogen in ammonium rhenate production wastewater in one step, shorten the process flow, save production costs, and generate a large number of hydroxyl radicals through the introduction of ultrafine bubbles, converting organic macromolecular pollutants into non-toxic and harmless carbon dioxide and water, while oxidizing ammonia water or ammonium ions into nitrogen and water, completely degrading COD and ammonia nitrogen without generating new waste, and completely solving the problem of secondary pollution. The operation method is simple, the process is simple and reliable, no reagents need to be added, and it is easy to industrialize and automate, with important economic and social benefits.

[0077] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process, characterized in that: The steps include: S1. Pre-treating ammonium rhenate production wastewater to remove large particle impurities and adjust the pH value; S2, pumping the pretreated wastewater into an advanced oxidation reaction tank; S3, connecting the inlet of the ultrafine bubble generator to the circulation pump, so that the outlet of the ultrafine bubble generator is open in the waste liquid, and at the same time ensuring that the air inlet is connected to the atmosphere; S4, turning on the circulation pump, the waste liquid is pumped from the advanced oxidation reaction tank into the ultrafine bubble generator to form ultrafine bubbles; S5, the ultrafine bubbles enter the advanced oxidation reaction tank from the outlet of the ultrafine bubble generator, and generate hydroxyl radicals in the waste liquid, and the hydroxyl radicals break the chain of the organic macromolecular pollutants in the waste liquid to form small molecular organic matter; S6. Some small molecular organic matter continues to react with hydroxyl radicals, decomposing and mineralizing into carbon dioxide and water. At the same time, hydroxyl radicals will also deeply oxidize ammonia water or ammonium ions, converting them into nitrogen and water, and nitrogen will directly overflow from the solution; S7. React at a temperature of 25-45°C for 18-36 hours, monitor the treated water, and determine whether to discharge the wastewater based on the monitoring results.

2. A method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process according to claim 1, characterized in that: The ammonium rhenate production wastewater is pretreated, comprising the following steps: A1. Remove large particles of impurities from wastewater through screens or filters. Large particles of impurities include suspended solids and sediments. A2. Use acidic or alkaline chemicals to adjust the pH value of wastewater to an appropriate range; A3. If the composition of wastewater changes greatly over time, homogenization treatment is required to ensure that the composition of wastewater entering the subsequent treatment stage is relatively stable; A4. Promote the aggregation and precipitation of tiny particles by adding flocculants or coagulants; A5. If the wastewater contains oily substances, oil-water separation is required.

3. A method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process according to claim 2, characterized in that: In step A2, the pH value adjustment range depends on the specific oxidant and catalyst used in the advanced oxidation reaction tank. Different oxidants and catalysts have different pH ranges. There are the following three situations: 1) When the oxidant is ozone, the catalyst needs to use activated carbon or metal oxide, and the pH value of the wastewater is adjusted to between 7 and 8; 2) When the oxidant is hydrogen peroxide, the catalyst needs to use ferrous ions, and the pH value of the wastewater is adjusted to between 3-5: 3) When the oxidant is oxygen or air, the catalyst uses a semiconductor photocatalyst and the pH value of the wastewater is adjusted to be between 5 and 9.

4. A method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process according to claim 3, characterized in that: The oxidation reaction occurring in the advanced oxidation reaction tank is set to be one of the Fenton reaction, the photocatalytic oxidation reaction and the ozone oxidation reaction, wherein the reaction process of the Fenton reaction is: pumping the pretreated wastewater into the advanced oxidation reaction tank, adjusting the pH value of the wastewater to 3-5, then adding hydrogen peroxide and ferrous ions to the wastewater to react, generating hydroxyl radicals to attack organic matter, oxidizing the organic matter into small molecules or mineralizing it into carbon dioxide and water, adjusting the pH value after the reaction is completed to precipitate iron mud, and finally performing solid-liquid separation; The reaction process of the photocatalytic oxidation reaction is as follows: the pretreated wastewater is pumped into an advanced oxidation reaction tank filled with a photocatalyst, ultraviolet light or sunlight is used to irradiate the reactor, the photocatalyst is excited to generate electron-hole pairs, the holes react with water molecules or OH- ions to generate hydroxyl radicals, the electrons react with oxygen to generate superoxide anions, and further react to generate other active oxygen species, which jointly participate in the oxidation and mineralization of organic matter; The reaction process of ozone oxidation reaction is: pump the pretreated wastewater into the advanced oxidation reaction tank containing ozone, inject ozone gas into the wastewater, ozone directly oxidizes organic matter or indirectly oxidizes organic matter by generating hydroxyl radicals, and the remaining ozone after the reaction needs to be degassed or further treated to meet emission standards.

5. A method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process according to claim 4, characterized in that: The ultrafine bubble generator includes a microporous material for generating ultrafine bubbles and a generator body for supporting the microporous material. The generator body is provided with a chamber for liquid to flow through the microporous material inside the generator body. One end of the generator body is provided with a liquid inlet for waste liquid to enter. The generator body is also provided with an air inlet for allowing atmospheric gas to enter the interior thereof and a liquid outlet for the waste liquid containing ultrafine bubbles to flow out.

6. A method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process according to claim 5, characterized in that: The diameter of the raw ultrafine bubbles generated by the ultrafine bubble generator is less than 50 microns. The waste liquid is pressurized by a circulating pump and then sent into the generator. Inside the ultrafine bubble generator, the waste liquid passes through a large number of microporous materials. When the waste liquid passes through the microporous materials, due to the change in pressure, the gas dissolved in the waste liquid is released to form tiny bubbles. At the same time, if the air inlet is connected to the atmosphere, the gas in the atmosphere is sucked in, increasing the generation of bubbles. The generated bubbles flow out of the ultrafine bubble generator with the waste liquid and enter the advanced oxidation reaction tank.

7. A short-process method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater according to claim 6, characterized in that: In step S5, the organic macromolecular pollutants in the waste liquid are mainly one or more of organic amines, lower alcohols and oils.

8. A method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process according to claim 7, characterized in that: The ultrafine bubbles can be suspended in water for a long time. During the rising process of the ultrafine bubbles in the waste liquid, hydroxyl radicals are generated due to pressure changes. The hydroxyl radicals are strong oxidants and can attack organic molecules. The hydroxyl radicals react with organic macromolecular pollutants in the waste liquid and convert the pollutants into small molecular organic matter through oxidative chain scission. The hydroxyl radicals will continue to attack the organic matter until it is completely mineralized into carbon dioxide and water. As the reaction proceeds, the hydroxyl radicals are gradually consumed and finally generate harmless substances.

9. A method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater in a short process according to claim 8, characterized in that: In step S6, when some small molecular organic matter continues to react with hydroxyl radicals, an oxidant and a catalyst need to be added to make the pH value of the wastewater during the reaction between 2.5 and 4.

5.

10. A short-process method for removing COD and ammonia nitrogen from ammonium rhenate production wastewater according to claim 9, characterized in that: In step S7, the standard for wastewater discharge is to discharge when the monitored value meets the national environmental protection standard. When the monitored value does not meet the national environmental protection standard, S1-S7 are repeated, and the contents monitored for the treated water include COD, ammonia nitrogen content and BOD.

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