Cooperative treatment method for wastewater of nuclear power plant
By classifying and mixing nuclear power plant wastewater to generate ammonium phosphate precipitate and recycle it, the problems of high reagent consumption, low efficiency and high energy consumption in existing technologies are solved, and efficient and low-cost wastewater treatment and resource recycling are achieved.
Patent Information
- Application Number
- CN202511531982.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-24
- Publication Date
- 2026-01-02
AI Technical Summary
Existing nuclear power plant wastewater treatment technologies suffer from problems such as high reagent consumption, low treatment efficiency, low resource utilization, and high energy consumption. Furthermore, the coordination between different treatment units is poor, and substances are not effectively utilized.
Nuclear power plant wastewater is classified into five categories, collected separately, and treated together. Through steps such as settling, stripping, electrochemical reaction, and biological treatment, the wastewater is treated in a synergistic manner, generating ammonium phosphate precipitate for recycling and reducing the use of external chemical agents.
It achieves efficient and low-cost wastewater treatment, resource recycling, reduced reagent consumption and energy consumption, and achieves efficient removal of phosphorus and ammonia nitrogen. The generated ammonium phosphate can be recycled as fertilizer, and the effluent quality stably meets the discharge standards.
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Figure CN121248060A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of industrial wastewater treatment, and particularly relates to a nuclear power plant wastewater collaborative treatment method. BACKGROUND
[0002] A nuclear power plant generates various non-radioactive industrial wastewater during operation. The wastewater has the following characteristics: the pollutants come from multiple systems, including phosphorus, ammonia nitrogen, and substances with high chemical oxygen demand (COD); the concentration of pollutants fluctuates greatly, and the concentration of some pollutants is extremely high (for example, the concentration of total phosphorus in the wastewater discharged by a nuclear power plant can reach 127 mg / L, which is 254 times higher than the standard, and the concentration of ammonia nitrogen can reach 1238 mg / L, which is 124 times higher than the standard); the water quality is complex, and there are problems such as mixed acid and alkali, and excessive color. The existing treatment technology has the following defects: a unified mixing treatment method is used, the consumption of chemicals is large, and the treatment efficiency is low; the collaboration of each treatment unit is poor, and effective use of substances cannot be achieved; by-products cannot be effectively recovered, and the resource utilization rate is low; and the energy consumption of electrochemical oxidation and other advanced oxidation processes is too high due to insufficient wastewater conductivity. Therefore, it is necessary to develop a nuclear power plant non-radioactive industrial wastewater treatment method that does not depend on external chemicals, treats pollutants in stages, recycles substances, and synergistically enhances the treatment units. SUMMARY
[0003] The present application provides a nuclear power plant wastewater collaborative treatment method to reduce the consumption of chemicals during the treatment of nuclear power plant wastewater and improve the treatment efficiency.
[0004] The present application provides a nuclear power plant wastewater collaborative treatment method, which comprises the following steps:
[0005] Collecting a first wastewater, a second wastewater, a third wastewater, a fourth wastewater, and a fifth wastewater, respectively, wherein the first wastewater is phosphorus-containing wastewater, the second wastewater is ammonia nitrogen-containing wastewater, the third wastewater is anion resin regeneration wastewater, the fourth wastewater is cation resin regeneration wastewater, and the fifth wastewater is resin backwash water;
[0006] Mixing the first wastewater and the second wastewater to obtain a first mixed solution;
[0007] Mixing the third wastewater, the fourth wastewater, the fifth wastewater, and the first mixed solution to obtain a second mixed solution, and subjecting the second mixed solution to standing treatment to obtain a supernatant;
[0008] Placing the supernatant in a stripping tower, and adding the third wastewater to the stripping tower to obtain a third mixed solution;
[0009] The third mixed solution is subjected to stripping treatment, and the stripping gas is introduced into an absorption tower and absorbed by the first type of wastewater to obtain a fourth mixed solution;
[0010] The fourth mixed solution is mixed with the third type of wastewater, the fourth type of wastewater and the fifth type of wastewater to obtain a fifth mixed solution, and the fifth mixed solution is treated by an electrochemical reactor to obtain a sixth mixed solution;
[0011] The sixth mixed solution is introduced into a biological tank for treatment.
[0012] In an embodiment of the present application, the phosphorus content of the first type of wastewater is greater than or equal to 100 mg / L, the ammonia nitrogen content of the second type of wastewater is greater than or equal to 1000 mg / L, and the pH of the second type of wastewater is greater than or equal to 10.0.
[0013] In an embodiment of the present application, the molar ratio of the first type of wastewater to the second type of wastewater in the first mixed solution is 1:3.
[0014] In an embodiment of the present application, the pH of the second mixed solution is 7.5-8.5.
[0015] In an embodiment of the present application, the temperature of the stripping tower is 40-45℃.
[0016] In an embodiment of the present application, the pH of the third mixed solution is 10.5-11.0.
[0017] In an embodiment of the present application, the pH of the fifth mixed solution is 7.0-7.5.
[0018] In an embodiment of the present application, the current density of the electrochemical reactor is 25-35 mA / cm 2 , and the reaction time is 40-50 min.
[0019] In an embodiment of the present application, the concentration of dissolved oxygen in the biological tank is 2.0-3.0 mg / L, and the hydraulic retention time of the sixth mixed solution in the biological tank is 8-10 h.
[0020] In an embodiment of the present application, the electrode of the electrochemical reactor is a titanium-based electrode.
[0021] The application has the following beneficial effects: the nuclear power plant wastewater collaborative treatment method provided by the application mixes a first wastewater with a second wastewater, a third wastewater, a fourth wastewater and a fifth wastewater to obtain a second mixed liquid, and phosphorus and ammonia nitrogen in the second mixed liquid react to generate ammonium phosphate precipitate, so as to remove the phosphorus and part of the ammonia nitrogen in the second mixed liquid. The supernatant of the second mixed liquid is mixed with the third wastewater to obtain a third mixed liquid, the third mixed liquid is subjected to stripping treatment to remove ammonia gas in the third mixed liquid, the first wastewater is used as an absorption liquid to absorb the waste gas generated by the stripping, and the wastewater is sequentially treated by an electrochemical reactor and a biological pool, so that the discharged wastewater meets the discharge standard. The treatment method does not need to add chemical reagents, and can reduce the treatment cost. BRIEF DESCRIPTION OF DRAWINGS
[0022] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one embodiment consistent with the application and, together with the description, serve to explain the principles of the application. It is apparent that the accompanying drawings in the following description are only some embodiments of the application, and other drawings can be obtained from these drawings without creative labor for those skilled in the art.
[0023] In the drawings:
[0024] Figure 1 A flow chart of the nuclear power plant wastewater collaborative treatment provided by an embodiment of the application is shown in the figure.
[0025] Figure 2 A schematic diagram of the nuclear power plant wastewater collaborative treatment provided by an embodiment of the application is shown in the figure.
[0026] The reference signs are as follows:
[0027] 100, first liquid storage tank; 110, second liquid storage tank; 120, third liquid storage tank; 130, fourth liquid storage tank; 140, fifth liquid storage tank; 200, reaction pool; 300, stripping tower; 400, absorption tower; 500, electrochemical reactor; 600, biological pool. DETAILED DESCRIPTION
[0028] The embodiments of the application are described below through specific, concrete examples, and those skilled in the art can easily understand other advantages and effects of the application from the disclosure in the specification. The application can also be implemented or applied through other different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the application, and the following embodiments and features in the embodiments can be combined with each other without conflict.
[0029] It is to be noted that the drawings provided in the following embodiments merely illustrate the basic concept of the present application in a schematic manner, and the drawings only show the components related to the present application, not the number, shape and size of the components when actually implemented. The actual implementation of each component can be a random change, and the component layout pattern can be more complex.
[0030] In the following description, numerous specific details are discussed in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to one of ordinary skill in the art that the embodiments of the present application can be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the embodiments of the present application.
[0031] Herein, with respect to a numerical range, if not otherwise specified, the distribution of the selectable values in the numerical range is considered to be continuous, and includes both numerical end points (i.e. the minimum value and the maximum value) of the numerical range, and each value between the two numerical end points. When multiple numerical ranges are provided to describe a feature or a characteristic, the numerical ranges can be combined.
[0032] Please refer to Figure 1 and Figure 2 The present application provides a nuclear power plant wastewater collaborative treatment method, which comprises the following steps:
[0033] S1, collecting a type of wastewater, a type of wastewater, a type of wastewater, a type of wastewater and a type of wastewater respectively, the a type of wastewater is phosphorus-containing wastewater, the a type of wastewater is ammonia nitrogen-containing wastewater, the a type of wastewater is anion resin regeneration wastewater, the a type of wastewater is cation resin regeneration wastewater, and the a type of wastewater is resin backwashing water.
[0034] S2, mixing and stirring the a type of wastewater and the a type of wastewater uniformly to obtain a first mixed solution.
[0035] S3, mixing the a type of wastewater, the a type of wastewater, the a type of wastewater and the first mixed solution to obtain a second mixed solution, and performing standing treatment on the second mixed solution to obtain a supernatant.
[0036] S4, placing the supernatant in a stripping tower 300, and adding the a type of wastewater into the stripping tower 300 to obtain a third mixed solution.
[0037] S5, performing stripping treatment on the third mixed solution, and introducing the gas generated by stripping into an absorption tower 400, and using the a type of wastewater as an absorption liquid to obtain a fourth mixed solution.
[0038] S6, mixing the fourth mixed solution with the a type of wastewater, the a type of wastewater and the a type of wastewater to obtain a fifth mixed solution, and using an electrochemical reactor 500 to treat the fifth mixed solution to obtain a sixth mixed solution.
[0039] S7, the sixth mixed solution is introduced into the biological tank 600 for treatment.
[0040] In step S1, in an embodiment, a first type of wastewater is collected into the first storage tank 100, a second type of wastewater is collected into the second storage tank 110, a third type of wastewater is collected into the third storage tank 120, a fourth type of wastewater is collected into the fourth storage tank 130, and a fifth type of wastewater is collected into the fifth storage tank 140. The first storage tank 100 is provided with a phosphorus detection device for detecting the phosphorus content in the first type of wastewater, and the second storage tank 110 is provided with a first ammonia nitrogen detection device for detecting the ammonia nitrogen content in the second type of wastewater and a first pH detection device for detecting the pH of the second type of wastewater. For example, the phosphorus content in the first type of wastewater is ≥100 mg / L, the ammonia nitrogen content in the second type of wastewater is ≥1000 mg / L, and the pH of the second type of wastewater is ≥10.0. The third storage tank 120 is provided with a second pH detection device for detecting the pH of the third type of wastewater.
[0041] In step S2, the first type of wastewater and the second type of wastewater are flowed into the reaction tank 200 for reaction. When the first type of wastewater is mixed with the second type of wastewater, the first type of wastewater and the second type of wastewater are mixed at a molar ratio of 1:3 of the phosphorus content in the first type of wastewater to the ammonia nitrogen content in the second type of wastewater, and the phosphorus in the first type of wastewater and the ammonia nitrogen in the third type of wastewater can preliminarily react to generate ammonium phosphate under the condition of no additional reagent. After the first type of wastewater is mixed with the second type of wastewater, the first type of wastewater and the second type of wastewater are fully stirred, for example, the stirring time of the first type of wastewater and the second type of wastewater is 15 min.
[0042] In step S3, the third type of wastewater, the fourth type of wastewater, and the fifth type of wastewater are added to the reaction tank 200 to mix with the first mixed solution to form a second mixture. The reaction tank 200 is provided with a third pH detection device for detecting the pH of the second mixed solution. The ammonia nitrogen in the third type of wastewater, the fourth type of wastewater, and the fifth type of wastewater can react with the residual phosphorus in the first mixed solution to generate ammonium phosphate, and by adjusting the ratio of the third type of wastewater and the fourth type of wastewater, the pH of the solution can also be adjusted to promote the crystallization of ammonium phosphate. For example, the pH of the second mixed solution is 7.5-8.5, for example, 7.5, 8.0, or 8.5, or any value in the range of 7.5-8.5. The second mixed solution is allowed to stand for treatment, so that the phosphorus and the ammonia nitrogen are fully reacted to obtain ammonium phosphate precipitate, realizing the simultaneous removal of phosphorus and ammonia nitrogen. The generated ammonium phosphate precipitate can be recovered as fertilizer, realizing the goal of recycling waste into treasure. The obtained supernatant is further treated to meet the discharge standard. The standing time is not limited here, and the precipitate can be separated from the supernatant.
[0043] In step S4, the pH of the solution is adjusted by mixing the three types of wastewater with the supernatant in the stripping tower 300 to reduce the content of ammonia nitrogen in the third mixed solution by stripping ammonia nitrogen. Exemplarily, the pH of the third mixed solution is 10.5-11.0, for example, any value in the range of 10.5-11.0, such as 10.5, 10.8, or 11.0. The temperature of the stripping tower 300 is 40-45°C, for example, any value in the range of 40-45°C, such as 40°C, 43°C, or 45°C. In an embodiment, a second ammonia nitrogen detection device is arranged on the stripping tower 300 to detect the content of ammonia nitrogen in the third mixed solution. When the content of ammonia nitrogen in the third mixed solution is reduced to 10 mg / L or less, it indicates that the removal of ammonia nitrogen in the third mixed solution after stripping reaches the discharge standard, and the exhaust gas generated by stripping in the stripping tower 300 is further treated.
[0044] In step S5, the exhaust gas generated by stripping in the stripping tower 300 is introduced into the absorption tower containing the first type of wastewater for absorption treatment. The exhaust gas generated by stripping contains ammonia gas, which reacts with phosphorus in the first type of wastewater to generate ammonium phosphate. Therefore, the fourth mixed solution obtained by introducing the exhaust gas generated by stripping into the first type of wastewater contains ammonium phosphate.
[0045] In step S6, a fourth pH detection device is arranged on the electrochemical reactor to detect the pH of the fifth mixed solution. Mixing the fourth mixed solution with the third type of wastewater, the fourth type of wastewater, and the fifth type of wastewater can adjust the pH of the solution. Exemplarily, the pH of the fifth mixed solution is 7.0-7.5, for example, any value in the range of 7.0-7.5, such as 7.0, 7.2, or 7.5. The treatment of the fifth mixed solution in the electrochemical reactor can remove ammonia nitrogen and COD in the fifth mixed solution. Exemplarily, the electrochemical oxidation of the fifth mixed solution is carried out by using a three-dimensional electrode, for example, a titanium-based electrode. The electrochemical oxidation can be realized by using the electrical conductivity of the fifth mixed solution itself. Exemplarily, the current density of the electrochemical reactor is 25-35 mA / cm 2 , for example, any value in the range of 25-35 mA / cm 2 , such as 25 mA / cm 2 , 30 mA / cm 2 , or 35 mA / cm 2 . The reaction time is 40-50 min, for example, any value in the range of 40-50 min, such as 40 min, 45 min, or 50 min. Since ammonium phosphate is generated in the fourth mixed solution in step S5, the fifth mixed solution obtained by mixing the fourth mixed solution with the third type of wastewater, the fourth type of wastewater, and the fifth type of wastewater contains ammonium phosphate, which can improve the electrical conductivity during the electrochemical reaction. The electrical conductivity of the fifth mixed solution is ≥3.0 mS / cm.
[0046] In step S7, in the field of wastewater treatment, the biological tank is a core treatment unit for degrading pollutants by using metabolic action of microorganisms. The essence thereof is to provide a suitable living environment for microorganisms, and purify water quality by decomposition and conversion of organic matter, nitrogen, phosphorus and other pollutants by microorganisms. In the present application, the residual nitrogen and phosphorus in the sixth mixed solution are used as a nutrient source for microorganisms to remove nitrogen and phosphorus in the sixth mixture. Exemplarily, the concentration of dissolved oxygen (DO) in the biological tank is 2.0-3.0 mg / L, for example, 2.0 mg / L, 2.5 mg / L or 3.0 mg / L, or any value in the range of 2.0-3.0 mg / L. The hydraulic retention time of the sixth mixed solution in the biological tank is 8-10 h, for example, 8 h, 9 h or 10 h, or any value in the range of 8-10 h.
[0047] The wastewater treatment method of the present application is a method for treating non-radioactive industrial wastewater of a nuclear power plant by process synergy and material circulation. It is suitable for treating industrial wastewater containing high-concentration phosphorus, high-concentration ammonia nitrogen and complex mixed pollutants. The method has the following advantages:
[0048] No additional chemical agents are required, which can reduce the treatment cost and avoid the risk of storage and transportation of agents.
[0049] Efficient recycling of multiple types of wastewater materials is achieved, and the removal rates of nitrogen and phosphorus are above 99% and 98%, respectively.
[0050] A pH self-regulating system is constructed by using the characteristics of wastewater, and the control accuracy is ±0.3.
[0051] The generated ammonium phosphate precipitate can be recycled as fertilizer, achieving the goal of recycling waste into treasure.
[0052] In the electrochemical treatment stage, the energy consumption is reduced due to the naturally formed electrolyte.
[0053] The biological treatment unit uses the original pollutants as a nutrient source, reducing sludge production.
[0054] The final effluent has stable quality: total phosphorus ≤0.5 mg / L, ammonia nitrogen ≤1.0 mg / L, COD ≤50 mg / L, and colority ≤15.
[0055] The technical solutions of the present application will be described in detail below through several specific examples. Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by conventional methods in the art, and the instruments used in the examples are commercially available.
[0056] Example 1
[0057] In this embodiment, the wastewater treatment of the nuclear power plant includes the following steps:
[0058] The first type of wastewater, the second type of wastewater, the third type of wastewater, the fourth type of wastewater and the fifth type of wastewater are collected respectively. The first type of wastewater is phosphorus-containing wastewater, the second type of wastewater is ammonia nitrogen-containing wastewater, the third type of wastewater is anion resin regeneration wastewater, the fourth type of wastewater is cation resin regeneration wastewater, and the fifth type of wastewater is resin backwashing water. The phosphorus content in the first type of wastewater is 127 mg / L, the pH of the first type of wastewater is 10.2, the ammonia nitrogen concentration of the second type of wastewater is 1238 mg / L, the pH of the second type of wastewater is 9.8, the NaOH concentration of the third type of wastewater is 1.1 g / L, the colority is 23, the HCl concentration of the fourth type of wastewater is 1.5 g / L, the colority is 18, the ammonia nitrogen concentration of the fifth type of wastewater is 169 mg / L, the COD Cr concentration is 513 mg / L, and the colority is 40.
[0059] The first type of wastewater and the second type of wastewater are mixed in a proportion of 1:3 of phosphorus to ammonia nitrogen molar ratio to obtain a first mixed solution.
[0060] The third type of wastewater, the fourth type of wastewater, the fifth type of wastewater and the first mixed solution are mixed to obtain a second mixed solution, and the pH of the second mixed solution is 8.5. The second mixed solution is allowed to stand for 20 min to obtain a supernatant. The generated ammonium phosphate precipitate can be used as a fertilizer. The total phosphorus in the supernatant is reduced to 3.8 mg / L, and the ammonia nitrogen is reduced to 856 mg / L.
[0061] The supernatant is placed in a stripping tower, and the third type of wastewater is added to the stripping tower to obtain a third mixed solution. The pH of the third mixed solution is 10.8, the temperature of the stripping tower is 42℃, and the stripping time is 35 min. The ammonia nitrogen content in the third mixed solution is 9 mg / L.
[0062] The third mixed solution is subjected to stripping treatment, and the gas generated by stripping is introduced into an absorption tower, and the first type of wastewater is used as an absorption liquid to obtain a fourth mixed solution. The ammonium phosphate concentration in the fourth mixed solution is 1.5%.
[0063] The fourth mixed solution, the third type of wastewater, the fourth type of wastewater and the fifth type of wastewater are mixed to obtain a fifth mixed solution. The pH of the fifth mixed solution is 7.2. The fifth mixed solution is treated by using a three-dimensional electrode to obtain a sixth mixed solution. The current density of the three-dimensional electrode is 30 mA / cm 2 , and the COD of the sixth mixed solution obtained after 45 min of reaction is reduced to 72 mg / L.
[0064] The sixth mixed solution is introduced into a biological pool for treatment. The dissolved oxygen concentration in the biological pool is 2.5 mg / L, and the hydraulic retention time of the sixth mixed solution is 9 h. After detection, the phosphorus content in the wastewater treated by the biological pool is 0.45 mg / L, the ammonia nitrogen content is 0.92 mg / L, the COD is 35 mg / L, and the colority is 12, which meets the discharge standard.
[0065] Example 2
[0066] The wastewater of the nuclear power plant in the embodiment is treated by the following steps:
[0067] The first wastewater, the second wastewater, the third wastewater, the fourth wastewater and the fifth wastewater are collected respectively. The first wastewater is phosphorus-containing wastewater, the second wastewater is ammonia nitrogen-containing wastewater, the third wastewater is anion resin regeneration wastewater, the fourth wastewater is cation resin regeneration wastewater, and the fifth wastewater is resin backwash water. The phosphorus content in the first wastewater is 285 mg / L, the pH of the first wastewater is 9.4, the ammonia nitrogen concentration of the second wastewater is 1960 mg / L, the pH of the second wastewater is 10.2, the NaOH concentration of the third wastewater is 1.8 g / L, the colority is 15, the HCl concentration of the fourth wastewater is 2.7 g / L, the colority is 12, the ammonia nitrogen concentration of the fifth wastewater is 155 mg / L, the COD concentration is 156 mg / L, and the colority is 36. Cr
[0068] The first wastewater and the second wastewater are mixed at a molar ratio of phosphorus to ammonia nitrogen of 1:3 to obtain a first mixed solution.
[0069] The third wastewater, the fourth wastewater, the fifth wastewater and the first mixed solution are mixed to obtain a second mixed solution. The pH of the second mixed solution is 7.5. The second mixed solution is subjected to static treatment to obtain a supernatant. The generated ammonium phosphate precipitate can be used as fertilizer.
[0070] The supernatant is placed in a stripping tower, and the third wastewater is added to the stripping tower to obtain a third mixed solution. The pH of the third mixed solution is 11.0. The temperature of the stripping tower is 40°C. The stripping time is 35 min. The ammonia nitrogen content in the third mixed solution is 10 mg / L.
[0071] The third mixed solution is subjected to stripping treatment. The stripping gas is introduced into an absorption tower, and the first wastewater is used as the absorption liquid to obtain a fourth mixed solution. The ammonium phosphate concentration in the fourth mixed solution is 2.4%.
[0072] The fourth mixed solution, the third wastewater, the fourth wastewater and the fifth wastewater are mixed to obtain a fifth mixed solution. The pH of the fifth mixed solution is 7.5. The fifth mixed solution is treated by using a three-dimensional electrode to obtain a sixth mixed solution. The current density of the three-dimensional electrode is 25 mA / cm 2 After 50 min of reaction, the COD of the sixth mixed solution is reduced to 36 mg / L.
[0073] The sixth mixed solution is introduced into a biological tank for treatment. The dissolved oxygen concentration in the biological tank is 3.0 mg / L. The hydraulic retention time of the sixth mixed solution is 8 h. After the treatment of the biological tank, the phosphorus content in the wastewater is 0.35 mg / L, the ammonia nitrogen content is 1.25 mg / L, the COD is 15 mg / L, and the colority is 7, which meets the discharge standard.
[0074] Example 3
[0075] The wastewater of nuclear power plant in this embodiment is treated by the following steps:
[0076] Collecting the first, second, third, fourth and fifth wastewater respectively, the first wastewater is phosphorus-containing wastewater, the second wastewater is ammonia-nitrogen-containing wastewater, the third wastewater is anion resin regeneration wastewater, the fourth wastewater is cation resin regeneration wastewater, and the fifth wastewater is resin backwash water. The phosphorus content in the first wastewater is 369 mg / L, the pH of the first wastewater is 8.5, the ammonia-nitrogen concentration of the second wastewater is 2150 mg / L, the pH of the second wastewater is 10.5, the NaOH concentration of the third wastewater is 2.3 g / L, the colority is 10, the HCl concentration of the fourth wastewater is 3.4 g / L, the colority is 15, the ammonia-nitrogen concentration of the fifth wastewater is 133.8 mg / L, the COD Cr concentration is 240 mg / L, the BOD5 is 94.7 mg / L, and the colority is 36.
[0077] Mixing the first wastewater and the second wastewater according to the molar ratio of phosphorus to ammonia-nitrogen of 1:3 to obtain a first mixed solution;
[0078] Mixing the third, fourth and fifth wastewater with the first mixed solution to obtain a second mixed solution, the pH of the second mixed solution is 8, and the second mixed solution is subjected to static treatment to obtain a supernatant, and the generated ammonium phosphate precipitate can be used as fertilizer;
[0079] Placing the supernatant in a stripping tower, and adding the third wastewater to the stripping tower to obtain a third mixed solution, the pH of the third mixed solution is 10.5, the temperature of the stripping tower is 45°C, the stripping time is 40 min, and the ammonia-nitrogen content in the third mixed solution is 9.5 mg / L;
[0080] Stripping the third mixed solution, and passing the gas generated by stripping into an absorption tower, and using the first wastewater as the absorption liquid to obtain a fourth mixed solution, the ammonium phosphate concentration in the fourth mixed solution is 4.4%;
[0081] Mixing the fourth mixed solution with the third, fourth and fifth wastewater to obtain a fifth mixed solution, the pH of the fifth mixed solution is 7.0, and the fifth mixed solution is treated by using a three-dimensional electrode to obtain a sixth mixed solution. The current density of the three-dimensional electrode is 35 mA / cm 2 , and the COD of the sixth mixed solution obtained after reacting for 40 min is reduced to 110 mg / L.
[0082] The sixth mixed solution is introduced into the biological tank for treatment, the dissolved oxygen concentration in the biological tank is 2.0 mg / L, and the hydraulic retention time of the sixth mixed solution is 10 h. After detection, the phosphorus content in the wastewater treated by the biological tank is 0.75 mg / L, the ammonia nitrogen content is 0.59 mg / L, the COD is 52 mg / L, and the color is 10, which meets the emission standard.
[0083] The application provides a nuclear power plant wastewater collaborative treatment method, a first wastewater is mixed with second wastewater, third wastewater, fourth wastewater and fifth wastewater to obtain second mixed solution, phosphorus and ammonia nitrogen in the second mixed solution react to generate ammonium phosphate precipitate, so that the phosphorus and part of the ammonia nitrogen in the second mixed solution are removed. The supernatant of the second mixed solution is mixed with the third wastewater to obtain third mixed solution, the third mixed solution is subjected to blow-off treatment to remove ammonia gas in the third mixed solution, the first wastewater is used as an absorption liquid to absorb the waste gas generated by blow-off, and the first wastewater is sequentially subjected to electrochemical reactor treatment and biological tank treatment, so that the discharged wastewater meets the emission standard. The treatment method does not need to add chemical reagents, and the treatment cost can be reduced.
[0084] The above examples only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.
Claims
1. A method for co-treatment of nuclear power plant wastewater, characterized in that, Includes the following steps: Wastewater of type I, type II, type III, type IV and type V are collected separately. Type I wastewater is phosphorus-containing wastewater, type II wastewater is ammonia-nitrogen-containing wastewater, type III wastewater is anion exchange resin regeneration wastewater, type IV wastewater is cation exchange resin regeneration wastewater and type V wastewater is resin backwash water. The first type of wastewater is mixed with the second type of wastewater to obtain a first mixed liquid; The three types of wastewater, the four types of wastewater, and the five types of wastewater are mixed with the first mixture to obtain a second mixture. The second mixture is then allowed to stand to obtain a supernatant. The supernatant is placed in a stripping tower, and the three types of wastewater are added to the stripping tower to obtain a third mixed liquid; The third mixture is stripped, and the gas generated from the stripping is passed into an absorption tower. The first type of wastewater is used as the absorbent to obtain the fourth mixture. The fourth mixture is mixed with the third type of wastewater, the fourth type of wastewater and the fifth type of wastewater to obtain the fifth mixture, and the fifth mixture is treated using an electrochemical reactor to obtain the sixth mixture; The sixth mixture is then introduced into a biological treatment tank for further processing.
2. The processing method according to claim 1, characterized in that, The Class I wastewater has a phosphorus content ≥100mg / L, the Class II wastewater has an ammonia nitrogen content ≥1000mg / L, and the Class II wastewater has a pH ≥10.
0.
3. The processing method according to claim 1, characterized in that, The molar ratio of the first type of wastewater to the second type of wastewater in the first mixture is 1:
3.
4. The processing method according to claim 1, characterized in that, The pH of the second mixture is 7.5 to 8.
5.
5. The processing method according to claim 1, characterized in that, The temperature of the stripping tower is 40–45°C.
6. The processing method according to claim 1, characterized in that, The pH of the third mixture is 10.5 to 11.
0.
7. The processing method according to claim 1, characterized in that, The pH of the fifth mixture is 7.0 to 7.
5.
8. The processing method according to claim 1, characterized in that, The current density of the electrochemical reactor is 25–35 mA / cm². 2 The reaction time is 40–50 min.
9. The processing method according to claim 1, characterized in that, The dissolved oxygen concentration in the biological tank is 2.0–3.0 mg / L, and the hydraulic retention time of the sixth mixed liquor in the biological tank is 8–10 h.
10. The processing method according to claim 1, characterized in that, The electrodes of the electrochemical reactor are titanium-based electrodes.