Sodium azide wastewater treatment system

Abstract

The utility model relates to the field of wastewater treatment, and discloses a sodium azide wastewater treatment system which comprises a two-stage denitrification unit, an advanced oxidation pond, a PH (Potential of Hydrogen) regulating pond, a flocculation treatment unit, a hydrolysis acidification pond, an A / O (Anaerobic / Oxic) reaction unit, an activated carbon adsorption pond, a treatment system water outlet unit and a sludge treatment unit for treating sludge which are sequentially communicated, the two-stage denitrification unit and the advanced oxidation pond are used for removing sodium azide and potassium cyanide in the wastewater; the A / O reaction unit is used for reducing the chemical oxidation amount and the total amount of total nitrogen and phosphorus in the wastewater; the flocculation treatment unit and the A / O reaction unit are both communicated with the sludge treatment unit. According to the embodiment of the invention, sodium azide and potassium cyanide can be efficiently decomposed through a combined process of the two-stage denitrification unit and the advanced oxidation pond.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment, specifically to a sodium azide wastewater treatment system. Background Technology

[0002] The treatment of sodium azide wastewater has always been a challenging problem in chemical production. Sodium azide (NaN3) and potassium cyanide (KCN) are highly toxic, and direct discharge without effective treatment poses a serious threat to the ecological environment and biosafety. Traditional treatment processes often struggle to simultaneously and efficiently remove azide ions (N3). - ) and cyanide ions (CN) - Furthermore, the existing treatment systems are not effective in synergistically treating pollutants such as chemical oxygen demand (COD), total nitrogen (TN), and phosphorus (TP) in wastewater. Some processes can only treat a single pollutant, failing to meet stringent emission standards. In addition, existing treatment systems suffer from fragmented processes, long treatment cycles, and fluctuating water quality in intermediate stages, making them unsuitable for large-scale industrial treatment needs. Moreover, sludge treatment is often neglected, failing to reduce sludge volume and utilize it as a resource, which not only increases treatment costs but also poses a risk of secondary pollution.

[0003] In existing technologies, such as the Chinese patent with publication number CN220364457U, a wastewater treatment system is disclosed, which includes an equalization tank, a high-efficiency sedimentation tank, a Fenton oxidation tank, a deep hydrolysis acidification tank, a primary two-stage A / O reaction tank, a sedimentation tank, an ozone catalytic oxidation tank, a secondary A / O reaction tank, an MBR system, an activated carbon system, a sterilization tank, and a sludge treatment system for treating sludge, all connected in sequence. The primary two-stage A / O reaction tank is used to remove biodegradable BOD from wastewater and reduce the COD of wastewater. The MBR system utilizes the high-efficiency separation effect of the MBR membrane to retain large fixed particles and colloids in the water. The Fenton oxidation tank, the deep hydrolysis acidification tank, the sedimentation tank, and the MBR system are all connected to the sludge treatment system.

[0004] The existing technologies mentioned above also have the following drawbacks: The existing technologies only enhance the denitrification effect by adding a first-stage two-stage A / O process, a second-stage A / O process, and an MBR system. However, the decomposition efficiency of sodium azide and potassium cyanide by the single chemical oxidation method in the advanced oxidation tank is limited, and the A / O process has a low removal effect on sodium azide and potassium cyanide. Therefore, the residual toxic substances in the wastewater will inhibit the microbial activity in the subsequent second-stage A / O process and MBR system, resulting in poor wastewater treatment effect. Utility Model Content

[0005] The present invention aims to provide a sodium azide wastewater treatment system to effectively remove sodium azide from wastewater.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A sodium azide wastewater treatment system includes, in sequence, a wastewater collection tank, a two-stage denitrification unit, an advanced oxidation tank, a pH adjustment tank, a flocculation treatment unit, a hydrolysis acidification tank, an A / O reaction unit, an activated carbon adsorption tank, a treatment system effluent unit, and a sludge treatment unit for sludge treatment. The two-stage denitrification unit includes a primary denitrification tank and a secondary denitrification tank. Each tank wall has an inlet and an outlet, and the inlet of the previous stage is connected to the outlet of the next stage. The top of both the primary and secondary denitrification tanks is equipped with a discharge device, which includes a sodium hypochlorite inlet and a conversion agent inlet. The discharge outlet and inlet of the primary and secondary denitrification tanks are on the same horizontal plane. A mixer is installed at the bottom of each of the primary, secondary, and advanced oxidation tanks.

[0008] Beneficial effects: 1. By using sodium hypochlorite and specific conversion agents (such as acids or catalysts) in the front-end two-stage denitrification unit, highly toxic and explosive sodium azide can be decomposed into harmless nitrogen gas (N2) efficiently and thoroughly. This source-targeted detoxification not only has a fast reaction speed and high efficiency, but more importantly, it reduces the risk of toxicity of azide to subsequent biological treatment units (hydrolysis acidification, A / O) and significantly improves the safety of the entire system, laying a reliable foundation for subsequent treatment.

[0009] 2. The two-stage denitrification unit combined with the advanced oxidation tank forms a process that can efficiently decompose sodium azide (NaN3) and potassium cyanide (KCN). The advanced oxidation tank, by generating strong oxidants such as hydroxyl radicals (-OH), decomposes azide ions (N3+). - ) and cyanide ions (CN) - It is oxidized into harmless substances such as nitrogen (N2) and carbon dioxide (CO2), avoiding the direct emission of highly toxic substances that would harm the environment and organisms.

[0010] 3. The pH adjustment tank ensures that the wastewater has a suitable acidity or alkalinity, creating favorable conditions for subsequent treatment; the flocculation treatment unit quickly separates suspended solids and colloids, reducing the pressure on subsequent treatment.

[0011] 4. The hydrolysis acidification tank and A / O reaction unit (anaerobic-aerobic process) simultaneously remove chemical oxygen demand (COD), total nitrogen (TN) and phosphorus (TP) through microbial metabolism, significantly improving water quality.

[0012] 5. The activated carbon adsorption tank further removes residual organic matter, color, and odor through physical and chemical adsorption, ensuring that the effluent quality meets reuse or strict discharge standards; and the flocculation treatment unit removes suspended solids and colloids by adding flocculants (such as PAC and PAM), reducing the load on subsequent treatment.

[0013] 6. The sludge produced by the flocculation treatment unit and the A / O reaction unit are uniformly fed into the sludge treatment unit, where it is reduced in volume through processes such as dewatering and concentration. Some of the sludge can be recycled as a nutrient source for microorganisms (such as sludge recycling from the A / O unit) to reduce the consumption of chemicals. The remaining sludge can be safely disposed of after harmless treatment to avoid secondary pollution.

[0014] 7. Through the whole process design of "detoxification-oxidation-biochemical treatment-deep treatment-sludge disposal", the efficient removal of toxic pollutants, comprehensive water purification and harmless treatment of sludge are achieved. Moreover, the removal of toxic substances in the early stage reduces the amount of subsequent reagents, which greatly reduces operating costs.

[0015] 8. The staged treatment disperses the pollutant load, reduces the treatment pressure of a single device, lowers the risk of blockage or corrosion in the primary denitrification tank, extends the service life of the equipment, and reduces the frequency and cost of maintenance. At the same time, the advanced treatment in the secondary denitrification tank can buffer the impact of upstream process fluctuations on the subsequent advanced oxidation tank, and prevent the advanced oxidation tank from operating under overload due to sudden changes in influent water quality.

[0016] Preferably, as an improvement, the top of the advanced oxidation tank is provided with an ozone vent, and the discharge port and the inlet are respectively connected to the discharge port of the secondary denitrification tank and the inlet of the pH adjustment tank.

[0017] Beneficial effects:

[0018] Preferably, as an improvement, the flocculation treatment unit includes a flocculation reaction tank and a flocculation sedimentation tank connected in sequence. The discharge outlet and inlet of the flocculation reaction tank and the flocculation sedimentation tank are located on the same horizontal plane on the upper side of the tank wall. The inlet of the flocculation reaction tank is connected to the discharge outlet of the pH adjustment tank. A stirrer is located at the center of the top of the flocculation reaction tank, and flocculant dosing outlets are also provided around the top. The discharge outlet of the flocculation sedimentation tank is connected to the hydrolysis acidification tank.

[0019] Beneficial effects: The flocculation reactor, by adding flocculants such as polyaluminum chloride (PAC) and polyacrylamide (PAM), causes suspended solids and colloidal particles in the wastewater to aggregate and adsorb and bridge, forming micro-flocculations. The flocculation sedimentation tank utilizes the principle of gravity settling to further aggregate and settle the flocs generated in the reactor, ultimately separating the supernatant and sludge. The supernatant after flocculation and sedimentation enters the hydrolysis acidification tank. Due to the significant reduction in suspended solids, it avoids clogging of the packing or pipes of subsequent biological units and reduces the risk of sludge bulking in the hydrolysis acidification tank. At the same time, it reduces the impact of sludge production on the microbial activity of the A / O reactor, ensuring the efficiency of biological treatment.

[0020] Preferably, as an improvement, the A / O reaction unit includes an anoxic tank and an aerobic tank that are interconnected. The upper side of the walls of the anoxic tank and the aerobic tank are also provided with the discharge port and the inlet. The inlet of the anoxic tank is connected to the discharge port of the hydrolysis acidification tank, and the inlet of the anoxic tank is lower than the discharge port of the hydrolysis acidification tank. The discharge port of the aerobic tank is connected to the activated carbon adsorption tank.

[0021] Beneficial effects: Through the synergistic operation of the anoxic and aerobic tanks, efficient removal of multiple pollutants and stable system operation are achieved. It utilizes nitrification-denitrification for deep nitrogen removal, phosphorus-accumulating bacteria for simultaneous phosphorus release and uptake, and aerobic microorganisms for organic matter degradation. COD and total nitrogen removal rates can reach 80%-90% and 70%-85%, respectively. This unit has strong shock resistance, can adapt to water quality fluctuations, and is closely connected to upstream and downstream units, reducing the load on subsequent treatment processes. Simultaneously, it reduces sludge production through anaerobic metabolism, saves on reagents by utilizing wastewater carbon sources, and lowers aeration energy consumption compared to a fully aerobic process.

[0022] Preferably, as an improvement, the aerobic tank is equipped with an MBR membrane tank for filtering macromolecular fixed particles and colloids in the water. The MBR membrane tank is located at the discharge port of the aerobic tank, and the discharge port is located on the lower side of the aerobic tank wall and is connected to the activated carbon adsorption tank.

[0023] Beneficial effects: The addition of an MBR membrane tank within the aerobic tank significantly improves wastewater treatment efficiency through deep coupling of membrane separation and biological treatment. The filtration function of the MBR membrane tank efficiently traps large fixed particles, colloids, and activated sludge microorganisms, achieving rapid sludge-water separation. The effluent has nearly zero suspended solids and significantly reduced turbidity, effectively ensuring water clarity. Simultaneously, microorganisms are forcibly retained within the system by the membrane module, resulting in a substantial increase in sludge concentration, enhanced biodegradation efficiency, and further improved COD removal rate. Furthermore, the separation of sludge retention time and hydraulic retention time makes the system operation more flexible and stable, significantly improving its shock resistance. In addition, the pure effluent treated by the MBR membrane tank greatly reduces the treatment load on the subsequent activated carbon adsorption tank, extends the service life of activated carbon, and reduces replacement frequency and operating costs.

[0024] Preferably, as an improvement, an aeration device is provided at the bottom of the aerobic tank. The aeration device includes an air supply pump and an air outlet. The air supply pump is located outside the aerobic tank and is connected to the air outlet located at the bottom of the aerobic tank through an air inlet provided at the top of the aerobic tank. Some of the air outlets are located at the bottom of the MBR membrane tank and are used to flush the MBR membrane.

[0025] Beneficial effects: The aeration device continuously supplies air or oxygen to the aerobic tank, providing sufficient dissolved oxygen for aerobic microbial metabolism, enhancing biochemical processes such as organic matter degradation and nitrification, and ensuring efficient removal of pollutants such as COD and ammonia nitrogen. Located below the MBR membrane tank, the aeration device generates a mixed air-water flow that washes the membrane surface, effectively removing sludge and pollutants, preventing membrane pore blockage, slowing the membrane fouling rate, extending the MBR membrane flux decay cycle, and reducing membrane cleaning frequency and replacement costs.

[0026] Preferably, as an improvement, the sludge treatment unit includes a sludge tank and a dewatering mechanism connected together. The bottom of the sludge tank is equipped with an extraction device for conveying the sludge in the sludge tank to the dewatering mechanism; and the top of the sludge tank is equipped with a discharge port.

[0027] Beneficial effects: The sludge tank serves as a temporary storage space, temporarily accommodating sludge generated by flocculation and A / O reaction units, buffering fluctuations in sludge generation time and quantity, and preventing sludge accumulation from affecting the operation of upstream treatment units; the bottom extraction device can stably and continuously transport sludge to the dewatering unit, ensuring the continuity of the sludge treatment process; the dewatering unit, through mechanical compression, centrifugal separation, and other technologies, significantly reduces the sludge moisture content, achieving sludge reduction and decreasing the sludge disposal volume by 60%-80%, thus lowering subsequent sludge transportation and landfill costs; simultaneously, the dewatered sludge can be further processed for resource recovery such as composting and incineration power generation, effectively preventing secondary pollution of the environment by residual pollutants in the sludge, and ensuring the environmental friendliness and economy of the entire wastewater treatment system.

[0028] Preferably, as an improvement, the bottom of the flocculation sedimentation tank, the hydrolysis acidification tank, the anoxic tank, and the aerobic tank are all equipped with the extraction device, and the top is equipped with a sludge discharge port. The extraction device passes through the sludge discharge port and is connected to the sludge tank.

[0029] Beneficial effects: By uniformly setting up extraction mechanisms at the bottom of the flocculation sedimentation tank, hydrolysis acidification tank, anoxic tank, and aerobic tank, centralized and efficient transfer of sludge is achieved, effectively preventing sludge deposition and accumulation in each treatment unit, and ensuring the stable operation efficiency and treatment effect of each treatment tank. At the same time, the standardized extraction mechanism simplifies the sludge treatment process, reduces equipment maintenance and management costs, and timely sludge extraction helps reduce the residence time of sludge in the system, preventing secondary pollution caused by sludge aging, enhancing the stability and reliability of the entire wastewater treatment system, providing convenient conditions for subsequent sludge treatment and disposal, and improving the overall efficiency of the wastewater treatment process.

[0030] Preferably, as an improvement, the effluent unit of the treatment system includes a primary disinfection tank, a clear water tank, an observation tank, a secondary disinfection tank, and an effluent tank connected in sequence. The effluent outlet of the primary disinfection tank is connected to the inlet of the activated carbon adsorption tank. A reflux device is provided at the top of the effluent tank, and the reflux device is connected to the hydrolysis acidification tank and the aerobic tank.

[0031] Beneficial effects: The primary disinfection tank is connected to the activated carbon adsorption tank, which can perform preliminary disinfection on the water after adsorption treatment, reducing the microbial content in the water; the clear water tank is connected to the hydrolysis acidification tank and the aerobic tank, which can rationally recycle the treated clear water, realize the efficient reuse of water resources, and reduce treatment costs; the observation tank can directly monitor the water quality, which is convenient for timely adjustment of the treatment process; the secondary disinfection tank further enhances the disinfection effect, ensuring that the effluent meets the discharge standards; the discharge tank provides a temporary storage and discharge buffer for the final effluent; the entire process, through multi-stage treatment and recycling, effectively improves the effluent quality, enhances the flexibility and stability of system operation, and takes into account both environmental and economic benefits. Attached Figure Description

[0032] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model. Detailed Implementation

[0033] The following detailed description illustrates the specific implementation method:

[0034] The reference numerals in the accompanying drawings include: wastewater collection tank 000, two-stage denitrification unit 100, primary denitrification tank 110, secondary denitrification tank 120, advanced oxidation tank 200, pH adjustment tank 300, flocculation treatment unit 400, flocculation reaction tank 410, frame mixer 411, flocculation sedimentation tank 420, hydrolysis acidification tank 500, A / O reaction unit 600, anoxic tank 610, aerobic tank 620, aeration device 621, MBR membrane tank 622, activated carbon adsorption tank 700, sludge treatment unit 800, sludge tank 810, dewatering mechanism 820, effluent unit of treatment system 900, primary disinfection tank 910, clear water tank 920, observation tank 930, secondary disinfection tank 940, and discharge tank 950.

[0035] The basic implementation examples are as follows: Figure 1 As shown:

[0036] This embodiment provides a sodium azide wastewater treatment system, the treatment process of which unfolds in a physically connected sequence. The system includes a two-stage denitrification unit 100, an advanced oxidation tank 200, a pH adjustment tank 300, a flocculation treatment unit 400, a hydrolysis acidification tank 500, an A / O reaction unit 600, an activated carbon adsorption tank 700, a treatment system effluent unit 900, and a sludge treatment unit 800 for treating sludge, all connected in sequence. Wastewater collection tank 000 serves as the starting point and is connected to sludge treatment unit 800. It is used to collect industrial wastewater and filtered water from sludge treatment unit 800, and can also be used to adjust the concentration of various substances in the wastewater. After adjustment by the collection tank, the fluctuation range of various substances in the wastewater can be reduced, so that the influent concentration of wastewater is within a certain amount, creating stable influent conditions for subsequent treatment units. Each of the above-mentioned tanks is equipped with an inlet and an outlet, and the outlet of the previous stage is connected to the inlet of the next stage. Specifically, an LC detection device is installed at the top of wastewater collection tank 000 to detect metal ions such as copper and zinc bound to organic ligands and to monitor the concentration of organic matter in the influent and effluent of the wastewater treatment plant (such as correlation analysis of COD and BOD).

[0037] In this embodiment, the influent flow rate is 90m³. 3 / d, in this influent volume, the contents of chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP) and sodium azide are 1500 mg / L, 100 mg / L, 40 mg / L and 150 mg / L, respectively. For specific removal data, please refer to Table 1.

[0038] Table 1 - Wastewater Treatment Effect Analysis Table

[0039]

[0040]

[0041] The main process begins at wastewater collection tank 000. Wastewater first enters a two-stage denitrification unit 100. Specifically, this unit, from left to right, includes a primary denitrification tank 110 and a secondary denitrification tank 120 connected together. The inlet of the primary denitrification tank 110 is connected to the wastewater collection tank 000 to receive the diluted water. Both the primary and secondary denitrification tanks 110 and 120 are continuously filled with sodium hypochlorite (NaClO) through top-mounted sodium hypochlorite inlets. This allows the sodium hypochlorite in the primary and secondary denitrification tanks 110 and 120 to react with sodium azide, thereby removing sodium azide from the wastewater. At this point, the removal rates of chemical oxygen demand (COD), total nitrogen (TN), and sodium azide are 10%, 5%, and 99%, respectively. To prevent sodium azide from reacting with sodium nitrate... The toxic gas produced by the ammonium hypochlorite reaction is discharged outside the tank and then a sodium hydroxide solution is added through the sodium hydroxide conversion agent inlet to convert ammonia and chlorine. Hydrochloric acid is added to the secondary denitrification tank 120 through the hydrochloric acid conversion agent inlet to adjust the pH value of the wastewater. Since the discharge outlet of the secondary denitrification tank 120 is connected to the advanced oxidation tank 200, the wastewater with a large amount of sodium azide removed can be transported to the advanced oxidation tank 200. Ozone (O3) is introduced into the advanced oxidation tank 200 through the ozone vent at the top, causing the wastewater to undergo an oxidation reaction within the advanced oxidation tank 200, further removing the remaining sodium azide. At this point, the removal rates of chemical oxygen demand (COD), total nitrogen (TN), and sodium azide are 20%, 5%, and 95%, respectively. The data shows that the combination of the two-stage denitrification tank and the advanced oxidation tank 200 can significantly reduce the sodium azide content in the wastewater. It is worth noting that the primary denitrification tank 110 undergoes alkaline treatment, while the secondary denitrification tank 120 undergoes acidic treatment. To ensure that the pH values ​​in the two denitrification tanks are within a suitable range, pH meters are installed on both denitrification tanks.

[0042] The oxidized wastewater continues to flow into the pH adjustment tank 300 for acid-base adjustment. A pH meter is also installed in the pH adjustment tank 300 to facilitate the observation of the acid-base value of the wastewater. The adjusted wastewater then enters the flocculation treatment unit 400. The unit, from left to right, includes a flocculation reaction tank 410 and a flocculation sedimentation tank 420. The inlet of the flocculation reaction tank 410 is connected to the pH adjustment tank 300, and a frame mixer 411 is installed inside the flocculation reaction tank 410 to ensure that impurities in the wastewater can fully contact the flocculants when flocculants such as polyaluminum chloride (PAC) and polyacrylamide (PAM) are added to the flocculation reaction tank 410. Then, the wastewater with flocculation enters the flocculation sedimentation tank 420 for sedimentation. The sludge after sedimentation is pumped into the sludge treatment unit 800 through the bottom pumping mechanism. Since the outlet of the flocculation sedimentation tank 420 is connected to the hydrolysis acidification tank 500, the clear water on the sludge flows into the hydrolysis acidification tank 500 for hydrolysis acidification. This process is mainly used to remove the total amount of phosphorus in wastewater. Through step-by-step treatment, the pollutant removal rate can be significantly improved, with a suspended solids (SS) removal rate of about 90%. Some dissolved organic matter and heavy metal ions can also be removed through adsorption and co-precipitation.

[0043] The hydrolyzed and acidified wastewater enters the A / O reaction unit 600, which consists of an anoxic tank 610 and an aerobic tank 620 connected from left to right. The inlet of the anoxic tank 610 receives the effluent from the hydrolyzed and acidified tank 500, and the inlet of the anoxic tank 610 is lower than the outlet of the hydrolyzed and acidified tank 500. The outlet of the aerobic tank 620 is connected to the activated carbon adsorption tank. The core function of this unit is to degrade the chemical oxygen demand (COD), total nitrogen, and total phosphorus in the wastewater. At this stage, the removal rates of COD, total nitrogen, and total phosphorus in the wastewater are 80%, 80%, and 10%, respectively. It is worth noting that the aerobic tank 620 embeds an MBR membrane tank 622, whose outlet is directly connected to the activated carbon adsorption tank 700, which can efficiently intercept large fixed particles and colloids. The bottom aeration device 621 has dual functions of oxygen supply and membrane flushing, and part of it is specially installed below the MBR membrane tank 622 to control pollution. The aeration device 621 is specifically an aeration blower, used to increase the dissolved oxygen content in the water, promote the growth and reproduction of microorganisms in the aerobic tank 620, thereby accelerating the degradation of pollutants.

[0044] Wastewater intercepted by the MBR membrane tank 622 is pumped from the bottom of the tank to the top of the activated carbon adsorption tank 700 for discharge, allowing for deep adsorption of the wastewater in the activated carbon adsorption tank 700. The deeply adsorbed wastewater then enters the effluent unit 900 of the treatment system. This unit is sequentially connected to the primary disinfection tank 910, the clear water tank 920, the observation tank 930, the secondary disinfection tank 940, and the discharge tank 950. The inlet of the primary disinfection tank 910 receives the effluent from the activated carbon adsorption tank 700. The discharge tank 950, as a critical node, is equipped with a detection device to monitor the chemical oxygen demand (COD), total nitrogen, total phosphorus, and sodium azide content in the wastewater. If the levels are not met, the wastewater in the clear water tank 920 can be pumped back to the hydrolysis acidification tank 500 and the aerobic tank 620 for further purification, achieving internal system circulation. Specifically, the primary disinfection pool 910 uses ultraviolet light for disinfection, while the secondary disinfection pool 940 uses sodium hypochlorite for disinfection.

[0045] The sludge co-treatment process is integrated throughout the entire process. The bottoms of the flocculation sedimentation tank 420, hydrolysis acidification tank 500, anoxic tank 610, and aerobic tank 620 are all equipped with extraction mechanisms to transport the settled sludge to the sludge treatment unit 800. This unit consists of a sludge tank 810 and a dewatering mechanism 820 connected together. The bottom of the sludge tank 810 is equipped with an extraction device to pump the collected sludge into the dewatering mechanism 820 for volume reduction treatment. The sludge transported to the dewatering mechanism 820 is then spun dry to form sludge cakes.

[0046] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A sodium azide wastewater treatment system, characterized in that: The system comprises, in sequence, a wastewater collection tank, a two-stage denitrification unit, an advanced oxidation tank, a pH adjustment tank, a flocculation treatment unit, a hydrolysis acidification tank, an A / O reaction unit, an activated carbon adsorption tank, a treatment system effluent unit, and a sludge treatment unit for sludge treatment. The two-stage denitrification unit includes a primary denitrification tank and a secondary denitrification tank. Each tank wall is equipped with an inlet and an outlet, with the inlet of the previous stage connected to the outlet of the next stage. Both the primary and secondary denitrification tanks are equipped with a discharge device at the top, which includes a sodium hypochlorite inlet and a conversion agent inlet. The discharge outlets and inlets of the primary and secondary denitrification tanks are on the same horizontal plane. A mixer is installed at the bottom of each of the primary, secondary, and advanced oxidation tanks.

2. The sodium azide wastewater treatment system according to claim 1, characterized in that: The top of the advanced oxidation tank is equipped with an ozone vent, and the discharge port and inlet are respectively connected to the discharge port of the secondary denitrification tank and the inlet of the pH adjustment tank.

3. The sodium azide wastewater treatment system according to claim 1, characterized in that: The flocculation treatment unit includes a flocculation reaction tank and a flocculation sedimentation tank connected in sequence. The discharge outlet and inlet of the flocculation reaction tank and the flocculation sedimentation tank are located on the same horizontal plane on the upper side of the tank wall. The inlet of the flocculation reaction tank is connected to the discharge outlet of the pH adjustment tank. There is a stirrer at the center of the top of the flocculation reaction tank, and there are also flocculation reagent dosing ports around the top. The discharge outlet of the flocculation sedimentation tank is connected to the hydrolysis acidification tank.

4. The sodium azide wastewater treatment system according to claim 3, characterized in that: The A / O reaction unit includes an anoxic tank and an aerobic tank that are interconnected. Both the anoxic tank and the aerobic tank have discharge outlets and inlets on their upper walls. The inlet of the anoxic tank is connected to the discharge outlet of the hydrolysis acidification tank, and the inlet of the anoxic tank is lower than the discharge outlet of the hydrolysis acidification tank. The discharge outlet of the aerobic tank is connected to the activated carbon adsorption tank.

5. The sodium azide wastewater treatment system according to claim 4, characterized in that: The aerobic tank is equipped with an MBR membrane tank for filtering large molecular fixed particles and colloids in the water. The MBR membrane tank is located at the discharge port of the aerobic tank, which is located on the lower side of the tank wall and is connected to the activated carbon adsorption tank.

6. The sodium azide wastewater treatment system according to claim 5, characterized in that: An aeration device is installed at the bottom of the aerobic tank. The aeration device includes an air supply pump and an air outlet. The air supply pump is located outside the aerobic tank and is connected to the air outlet located at the bottom of the aerobic tank through an air inlet at the top of the aerobic tank. Some of the air outlets are located at the bottom of the MBR membrane tank and are used to flush the MBR membrane.

7. The sodium azide wastewater treatment system according to claim 6, characterized in that: The sludge treatment unit includes a connected sludge tank and a dewatering mechanism. The bottom of the sludge tank is equipped with an extraction device for transporting the sludge in the sludge tank to the dewatering mechanism; the top of the sludge tank is equipped with a discharge outlet.

8. The sodium azide wastewater treatment system according to claim 7, characterized in that: The bottom of the flocculation sedimentation tank, hydrolysis acidification tank, anoxic tank, and aerobic tank are all equipped with the extraction device, and the top is equipped with a sludge discharge port. The extraction device passes through the sludge discharge port and is connected to the sludge tank.

9. The sodium azide wastewater treatment system according to claim 8, characterized in that: The effluent unit of the treatment system includes a primary disinfection tank, a clear water tank, an observation tank, a secondary disinfection tank, and an outlet tank connected in sequence. The outlet of the primary disinfection tank is connected to the inlet of the activated carbon adsorption tank. A reflux device is installed at the top of the outlet tank, and the reflux device is connected to the hydrolysis acidification tank and the aerobic tank.

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