Electro-oxidation device, wastewater treatment system and treatment method

Abstract

The application provides an electro-oxidation device, a wastewater treatment system and a treatment method. The electro-oxidation device comprises a first tank body, a second tank body and an aeration mechanism. The first tank body is provided with a first liquid inlet and a first liquid outlet, and is also provided with a buffer agent adding port. The second tank body is provided with a second liquid inlet and a second liquid outlet. A baffle assembly is arranged in the second tank body. The baffle assembly comprises a plurality of partitions. The baffle assembly forms a zigzag flow channel in the second tank body through the plurality of partitions. The zigzag flow channel is communicated with the second liquid inlet and the second liquid outlet. Electrode assemblies are arranged in the first tank body and the second tank body. The application has a deep removal effect on wastewater with high fluorine, chlorine, COD, color and ammonia nitrogen.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, and particularly relates to an electro-oxidation device, a wastewater treatment system, and a treatment method. Background Technology

[0002] Industrial wastewater is complex in composition, containing various ions such as fluoride, ammonia nitrogen, and chloride, and exhibiting high COD and color. Taking washing wastewater as an example, in the wet deacidification process of waste incinerators, the neutralization of acidic HCl gas in the flue gas with NaOH solution generates a large amount of flue gas scrubbing wastewater. This wastewater has a high salt content, typically between 1% and 10%, with NaCl being the primary salt. Due to the complex composition of the recovered materials, some organic matter may not be decomposed at the high temperature of the incinerator and may enter subsequent treatment units; therefore, the flue gas scrubbing wastewater contains some organic matter.

[0003] Chinese invention patent application CN105174389A discloses an electrochemical oxidation wastewater treatment device, which includes a pressure tank with an electrolytic cell vertically placed inside. While this pressurization method can increase dissolved oxygen concentration and thus improve electro-oxidation efficiency, the pressure tank not only occupies a large amount of space but also significantly increases energy consumption and cost. Therefore, it does not improve the electro-oxidation device itself to enhance treatment efficiency.

[0004] Therefore, it is necessary to provide an electro-oxidation device, a wastewater treatment system, and a treatment method to solve or at least alleviate the technical deficiencies in how to improve the efficiency of electro-oxidation treatment. Summary of the Invention

[0005] The main objective of this invention is to provide an electro-oxidation device, a wastewater treatment system, and a treatment method, which aims to solve or at least alleviate the technical problem of how to improve the efficiency of electro-oxidation treatment.

[0006] To achieve the above objectives, the present invention provides an electro-oxidation device, which includes a first tank, a second tank, and an aeration mechanism; the first tank is provided with a first liquid inlet and a first liquid outlet, and is also provided with a buffer dosing port; the second tank is provided with a second liquid inlet and a second liquid outlet, and the second liquid inlet and the first liquid outlet are connected.

[0007] The second tank is provided with a flow baffle assembly, which includes multiple baffles. The flow baffle assembly forms a zigzag flow channel in the second tank through the multiple baffles. The zigzag flow channel connects the second liquid inlet and the second liquid outlet.

[0008] Both the first tank and the second tank are provided with electrode assemblies, the electrode assemblies including an anode and a cathode; the electrode assembly in the second tank is arranged along the path of the zigzag flow channel;

[0009] The aeration mechanism includes a first aeration section and a second aeration section, wherein the first aeration section is located at the lower part of the first tank and the second aeration section is located at the lower part of the second tank.

[0010] Furthermore, the second tank has a first sidewall, a second sidewall, a third sidewall, and a fourth sidewall; the first sidewall and the second sidewall are arranged opposite to each other, and the third sidewall and the fourth sidewall are arranged opposite to each other;

[0011] The second tank is divided between the first sidewall and the second sidewall by multiple partitions to form multiple interconnected working areas; each working area has the electrode assembly;

[0012] The partition includes at least one first partition and at least one second partition, which are alternately arranged between the first sidewall and the second sidewall; the first partition is sealed to the third sidewall and forms a water flow path between it and the fourth sidewall; the second partition is sealed to the fourth sidewall and forms a water flow path between it and the third sidewall.

[0013] Furthermore, the electro-oxidation device also includes one or more of the following: a cover mechanism, a tail gas absorption mechanism, a defoaming mechanism, and an ultrasonic mechanism;

[0014] The cover mechanism includes a first cover and a second cover, wherein the first cover and the first groove are fitted together, and the second cover and the second groove are fitted together.

[0015] The exhaust gas absorption mechanism includes a first gas collecting end and a second gas collecting end, wherein the first gas collecting end is connected to the first tank and the second gas collecting end is connected to the second tank.

[0016] The defoaming mechanism includes a first rotary defoamer and a second rotary defoamer, wherein the first rotary defoamer is disposed at the top of the first tank and the second rotary defoamer is disposed at the top of the second tank.

[0017] The ultrasonic mechanism includes a first ultrasonic component and a second ultrasonic component, wherein the first ultrasonic component is disposed in the first tank and the second ultrasonic component is disposed in the second tank.

[0018] Furthermore, the first tank does not contain the baffle assembly; the buffer dosing port is located near the first liquid inlet.

[0019] The present invention also provides a wastewater treatment system, the wastewater treatment system comprising any of the electro-oxidation devices described above;

[0020] The wastewater treatment system further includes a filter press device, which includes at least one of a first receiving port and a second receiving port; the first receiving port is connected to the bottom of the first tank, and the second receiving port is connected to the bottom of the second tank; the partition has a gap with the bottom wall of the second tank.

[0021] Furthermore, the wastewater treatment system also includes a pretreatment device; the pretreatment device includes a dosing chamber and a sedimentation tank, the inlet ends of the dosing chamber and the sedimentation tank are connected, and the outlet end of the sedimentation tank is connected to the first inlet.

[0022] The present invention also provides a wastewater treatment method, comprising: treating organic water bodies using an electro-oxidation device as described above.

[0023] Furthermore, the wastewater treatment method includes the following steps:

[0024] S1, control the organic water to continuously flow into the first tank along the first inlet, and simultaneously perform first electro-oxidation and first aeration on the water in the first tank;

[0025] During the process of controlling the organic water to continuously flow into the first tank through the first inlet, a buffer is continuously added to the first tank through the buffer dosing port, and the pH of the water in the first tank is controlled to be 7-8 by the buffer. The buffer includes one or more of carbonates and bicarbonates.

[0026] S2, control the water in the first tank to flow out along the first outlet, and then continuously flow into the second tank from the second inlet, and simultaneously perform second electro-oxidation and second aeration on the water in the second tank; the gas used for the first aeration and the second aeration both include oxygen-containing gas; the water in the second tank forms a zigzag flow path along the zigzag channel;

[0027] S3, control the water in the second tank to flow out along the second outlet, and collect the purified water.

[0028] Furthermore, the current density used for both the first and second electro-oxidation processes is 8-20 A / m. 2 ;

[0029] During the first electro-oxidation process, the water in the first tank is subjected to first ultrasound; during the second electro-oxidation process, the water in the second tank is subjected to second ultrasound; the power of the first ultrasound and the second ultrasound is 1-3Kw.

[0030] The aeration intensity used in both the first and second aeration processes is 1-10 m. 3 / m 2 ·h.

[0031] Furthermore, the method for obtaining the organic water body includes: pretreating the organic wastewater to obtain the organic water body;

[0032] The preprocessing process includes the following sub-steps:

[0033] S11, the organic wastewater and neutralizing agent are mixed, and the pH of the organic wastewater is controlled to 11-12 by the neutralizing agent. After precipitation, a first pretreated liquid is obtained; the neutralizing agent includes at least one of quicklime and lime milk.

[0034] S12, the first pretreatment solution and the defluoridation solution are mixed and precipitated to obtain the second pretreatment solution for the organic water body;

[0035] The defluorination solution contains a defluorinating agent, which includes one or more of aluminum salts and polyaluminum compounds; the mass concentration of the defluorinating agent in the defluorination solution is 60-70%, and the ratio of the organic wastewater to the defluorination solution is 1 m³ / s. 3 : 8-12kg.

[0036] Compared with the prior art, the present invention has at least the following advantages:

[0037] This invention employs a combined first and second tank for treatment, achieving deep removal of complex organic water and improving electro-oxidation efficiency even at lower current densities. By incorporating a buffer dosing port in the first tank, the invention not only controls and maintains pH stability within the first tank but also regulates the various reactions during electro-oxidation, ensuring treatment efficiency. Furthermore, since the water undergoes electro-oxidation first in the first tank and then in the second, the reaction intensity in the first tank is greater, leading to more significant pH fluctuations. The buffer dosing port in the first tank not only ensures the treatment efficiency of electro-oxidation in the first tank but also further stabilizes the pH of the water entering the second tank, thus guaranteeing the electro-oxidation efficiency within the second tank.

[0038] This invention reduces water hardness and electrode scaling by adding a buffer solution through a buffer dosing port in the first tank. It uses carbonates and bicarbonates such as sodium carbonate as buffers; the sodium salt generated by the reaction can react with the hydrogen chloride and hypochlorous acid produced in the complex oxidation stage, thus buffering the pH. Maintaining the water pH at a slightly alkaline level also reduces the risk of damage to the instrument. Since the organic water in this invention is typically obtained by neutralizing with lime slurry, it usually contains a small amount of Ca-F. Therefore, by introducing a buffer, this invention reduces the impact of chlorine on pH, prevents the opening of Ca-F bonds in CaF, and avoids electrode corrosion and scaling.

[0039] This invention, by setting a baffle assembly in the second tank, can form a zigzag flow channel in the second tank, so that the water purified by the first tank can undergo deep electro-oxidation in the second tank, thereby achieving deep treatment of the water; and since the water has already undergone initial electro-oxidation in the first tank and pH control has been performed in the first tank, this invention can ensure that the deep electro-oxidation in the second tank can proceed smoothly.

[0040] Furthermore, by incorporating an ultrasonic mechanism within the tank, this invention can disperse the salt precipitated on the electrode surface, significantly reducing scaling and drastically decreasing the frequency of electrode replacement and cleaning. Additionally, the ultrasonic mechanism enhances water flow turbulence, increasing the contact area between the water and the electrode, thereby further improving the composite oxidation efficiency. Moreover, the ultrasonic waves disperse the foam and scum that adhere to the electrode, reducing corrosion of the conductive rods. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0042] Figure 1 This is a partial structural diagram of a wastewater treatment system according to one embodiment of the present invention (partial partition not shown);

[0043] Figure 2 This is a schematic diagram of the folded flow channel in one embodiment of the present invention;

[0044] Figure 3 This is a partial structural diagram of the second tank in one embodiment of the present invention (electrode assembly not shown).

[0045] Reference numerals: 1. First tank; 11. First inlet; 12. First outlet; 13. Buffer dosing port; 14. First cover; 15. First ultrasonic component; 2. Second tank; 21. Second inlet; 22. Second outlet; 23. Third sidewall; 24. Fourth sidewall; 25. First partition; 26. Second partition; 27. Second cover; 28. Second ultrasonic component; 3. Air supply device; 31. First aeration section; 32. Second aeration section; 4. Defoaming mechanism; 5. Tail gas absorption mechanism; 6. Filter press; 7. Electrode assembly.

[0046] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0049] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of the invention, can be implemented using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of the invention. In this invention, delivery pumps can be adaptively installed in each pipeline, and valves can be installed at each opening.

[0050] See Figure 1-3 To understand this invention, we provide an electro-oxidation device, which includes a first tank 1, a second tank 2, and an aeration mechanism; both the first tank 1 and the second tank 2 can perform combined oxidation of water; wherein, wastewater (organic water) can first flow into the first tank 1, and then flow from the first tank 1 to the second tank 2.

[0051] To ensure continuous flow of wastewater in the first tank 1, a first inlet 11 and a first outlet 12 are provided on the tank wall of the first tank 1. To ensure effective retention of wastewater in the first tank 1, the first inlet 11 and the first outlet 12 are located at opposite ends (horizontally). For example, the tank wall with the first inlet 11 and the tank wall with the first outlet 12 are arranged opposite each other, and both the first inlet 11 and the first outlet 12 are located on the upper part of the side wall of the tank. The electrode assembly 7 in the first tank 1 is arranged between the first inlet 11 and the first outlet 12. That is, the first tank 1 has two tank walls arranged opposite each other, one of which has the first inlet 11 and the other has the first outlet 12, and the electrode assembly 7 is arranged between the two tank walls.

[0052] To improve the efficiency of electro-oxidation, control the pH stability of the water, regulate the reaction during the electro-oxidation process, prevent the opening of Ca-F bonds in CaF2 leading to the release of fluoride ions that corrode the electrode plates, avoid damage to the instrument due to low pH, and prevent scale buildup on the electrode plates, this invention also provides a buffer dosing port 13 (which can be understood as a pH buffer dosing port 13) on the first tank body 1. The buffer dosing port 13 is located near the first liquid inlet 11 (located below the first liquid inlet 11), specifically on the same side wall of the first tank body 1 as the first liquid inlet 11. The buffer dosing port 13 can be connected to a buffer dosing pipeline, which can be connected to a buffer storage tank containing a buffer, which includes one or more of carbonates and bicarbonates. Valves can be appropriately installed on the buffer dosing port 13 and / or the buffer dosing pipeline. By providing the buffer dosing port 13, a specific pH-adjusting buffer can be continuously added to the first tank 1, thereby allowing the buffer to participate in the reaction in the first tank 1 and control the pH; the second tank 2 does not have the buffer dosing port 13.

[0053] To ensure continuous flow of wastewater in the second tank 2, the second tank 2 is provided with a second inlet 21 and a second outlet 22, which are connected to each other. The second tank 2 has a first sidewall, a second sidewall, a third sidewall 23, and a fourth sidewall 24; the first sidewall and the second sidewall are arranged opposite to each other, and the third sidewall 23 and the fourth sidewall 24 are arranged opposite to each other.

[0054] To extend the hydraulic residence time and improve the efficiency of secondary deep composite oxidation, a baffle assembly is provided in the second tank 2. The baffle assembly includes multiple baffles, which form a zigzag flow channel within the second tank 2. This zigzag flow channel connects the second inlet 21 and the second outlet 22, which serve as the starting and ending points of the zigzag flow channel, respectively. The baffles have gaps with the bottom wall of the second tank 2 to ensure proper drainage of liquid and material from the bottom of the second tank 2.

[0055] Both the first tank 1 and the second tank 2 are provided with one or more sets of electrode assemblies 7. Each electrode assembly 7 includes an anode and a cathode, specifically one cathode and one anode. The electrode assembly 7 in the second tank 2 is arranged along the path of the zigzag flow channel, such that the electrode assembly 7 in the second tank 2 extends into the zigzag flow channel. The second tank 2 is divided between the first sidewall and the second sidewall by multiple partitions to form multiple interconnected working areas. Each working area has one or more sets of electrode assemblies 7, that is, the anode and cathode of the electrode assembly 7 extend into each working area. In a specific arrangement, the electrode assembly 7 and the partitions are arranged alternately, and the electrode plates in the electrode assembly 7 are arranged parallel to the partitions. There is a certain distance between the partitions and the sidewalls of the tank, and between the partitions themselves, forming the working area to facilitate the placement of the electrode assembly 7 and to allow water to flow through the electrode assembly 7.

[0056] The partition includes at least one first partition 25 and at least one second partition 26, which are arranged alternately between the first sidewall and the second sidewall. The first partition 25 is sealed to the third sidewall 23 and forms a water flow path (water flow gap) between itself and the fourth sidewall 24. The second partition 26 is sealed to the fourth sidewall 24 and forms a water flow path (water flow gap) between itself and the third sidewall 23. Each working area is connected through the water flow path.

[0057] To ensure effective retention of wastewater in the first tank 1, the second inlet 21 and the second outlet 22 are located at opposite ends of the second tank 2, and both are situated between the partition and the side wall of the second tank 2, with both inlets 21 and 22 positioned away from the water flow channel. For example, the second inlet 21 may be located on the first side wall, and the second outlet 22 may be located on the second side wall; alternatively, the second inlet 21 may be located on the fourth side wall 24, and the second outlet 22 may be located on the third side wall 23.

[0058] It should be noted that, because the second tank 2 is equipped with the baffle assembly and deep electro-oxidation is required in the second tank 2, the buffer dosing port 13 is not provided in the second tank 2; similarly, because the first tank 1 has the buffer dosing port 13 and initial electro-oxidation is required in the first tank 1, the baffle assembly is not provided in the first tank 1. The buffer dosing port 13 in the first tank 1 can introduce a buffer during the first composite oxidation reaction, thereby overcoming the technical defects in the composite oxidation process; while the baffle assembly in the second tank 2 ensures deep composite oxidation.

[0059] The aeration mechanism includes a first aeration section 31 and a second aeration section 32. The first aeration section 31 is located at the lower part or inner bottom of the first tank 1, and the second aeration section 32 is located at the lower part or inner bottom of the second tank 2. The first aeration section 31 and the second aeration section 32 may include aeration discs. The aeration discs of the second aeration section 32 can be evenly distributed in the lower part of each working area. The first aeration section 31 and the second aeration section 32 can be connected to the air supply device 3. The aeration mechanism can improve the ORP of wastewater, improve the composite oxidation efficiency, and flush away scale buildup on the electrode plates and the inner wall of the tank.

[0060] In this invention, the electro-oxidation device may further include one or more of the following: a cover mechanism, an aeration mechanism, a tail gas absorption mechanism 5, a defoaming mechanism 4, and an ultrasonic mechanism.

[0061] The cover mechanism includes a first cover 14 and a second cover 27. The first cover 14 is fitted onto the first groove 1, and the first cover 14 is fitted onto the top of the first groove 1. The second cover 27 is fitted onto the second groove 2, and the second cover 27 is fitted onto the top of the second groove 2.

[0062] The exhaust gas absorption mechanism 5 includes a first gas collecting end and a second gas collecting end. The first gas collecting end is connected to the first tank 1, and the second gas collecting end is connected to the second tank 2. Specifically, the gas collecting port of the first gas collecting end can be opened on the first cover 14, and the gas collecting port of the second gas collecting end can be opened on the second cover 27. Both the first and second gas collecting ends can be connected to an alkaline spraying device to achieve exhaust gas absorption.

[0063] The defoaming mechanism 4 includes a first rotary defoamer and a second rotary defoamer. The first rotary defoamer is disposed at the top of the first tank 1, and the second rotary defoamer is disposed at the top of the second tank 2. The first rotary defoamer and the first aeration unit 31 share an air source, and the second rotary defoamer and the second aeration unit 32 share an air source. It should be understood that the first and second rotary defoamers can scrape away foam from the water surface by rotating.

[0064] By setting the first and second rotary defoamers, the foam generated above the electrode plate during the composite oxidation process is dispersed, and excess splashed foam adheres to the inclined plate of the gas collecting hood and slides down into the tank. At this time, the first cover 14 can be the first gas collecting hood, and the second cover 27 can be the second gas collecting hood; the first gas collecting hood has a first gas collecting port, and the second gas collecting hood has a second gas collecting port. The first and second gas collecting hoods are surrounded by inclined plates, and the inner ends of the inclined plates are close to the tank.

[0065] The ultrasonic mechanism includes a first ultrasonic component 15 and a second ultrasonic component 28. The first ultrasonic component 15 is disposed within the first tank 1, and the second ultrasonic component 28 is disposed within the second tank 2. The ultrasonic mechanism can improve the composite oxidation efficiency, delay scale formation on the electrode plates, and further promote electro-oxidation. It should be understood that the oscillation waves generated during ultrasonic wave transmission cause resonance in the scale, water, and pipe inner wall. Due to the different oscillation frequencies of the scale, water, and pipe inner wall, water molecules in the pipe collide violently, generating a strong impact force that impacts the scale layer on the heat exchange surface, causing it to become brittle, peel off, detach, and pulverize.

[0066] The present invention also provides a wastewater treatment system, the wastewater treatment system comprising any of the electro-oxidation devices described above.

[0067] The wastewater treatment system may further include a filter press device 6, which includes at least one of a first receiving port and a second receiving port; the first receiving port is connected to the bottom of the first tank 1, and the bottom of the first tank 1 has a first discharge port, which is connected to the first receiving port; the second receiving port is connected to the bottom of the second tank 2, and the bottom of the second tank 2 has a second discharge port, which is connected to the second receiving port.

[0068] The filter press device 6 may also include a slag discharge port and a liquid discharge port. The liquid discharge port may be connected to the first liquid inlet 11 of the first tank 1 so that the liquid generated after filter press can continue to flow back to the first tank 1 and the second tank 2 for processing.

[0069] Optionally, the wastewater treatment system may further include a pretreatment device, which includes a dosing chamber and a sedimentation tank. The dosing chamber is equipped with baffles to allow flow along a long water flow path. The inlet ends of the dosing chamber and the sedimentation tank are connected, and the outlet end of the sedimentation tank is connected to the first inlet 11 of the first tank 1. For example, there may be two dosing chambers: a neutralizing agent dosing chamber and a defluoridating agent dosing chamber. The number of sedimentation tanks can be adjusted according to the number of dosing chambers.

[0070] This invention also provides a wastewater treatment method, comprising: treating organic water body using any of the electro-oxidation devices described above, wherein the organic water body can be understood as pretreated wastewater; the pH of the organic water body can be 9-10, COD can be 1200-1700 mg / L, color can be 800-910 pcu, ammonia nitrogen content can be 1540-1640 mg / L, fluoride ion content can be 7.0-7.5 mg / L, and chloride ion content can be 25000-32000 mg / L; the organic water body contains specific metal cations, wherein the metal cations include one or more of calcium ions and magnesium ions; the organic water body can include water body obtained after neutralization with lime slurry; even after precipitation separation, the water body obtained after neutralization with lime slurry will still contain CaF2 (in small amounts) and has Ca-F bonds.

[0071] The wastewater treatment method includes the following steps:

[0072] S1, control the organic water to continuously flow into the first tank 1 along the first inlet 11, and simultaneously perform the first electro-oxidation and the first aeration on the water in the first tank 1.

[0073] During the process of controlling the continuous flow of the organic water into the first tank 1 through the first inlet 11, a buffer is continuously added to the first tank 1 through the buffer dosing port 13, and the pH of the water in the first tank 1 is controlled to be 7-8 by the buffer. The buffer includes one or more of carbonates and bicarbonates, specifically including one or more of carbonate solutions and bicarbonate solutions. The mass concentration of the carbonate solution and the bicarbonate solution can be 5-15%. The carbonate can include one or more of sodium carbonate and potassium carbonate, and the bicarbonate can include one or more of sodium bicarbonate and potassium bicarbonate. The flow rate of the organic water flowing into the first tank 1 through the first inlet 11 can be 20-100 L / h.

[0074] The method for obtaining the organic water body includes: pretreating organic wastewater to obtain the organic water body; the organic wastewater may have a pH of 6-7, a COD of 1600-2100 mg / L, a color of 850-950 pcu, an ammonia nitrogen content of 2100-2300 mg / L, a fluoride ion content of 120-140 mg / L, and a chloride ion content of 28000-32000 mg / L; the organic wastewater contains specific metal cations, including one or more of calcium ions and magnesium ions.

[0075] The preprocessing process includes the following sub-steps:

[0076] S11, the organic wastewater and neutralizing agent are mixed, and the pH of the organic wastewater is controlled to 11-12 by the neutralizing agent. After precipitation and separation, a first pretreated liquid is obtained. The neutralizing agent includes at least one of quicklime and lime slurry. Taking lime slurry as an example, the mass concentration of calcium ions in the lime slurry can be 5-20%, and the ratio of the organic wastewater to the lime slurry can be 1 m³ / h. 3 80-130kg; there is no specific time limit for mixing, but it can be based on the pH of the water reaching a stable state after the addition of the neutralizing agent.

[0077] S12, the first pretreatment solution and the defluoridation solution are mixed, and after precipitation and separation, the second pretreatment solution for the organic water body is obtained; the mixing time is not specifically limited, and can be based on the fact that the concentration of fluoride ions in the water body is stable after the addition of the defluoridation agent.

[0078] The defluorination solution contains a defluorinating agent, which includes one or more of aluminum salts and polyaluminum compounds; the mass concentration of the defluorinating agent in the defluorination solution is 60-70%, and the ratio of the organic wastewater to the defluorination solution is 1 m³ / s. 3 : 8-12kg.

[0079] S2, the water in the first tank 1 is controlled to flow out along the first outlet 12, and then continuously flow into the second tank 2 from the second inlet 21, and the water in the second tank 2 is simultaneously subjected to second electro-oxidation and second aeration; the gas used for the first aeration and the second aeration both include oxygen-containing gas, which may include air or oxygen; the water in the second tank 2 forms a zigzag (specifically S-shaped) flow path along the zigzag channel.

[0080] S3, control the water in the second tank 2 to flow out along the second outlet 22, and collect the purified water.

[0081] In this invention, the current density used for both the first and second electro-oxidation processes can be 8-20 A / m. 2Or 10-16A / m 2 During the first electro-oxidation process, the water in the first tank 1 is simultaneously subjected to first ultrasonic treatment; during the second electro-oxidation process, the water in the second tank 2 is simultaneously subjected to second ultrasonic treatment; the power of both the first and second ultrasonic treatments can be 1-3 kW; the aeration intensity of both the first and second aeration can be 1-10 m³ / h. 3 / m 2 ·h.

[0082] In this invention, the wastewater treatment method may further include: absorbing the tail gas generated in the first tank 1 and the second tank 2, wherein the spray liquid used to absorb the tail gas may include sodium hydroxide solution, and the concentration may be controlled at a pH of 13-14.

[0083] The main difficulties encountered in this invention include:

[0084] 1. During the reaction, crystals will precipitate on the surface of the electrode plate, affecting the efficiency of composite oxidation.

[0085] This invention, by setting an ultrasonic mechanism in the tank, can disperse the salt precipitated on the surface of the electrode plate, greatly reducing scaling and significantly reducing the frequency of electrode plate replacement and cleaning; in addition, the ultrasonic mechanism can increase the turbulence of the water flow, increase the contact area between the wastewater and the electrode plate, and improve the composite oxidation efficiency; furthermore, the ultrasonic waves can disperse the foam and scum attached to the electrode plate, which can reduce the corrosion of the conductive rod.

[0086] 2. During the composite oxidation process, it was found that the treatment sequence of wastewater components is important. Chloride ions often precipitate in the later stages of the reaction, generating a large amount of chlorine gas. This makes it difficult to control the pH of the wastewater. Improper pH control will affect the treatment efficiency of electro-oxidation and will also break the Ca-F bonds of the extremely fine CaF2 particles in the wastewater that have not been filtered out, releasing fluoride ions that corrode the electrode plates. Moreover, due to the generation of chlorine gas in the composite oxidation tank, the pH of the wastewater is very low after the chlorine dissolves in the water. The pH meter and ORP meter are immersed in water for a long time, resulting in a shorter service life of the instruments.

[0087] This invention reduces wastewater hardness and scale buildup on the electrode plates by adding a buffer to the first electrolytic cell. Furthermore, the sodium salt generated by the reaction displacement can react with the hydrogen chloride and hypochlorous acid produced in the composite oxidation stage, thus acting as a pH buffer. In addition, maintaining the wastewater pH at a slightly alkaline level reduces wear and tear on the instruments.

[0088] 3. Deep composite oxidation treatment and buffering agents are difficult to achieve in the same tank.

[0089] This invention comprises a first tank 1 and a second tank 2. The first tank 1 has a buffer dosing port 13 but no baffle assembly. The second tank 2 has a baffle assembly but no buffer dosing port 13. This configuration maintains pH stability, prevents the release of fluoride ions and the effects of chlorine, reduces wastewater hardness, and prevents scaling of metal cations such as calcium and magnesium on the electrode plates. Furthermore, it enables deep composite oxidation of the water. The baffle assembly in the second tank 2 separates the water flow, extends the water flow distance, and increases the hydraulic residence time. The aeration device located in the middle of the lower part of the tank agitates the water flow, increasing the contact area between the water and the electrode plates and improving the efficiency of deep composite oxidation.

[0090] It should be noted that during the electro-oxidation process, "direct oxidation" and "indirect oxidation" occur simultaneously, with both the cathode and anode acting as co-catalysts. Therefore, this stage is named "composite oxidation." In composite oxidation equipment, organic pollutants are oxidized and degraded through hydroxyl radicals and other active substances generated by the anode reaction. It mainly includes two oxidation mechanisms: direct oxidation and indirect oxidation.

[0091] Direct oxidation refers to the direct participation of some active oxides in the reaction process. The representative substance is the metal oxide [M(·OH)] that adsorbs hydroxyl radicals. Through reaction formula (3), a high-valence metal oxide (MO) can be formed. Organic pollutants (R: organic pollutants) are mainly removed through reaction formulas (4) and (5).

[0092] 2H₂O→O₂+4H + +4e - (1)

[0093] M + H₂O → M(·OH) + H₂ + +e - (2)

[0094] M(·OH)→MO+H + +e - (3)

[0095] R + M(·OH) → M + CO₂ + H₂O + H₂ + +e - (4)

[0096] MO+R→M+RO (5)

[0097] Indirect oxidation refers to the degradation of organic pollutants by generating active substances such as active chlorine (RCS) and active oxygen (ROS) through oxidation, mainly through reaction formulas (6) to (14).

[0098]

[0099] 2M(·OH)→2M+H2O2 (8)

[0100] O2+2e - +2H + →H2O2 (9)

[0101] H2O2 + 2e - +2H + →2H2O (10)

[0102] Cl - +e - →2Cl2(aq) (11)

[0103]

[0104] Cl - +2H₂O→ClO₂ - +4H + +5e - (14)

[0105] Among them, RCS is widely used in wastewater treatment, and the main types are chlorite, chlorate and hypochlorite.

[0106] The following are specific examples of the present invention:

[0107] Example 1

[0108] This embodiment provides an electro-oxidation device. The electro-oxidation device includes a first tank 1 and a second tank 2. The first tank 1 has opposing sidewalls A and B, and opposing sidewalls C and D. A first inlet 11 is provided at the upper part of sidewall A, and a buffer dosing port 13 is provided below the first inlet 11. A first outlet 12 is provided at the upper part of sidewall B. The second tank 2 has opposing first and second sidewalls, and opposing third and fourth sidewalls 23 and 24. A second inlet 21 is provided at the upper part of the first sidewall, and a second outlet 22 is provided at the upper part of the second sidewall. The first outlet 12 and the second inlet 21 are connected via a delivery pipeline.

[0109] Both the first tank 1 and the second tank 2 are equipped with electrode assemblies 7 and ultrasonic mechanisms (the ultrasonic mechanisms include ultrasonic rods, which are respectively installed at the top of the first tank 1 and the second tank 2, connected by flanges, and emit ultrasonic waves into the tanks). The electrode assembly 7 consists of one anode and one cathode. The first tank 1 has 10 anodes and 10 cathodes, which are arranged alternately to form 10 sets of electrode assemblies 7. The electrodes in the first tank 1 are arranged parallel to the side wall A. The second tank 2 also has 10 anodes and 10 cathodes, which are arranged alternately to form 10 sets of electrode assemblies 7. The electrodes in the second tank 2 are arranged parallel to the first side wall.

[0110] The second tank 2 is also equipped with a flow-bending assembly, which consists of multiple baffles. The flow-bending assembly includes multiple baffles, which form a zigzag flow channel in the second tank 2. The zigzag flow channel connects the second liquid inlet 21 and the second liquid outlet 22. In the second tank 2, a baffle is provided between two adjacent electrode assemblies 7, and the two adjacent (close) baffles are the first baffle 25 and the second baffle 26, that is, the first baffle 25 and the second baffle 26 are alternately arranged along the arrangement direction of the electrode assemblies 7. The first baffle 25 is sealed to the third side wall 23 and forms a water flow path between it and the fourth side wall 24. The second baffle 26 is sealed to the fourth side wall 24 and forms a water flow path between it and the third side wall 23. The second liquid inlet 21 and the second liquid outlet 22 are both located away from the water flow path. The first baffle 25 and the second baffle 26 both have gaps with the bottom wall of the second tank 2.

[0111] In this embodiment, the electro-oxidation device also includes a cover mechanism, an aeration mechanism, a tail gas absorption mechanism 5, and a defoaming mechanism 4.

[0112] The cover mechanism includes a first cover 14 and a second cover 27. The first cover 14 and the first trough 1 are covered together, and the second cover 27 and the second trough 2 are covered together. The first cover 14 is a first gas collecting hood, and the second cover 27 is a second gas collecting hood. The first gas collecting hood has a first gas collecting port, and the second gas collecting hood has a second gas collecting port. The first gas collecting hood and the second gas collecting hood are surrounded by inclined plates, and the inner end of the inclined plates is close to the trough.

[0113] The exhaust gas absorption mechanism 5 includes a first gas collecting end and a second gas collecting end. The first gas collecting end is connected to the first tank 1 through a first collecting port, and the second gas collecting end is connected to the second tank 2 through a second collecting port. Both the first gas collecting end and the second gas collecting end are connected to the alkaline spraying device.

[0114] The aeration mechanism includes a first aeration section 31 and a second aeration section 32. The first aeration section 31 is located at the bottom inner wall of the first tank 1, and the second aeration section 32 is located at the bottom inner wall of the second tank 2. Both the first aeration section 31 and the second aeration section 32 are equipped with aeration discs.

[0115] The defoaming mechanism 4 includes a first electric rotary defoamer and a second electric rotary defoamer. The first electric rotary defoamer is located at the top of the first tank 1 and below the first cover 14; the second electric rotary defoamer is located at the top of the second tank 2 and below the second cover 27.

[0116] In this embodiment, the dimensions of the first tank 1 and the second tank 2 are approximately 1m long, 0.5m wide, and 0.7m high, and the material is insulating material; the dimensions of the electrodes in the first tank 1 and the second tank 2 are both 0.3cm long, 0.4m wide, and 0.6m high; the anode is a titanium plate plated with ruthenium-iridium, and the cathode is a titanium plate; the electrode assembly 7 is mounted on a conductive rod, and the conductive rod is a copper rod; in this embodiment, a pH meter and an ORP meter are provided in the first tank 1 and the second tank 2.

[0117] Example 2

[0118] The pretreatment process for organic wastewater includes:

[0119] 1. Obtain organic wastewater with a pH of 6.7, COD of 2057 mg / L, color of 895 pcu, ammonia nitrogen content of 2213 mg / L, fluoride ion content of 136 mg / L, and chloride ion content of 30200 mg / L; the organic wastewater contains metal cations such as calcium and magnesium.

[0120] 2. Control organic wastewater to 3m 3 A flow rate of / h continuously flows into the neutralizing agent dosing chamber, and neutralizing agent is continuously added to the neutralizing agent dosing chamber (by stirring and mixing). The pH of the organic wastewater is adjusted to 11-12 by the neutralizing agent. The mixed water in the neutralizing agent dosing chamber is controlled to flow into the inclined plate sedimentation tank for sedimentation. After sedimentation, the first pretreated liquid is obtained.

[0121] In this embodiment, the neutralizing agent is lime slurry, the mass concentration of calcium ions in the lime slurry is 10%, and the overall ratio of organic wastewater to lime slurry is 1 m³ / h. 3 100kg.

[0122] 3. Control the first pretreatment liquid to continuously flow into the defluorinating agent dosing chamber, and continuously add defluorinating liquid (stirring and mixing) into the defluorinating agent dosing chamber; control the mixed water in the defluorinating agent dosing chamber to flow into the inclined plate sedimentation tank for sedimentation, and after sedimentation, the second pretreatment liquid (denoted as organic water) is obtained to flow into the first tank.

[0123] The defluorination solution contains a defluorinating agent, specifically aluminum sulfate; the defluorinating agent concentration in the solution is 65% by mass, and the overall ratio of organic wastewater to the defluorination solution is 1 m³ / min. 3 10kg.

[0124] The second pretreatment solution has a pH of 9.5, a COD of 1470 mg / L, a color of 880 pcu, an ammonia nitrogen content of 1590 mg / L, a fluoride ion content of 7.1 mg / L, and a chloride ion content of 27000 mg / L; the second pretreatment solution contains metal cations such as calcium and magnesium.

[0125] Example 3

[0126] The organic water obtained in Example 2 was treated using the electro-oxidation device described in Example 1. The specific steps are as follows:

[0127] 1. The second pretreatment liquid (organic water) is continuously fed into the first tank through the first inlet at a flow rate of 60L / h, and the water in the first tank is simultaneously subjected to first electro-oxidation, first ultrasonication and first aeration.

[0128] During the process of controlling the continuous flow of the second pretreatment liquid into the first tank through the first inlet, a buffer is continuously added to the first tank through the buffer dosing port, and the pH of the first tank is controlled to be 7-8 by the buffer. The buffer is a 10% sodium carbonate solution; the overall ratio of organic wastewater to buffer is 1 m³ / h. 3 30kg.

[0129] 2. The water in the first tank is controlled to flow out through the first outlet and then into the second tank through the second inlet. The water in the second tank is simultaneously subjected to second electro-oxidation, second ultrasonication, and second aeration. The gas used for the first aeration and the second aeration is air. The water in the second tank forms an S-shaped flow path along the zigzag channel.

[0130] 3. Control the water in the second tank to flow out along the second outlet and collect the purified water.

[0131] In this embodiment, the current density used for both the first and second electro-oxidation processes is 11.2 A / m. 2 The power of both the first and second ultrasonic aeration systems is 2 kW; the aeration intensity of both the first and second aeration systems is 3 m³ / s. 3 / m 2 •h; In this embodiment, the first electric rotary defoamer and the second electric rotary defoamer are activated during operation to remove surface foam.

[0132] In this embodiment, the treatment lasted 8 hours, and the electricity consumption generated by electro-oxidation was 17.92 kWh.

[0133] In this embodiment, the COD of the purified water is 367.1 mg / L, the color is 0 pcu, the ammonia nitrogen content is 77 mg / L, the fluoride ion content is 5.2 mg / L, and the chloride ion content is 13800 mg / L.

[0134] In this embodiment, after 8 hours of treatment, no corrosion or scaling was observed at either the anode or the cathode.

[0135] Example 4

[0136] Compared to Example 3, this embodiment only adjusts the current density used for the first and second electro-oxidation processes to 13.6 A / m. 2 All other conditions remain unchanged.

[0137] In this embodiment, the treatment lasted 8 hours, and the electricity consumption generated by electro-oxidation was 21.76 kWh.

[0138] In this embodiment, the COD of the purified water is 224.7 mg / L, the color is 0 pcu, the ammonia nitrogen content is 58 mg / L, the fluoride ion content is 4.9 mg / L, and the chloride ion content is 11300 mg / L.

[0139] In this embodiment, after 8 hours of treatment, no corrosion or scaling was observed at either the anode or the cathode.

[0140] Example 5

[0141] Compared to Example 3, this embodiment only adjusts the current density used for the first and second electro-oxidation processes to 15.2 A / m. 2 All other conditions remain unchanged.

[0142] In this embodiment, the treatment lasted 8 hours, and the electricity consumption generated by electro-oxidation was 24.32 kWh.

[0143] In this embodiment, the COD of the purified water is 189.8 mg / L, the color is 0 pcu, the ammonia nitrogen content is 46 mg / L, the fluoride ion content is 4.8 mg / L, and the chloride ion content is 8317 mg / L.

[0144] In this embodiment, after 8 hours of treatment, no corrosion or scaling was observed at either the anode or the cathode.

[0145] Comparative Example 1

[0146] Compared to Example 3, this comparative example omits the buffer (i.e., no buffer is added to the first tank), while all other conditions remain unchanged.

[0147] In this comparative example, the COD of the purified water was 1219 mg / L, the color was 0.8 pcu, the ammonia nitrogen content was 187 mg / L, the fluoride ion content was 12.5 mg / L, and the chloride ion content was 14100 mg / L.

[0148] In this comparative example, after 8 hours of treatment, slight corrosion was observed at the anode and slight scaling was observed at the cathode.

[0149] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. An electro-oxidation device, characterized in that, The electro-oxidation device comprises a first tank, a second tank and an aeration mechanism; the first tank is provided with a first liquid inlet and a first liquid outlet, and is also provided with a buffer agent adding port; the second tank is provided with a second liquid inlet and a second liquid outlet, and the second liquid inlet and the first liquid outlet are in communication; The second tank is provided with a baffle assembly, which comprises a plurality of partitions; the baffle assembly forms a zigzag flow channel in the second tank through the plurality of partitions; the zigzag flow channel is in communication with the second liquid inlet and the second liquid outlet; The first tank and the second tank are both provided with an electrode assembly, which comprises an anode and a cathode; the electrode assembly in the second tank is arranged along the path of the zigzag flow channel; The aeration mechanism comprises a first aeration part and a second aeration part; the first aeration part is arranged at the lower part of the first tank, and the second aeration part is arranged at the lower part of the second tank.

2. The electro-oxidation device of claim 1, wherein, The second tank has a first side wall, a second side wall, a third side wall and a fourth side wall; the first side wall and the second side wall are arranged oppositely, and the third side wall and the fourth side wall are arranged oppositely; The second tank is divided into a plurality of working zones in communication with each other through the plurality of partitions between the first side wall and the second side wall; each working zone is provided with the electrode assembly; The partitions comprise at least one first partition and at least one second partition; the first partitions and the second partitions are arranged alternately between the first side wall and the second side wall; the first partitions are in sealing connection with the third side wall and form a water flow passage with the fourth side wall; The second partitions are in sealing connection with the fourth side wall and form a water flow passage with the third side wall.

3. The electro-oxidation device of claim 1, wherein The electro-oxidation device further comprises one or more of a cover mechanism, a tail gas absorption mechanism, a defoaming mechanism and an ultrasonic mechanism; The cover mechanism comprises a first cover and a second cover; the first cover is in covering connection with the first tank, and the second cover is in covering connection with the second tank; The tail gas absorption mechanism comprises a first gas collecting end and a second gas collecting end; the first gas collecting end is in communication with the first tank, and the second gas collecting end is in communication with the second tank; The defoaming mechanism comprises a first rotating defoamer and a second rotating defoamer; the first rotating defoamer is arranged at the top of the first tank, and the second rotating defoamer is arranged at the top of the second tank; The ultrasonic mechanism comprises a first ultrasonic assembly and a second ultrasonic assembly; the first ultrasonic assembly is arranged in the first tank, and the second ultrasonic assembly is arranged in the second tank.

4. The electro-oxidation device according to any one of claims 1 to 3, characterized in that, The first tank is not provided with the baffle assembly; the buffer agent adding port is arranged close to the first liquid inlet.

5. A wastewater treatment system, characterized by, The wastewater treatment system comprises the electro-oxidation device according to any one of claims 1-4. The wastewater treatment system further comprises a filter press device, the filter press device comprises at least one of a first material receiving port and a second material receiving port; the first material receiving port is in communication with the bottom of the first tank body, and the second material receiving port is in communication with the bottom of the second tank body; the partition plate has a gap with the bottom wall of the second tank body.

6. The wastewater treatment system of claim 5, wherein, The wastewater treatment system further comprises a pretreatment device; the pretreatment device comprises a dosing chamber and a sedimentation tank, the liquid inlet ends of the dosing chamber and the sedimentation tank are in communication, and the liquid outlet end of the sedimentation tank is in communication with the first liquid inlet.

7. A method of treating wastewater, characterized by, Comprise: An organic water body is treated by using the electro-oxidation device according to any one of claims 1-4.

8. The wastewater treatment method according to claim 7, characterized by, The wastewater treatment method comprises the steps of: S1, controlling the organic water body to continuously flow into the first tank body through the first liquid inlet, and simultaneously performing first electro-oxidation and first aeration on the water body in the first tank body; During the process of controlling the organic water body to continuously flow into the first tank body through the first liquid inlet, a buffering agent is continuously added to the first tank body through the buffering agent dosing port, and the pH of the water body in the first tank body is controlled to be 7-8 by the buffering agent, the buffering agent comprising one or more of carbonates and bicarbonates; S2, controlling the water body in the first tank body to flow out through the first liquid outlet, and then continuously flowing into the second tank body from the second liquid inlet, and simultaneously performing second electro-oxidation and second aeration on the water body in the second tank body; the gas used for the first aeration and the second aeration both comprises oxygen-containing gas; the water body in the second tank body forms a zigzag flow path along the zigzag flow channel; S3, controlling the water body in the second tank body to flow out through the second liquid outlet, and collecting the purified water body.

9. The wastewater treatment method according to claim 8, characterized by, The first electro-oxidation and the second electro-oxidation employ a current density of 8-20 A / m 2 ; During the process of performing the first electro-oxidation, first ultrasonic is performed on the water body in the first tank body; during the process of performing the second electro-oxidation, second ultrasonic is performed on the water body in the second tank body; the power of the first ultrasonic and the second ultrasonic is 1-3Kw; The first aeration and the second aeration each employ an aeration intensity of 1-10 m 3 / m 2 ·h.

10. The wastewater treatment method according to claim 8 or 9, characterized by, The method for obtaining the organic water body comprises: pretreating organic wastewater to obtain the organic water body; The process of the pretreatment comprises the following sub-steps: S11, mixing the organic wastewater and a neutralizing agent, and controlling the pH of the organic wastewater to be 11-12 by the neutralizing agent, and obtaining a first pretreated liquid after precipitation; the neutralizing agent comprises at least one of quicklime and lime milk; S12, mixing the first pretreated liquid and a defluorination liquid, and obtaining a second pretreated liquid as the organic water body after precipitation; The defluorination liquid contains a defluorination agent, which includes one or more of aluminum salt and polyaluminum type substance; the mass concentration of the defluorination agent in the defluorination liquid is 60-70%, the ratio of the organic wastewater and the defluorination liquid is 1m 3 :8-12kg.

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