A Fenton reaction device for wastewater treatment

Abstract

This application relates to the technical field of wastewater treatment, and particularly to a Fenton reaction device for wastewater treatment, which includes: reaction tanks, multiple in number, with reaction chambers formed inside, and equipped with stirring mechanisms, respectively used for primary oxidation, premixing, secondary oxidation, complexation reaction, and flocculation reaction treatment of wastewater, and the multiple reaction tanks are connected in sequence; a chemical dosing device, including a first chemical addition mechanism and a second chemical addition mechanism, the first chemical addition mechanism includes a rotating dosing disk, the rotating dosing disk rotates in the middle of the reaction tank, is connected to the stirring mechanism, and is used for rotating and dosing a solid additive dissolution solution, a liquid additive, or magnetic powder; the second chemical addition mechanism includes an atomization structure arranged in the reaction tank, which is used for atomizing and spraying a liquid additive. This application has the effects of improving the chemical mixing efficiency and reducing local uneven mixing.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and in particular, to a Fenton reaction device for wastewater treatment. Background Art

[0002] Currently, as a classic advanced oxidation technology (AOPs), the core principle of the Fenton reaction is to catalyze the decomposition of hydrogen peroxide (H2O2) by ferrous ions to generate highly oxidizing hydroxyl radicals, thereby efficiently decomposing refractory organic matter.

[0003] In the prior art, Chinese Patent No. CN116081903A discloses a method for advanced treatment of wastewater by Fenton, which includes the following steps: 1) adjusting the pH of the wastewater to acidic to obtain acidified wastewater; 2) introducing ozone under an external magnetic field, stirring and mixing, and continuously reacting for 15 - 30 min to obtain primary oxidized wastewater; 3) adding ferrous salt to the primary oxidized wastewater, stirring and mixing to obtain premixed wastewater; 4) adding hydrogen peroxide to the premixed wastewater, stirring and mixing, and continuously reacting for 30 - 45 min under an external magnetic field to obtain secondary oxidized wastewater; 5) aerating the secondary oxidized wastewater and adding carbonate to adjust the pH of the wastewater to 5 - 6 to obtain pre-neutralized wastewater; 6) adding a complexing defluorinating agent and magnetic powder to the obtained pre-neutralized wastewater, stirring and mixing, and continuously reacting for 10 - 20 min to obtain complexing reaction wastewater; 7) adding an alkali solution to the obtained complexing reaction wastewater, stirring and mixing, adjusting the pH of the complexing reaction wastewater to 6 - 7, and continuously reacting for 10 - 15 min under stirring conditions to obtain secondary neutralized wastewater; 8) adding a coagulant aid to the obtained secondary neutralized wastewater, stirring and mixing, and then separating by precipitation. The supernatant is the purified wastewater.

[0004] However, when implementing each step of the above method, a stirring tank is usually used for mixing and stirring. When preparing the premixed wastewater, since the addition of ferrous salt usually forms a solution after dissolution and then is directly added through the feeding port of the stirring tank, the direct addition method results in a slow mixing rate, which in turn leads to a too high local Fe 2+ concentration, causing premature precipitation of Fe 3+ and reducing the catalytic efficiency, resulting in uneven mixing. Summary of the Invention

[0005] In order to improve the mixing efficiency of the medicament and reduce local uneven mixing, the present application provides a Fenton reaction device for wastewater treatment.

[0006] The Fenton reaction device for wastewater treatment provided by the present application adopts the following technical solutions:

[0007] A Fenton reaction device for wastewater treatment, comprising:

[0008] Reaction tanks, multiple of them are provided, reaction chambers are formed inside, and stirring mechanisms are provided, which are respectively used for primary oxidation, premixing, secondary oxidation, complexation reaction and flocculation reaction treatment of wastewater, and the multiple reaction tanks are connected in sequence;

[0009] Reagent dosing device, including a first dosing mechanism and a second dosing mechanism, the first dosing mechanism includes a rotating dosing disk, the rotating dosing disk rotates in the middle of the reaction tank, is connected to the stirring mechanism, and is used for rotating and dosing a solid additive dissolution solution or a liquid additive or magnetic powder;

[0010] The second dosing mechanism includes an atomization structure arranged in the reaction tank, which is used for atomizing and spraying a liquid additive.

[0011] By adopting the above technical solution, when treating wastewater, first add the wastewater into the reaction tank for primary oxidation, then add acid into the wastewater through the rotating dosing disk to adjust the pH value of the wastewater to acidic, and obtain acidified wastewater. Under the condition of an external magnetic field, introduce ozone, stir and mix, and after continuous reaction for 15 - 30 min, obtain primary oxidation wastewater; then flow the primary oxidation wastewater into the reaction tank for premixing, and then add the solution prepared by dissolving ferrous salt during stirring through the rotating dosing disk to obtain premixed wastewater; then add hydrogen peroxide into the reaction tank through the atomization mechanism, stir and mix, under the condition of applying a magnetic field outside the reaction tank, and carry out continuous reaction for 30 - 45 min to obtain secondary oxidation wastewater, then carry out aeration, and add carbonate to adjust the pH of the wastewater to 5 - 6 to obtain pre-neutralized wastewater; introduce the pre-neutralized wastewater into the reaction tank for complexation reaction, then add a complexing defluorination agent through the atomization structure, and put magnetic powder through the rotating dosing disk, stir and mix, and carry out continuous reaction for 10 - 20 min to obtain complexation reaction wastewater; add an alkali solution to the obtained complexation reaction wastewater, stir and mix, adjust the pH of the complexation reaction wastewater to 6 - 7, and carry out continuous reaction for 10 - 15 min under stirring conditions to obtain secondary neutralized wastewater; then introduce the secondary neutralized wastewater into the reaction tank for flocculation reaction, then add a coagulant aid to the obtained secondary neutralized wastewater, stir and mix and then carry out sedimentation separation, and the supernatant is the purified wastewater, and the supernatant is discharged; among them, premixing and secondary oxidation are carried out in the same reaction tank to improve the utilization rate of the reaction tank.

[0012] Through the settings of the first feeding mechanism and the second feeding mechanism, the addition of the dissolved solid additive solution and the liquid additive after dissolution becomes more convenient, and they can be mixed more evenly; ferrous salt solution is prone to oxidation reaction when contacting with air too much. In the step of adding ferrous salt solution, by means of rotary feeding, large droplets or linear pouring is used to add ferrous salt solution, which improves the dispersion efficiency. At the same time, it can reduce the contact between ferrous salt solution and oxygen, reduce the waste caused by premature oxidation of ferrous salt solution, and through the rotary feeding method, reduce the risk of Fe 3+ precipitation; the atomization coverage area of H2O2 increases, the utilization rate of free radicals is improved, which further makes the mixture uniform, improves the resource utilization rate, reduces resource waste, improves the mixing efficiency of the medicament, and reduces local uneven mixing; and the addition of acid-base solvents is carried out through the first feeding mechanism and the second feeding mechanism, which is convenient for adjusting the pH value, and can make the solution disperse evenly, facilitating the rapid adjustment of the pH value.

[0013] Optionally, the rotation direction of the rotary feeding disk is opposite to the rotation direction of the stirring mechanism.

[0014] By adopting the above technical solution, the stirring mechanism rotates clockwise and the feeding disk rotates counterclockwise, forming a shear flow field. The reverse rotation enhances the turbulent mixing, further shortening the mixing time of the ferrous salt solution and the wastewater, improving the catalyst activity, accelerating the mixing, and improving the wastewater treatment effect.

[0015] Optionally, the first additive mechanism further includes a transmission component, and the transmission component includes a first gear, a second gear and a gear ring. The first gear is coaxially arranged with the stirring mechanism, the second gear rotates on the reaction tank and meshes with the first gear, the gear ring rotates on the reaction tank and meshes with the second gear, and the gear ring is connected to the rotary feeding disk.

[0016] By adopting the above technical solution, when the stirring mechanism rotates for stirring, by driving the first gear to rotate, the first gear drives the second gear to rotate, the second gear drives the gear ring to rotate, and the gear ring drives the rotary feeding disk to rotate, so that the rotation directions of the stirring mechanism and the rotary feeding disk are opposite, and the movement trajectories of the wastewater and the dissolved solid additive are reversed, resulting in collisions, increasing the contact and contact duration between the wastewater and the solid additive solution. At the same time, the collisions can accelerate the mixing effect, increase the mixing efficiency, and improve the wastewater treatment effect.

[0017] Optionally, the atomization structure is arranged outside the rotary feeding disk.

[0018] By adopting the above technical solution, when adding liquid hydrogen peroxide, it can be added simultaneously with the ferrous salt solution, or the ferrous salt can be dissolved and stirred first, and then hydrogen peroxide can be added; in other reaction tanks, according to the process requirements, the addition timing of the solid additive dissolution solution and the liquid additive can be adjusted. When adding simultaneously or there is an overlapping addition time, the solid additive dissolution solution rotates and separates to contact and collide with the atomized liquid additive, so that the liquid additive adheres to the solid additive dissolution solution, and then mixes with the wastewater, which is convenient for improving the reaction efficiency, making the mixing of the solid additive dissolution solution and the liquid additive uniform, and further improving the treatment effect of the wastewater; and for solutions with high requirements for the acid-base environment, through the mixed addition of the first additive mechanism and the second additive mechanism, the solution can be made to adapt to the acid-base environment in advance, quickly start the catalytic effect, reduce the addition of the acid-base adjustment liquid, and improve the resource utilization rate.

[0019] Optionally, the atomization structure includes an annular pipe, atomizing nozzles and a reagent supply assembly. The annular pipe is arranged in the reaction tank, the annular pipe is connected to the reagent supply assembly, and the reagent supply assembly is arranged on the reaction tank for providing liquid reactants; a plurality of atomizing nozzles are arranged and evenly arranged on the annular pipe, and one end of the atomizing nozzle close to the bottom of the reaction tank faces the rotary feeding tray.

[0020] By adopting the above technical solution, the reagent supply assembly supplies the liquid additive into the annular pipe and forms a spray through the atomizing nozzles, which fully contacts the wastewater, thereby improving the mixing effect of the liquid additive, improving the reaction efficiency, and improving the treatment of the wastewater.

[0021] Optionally, a reflux mechanism is arranged on the reaction tank. The reflux mechanism includes a water inlet pipe, a reflux pump and a water return pipe. The water inlet pipe is arranged at the bottom of the reaction tank; the reflux pump is arranged on the reaction tank, the water inlet end is connected to the water inlet pipe, and the water outlet end is connected to the water return pipe; the water return pipe is arranged at the upper part of the side wall of the reaction tank and communicates with the reaction chamber.

[0022] By adopting the above technical solution, during the stirring process, or when adding the solid additive dissolution solution and / or adding the liquid additive, by starting the reflux pump, the reflux pump pumps out the wastewater in the reaction tank through the water inlet pipe, and then returns to the upper layer of the reaction tank through the water return pipe, increasing the mixing effect, and at the same time making the addition of the solid additive dissolution solution or the liquid additive more uniform and improving the reaction efficiency.

[0023] Optionally, one end of the water return pipe located in the reaction chamber has a flat outlet and is located on one side of the atomization structure close to the bottom of the reaction tank.

[0024] By adopting the above technical solution, the flat-shaped outlet facilitates an increase in the contact area between the discharged wastewater and the dissolved solution of the solid additive or the liquid additive, further improving the mixing effect, facilitating the progress of the oxidation reaction, and enhancing the mixing effect.

[0025] Optionally, a flow guide plate is arranged in the reaction tank for guiding the water sprayed out by the return water pipe and forming a laminar flow.

[0026] By adopting the above technical solution, the arrangement of the flow guide plate makes the sprayed water area larger, further increasing the contact area with the dissolved solution of the solid additive or the liquid additive, mixing more uniformly, improving the reaction efficiency and reaction effect, and at the same time, reducing the waste of reactants.

[0027] Optionally, the flow guide plate is arranged around the stirring mechanism, and one end close to the stirring mechanism is inclined and close to the bottom of the reaction tank.

[0028] By adopting the above technical solution, the wastewater mixed with the dissolved solution of the solid additive and / or the liquid additive approaches the stirring mechanism through the flow guide plate, enabling the stirring mechanism to rotate and beat the mixed wastewater, improving the reaction effect, making the wastewater approach the outer side of the reaction tank, causing an impact on the wastewater in the reaction tank, and enhancing the mixing reaction effect.

[0029] Optionally, a beating plate is arranged on the stirring mechanism, and the beating plate rotates with the stirring mechanism and beats the water flowing down from the flow guide plate.

[0030] By adopting the above technical solution, the beating plate rotates to strike the mixed wastewater or break the previously formed flocs, avoiding the premature formation of Fe 3+ precipitation, improving the complexation effect, breaking large particles, facilitating the full reaction of the iron carboxylate complex with organic pollutants, improving the wastewater treatment effect, uniformly reducing the floc particle size, shortening the precipitation time, and at the same time, reducing the sludge moisture content and enhancing the pressure filtration efficiency.

[0031] In summary, the present application includes at least one of the following beneficial technical effects:

[0032] 1. By performing different reaction processes in multiple tanks, the generation of by-products is reduced, the COD removal rate is increased, and the addition methods of the dissolved solution of the solid additive and the liquid additive improve the mixing uniformity and reduce the waste of chemicals;

[0033] 2. By adopting the reverse rotation of the rotary feeding tray and the stirring mechanism and setting a flow guide laminar flow, the reaction efficiency is improved and the energy consumption is reduced;

[0034] 3. By breaking with the beating plate and closed-loop diversion, the sludge volume is reduced and the pressure filtration cost is lowered. Brief Description of the Drawings

[0035] Figure 1 is the connection system diagram between the reaction vessels in the embodiments of the present application;

[0036] Figure 2 is the display diagram of the reaction vessel in the embodiments of the present application;

[0037] Figure 3 is the sectional view of the reaction vessel in the embodiments of the present application;

[0038] Figure 4 is the display diagram of the loop pipe in the embodiments of the present application;

[0039] Figure 5 is the sectional view of the rotary feeding tray in the embodiments of the present application;

[0040] Figure 6 is the three-dimensional structure diagram of the rotary feeding tray in the embodiments of the present application;

[0041] Figure 7 is the display diagram of the feeding hole in the embodiments of the present application;

[0042] Figure 8 is Figure 5 the partial enlarged view of area A in

[0043] Reference Signs: 100, reaction vessel; 110, first tank; 120, second tank; 130, third tank; 140, fourth tank; 150, Venturi mixer; 170, waste discharge pipe; 180, liquid discharge pipe; 190, reaction chamber; 200, stirring mechanism; 210, rotating shaft; 220, motor; 230, paddle; 300, first additive mechanism; 310, rotary feeding tray; 311, cylindrical barrel; 312, dispersion plate; 313, fixed plate; 314, feeding area; 315, storage cavity; 316, feeding hole; 320, transmission assembly; 321, first gear; 322, second gear; 323, gear ring; 330, rotating frame; 340, feeding bin; 400, second additive mechanism; 410, loop pipe; 420, atomizing nozzle; 500, reflux mechanism; 510, water inlet pipe; 520, reflux pump; 530, return water pipe; 610, guide plate; 620, flapping plate; 630, support frame. Detailed Description of the Embodiments

[0044] The following Figures 1 to 8 will further describe the present application in detail.

[0045] This embodiment discloses a Fenton reaction device for wastewater treatment.

[0046] Referring to Figure 1 and Figure 2, the Fenton reaction device of the present invention includes multiple serially connected reaction tanks 100, a chemical dosing device, a supporting stirring mechanism 200, a reflux mechanism 500, and a diversion structure; the multiple reaction tanks 100 are sequentially connected along the wastewater flow direction through a Venturi mixer 150, and are respectively used for primary oxidation, premixing and secondary oxidation, complexation reaction, and flocculation reaction. It also includes a drain pipe 180 for discharging the supernatant and a waste discharge pipe 170 for discharging waste, which are arranged on the last reaction tank 100; wherein, the premixing and secondary oxidation stages share the same reaction tank 100, and the stirring mechanism 200 and the chemical dosing device cooperate to complete the uniform or mixed addition of the solid additive solution and the liquid additive, and complete each process step.

[0047] The multiple reaction tanks 100 are arranged in a straight line. In this embodiment, preferably four, and are named the first tank 110, the second tank 120, the third tank 130, and the fourth tank 140 in the reaction order. The adjacent tanks are connected through a Venturi mixer 150, and the lower end of the reaction tank 100 for the previous reaction is connected to the upper end of the reaction tank 100 for the subsequent reaction. The tank body is made of 316L stainless steel, the inner wall is polished (Ra≤0.8μm), the volume is 2-5m³, and it is configured according to the treatment scale. A cylindrical reaction chamber 190 is formed inside each reaction tank 100. A feeding port for pH adjustment with a sealed cover is provided at the top, and a slag discharge valve is provided at the bottom. The height of the reaction tank 100 for premixing and secondary oxidation is 1.2 times that of other tanks to extend the reaction residence time, and an external magnetization device, an electromagnet of the magnetization device, is arranged outside the reaction tank 100 for adjustment according to the magnetic field requirements.

[0048] Among them, the waste discharge pipe 170 is fixedly connected to the bottom wall of the reaction tank 100 and communicates with the reaction chamber 190, and a control valve is provided. The drain pipe 180 is located on the side wall of the reaction tank 100 and close to the upper part, and one end is located inside the reaction tank 100, and the end located inside the reaction tank 100 extends towards the bottom wall of the reaction tank 100, and a plurality of water inlet holes are opened on the side wall, and the water inlet holes are evenly distributed along its length direction; and booster pumps are provided on both the drain pipe 180 and the waste discharge pipe 170 to facilitate liquid discharge and waste discharge.

[0049] An aeration mechanism is arranged inside the reaction tank 100. The aeration mechanism includes an aeration head and a gas source. The aeration head is arranged inside the reaction tank 100 and close to the bottom, and the gas source is arranged outside and connected to the aeration head. The gas source is used to supply air or ozone to form an aeration effect; whether aeration is required and what kind of gas is used for aeration can be selected according to the process steps.

[0050] Refer to Figure 3, the stirring mechanism 200 includes a support frame 630 fixedly connected to the reaction tank 100, a vertically arranged rotating shaft 210, and three groups of paddle blades 230. The three groups of paddle blades 230 are arranged along the length direction of the rotating shaft 210. The rotating shaft 210 is rotatably connected to the top wall of the reaction tank 100, is coaxial with the reaction tank 100, and is rotatably connected to the support frame 630. The top end of the rotating shaft 210 passes through the support frame 630 and is connected to a motor 220; a plurality of flapping plates 620 are fixedly connected to the part of the rotating shaft 210 located inside the reaction tank 100. The flapping plates 620 are arranged at equal intervals along the circumferential direction of the rotating shaft 210. The flapping plates 620 are rectangular steel plates and are located above the liquid level of the reaction tank 100.

[0051] The reflux mechanism 500 includes a water inlet pipe 510, a reflux pump 520, and a water return pipe 530. The water inlet pipe 510 is arranged at the center of the bottom of the reaction tank 100 and is connected to the inside of the reaction tank 100 through a three-way control valve. The Venturi mixer 150 is connected to the other outlet of the three-way control valve. The reflux pump is detachably connected to the side wall of the reaction tank 100 through bolts. The water inlet pipe 510 is connected to the inlet of the reflux pump 520. The water return pipe 530 is inserted into the side wall of the tank body and is located in the upper part of the reaction tank 100. The end of the water return pipe 530 is higher than the heights of the flapping plates 620 and the paddle blades 230. The long side of the flat outlet at the end is horizontally arranged, and a diversion structure is corresponding to the outlet plane. The diversion structure is a diversion plate 610. The diversion plate 610 is an arc-shaped stainless steel plate and is arranged radially around the rotating shaft 210 at an angle of 15°. The end close to the rotating shaft 210 is close to the bottom of the reaction tank 100. The upper end is flush with the flat outlet of the water return pipe 530. The jet flow direction is towards the diversion plate 610 and there is a 3° angle with the diversion plate 610; and the lower end of the diversion plate 610 is 40 mm - 50 mm higher than the height range where the flapping plates 620 are located. The flow rate of the reflux pump 520 is adjustable, and the maximum circulation volume is 3 times the volume of the tank per hour.

[0052] Refer to Figure 4 and Figure 5, the chemical dosing device includes a first dosing mechanism 300 and a second dosing mechanism 400; both the first dosing mechanism 300 and the second dosing mechanism 400 are provided with multiple ones, and respectively correspond to multiple reaction tanks 100; among them, the first dosing mechanism 300 is used for adding the solid additive dissolution solution, including a rotating frame 330, a rotating feeding disk 310, a feeding bin 340 and a transmission assembly 320. The rotating frame 330 is fixedly connected to the support frame 630, and a connecting ring is integrally arranged on the rotating frame 330. The connecting ring is arranged around the rotating shaft 210 and is rotatably connected to the rotating shaft 210; the rotating feeding disk 310 includes two cylindrical barrels 311, a fixed disk 313 and multiple dispersion plates 312. The two cylindrical barrels 311 are concentrically sleeved, the length of the outer cylindrical barrel 311 is shorter than that of the inner cylindrical barrel 311. The fixed disk 313 is fixedly connected to one end of the inner cylindrical barrel 311 located in the reaction chamber 190 and is rotatably connected to the rotating shaft 210. Multiple dispersion plates 312 are fixedly connected to the fixed disk 313 and connect the outer cylindrical barrel 311 and the inner cylindrical barrel 311. The multiple dispersion plates 312 are equidistantly arranged along the circumferential direction of the fixed disk 313 and form multiple non-connected feeding areas 314. The channel formed between the two cylindrical barrels 311 is a storage cavity 315, and the storage cavity 315 is communicated with the feeding area 314.

[0053] Referring to Figure 6 and Figure 7 , multiple feeding holes 316 are opened on the outer cylindrical barrel 311. The feeding holes 316 are located inside the rotating frame 330 and outside the reaction tank 100, and the feeding holes 316 are communicated with the storage cavity 315; multiple feeding bins 340 are provided, and electromagnetic control valves are arranged on all of them. The discharging end of the feeding bin 340 is fixedly connected to the rotating frame 330 and extends to the outer cylindrical barrel 311 of the rotating feeding disk 310, and is rotatably and sealingly connected and communicated with the side of the rotating feeding disk 310 where the feeding holes 316 are opened; the transmission assembly 320 is arranged on the rotating shaft 210 of the stirring mechanism 200, is connected to the rotating frame 330 and the rotating feeding disk 310, and drives the rotating feeding disk 310 to rotate, and the rotating direction of the rotating feeding disk 310 is opposite to the rotating direction of the rotating shaft 210.

[0054] Referring to Figure 8 , the transmission assembly 320 includes a first gear 321 coaxially fixed on the rotating shaft 210 of the stirring mechanism 200, a second gear 322 meshing with the first gear 321, and a gear ring 323 whose inner circumference meshes with the second gear 322. Among them, the second gear 322 is detachably and rotatably connected to the support frame 630 by bolts. The gear ring 323 is rotatably connected to the support frame 630, and the gear ring 323 is fixedly connected to the rotating feeding disk 310, driving the rotating feeding disk 310 to rotate in the direction opposite to the rotating shaft 210.

[0055] The second additive mechanism 400 is used for atomizing and adding liquid medicaments, and includes an annular pipe 410, atomizing nozzles 420 and a dosing assembly. The annular pipe 410 is horizontally arranged around the outer edge of the rotary feeding tray 310, and the height of the annular pipe 410 is higher than the lower surface of the rotary feeding tray 310; the annular pipe 410 is fixed to the inner wall of the tank through a bracket, and 12 atomizing nozzles 420 are evenly welded on its outer periphery, and the nozzles are inclined downward by 30° and point to the edge of the feeding tray. The dosing assembly includes a metering pump and a liquid storage tank. The metering pump and the liquid storage tank are arranged outside the reaction tank 100 and are connected to the annular pipe 410 through a hose for supplementing liquid additives to the annular pipe 410.

[0056] The medicaments are added through the cooperation of the rotary feeding tray 310 and the atomizing structure to achieve efficient mixing and reaction; and the first additive mechanism 300 is used for adding solutions that are easy to oxidize or have a large dosage. Through the rotation of the rotary feeding tray 310, large liquid droplets or linear water columns are formed; the second additive mechanism 400 is used for adding solutions that are not easy to oxidize, have a small addition amount or a long duration, and filtration is required during addition to reduce blockage; for the addition of the same solution, it can be mixed and added through the first additive mechanism 300 and the second additive mechanism 400 to improve the addition efficiency, and the addition of the pH adjustment solvent can also be carried out through the above two structures.

[0057] A stirring mechanism 200 is provided in each reaction tank 100. Its rotating shaft 210 vertically penetrates the center of the tank body and drives the rotary feeding tray 310 to rotate in the reverse direction through a transmission assembly 320. The water inlet pipe 510 is arranged at the bottom of the reaction tank 100, and the water return pipe 530 with a flat outlet is arranged on the top side wall, and circulating mixing is realized through a reflux pump 520. The guide plate 610 is arranged obliquely around the stirring mechanism 200 and cooperates with the flapping plate 620 to enhance the floc breaking effect, and at the same time forms a laminar flow, which cooperates with the atomizing structure and the rotary feeding tray 310 to increase the contact between the wastewater and the dissolved solution of the solid additive and / or the liquid additive.

[0058] When treating wastewater, it operates according to the following steps: First, adjust the pH value of the wastewater to acidic, and then perform a primary oxidation step. The pH regulator can be mixed and added through the first additive mechanism 300 and / or the second additive mechanism 400.

[0059] Primary oxidation: The acidified wastewater is injected from the top of the first reaction tank 100, and the stirring mechanism 200 rotates clockwise at 120 rpm. At the same time, ozone is introduced from the aeration head at the bottom of the tank; at this time, the rotary feeding tray 310 is driven by the transmission assembly 320 to rotate counterclockwise at 80 rpm to form a shear flow field. It is also possible to choose to disassemble the second gear 322 and stop the rotation of the rotary feeding tray 310.

[0060] Premixing and Secondary Oxidation: After the wastewater flows into the second reaction tank 100, the ferrous salt solution is evenly scattered through the rotary feeding tray 310. By adjusting the supply rate, large droplets or linear water columns can be controlled to form. The ferrous salt solution violently collides and dissolves with the reversely rotating wastewater to form premixed wastewater. After 15 minutes, the atomizing nozzle 420 is turned on, and the 30% hydrogen peroxide solution forms a conical mist curtain covering the falling area of the rotary feeding tray 310. At the same time, the reflux pump 520 extracts the bottom wastewater at a flow rate of 2 times and sprays it in a fan shape towards the deflector 610 through a flat outlet. The water flow forms a laminar flow along the deflector 610 and flows downward, contacts and mixes with the atomized hydrogen peroxide. The wastewater continues to fall and is broken by the flapper 620 to generate micro-vortices, promoting Fe 2+ to fully contact with H2O2; and during the addition and stirring of hydrogen peroxide, an external magnetic field is applied, and the reaction continues for 30 - 45 min to form secondary oxidized wastewater.

[0061] Secondary Aeration: The secondary oxidized wastewater is aerated with an aeration head. During aeration, ozone aeration or air can be used for aeration. In this embodiment, ozone aeration is preferably used. Then, carbonate is added through the feeding port above the reaction tank 100 or the first additive mechanism 300 and / or the second additive mechanism 400 to adjust the pH value to 5 - 6, and pre-neutralized wastewater is obtained;

[0062] Complexation Reaction: The pre-neutralized wastewater is introduced into the reaction tank 100 for complexation reaction. Then, a complexing defluorinating agent is added through an atomizing structure, and magnetic powder is put in through the rotary feeding tray 310. The complexing defluorinating agent and the magnetic powder are added simultaneously. The magnetic powder is intervened by the rotary feeding tray 310, rotates and contacts the complexing defluorinating agent, and then enters the wastewater. Continuous stirring and mixing are carried out, and the reaction continues for 10 - 20 min to obtain complexation reaction wastewater; An alkali solution is added to the obtained complexation reaction wastewater, stirred and mixed, and the pH of the complexation reaction wastewater is adjusted to 6 - 7, and the reaction continues for 10 - 15 min under stirring conditions to obtain secondary neutralized wastewater.

[0063] Flocculation Reaction: Then, the secondary neutralized wastewater is introduced into the reaction tank 100 for flocculation reaction. Then, a coagulant aid is added to the obtained secondary neutralized wastewater, stirred and mixed, and then separated by precipitation. The supernatant is the purified wastewater, and the supernatant and the generated precipitate are discharged respectively.

[0064] In other embodiments, in the premixing and secondary oxidation steps, hydrogen peroxide and the ferrous salt solution can be added simultaneously. When adding, the input ratio is controlled so that the hydrogen peroxide and the ferrous salt solution are evenly mixed and then enter the wastewater, and the premixing and secondary oxidation are carried out simultaneously, which can improve the reaction efficiency and reduce the waste of chemicals at the same time.

[0065] The above are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. A Fenton reaction device for wastewater treatment, characterized in that: Including: Reaction vessels (100), multiple of which are provided, with reaction chambers (190) formed inside, and stirring mechanisms (200) provided, respectively used for performing primary oxidation, premixing, secondary oxidation, complexation reaction, and flocculation reaction on wastewater, and the multiple reaction vessels (100) are connected in sequence; Reagent dosing device, including a first dosing mechanism (300) and a second dosing mechanism (400), the first dosing mechanism (300) includes a rotating dosing tray (310), the rotating dosing tray (310) rotates in the middle of the reaction vessel (100), is connected to the stirring mechanism (200), and is used for rotating and dosing a solid additive dissolution solution or a liquid additive; Through the rotating dosing of the rotating dosing tray (310), large liquid droplets or linear water columns are formed; The second dosing mechanism (400) includes an atomization structure arranged inside the reaction vessel (100) for atomizing and spraying a liquid additive; The atomization structure is arranged outside the rotating dosing tray (310); A reflux mechanism (500) is arranged on the reaction vessel (100), the reflux mechanism (500) includes a return water pipe (530), the return water pipe (530) is arranged at the upper part of the side wall of the reaction vessel (100) and is communicated with the reaction chamber (190), and is used for returning the bottom of the reaction vessel (100) to the upper layer of the reaction vessel (100); A baffle plate (610) is arranged inside the reaction vessel (100) for guiding the water sprayed out by the return water pipe (530) and forming a laminar flow; One end of the return water pipe (530) located inside the reaction chamber (190) has a flat outlet and is located on one side of the atomization structure close to the bottom of the reaction vessel (100).

2. The Fenton reaction device for wastewater treatment according to claim 1, wherein: The rotating direction of the rotating dosing tray (310) is opposite to the rotating direction of the stirring mechanism (200).

3. The Fenton reaction device for wastewater treatment according to claim 2, wherein: The first dosing mechanism (300) further includes a transmission assembly (320), the transmission assembly (320) includes a first gear (321), a second gear (322), and a gear ring (323), the first gear (321) is coaxially arranged with the stirring mechanism (200), the second gear (322) rotates on the reaction vessel (100) and meshes with the first gear (321), the gear ring (323) rotates on the reaction vessel (100) and meshes with the second gear (322), and the gear ring (323) is connected to the rotating dosing tray (310).

4. The Fenton reaction device for wastewater treatment according to any one of claims 1-3, characterized in that: The atomization structure includes an annular pipe (410), atomizing nozzles (420), and a reagent supply assembly, the annular pipe (410) is arranged inside the reaction vessel (100), the annular pipe (410) is connected to the reagent supply assembly, the reagent supply assembly is arranged on the reaction vessel (100) for providing a liquid reactant; multiple atomizing nozzles (420) are provided and are evenly arranged on the annular pipe (410), and one end of the atomizing nozzle (420) close to the bottom of the reaction vessel (100) approaches the rotating dosing tray (310).

5. The Fenton reaction device for wastewater treatment according to claim 1, characterized in that: The reflux mechanism (500) further includes a water inlet pipe (510) and a reflux pump (520). The water inlet pipe (510) is arranged at the bottom of the reaction tank (100); the reflux pump (520) is arranged on the reaction tank (100), the water inlet end is connected to the water inlet pipe (510), and the water outlet end is connected to the water return pipe (530).

6. The Fenton reaction device for wastewater treatment according to claim 1, wherein: The deflector plate (610) is arranged around the stirring mechanism (200), and one end close to the stirring mechanism (200) is inclined and close to the bottom of the reaction tank (100).

7. The Fenton reaction device for wastewater treatment according to claim 1, characterized in that: A flapping plate (620) is arranged on the stirring mechanism (200). The flapping plate (620) rotates with the stirring mechanism (200) and flaps the water flowing down from the deflector plate (610).

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