Method for deeply decolorizing by utilizing Fenton-like process and mixed reaction device

Abstract

The invention discloses a method for deep decolorization by using a Fenton-like process and a mixed reaction device, and belongs to the technical field of deep decolorization treatment, and the method comprises the following steps: S1, carrying out pretreatment and pH adjustment, S2, adding ferric salt and carrying out secondary pH adjustment, S3, adding sodium hypochlorite and carrying out a reaction, S4, carrying out neutralization and pH adjustment, and S5, adding a flocculating agent to complete decolorization. The deep decolorization of the landfill leachate and the swine wastewater is realized, the decolorization effect is obvious, the chromaticity of original sewage can be reduced from 432 times to 30-50 times, the treatment effect is far superior to that of 150-190 times of a traditional process, the COD removal rate of 80% or above and the efficient removal of total phosphorus are synchronously achieved, multiple effects are achieved by one process, different pollution characteristics of the landfill leachate and the swine wastewater are adapted, and the method is suitable for industrial production. The method breaks through the limitation of the traditional process, is simple and controllable to operate, does not need complex equipment, is easy to industrially popularize, achieves the standard chromaticity of the treated water, simplifies the process and reduces the treatment cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of water pollution control and treatment, and more particularly to a method and a mixed reaction device for deep decolorization using Fenton-like process. BACKGROUND

[0002] In the decolorization treatment of water pollution, raw water (landfill leachate and pig wastewater) is a typical high-difficulty industrial wastewater, which has the characteristics of extremely high color, complex pollutant composition and strong stability. It contains not only a large amount of colored groups with conjugated structures such as benzene rings, but also heavy metal ions such as copper, zinc and iron, and emits strong odor, which poses a serious threat to the ecological environment and human health. Among them, the blackening and odor of landfill leachate are mainly caused by humic substances (such as humic acid and fulvic acid) produced by microbial decomposition during long-term landfill of garbage, aromatic pollutants (such as polycyclic aromatic hydrocarbons) and nitrogen / sulfur heterocyclic compounds. The conjugated system in the molecules of these substances can strongly absorb visible light, which is the core chromogenic component. The dark color of pig wastewater is mainly caused by stable complexes formed by heavy metal ions and amino acids and humic substances, as well as black precipitates such as ferrous sulfide and copper sulfide generated by sulfate reduction in anaerobic environment, supplemented by the synergistic effect of small-molecule colored organic matter, which increases the difficulty of wastewater treatment.

[0003] At present, the traditional decolorization method for the above-mentioned wastewater is mainly physical and chemical flocculation, which generally uses the method of adding inorganic flocculants such as polyaluminum chloride, polymeric ferric sulfate or ferric chloride to remove part of the colored particles through adsorption and bridging. However, practice shows that the decolorization effect of this method is very limited. For raw water with a color of 432 times, the color after treatment can only be reduced to 150-190 times, which cannot meet the current strict discharge standard. More importantly, traditional flocculants can only act on suspended colored substances, and have weak removal capacity for dissolved conjugated structure organic matter, resulting in high COD and total phosphorus in the treated wastewater, which makes it difficult to achieve simultaneous standard of decolorization and pollutant degradation. Therefore, it is urgent to develop an efficient and comprehensive deep treatment technology to solve the above-mentioned bottleneck problem. SUMMARY

[0004] The technical solution of the present application provides a significantly different solution from the prior art to solve the technical problem that the prior art solution is too single. The deep decolorization treatment of the present application belongs to the field of water pollution control and treatment, and mainly provides a method and a mixed reaction device for deep decolorization using Fenton-like process to solve the technical problem that the existing decolorization method cannot effectively decolorize the unique pollution components in landfill leachate and pig wastewater.

[0005] The technical solution adopted by the present application to solve the above technical problem is: A method for deep decolorization using a Fenton-like process includes the following steps: S1: Take the pig farm wastewater or landfill leachate to be treated, place it in the equalization tank, monitor it in real time with an online pH monitor, and adjust its pH value to 8.0±0.2 with acid or alkali solution to obtain pretreated wastewater; S2: Ferric chloride solution is added to the pretreated wastewater using an iron salt metering pump. After being stirred evenly by a matching stirring device, the pH value of the system is adjusted to 3.0-4.0 by a pH online monitoring instrument to obtain an acidic reaction solution. S3: Slowly add a 10% sodium hypochlorite solution to the acidic reaction solution using a sodium hypochlorite metering pump. The amount of sodium hypochlorite solution added is 4.3‰-5.25‰ of the wastewater mass. Start the reactor and stir continuously until no more tiny bubbles are generated. Stop stirring to complete the Fenton-like reaction and obtain the reaction liquid. The entire reaction process is recorded by a timer. S4: Neutralization and pH adjustment: An alkaline adjusting solution is added to the reaction solution using an alkaline reagent metering pump, and the pH value of the system is adjusted to 6.0±0.2 using an online pH monitor to obtain a neutralized solution; S5: Adding flocculant to complete decolorization: Add a pre-prepared polyacrylamide solution to the neutralized liquid through a flocculant metering pump. After mixing, transfer the solution to a flocculation sedimentation tank for settling. Deep decolorization is achieved through flocculation sedimentation to obtain decolorized wastewater.

[0006] Preferably, in S2, the target value of pH is 3.5 ± 0.1.

[0007] Preferably, in S3, the reaction time of continuous stirring is 10-50 minutes.

[0008] Preferably, in step S4, the alkaline conditioning solution is a sodium hydroxide solution or a composite alkaline solution.

[0009] A mixing reaction device for deep decolorization using a Fenton-like process includes a layered reaction mechanism and a mixing and stirring mechanism in a reaction vessel. The layered reaction mechanism includes multiple stacked reaction chambers, which are divided into a first reaction chamber, a second reaction chamber, a third reaction chamber, and a fourth reaction chamber, and are staggered. Each of the first, second, and third reaction chambers is provided with a suction channel, a connecting channel, and a height-limiting drain port. The mixing and stirring mechanism includes a rotating shaft and a sleeve. The sleeve is fitted onto the rotating shaft, which passes through a circular hole at the center of the bottom of each reaction chamber. The rotating shaft is circumferentially arranged with multiple adjusting grooves at equal intervals along the axial direction. Each adjusting groove is connected to a top block by bolts. The sleeve is circumferentially arranged with multiple notches at equal intervals along the axial direction. The adjusting grooves pass through the corresponding notches. Each notch has an installation groove at its upper edge. The installation grooves and adjusting grooves correspond one-to-one. Each installation groove is hinged with a stirring blade. After the stirring blade moves down and cooperates with the top block on the corresponding adjusting groove, it can be deflected in the vertical direction.

[0010] Preferably, each of the mounting slots has a guide opening on its side wall, and a limiting member is movably connected in each guide opening. The lower end of the limiting member is inserted into the circular hole of the corresponding stirring blade. Each mounting slot is connected to a cover plate by screws, and a return spring is provided between the cover plate and the upper end of the corresponding limiting member.

[0011] Preferably, each of the adjustment grooves has a top contact portion on both sides of its upper edge, and the top contact portion cooperates with the two ends of the corresponding upper limiting member.

[0012] Preferably, a shaft seal is provided at the connection between the sleeve and each reaction chamber, and a connecting block is provided between the first reaction chamber and the second reaction chamber in the reaction chamber. The connecting block connects the suction channel in the first reaction chamber and the connecting channel in the second reaction chamber. A first suction pipe and a second suction pipe are respectively provided at the upper end of the suction channel and the connecting channel in the first reaction chamber. An outlet pipe and a valve on the outlet pipe are provided at the bottom of the fourth reaction chamber in the reaction chamber.

[0013] Preferably, the upper end of the sleeve is provided with a lifting frame, the vertical part of the lifting frame is movably connected to the top cover of the reactor, the opening of the lifting frame is connected to an annular cover by bolts, and a bearing is provided in the annular cavity formed by the annular cover and the opening of the lifting frame, and the inner edge of the bearing is connected to the top end of the sleeve.

[0014] Preferably, the reactor has a feed inlet on the top cover, and a mounting frame and a motor are located near the feed inlet. A cylinder is mounted on the mounting frame, and the output end of the cylinder is connected to the top of the lifting frame. A drive shaft is mounted on the output end of the motor, and a first pulley is mounted on the drive shaft. A second pulley is connected to the first pulley via a belt, and the second pulley is sleeved on a rotating shaft. The upper end of the rotating shaft and the top cover of the reactor are rotatably connected.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The deep decolorization method of the present invention has achieved a significant improvement in the decolorization effect of raw water (landfill leachate and pig farm wastewater), which can reduce the color of raw water from 432 times to 30-50 times, which is far superior to the treatment level of 150-190 times of traditional process. It effectively solves the problem of "blackening and odor" of landfill leachate and pig farm wastewater, so that the color of the effluent meets the discharge standards and improves the appearance. It can also achieve a COD removal rate of more than 80% and a total phosphorus removal rate at the same time, achieving "one process with multiple effects", simplifying the treatment process and reducing costs. It is suitable for the different pollution characteristics of the two types of wastewater, breaks through the limitations of traditional process for decolorizing complex wastewater, and has the advantages of simple and controllable operation. The reaction conditions can be controlled by conventional detection and visual observation. No complicated equipment is required, which is convenient for industrial application in sewage treatment plants of different scales.

[0016] (2) The present invention, through the setting of a reaction vessel, a first reaction chamber, a second reaction chamber, a third reaction chamber, a fourth reaction chamber, an outlet pipe, a shaft seal, a height-limited discharge port, a suction channel, a connecting channel, a connecting block, a first suction pipe and a second suction pipe, realizes the division of the inner cavity of the reaction vessel into four equal series reaction chambers, which flow through the height-limited discharge port of each reaction chamber in sequence, achieving uniform liquid distribution, reducing the liquid layer thickness in each reaction chamber to 1 / 4 of the original cavity, greatly shortening the bubble floating path and time, and fundamentally solving the problem of bubble retention caused by high viscosity and high pollutant content in landfill leachate and pig farm wastewater; Furthermore, the design of nearby suction above each reaction chamber creates a synergistic defoaming effect of "short-distance floating + nearby suction," significantly improving the oxygen escape rate and the thoroughness of defoaming. This avoids the accumulation of bubbles that form air resistance. Efficient defoaming not only ensures uniform contact between sodium hypochlorite and wastewater, reducing waste caused by oxygen free radicals being carried away by bubbles, but also enhances the mass transfer efficiency and oxidative degradation effect of the Fenton-like reaction. It also avoids problems such as bubbles encapsulating flocs and interfering with the determination of the reaction endpoint, ensuring that the decolorization reaction in each chamber is sufficient and stable. Ultimately, this improves the overall decolorization efficiency and the effluent color compliance rate, while reducing the increase in energy consumption and equipment operation risks caused by bubble retention, further optimizing the technical advantages of "one process with multiple effects."

[0017] (3) This invention, through the setting of a rotating shaft, sleeve, lifting frame, bearing, annular cover, adjusting groove, top contact, top block, mounting groove, guide port, stirring blade, limiting component, return spring, cover plate, motor, drive shaft, first pulley, second pulley, mounting frame and cylinder, realizes the synergistic effect of directional enhanced stirring and efficient defoaming for Fenton-like reactions in each reaction chamber. The inverted conical structure formed by the deflection of the stirring blade, which is narrow at the bottom and wide at the top, constructs a directional circulation of "central liquid sinking and edge liquid rising" when rotating. The circulation field, combined with the linear velocity and shear force gradient of "low at the bottom and high at the top", causes the tiny bubbles at the bottom of the liquid to concentrate in the middle with the central sinking flow, and then be pushed to the top high shear zone by the edge rising flow, forming a step-like directional aggregation of "small bubbles → medium bubbles → large bubbles", which greatly improves the buoyancy and rising rate of the bubbles. Combined with the short-distance rising path of the stratified mechanism, it forms a triple bubble removal advantage of "directional aggregation + short-distance rising + nearby pumping", which completely solves the problem of small bubble retention in high viscosity and high pollutant content wastewater. Meanwhile, the rapid aggregation and discharge of bubbles can effectively prevent them from adhering to the surface of organic matter in wastewater for a long time and forming a liquid film. This breaks the barrier of the liquid film to the mass transfer of the reagent, ensures that sodium hypochlorite and iron ions fully contact and react, reduces the loss caused by the escape of oxygen free radicals carried by bubbles, significantly improves the mass transfer efficiency and oxidative degradation efficiency of the Fenton-like reaction, and the directional flow field can also make the liquid in each reaction chamber more uniformly mixed, avoid the problem of insufficient reaction caused by local air resistance, and allow color-producing substances (such as humic substances and benzene ring compounds) to be uniformly and thoroughly degraded by oxygen free radicals. It also eliminates the risk of floating color and color return caused by bubbles encapsulating flocs, making the effluent color more stable and meeting the standards, significantly improving the decolorization rate, and reducing reagent consumption and energy consumption, further optimizing the industrial application value of the process.

[0018] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the reactor structure of the present invention; Figure 2 This is a schematic diagram of the decomposition of the reaction vessel of the present invention; Figure 3 This is an exploded view of the layered reaction mechanism of the present invention; Figure 4 This is a schematic cross-sectional view of the layered reaction mechanism of the present invention; Figure 5 This is a schematic cross-sectional view of the first reaction chamber of the present invention; Figure 6 This is a schematic diagram of the mixing and stirring mechanism of the present invention; Figure 7 This is an exploded view of the mixing and stirring mechanism of the present invention; Figure 8 For the present inventionFigure 7 Enlarged diagram of area A; Figure 9 For the present invention Figure 7 Enlarged diagram of area B.

[0020] In the diagram: 1. Reactor; 11. Feed inlet; 2. Layered reaction mechanism; 21. First reaction chamber; 22. Second reaction chamber; 23. Third reaction chamber; 24. Fourth reaction chamber; 241. Outlet pipe; 242. Shaft seal; 25. Height-limited drain port; 26. Suction channel; 27. Connecting channel; 28. Connecting block; 29. ​​First suction pipe; 291. Second suction pipe; 3. Mixing and stirring mechanism; 31. Rotating shaft; 32. Sleeve; 321. Notch; 33. Lifting frame; 331. Bearing; 332. Annular cover; 34. Adjusting groove; 341. Top contact; 35. Top block; 36. Mounting groove; 361. Guide port; 37. Stirring blade; 38. Limiting component; 381. Return spring; 39. Cover plate; 4. Valve; 5. Motor; 51. Drive shaft; 52. First pulley; 53. Second pulley; 6. Mounting frame; 7. Cylinder. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] Example 1, please refer to the appendix for details. Figures 1-9As shown, a mixing reaction device for deep decolorization using a Fenton-like process includes a layered reaction mechanism 2 and a mixing and stirring mechanism 3 in a reaction vessel 1. The layered reaction mechanism 2 includes multiple stacked reaction chambers, divided into a first reaction chamber 21, a second reaction chamber 22, a third reaction chamber 23, and a fourth reaction chamber 24, which are staggered. The first reaction chamber 21, the second reaction chamber 22, and the third reaction chamber 23 are each provided with a suction channel 26, a connecting channel 27, and a height-limiting drain port 25. The mixing and stirring mechanism 3 includes a rotating shaft 31 and a sleeve 32, with the sleeve 32 fitted onto the rotating shaft 31. A circular hole passes through the center of the bottom of each reaction chamber. The rotating shaft 31 is provided with multiple adjusting grooves 34 at equal intervals along the axial direction. Each adjusting groove 34 is connected to a top block 35 by bolts. The sleeve 32 is provided with multiple notches 321 at equal intervals along the axial direction. The adjusting grooves 34 pass through the corresponding notches 321. Each notch 321 has an installation groove 36 at its upper edge. The installation grooves 36 and adjusting grooves 34 correspond one-to-one. Each installation groove 36 is hinged with a stirring blade 37. After the stirring blade 37 moves down and cooperates with the top block 35 on the corresponding adjusting groove 34, it can be deflected in the vertical direction.

[0025] The specific operation is as follows: First, raw water (landfill leachate and pig farm wastewater) is introduced into the stratified reaction mechanism 2 through the feed inlet 11 on the reactor 1, while sodium hypochlorite solution is added simultaneously to obtain the reaction liquid. The liquid first enters the first reaction chamber 21. As the liquid level in the first reaction chamber 21 increases, it can enter the second reaction chamber 22 through the height-limiting discharge port 25 in the first reaction chamber 21. Similarly, it enters the third reaction chamber 23 and the fourth reaction chamber 24 in sequence, dividing the liquid into four equal parts. Compared with the existing technology of reacting together, this can significantly shorten the rising distance of bubbles and increase the escape speed of bubbles. At the same time, the oxygen generated above each reaction chamber is... Near-suction (e.g., oxygen generated in the first reaction chamber 21 is extracted by the second suction pipe 291, oxygen generated in the second reaction chamber 22 is extracted by the first suction pipe 29 and the suction channel 26 on the first reaction chamber 21, oxygen generated in the third reaction chamber 23 is extracted by the second suction pipe 291, the connecting channel 27 on the first reaction chamber 21 and the suction channel 26 on the second reaction chamber 22, and oxygen generated in the fourth reaction chamber 24 is extracted by the first suction pipe 29, the suction channel 26 on the first reaction chamber 21, the connecting channel 27 on the second reaction chamber 22 and the suction channel 26 on the third reaction chamber 23). Simultaneously, motor 5 is turned on. Motor 5, through the engagement of drive shaft 51, first pulley 52, belt, and second pulley 53, drives rotating shaft 31. Due to the engagement of adjusting groove 34 and notch 321, sleeve 32 on rotating shaft 31 rotates synchronously. Therefore, sleeve 32 drives stirring blade 37 to stir and mix, performing a Fenton-like reaction and generating bubbles. Subsequently, cylinder 7, via lifting frame 33, moves sleeve 32 up and down on rotating shaft 31. Installation groove 36 gradually falls into the corresponding adjusting groove 34. Top contact 341 on adjusting groove 34 contacts limiting member 38 in installation groove 36, pushing limiting member 38 upward along guide opening 361, causing the lower end of limiting member 38 to be pulled out from the round hole on stirring blade 37. Return spring 381 is compressed, and simultaneously, top block 35 of adjusting groove 34 is fixed to the corresponding stirring blade 37. The lower side causes the stirring blade 37 to deflect upwards, forming an inverted conical structure during rotation. The gradient of its linear velocity and shear force will exhibit the characteristics of "low at the bottom and high at the top" (because the top of the stirring blade 37 is farther from the axis, the linear velocity v=2πr×n / 60 is higher, and the shear force is greater). The inverted conical structure, which is "narrow at the bottom and wide at the top", will form a unique circulating flow field of "central liquid sinking and edge liquid rising" during rotation. This allows the tiny bubbles at the bottom of the liquid to slowly gather in the middle with the central sinking flow, and then be carried to the high shear zone at the top by the edge rising flow, completing the step-like aggregation of "small bubbles → medium bubbles → large bubbles". Compared with the "disordered flow field" of traditional horizontal blades, this directional flow field can make the "aggregation path" of bubbles more concentrated, making it easier to quickly discharge small bubbles attached to organic matter in the liquid and avoid the formation of liquid film.

[0026] Example 2, please refer to the appendix for details. Figure 2 and attached Figures 7-9 As shown, each of the mounting slots 36 has a guide opening 361 on its side wall, and a limiting member 38 is movably connected in each guide opening 361. The lower end of the limiting member 38 is inserted into the round hole of the corresponding stirring blade 37. Each mounting slot 36 is connected to a cover plate 39 by screws. A return spring 381 is provided between the cover plate 39 and the upper end of the corresponding limiting member 38. Through the return spring 381, when the stirring blade 37 moves upward and separates from the top block 35, and rotates to a horizontal state due to its own weight and the structure of the mounting slot 36, the limiting member 38 is re-inserted into the round hole of the stirring blade 37 by the deformation restoration force to lock and position itself. Each of the adjustment slots 34 has a top contact 341 on both sides of its upper edge, and the top contact 341 cooperates with the two ends of the corresponding limiting member 38 above. Through the top contact 341, the lower end of the limiting member 38 can be pushed out from the round hole of the stirring blade 37 during the downward movement of the mounting slot 36. A lifting frame 33 is provided at the upper end of the sleeve 32. The vertical part of the lifting frame 33 is movably connected to the top cover of the reactor 1. An annular cover 332 is bolted to the opening of the lifting frame 33. A bearing 331 is provided in the annular cavity formed by the annular cover 332 and the opening of the lifting frame 33, and the inner edge of the bearing 331 is connected to the top end of the sleeve 32. A feed inlet 11 is provided on the upper side of the top cover of the reactor 1. A mounting frame 6 and a motor 5 are provided near the feed inlet 11. A cylinder 7 is provided on the mounting frame 6. The output end of the cylinder 7 is connected to the top end of the lifting frame 33. The cooperation between the sleeve 33 and the bearing 331 allows the sleeve 32 to move up and down on the rotating shaft 31 and to rotate synchronously with the rotating shaft 31. The output end of the motor 5 is provided with a drive shaft 51, and the drive shaft 51 is provided with a first pulley 52. ​​The first pulley 52 is connected to a second pulley 53 via a belt. The second pulley 53 is sleeved on the rotating shaft 31, and the upper end of the rotating shaft 31 is rotatably connected to the top cover of the reactor 1. Through the mutual cooperation between the motor 5, the drive shaft 51, the first pulley 52, the belt, and the second pulley 53, the driving force for the rotation of the rotating shaft 31 is realized.

[0027] Example 3, please refer to the appendix for details. Figures 3-5 As shown, a shaft seal 242 is provided at the connection between the sleeve 32 and each reaction chamber, which improves the stability and sealing of the connection. A connecting block 28 is provided between the first reaction chamber 21 and the second reaction chamber 22 in the reaction chamber. The connecting block 28 connects the suction channel 26 in the first reaction chamber 21 and the connecting channel 27 in the second reaction chamber 22. The upper ends of the suction channel 26 and the connecting channel 27 in the first reaction chamber 21 are respectively provided with a first suction pipe 29 and a second suction pipe 291. The two suction pipes can be connected to an external air pump to form a negative pressure suction (the air pump is an existing structure and is not shown in the figure). The bottom of the fourth reaction chamber 24 in the reaction chamber is provided with an outlet pipe 241 and a valve 4 on the outlet pipe 241. The valve 4 can control the opening and closing of the outlet pipe 241.

[0028] A method for deep decolorization using a Fenton-like process includes the following steps: S1 Pretreatment pH Adjustment: Take the pig farm wastewater or landfill leachate to be treated and place it in the equalization tank. Monitor the pH value in real time using an online pH monitor and adjust it to 8.0±0.2 using acid or alkali solution to obtain pretreated wastewater. This pre-neutralizes some alkaline pollutants, creating a relatively stable acid-base environment for subsequent treatment and reducing interference with subsequent reactions. S2 Addition of iron salt and secondary pH adjustment: Ferric chloride solution is added to the pretreated wastewater through an iron salt metering pump. After being stirred evenly by a matching stirring device, the pH value of the system is adjusted to 3.0-4.0, preferably 3.5±0.1, by controlling the pH online monitoring instrument to obtain an acidic reaction solution. This acidic condition is the key to the efficient progress of the Fenton-like reaction and can promote the effect of subsequent reagents. S3 Add sodium hypochlorite and react: Slowly add a 10% sodium hypochlorite solution to the acidic reaction solution using a sodium hypochlorite metering pump. The amount of sodium hypochlorite solution added is 4.3‰-5.25‰ of the wastewater mass. During the reaction, sodium hypochlorite reacts with iron ions under acidic conditions to generate oxygen free radicals with strong oxidizing properties. Start the reactor 1 and stir continuously for 10-50 minutes. Stop stirring when no more tiny bubbles are generated to complete the Fenton-like reaction and obtain the reaction liquid. The entire reaction process is recorded by a timer. S4 Neutralization and pH Adjustment: Sodium hydroxide solution or compound alkaline solution is added to the reaction liquid through an alkaline reagent metering pump. Combined with pH online monitoring instrument, the pH value of the system is adjusted to 6.0±0.2 to neutralize the acidity in the reaction system, so that the wastewater reaches the acid-base conditions suitable for subsequent flocculation treatment, while avoiding corrosion of equipment by acidic wastewater, and a neutralized liquid is obtained. S5. Adding flocculant to complete decolorization: Adding flocculant to complete decolorization: Add a pre-prepared polyacrylamide solution to the neutralized liquid through a flocculant metering pump. After mixing, transfer it to a flocculation sedimentation tank for settling. Deep decolorization is achieved through flocculation and sedimentation, resulting in decolorized wastewater. This deep decolorization can ultimately reduce the original water color from 432 times to 50 times (in actual treatment, it can be as low as 52.6 times).

[0029] The present invention has been described by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.

Claims

1. A method for advanced decolorization using a Fenton-like process, characterized in that , comprising the following steps: S1: take the pig wastewater or landfill leachate to be treated, place it in the conditioning tank, monitor it in real time through the pH online monitor, adjust its pH value to 8.0±0.2 by using acid or alkali, and obtain pretreated wastewater; S2: add ferric chloride solution to the pretreated wastewater through the ferric salt metering pump, stir it uniformly through the matching stirring device, control the pH value through the pH online monitor, adjust the pH value of the system to 3.0-4.0, and obtain an acidic reaction liquid; S3: slowly add 10% sodium hypochlorite solution to the acidic reaction liquid through the sodium hypochlorite metering pump, the addition amount of the sodium hypochlorite solution is 4.3‰-5.25‰ of the wastewater mass, start the reaction kettle (1) for continuous stirring, stop stirring when no more micro-bubbles are generated, complete the Fenton-like reaction, and obtain a post-reaction liquid, the whole reaction process is recorded by the timer; S4: neutralization and pH adjustment: add the alkaline adjusting liquid to the post-reaction liquid through the alkaline reagent metering pump, control the pH value through the pH online monitor, adjust the pH value of the system to 6.0±0.2, and obtain a neutralized liquid; S5: add a flocculating agent to complete decolorization: add the pre-configured polyacrylamide solution to the neutralized liquid through the flocculating agent metering pump, mix it, transfer it to the flocculation and sedimentation tank for standing, and obtain decolorized wastewater.

2. The method for advanced decolorization using Fenton-like process according to claim 1, characterized in that, In S2, the target value of the pH is 3.5±0.

1.

3. The method for advanced decolorization using Fenton-like process according to claim 1, characterized in that, In S3, the reaction time for continuous stirring is 10-50 minutes.

4. The method for advanced decolorization using Fenton-like process according to claim 1, characterized in that, In S4, the alkaline adjusting liquid is sodium hydroxide solution or composite alkali solution.

5. A mixed reaction device for advanced decolorization by Fenton-like process, comprising a layered reaction mechanism (2) and a mixing and stirring mechanism (3) in a reaction kettle (1), characterized in that, The layered reaction mechanism (2) comprises a plurality of reaction bins stacked one above another and is divided into a first reaction bin (21), a second reaction bin (22), a third reaction bin (23), and a fourth reaction bin (24), and is staggered and distributed, the first reaction bin (21), the second reaction bin (22), and the third reaction bin (23) are each provided with a suction channel (26), a connecting channel (27), and a height-limiting liquid discharge port (25), the mixing and stirring mechanism (3) comprises a rotating shaft (31) and a sleeve (32), the sleeve (32) is sleeved on the rotating shaft (31), the rotating shaft (31) penetrates through the circular holes at the bottom centers of each reaction bin, the rotating shaft (31) is circumferentially provided with a plurality of adjusting grooves (34) at equal intervals along the axial direction, each adjusting groove (34) is connected with a top block (35) through a bolt, the sleeve (32) is circumferentially provided with a plurality of notches (321) at equal intervals along the axial direction, the adjusting grooves (34) pass through the corresponding notches (321), the upper edge positions of each notch (321) are provided with a mounting groove (36), the mounting groove (36) and the adjusting groove (34) correspond one by one in the up-down direction, each mounting groove (36) is hingedly connected with a stirring blade (37), and the stirring blade (37) can be vertically deflected after being matched with the top block (35) on the corresponding adjusting groove (34) after being moved downward.

6. The mixed reaction device for advanced decolorization by Fenton-like process according to claim 5, characterized in that, The side wall of each mounting slot (36) is provided with a guide opening (361), each guide opening (361) movably connects a limiting piece (38), the lower end of the limiting piece (38) is inserted into the circular hole of the corresponding stirring blade (37), each mounting slot (36) is connected with a cover plate (39) through a screw, a reset spring (381) is arranged between the cover plate (39) and the upper end of the corresponding limiting piece (38).

7. The mixed reaction device for advanced decolorization by Fenton-like process according to claim 5, characterized in that, The upper edge of each adjusting slot (34) is provided with a top contact part (341) on both sides, and the top contact part (341) is matched with both ends of the corresponding limiting piece (38) above.

8. The mixed reaction device for advanced decolorization by Fenton-like process according to claim 5, characterized in that, The connecting part of the sleeve (32) and each reaction bin is provided with a shaft seal (242), the first reaction bin (21) and the second reaction bin (22) in the reaction bin are provided with a connecting block (28), the connecting block (28) connects the suction channel (26) in the first reaction bin (21) and the connecting channel (27) in the second reaction bin (22), the upper end of the suction channel (26) and the connecting channel (27) in the first reaction bin (21) is respectively provided with a first suction pipe (29) and a second suction pipe (291), the fourth reaction bin (24) in the reaction bin is provided with a discharge pipe (241) at the bottom, and a valve (4) is arranged on the discharge pipe (241).

9. The mixed reaction device for advanced decolorization by Fenton-like process according to claim 8, characterized in that, The upper end of the sleeve (32) is provided with a lifting frame (33), the vertical part of the lifting frame (33) is movably connected to the top cover of the reaction kettle (1), the opening of the lifting frame (33) is connected with an annular cover (332) through a bolt, a bearing (331) is arranged in the annular cavity formed by the annular cover (332) and the opening of the lifting frame (33), and the inner edge of the bearing (331) is connected with the top end of the sleeve (32).

10. The mixed reaction device for advanced decolorization by Fenton-like process according to claim 9, characterized in that, The top cover of the reaction kettle (1) is provided with a feeding port (11), a mounting frame (6) and a motor (5) are arranged on one side close to the feeding port (11), the mounting frame (6) is provided with a gas cylinder (7), the output end of the gas cylinder (7) is connected with the top end of the lifting frame (33), the output end of the motor (5) is provided with a driving shaft (51), the driving shaft (51) is provided with a first belt pulley (52), the first belt pulley (52) is connected with a second belt pulley (53) through a belt, the second belt pulley (53) is sleeved on the rotating shaft (31), and the upper end of the rotating shaft (31) is rotatably connected with the top cover of the reaction kettle (1).

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