Wastewater treatment system and method

Abstract

The invention provides a wastewater treatment system and method, and relates to the technical field of sewage treatment.The electro-Fenton device comprises a shell, a vertical partition plate is arranged in the shell and divides the interior of the shell into an electrolysis area and a water inlet area located on one side of the electrolysis area, and a connecting sliding rail is arranged above the electrolysis area and used for being electrically connected with a power source; an aeration area connected with the electrolysis area is arranged below the electrolysis area, and one end of the aeration area is communicated with the lower end of the water inlet area; the water outlet area is arranged at the upper end of the shell and is connected with the electrolysis area; the polar plate is inserted into the electrolysis area, and the upper end of the polar plate is slidably and electrically connected with the connecting sliding rail through a connecting part; the iron sludge recovery unit comprises a solid-liquid separation device, the input end of which is connected with the water outlet area; the input end of the sludge concentration device is connected with a solid outlet of the solid-liquid separation device, and a sludge outlet of the sludge concentration device is connected with the water inlet area through a sludge return pipeline; the problems of Fenton oxidation stagnation and low electrochemical oxidation efficiency are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and more specifically, relates to a wastewater treatment system and method. Background Art

[0002] The Fenton oxidation method is suitable for the treatment of wastewater containing difficult-to-degrade organic matter, such as paper industry wastewater, dyeing and finishing industry wastewater, coal chemical wastewater, petrochemical wastewater, landfill leachate and other wastewaters. It can be used as a pretreatment process before biochemical treatment, or as a deep treatment process after biochemical treatment. It has the advantage of strong oxidation ability. However, the disadvantages of the traditional Fenton process are also quite obvious. One is the large amount of reagents added, and the other is the large amount of iron sludge produced. Therefore, many Fenton-like processes have been developed and applied one after another; among them, electro-Fenton couples the two processes of electrolysis and Fenton reaction, which can not only produce H2O2 from molecular oxygen in situ at the cathode, but also convert Fe 3+ Reduction to Fe 2+ , promoting the recycling of divalent iron, thereby reducing the dosage of reagents and the amount of iron sludge produced, and has very good application prospects. It is not difficult to find that the electro-Fenton process involves anode reaction, cathode reaction and liquid phase reaction between the plates. 3+ , Fe 2+ , H2O2, organic matter and other reactants are transported from the main solution to the working electrode through convection, diffusion and electromigration. Therefore, a reasonable reactor design is very important for Fe 3+ , Fe 2+ The full contact of H2O2 and organic matter has a significant promoting effect, which is conducive to achieving the best treatment effect.

[0003] In the prior art, some electro-Fenton devices combine electro-Fenton technology with fluidized bed technology and add catalysts into the reactor; some electro-Fenton devices form multiple electro-Fenton areas inside the reactor by staggeredly arranging positive and negative plates at intervals, so as to improve the current efficiency and electro-Fenton effect; some electro-Fenton devices are equipped with electrolytic components and oxygenating components in the device, which are used as positive electrodes and oxygenating components to introduce oxygen into wastewater respectively, and the inner cavity of the device is used as a cathode. The electro-Fenton devices in the prior art optimize the traditional Fenton process from various directions, but they cannot fully reflect the advantages of electro-Fenton, namely, Fe 3+ Cathodic reduction to Fe 2+ , catalyst recycling. Summary of the invention

[0004] The purpose of the present invention is to provide a wastewater treatment system, which has an electric Fenton device and an iron sludge recovery unit. Not only does it adopt an upward flow water inlet mode in the shell to avoid causing a dead zone of water flow, but it also adopts a connecting slide rail and a connecting component to realize the electrical connection of the electrode plate, ensuring that the distance between the electrode plates is adjustable, and facilitating the electrical connection between the electrode plates and the power supply. In addition, the iron sludge recovery unit can be used to return the precipitated iron sludge to the electric Fenton device after being dissolved by adding acid, and Fe near the cathode plate 3+ Reduction to Fe 2+ , give full play to the advantages of electro-Fenton, and thus improve the current efficiency and electro-Fenton effect.

[0005] In order to achieve the above object, the present invention provides a wastewater treatment system, comprising:

[0006] An electro-Fenton device, the electro-Fenton device comprising:

[0007] A shell, wherein a vertical partition is arranged inside the shell, wherein the vertical partition divides the inside of the shell into an electrolysis zone and a water inlet zone located on one side of the electrolysis zone, wherein a connecting slide rail is arranged above the electrolysis zone, wherein a slide groove is provided along the length direction of the connecting slide rail, wherein the connecting slide rail is used to be electrically connected to a power source, wherein an aeration zone connected to the electrolysis zone is arranged below the electrolysis zone, wherein one end of the aeration zone is connected to the lower end of the water inlet zone;

[0008] A water outlet zone, which is arranged at the upper end of the shell and connected to the electrolysis zone;

[0009] An electrode plate, wherein the electrode plate is inserted in the electrolysis area, and the upper end of the electrode plate is electrically and slidingly connected to the connecting slide rail through a connecting component;

[0010] An iron mud recovery unit, the iron mud recovery unit comprising:

[0011] A solid-liquid separation device, wherein the input end of the solid-liquid separation device is connected to the water outlet area;

[0012] A sludge concentrating device, wherein the input end of the sludge concentrating device is connected to the solid outlet of the solid-liquid separation device, and the sludge outlet of the sludge concentrating device is connected to the water inlet area through a sludge return pipeline.

[0013] Optionally, the water outlet area is connected to the input end of the solid-liquid separation device through a water outlet pipe, and the supernatant outlet of the sludge thickening device is connected to the water outlet pipe through a supernatant reflux pipeline.

[0014] Optionally, it also includes a dosing device, an alkali dosing device and a first acid dosing device, the dosing device is used to add chemicals into the shell, the alkali dosing device is used to add alkali solution into the solid-liquid separation device, and the first acid dosing device is used to add acid solution into the sludge return pipeline.

[0015] Optionally, a pretreatment device is further included, and the pretreatment device includes a second formic acid device. The second acid adding device is used to add acid solution to the treated sewage to make its pH value within a first set threshold range.

[0016] Optionally, a water distribution plate is provided at the bottom of the electrolysis zone, the water distribution plate is connected to the lower end of the vertical partition and the inner wall of the shell, and the water distribution plate is provided with a plurality of air distribution holes.

[0017] Optionally, an aeration pipe is provided in the aeration zone, and the aeration pipe extends out of the shell and is used to connect to an aeration device.

[0018] Optionally, a plurality of mounting grooves are respectively provided on the opposite side walls of the electrolysis zone, and each of the electrode plates can be inserted into two opposite mounting grooves; the connecting component is a spring clip, and a planar portion is provided at one end of the spring clip, and a connecting hole is provided on the planar portion, and the planar portion can be fastened to the connecting slide rail by a bolt fastener passing through the connecting hole and the slide groove, and a clamp structure is provided at the other end of the spring clip, and the clamp structure can clamp the electrode plate.

[0019] Optionally, the electrode plate comprises a cathode plate and an anode plate, and the upper ends of the cathode plate and the anode plate are provided with conductive connecting parts extending upward, and the conductive connecting parts are electrically connected to the connecting component.

[0020] The present invention also provides a wastewater treatment method, using the above wastewater treatment system, comprising:

[0021] Adjusting the pH value of the treated sewage flowing to the inlet area so that it is within a first set threshold range;

[0022] The treated sewage is fed into the water inlet area, and reagents are added into the electrolysis area;

[0023] The treated wastewater is electrolyzed by an electro-Fenton device;

[0024] The liquid discharged from the water outlet area is input into a solid-liquid separation device, and an alkali solution is added into the solid-liquid separation device;

[0025] The material discharged from the solid outlet of the solid-liquid separation device is input into the sludge thickening device;

[0026] The sludge discharged from the sludge outlet of the sludge thickening device is input into the water inlet area through the sludge return pipeline, and acid is added into the sludge return pipeline to dissolve the iron sludge.

[0027] The invention provides a wastewater treatment system and method, and its beneficial effects are: the wastewater treatment system has an electro-Fenton device and an iron mud recovery unit, an electrolysis zone is arranged in the shell of the electro-Fenton device, a pole plate is installed in the electrolysis zone, an aeration zone is arranged below the electrolysis zone, the influent water after aeration enters the electrolysis zone from the bottom of the electrolysis zone, and flows from bottom to top in the electrolysis zone, and the water is discharged after electrolysis, so as to avoid the formation of a dead zone of water flow, thereby improving the treatment effect, the pole plate is vertically fixed in the electrolysis zone, and each pole plate can be inserted in different positions in order to adjust the pole plate spacing, and in order to facilitate the access of the power supply, the connecting slide rail is fixedly arranged above the electrolysis zone, and the pole plate is connected to the electrolysis zone through the connecting part. The sliding electrical connection between the parts and the connecting slide rail is convenient for adjusting the insertion position of the electrode plate while still being able to maintain electrical connection with the connecting slide rail and the power supply, so that the electro-Fenton device is not only simple in structure and fully electrolyzed, but also convenient for connecting the electrode plate with the power supply and adjusting the spacing between the electrode plates; the iron sludge recovery unit can separate the solid and liquid of the effluent of the electro-Fenton device through the solid-liquid separation device, and the separated liquid can be discharged, while the material discharged from the solid outlet is input into the sludge concentrating device for sludge concentrating, and the sludge discharged from the sludge outlet of the sludge concentrating device can be dissolved by adding acid in the sludge return pipeline and refluxed to the electro-Fenton device, near the cathode plate Fe 3+ Reduction to Fe 2+ , the catalyst is recycled, giving full play to the advantages of electro-Fenton, thereby improving the current efficiency and electro-Fenton effect.

[0028] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0030] Figure 1 A schematic structural diagram of a wastewater treatment system according to an embodiment of the present invention is shown.

[0031] Figure 2 A schematic diagram of the main structure of an electro-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0032] Figure 3 A schematic diagram of the top view of an electro-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0033] Figure 4 A schematic structural diagram of a water distribution plate of an electro-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0034] Figure 5 A schematic structural diagram of an aeration zone of an electro-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0035] Figure 6 A schematic structural diagram of a connecting slide rail of an electro-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0036] Figure 7 A schematic diagram of the main structure of the connection components of an electric-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0037] Figure 8 A schematic diagram of the top view of the structure of the connection components of an electro-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0038] Fig. 9 A schematic structural diagram of a cathode plate of an electro-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0039] Fig.10 A schematic structural diagram of an anode plate of an electro-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0040] Fig.11 A schematic structural diagram of an overflow weir of an electro-Fenton device of a wastewater treatment system according to an embodiment of the present invention is shown.

[0041] Fig.12 A flow chart of a wastewater treatment method according to an embodiment of the present invention is shown.

[0042] Description of reference numerals:

[0043] 1. Shell; 2. Electrolysis zone; 3. Connecting slide rail; 4. Aeration zone; 5. Water outlet zone; 6. Connecting parts; 7. Vertical partition; 8. Water inlet zone; 9. Water inlet pipe; 10. Water distribution plate; 11. Water distribution hole; 12. Aeration pipe; 13. Aeration hole; 14. Mounting groove; 15. Slide; 16. Plane part; 17. Clip structure; 18. Connecting hole; 19. Cathode plate; 20. Anode plate; 21. Conductive connecting part; 22. Overflow weir; 23. Water outlet trough; 24. Water outlet pipe; 25. Solid-liquid separation device; 26. Sludge concentration device; 27. Sludge return pipeline; 28. Supernatant return pipeline. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0045] like Figure 1 As shown, the present invention provides a wastewater treatment system, comprising:

[0046] Electro-Fenton device, the electro-Fenton device comprises:

[0047] A shell 1, wherein a vertical partition 7 is disposed inside the shell 1, and the vertical partition 7 divides the inside of the shell 1 into an electrolysis zone 2 and a water inlet zone 8 located on one side of the electrolysis zone 2; a connecting slide rail 3 is disposed above the electrolysis zone 2, and a slide groove 15 is provided along the length direction of the connecting slide rail 3, and the connecting slide rail 3 is used to be electrically connected to a power source; an aeration zone 4 connected to the electrolysis zone 2 is disposed below the electrolysis zone 2, and one end of the aeration zone 4 is connected to the lower end of the water inlet zone 8;

[0048] The water outlet area 5 is arranged at the upper end of the shell 1 and connected to the electrolysis area 2;

[0049] The electrode plate is inserted in the electrolysis area 2, and the upper end of the electrode plate is electrically connected to the connecting slide rail 3 through the connecting component 6;

[0050] Iron sludge recovery unit, the iron sludge recovery unit includes:

[0051] A solid-liquid separation device 25, the input end of which is connected to the water outlet area 5;

[0052] The sludge concentrating device 26 has its input end connected to the solid outlet of the solid-liquid separation device 25 , and its sludge outlet is connected to the water inlet area 8 via a sludge return pipeline 27 .

[0053] Specifically, in order to solve the problem of Fenton oxidation stagnation and low electrochemical oxidation efficiency, the wastewater treatment system provided by the present invention has an electro-Fenton device and an iron sludge recovery unit, such as Figure 2 and Figure 3As shown, an electrolysis zone 2 is provided in a shell 1 of the electro-Fenton device, and a pole plate is installed in the electrolysis zone 2. An aeration zone 4 is provided below the electrolysis zone 2. The aerated influent enters the electrolysis zone 2 from below the electrolysis zone 2, and flows from bottom to top in the electrolysis zone 2. Water is discharged after electrolysis to avoid dead zones of water flow, thereby improving the treatment effect. The pole plates are vertically fixed in the electrolysis zone 2. In order to adjust the distance between the pole plates, each pole plate can be inserted in different positions. In order to facilitate the access to the power supply, the connecting rail 3 is fixedly provided above the electrolysis zone 2. The pole plate is electrically connected to the connecting rail 3 through a connecting component 6, so that it is convenient to achieve connection with the connecting rail 3 and when adjusting the insertion position of the pole plate. The power supply remains electrically connected, so that the electro-Fenton device is not only simple in structure and sufficient in electrolysis, but also convenient for connecting the electrode plates to the power supply and adjusting the spacing between the electrode plates; the iron sludge recovery unit can perform solid-liquid separation on the effluent of the electro-Fenton device through the solid-liquid separation device 25, and the separated liquid can be discharged, while the material discharged from the solid outlet is input into the sludge concentrating device 26 for sludge concentrating, and the sludge discharged from the sludge outlet of the sludge concentrating device 26 can be dissolved by adding acid in the sludge return pipeline 27 and refluxed to the electro-Fenton device, and Fe3+ is reduced to Fe2+ near the cathode plate 19, and the catalyst is recycled, giving full play to the advantages of electro-Fenton, thereby improving the current efficiency and the electro-Fenton effect.

[0054] Furthermore, both ends of the vertical partition 7 are connected to a pair of opposite side walls of the shell 1, and a gap is formed between the lower end thereof and the bottom plate of the shell 1, forming an electrolysis zone 2 on one side of the vertical partition 7, and a water inlet zone 8 on the other side of the vertical partition 7. The water inlet zone 8 can take in water from the upper end, and after the water takes in water, it flows downward into the aeration zone 4. After aeration, the water enters the electrolysis zone 2 from the bottom of the electrolysis zone 2 upward, and forms a flow from bottom to top in the electrolysis zone 2.

[0055] In this embodiment, a water inlet pipe 9 is provided at one side of the upper end of the water inlet area 8 .

[0056] Optionally, the water outlet area 5 is connected to the input end of the solid-liquid separation device 25 through the water outlet pipe 24 , and the supernatant outlet of the sludge concentration device 26 is connected to the water outlet pipe 24 through the supernatant return pipeline 28 .

[0057] Specifically, the sludge concentrating device 26 concentrates the sludge and returns the supernatant to the solid-liquid separation device 25 .

[0058] Optionally, it also includes a dosing device, an alkali dosing device and a first acid dosing device, the dosing device is used to add chemicals into the shell 1, the alkali dosing device is used to add alkali solution into the solid-liquid separation device 25, and the first acid dosing device is used to add acid solution into the sludge return pipeline 27.

[0059] Specifically, the dosing device can add reagents into the shell 1 to achieve Fenton reaction, the alkali adding device can add alkali solution into the solid-liquid separation device 25 to adjust the internal pH value to 7-9, and the acid adding device can add acid solution into the sludge return pipeline 27 to dissolve the iron sludge in the sludge.

[0060] In this embodiment, the reagent includes ferrous sulfate and hydrogen peroxide.

[0061] Optionally, a pretreatment device is also included, the pretreatment device includes a second formic acid device, and the second acid adding device is used to add acid solution to the treated sewage to make its pH value within a first set threshold range.

[0062] Specifically, the pH value of the treated sewage is adjusted by the pretreatment device before entering the electro-Fenton device, and the pH value of the treated sewage is adjusted to 3-4 by the second acid addition device.

[0063] Optionally, a water distribution plate 10 is provided at the bottom of the electrolysis zone 2 , the water distribution plate 10 is connected to the lower end of the vertical partition 7 and the inner wall of the shell 1 , and the water distribution plate 10 is provided with a plurality of air distribution holes.

[0064] Specifically, Figure 4 As shown, the water distribution plate 10 is a perforated plate, so that the water distribution is more uniform.

[0065] Optionally, an aeration pipe 12 is provided in the aeration zone 4, and the aeration pipe 12 extends out of the shell 1 and is used to connect to an aeration device.

[0066] Specifically, Figure 5 As shown, a plurality of aeration pipes 12 are provided in the aeration zone 4, and air is supplied through the aeration device to achieve aeration of the incoming water.

[0067] In this embodiment, the aeration device includes an air pump.

[0068] Optionally, a plurality of mounting grooves 14 are respectively provided on the opposite side walls of the electrolysis zone 2, and each electrode plate can be inserted into two opposite mounting grooves 14; the connecting component 6 is a spring clip, and a planar portion 16 is provided at one end of the spring clip, and a connecting hole 18 is opened on the planar portion 16. The planar portion 16 can be fastened to the connecting slide rail 3 by a bolt fastener passing through the connecting hole 18 and the slide groove 15, and a clamp structure 17 is provided at the other end of the spring clip, and the clamp structure 17 can clamp the electrode plate.

[0069] Specifically, a plurality of mounting plates are respectively disposed on a pair of opposite side walls of the electrolysis zone 2, and a mounting groove 14 is formed between two adjacent mounting plates for inserting the electrode plates; Figure 6 As shown, the slide groove 15 in the connecting slide rail 3 extends along its length direction, so that the connecting component 6 can slide along the slide groove 15; Figure 7 and Figure 8As shown, two ends of the flat plate are integrally connected with clamping plates, and a pair of clamping plates are gradually closed to form a clamp structure 17.

[0070] In this embodiment, a guide bending portion is provided at one end of each clamping plate away from the flat plate portion, and a pair of guide bending portions form a gradually expanding structure to facilitate the insertion of the electrode plate.

[0071] In this embodiment, the extending direction of the connecting slide rail 3 is perpendicular to the surface of the electrode plate.

[0072] Specifically, the mounting grooves 14 are arranged along a first direction, and the connecting rails 3 extend along a second direction perpendicular to the first direction.

[0073] Optionally, the electrode plate includes a cathode plate 19 and an anode plate 20 , and the upper ends of the cathode plate 19 and the anode plate 20 are provided with a conductive connection portion 21 extending upward, and the conductive connection portion 21 is electrically connected to the connection component 6 .

[0074] Specifically, Fig. 9 and Fig.10 As shown, the upper ends of the cathode plate 19 and the anode plate 20 are provided with conductive connecting parts 21, which function as terminal blocks. The clamp structure 17 is clamped on the conductive connecting parts 21 to achieve electrical connection between the plates and the power supply.

[0075] In this embodiment, the electrode plates are fixed by upper and lower electrode plate grooves, and the distance between the electrode plates is adjusted by placing the electrode plates in different electrode plate grooves. The material of the anode plate 20 can be graphite, precious metals (such as Pt electrodes, etc.), doped boron diamond (BDD electrodes) electrodes and titanium-based metal oxide electrodes (DSA electrodes), and the material of the cathode plate 19 can be stainless steel, cast iron, carbon steel, etc.

[0076] In this embodiment, an overflow weir 22 is provided on the side of the upper end of the shell 1 away from the water inlet area 8, a water outlet trough 23 is provided outside the overflow weir 22, a water outlet area 5 is formed in the water outlet trough 23, and a water outlet pipe 24 is provided at the bottom of the water outlet trough 23.

[0077] Specifically, after the influent is aerated and distributed into the electrolysis zone 2 for treatment, it overflows from the overflow weir 22 at the upper end of the electrolysis zone 2 , and the effluent enters the outlet trough 23 and can be discharged through the outlet pipe 24 .

[0078] In this embodiment, the materials of the water inlet pipe 9, the aeration pipe 12, and the water outlet pipe 24 can be polyvinyl chloride PVC, polyethylene PE, etc. The water inlet flow rate of the water inlet pipe 9 is 0.8-1.2m / s; the gas flow rate in the aeration pipe 1212 is 4-5m / s, and the aeration hole 13 is opened just above the aeration pipe 12. The aperture of the aeration hole 13 is 2mm-4mm, the hole spacing is 10mm-20mm, and the through-hole flow rate is 10-15m / s; the diameter of the water distribution holes 11 on the water distribution plate 10 is 3-5mm, the hole spacing is 10-20mm, and the rectangular array arrangement has a through-hole flow rate of 0.15-0.2m / s; Fig.11 As shown, the overflow weir 22 is a triangular weir, and the load on the weir is 1.7-2.9 L / (m / s).

[0079] like Fig.12 As shown, the present invention also provides a wastewater treatment method, using the above-mentioned wastewater treatment system, comprising:

[0080] Adjusting the pH value of the treated sewage flowing to the water inlet area 8 so that it is within a first set threshold range;

[0081] The treated sewage is fed into the water inlet area 8, and the reagent is added into the electrolysis area 2;

[0082] The treated wastewater is electrolyzed by an electro-Fenton device;

[0083] The liquid discharged from the water outlet area 5 is input into the solid-liquid separation device 25, and alkaline solution is added into the solid-liquid separation device 25;

[0084] The material discharged from the solid outlet of the solid-liquid separation device 25 is input into the sludge concentration device 26;

[0085] The sludge discharged from the sludge outlet of the sludge thickening device 26 is input into the water inlet area 8 through the sludge return pipeline 27, and acid is added into the sludge return pipeline 27 to dissolve the iron sludge.

[0086] Specifically, when the wastewater treatment method is implemented, the above-mentioned wastewater treatment device is used, and the treated sewage is first pretreated to adjust its pH value to 3-4; the peripheral equipment is first connected: the water inlet pipe 9 is connected to the water inlet pump, the water outlet pipe 24 is connected to the input end of the solid-liquid separation device 25, the aeration pipe 12 is connected to the air pump, the electrode plate is placed in the electrode plate tank, and each electrode plate is connected to the connecting slide rail 3 through the connecting component 6, and the power supply is electrically connected to the connecting slide rail 3;; Operation: the pretreated treated sewage is input into the water inlet area 8 of the electric Fenton device, and then flows through the aeration area 4, passes through the water distribution plate 10 and enters the electrolysis area 2, and ferrous sulfate and hydrogen peroxide are added to the electric Fenton device; in this process, the aeration pump is started, and the gas passes through the aeration pipe 12 and the aeration hole 13 through the water distribution plate 10, enter the electrolysis zone 2, continue to aerate the surface of the plate, and power the plate through a DC power supply. The DC power supply can work in a steady current mode or a steady voltage mode, and is adjusted to the designed voltage and current through the voltage and current adjustment knobs; after the electrolysis is completed, the effluent of the electro-Fenton device enters the solid-liquid separation device 25, and alkali is added to adjust the pH to 7-9. After separation by the solid-liquid separation device 25, the effluent meets the discharge standard, and the material discharged from the solid outlet of the solid-liquid separation device 25 is input into the sludge concentration device 26. The concentrated sludge is returned to the water inlet pipe 9, and acid is added to the sludge return pipe 27 to dissolve the iron sludge, so as to complete the recovery and reuse of the iron sludge; when the treated sewage is treated, the voltage and current of the DC power supply are gradually reduced to 0, and then the aeration pump and the water inlet pump are turned off.

[0087] Take the sewage treatment of textile dyeing and finishing wastewater as an example: Since the effluent of the biochemical system, that is, the effluent of the secondary sedimentation tank, has a high organic concentration, in order to ensure the stable operation of the subsequent reverse osmosis system, the wastewater needs to be subjected to advanced oxidation treatment. The above-mentioned wastewater treatment method is used for treatment, and the material of the anode plate 20 is selected as the BDD electrode, and the material of the cathode plate 19 is selected as the ruthenium iridium electrode, and the steady flow mode; the specific steps are as follows: for the treated sewage, adjust the acid pH to 3-3.5; add ferrous sulfate; add hydrogen peroxide; the reaction time is 45min, and water samples are taken every 10min; adjust the acid and aerate for 3.0h to remove residual chlorine; add sodium bisulfite at a mass ratio of 1:3 to remove residual chlorine; adjust the alkali and add PAM; filter the permeate with filter paper to detect CODcr. The test results are shown in the following table.

[0088]

[0089] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A wastewater treatment system, characterized in that: include: An electro-Fenton device, the electro-Fenton device comprising: A shell, wherein a vertical partition is arranged inside the shell, wherein the vertical partition divides the inside of the shell into an electrolysis zone and a water inlet zone located on one side of the electrolysis zone, wherein a connecting slide rail is arranged above the electrolysis zone, wherein a slide groove is provided along the length direction of the connecting slide rail, wherein the connecting slide rail is used to be electrically connected to a power source, wherein an aeration zone connected to the electrolysis zone is arranged below the electrolysis zone, wherein one end of the aeration zone is connected to the lower end of the water inlet zone; A water outlet zone, which is arranged at the upper end of the shell and connected to the electrolysis zone; An electrode plate, wherein the electrode plate is inserted in the electrolysis area, and the upper end of the electrode plate is electrically and slidingly connected to the connecting slide rail through a connecting component; An iron mud recovery unit, the iron mud recovery unit comprising: A solid-liquid separation device, wherein the input end of the solid-liquid separation device is connected to the water outlet area; A sludge concentrating device, wherein the input end of the sludge concentrating device is connected to the solid outlet of the solid-liquid separation device, and the sludge outlet of the sludge concentrating device is connected to the water inlet area through a sludge return pipeline.

2. The wastewater treatment system according to claim 1, characterized in that: The water outlet area is connected to the input end of the solid-liquid separation device through a water outlet pipe, and the supernatant liquid outlet of the sludge concentration device is connected to the water outlet pipe through a supernatant liquid reflux pipeline.

3. The wastewater treatment system according to claim 1, characterized in that: It also includes a dosing device, an alkali dosing device and a first acid dosing device. The dosing device is used to add chemicals into the shell, the alkali dosing device is used to add alkali solution into the solid-liquid separation device, and the first acid dosing device is used to add acid solution into the sludge return pipeline.

4. The wastewater treatment system according to claim 1, characterized in that: It also includes a pretreatment device, which includes a second formic acid device. The second acid adding device is used to add acid solution to the treated sewage to make its pH value fall within a first set threshold range.

5. The wastewater treatment system according to claim 1, characterized in that: A water distribution plate is arranged at the bottom of the electrolysis zone, the water distribution plate is connected to the lower end of the vertical partition plate and the inner wall of the shell, and the water distribution plate is provided with a plurality of air distribution holes.

6. The wastewater treatment system according to claim 1, characterized in that: An aeration pipe is arranged in the aeration zone, and the aeration pipe extends out of the shell and is used to connect an aeration device.

7. The wastewater treatment system according to claim 1, characterized in that: A plurality of mounting grooves are respectively arranged on the opposite side walls of the electrolysis zone, and each of the pole plates can be inserted into two opposite mounting grooves; the connecting component is a spring clip, and a planar portion is arranged at one end of the spring clip, and a connecting hole is opened on the planar portion, and the planar portion can be fastened and connected to the connecting slide rail by a bolt fastener passing through the connecting hole and the slide groove, and a clamp structure is arranged at the other end of the spring clip, and the clamp structure can clamp the pole plate.

8. The wastewater treatment system according to claim 1, characterized in that: The electrode plate includes a cathode plate and an anode plate. The upper ends of the cathode plate and the anode plate are provided with conductive connecting parts extending upward, and the conductive connecting parts are electrically connected to the connecting component.

9. A method for treating wastewater, using the wastewater treatment system according to any one of claims 1 to 8, comprising: Adjusting the pH value of the treated sewage flowing to the inlet area so that it is within a first set threshold range; The treated sewage is fed into the water inlet area, and reagents are added into the electrolysis area; The treated wastewater is electrolyzed by an electro-Fenton device; The liquid discharged from the water outlet area is input into a solid-liquid separation device, and an alkali solution is added into the solid-liquid separation device; The material discharged from the solid outlet of the solid-liquid separation device is input into the sludge thickening device; The sludge discharged from the sludge outlet of the sludge thickening device is input into the water inlet area through the sludge return pipeline, and acid is added into the sludge return pipeline to dissolve the iron sludge.

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