Electro-Fenton equipment and method for pretreatment of high-concentration refractory organic wastewater

Abstract

The present invention relates to the technical field of sewage treatment, and specifically discloses an electro-Fenton equipment and method for pre-treatment of high-concentration refractory organic wastewater, which is used to solve the problem of poor treatment methods in the prior art; it comprises an electro-Fenton treatment box, a partition partition is arranged at the center of the inner cavity of the electro-Fenton treatment box, and an inlet partition and an outlet partition are respectively arranged in the electro-Fenton treatment box on both sides of the partition partition, a first reaction zone is constructed between the inlet partition and the partition partition, and a second reaction zone is constructed between the outlet partition and the partition partition. The present invention overcomes the condition that the traditional Fenton must react under the condition of pH 3 to 4, and saves the addition of acid, alkali and other agents. During the reaction process, no ferrous salt is added, only hydrogen peroxide is added, the amount of sludge is reduced, and the sewage treatment effect and treatment speed are enhanced, and the stability of the treatment effect is improved, and the adaptability to water quality changes is strong.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to an electro-Fenton device and method for pre-treating high-concentration refractory organic wastewater. Background Art

[0002] Fenton oxidation and heterogeneous electrocatalytic oxidation are used in sewage treatment:

[0003] 1. Fenton oxidation is carried out under acidic conditions (pH 3~4), where H2O2 reacts with Fe 2＋ In the presence of hydroxyl radicals, strong oxidizing ability is generated, which trigger more other active oxygen species to achieve the degradation of organic matter. The oxidation process is a chain reaction; the generation of hydroxyl radicals is the beginning of the chain, while other active oxygen species and reaction intermediates constitute the nodes of the chain. Each active oxygen species is consumed and the reaction chain terminates.

[0004] The Fenton process for treating wastewater has the advantages of good effect and low one-time investment.

[0005] 2. Heterogeneous electrocatalytic oxidation: Based on the principle of electrolysis, it relies on the oxidation and reduction reactions occurring on the cathode and anode plates of the electrolytic cell to degrade organic pollutants in sewage. The chemical reactions of organic pollutants in sewage on the electrodes include direct electrolysis and indirect electrolysis.

[0006] The method of filling specific solid particulate materials with catalytic activity between the cathode and anode electrode plates constitutes heterogeneous electrocatalytic oxidation, and the filler plays a catalytic role and acts as a particle electrode at the same time. Using the heterogeneous electrocatalytic oxidation method, a large number of hydroxyl free radicals with high oxidation performance will be produced in the electrolyzer, and its oxidation performance is second only to fluorine. Various organic pollutants in sewage can be effectively destroyed, their biological toxicity can be reduced, and their concentration can be reduced through chemical combustion, and even inorganicization can be achieved.

[0007] Heterogeneous electrocatalytic oxidation has the advantages of good treatment effect, lower power consumption compared to direct electrolysis, less sludge production, simple operation and wide adaptability.

[0008] However, the Fenton oxidation method for treating sewage has the following disadvantages: many types of reagents are added and the dosage of reagents is large. During the Fenton reaction, it is necessary to add acid (pH3~4), ferrous sulfate, hydrogen peroxide, alkali (adjusted to pH7-8) and other reagents, with many types and large dosages. The amount of sludge produced is large, and the addition of ferrous ions will produce a large amount of iron-containing sludge. The operation is complicated; due to the large number of types of reagents and the large dosage, the operation workload is large and complicated; it is difficult to adjust the dosage in time according to the changes in the influent concentration to maintain the stability of the treatment effect; since the influent concentration is generally changing all the time, and the dosage is difficult to adjust in time according to the changes in the influent concentration, it is difficult to ensure the stability of the treatment effect; the operating cost is high, and due to the large total dosage of reagents and the large amount of sludge produced, the operating cost is also high; the reaction speed is slow: the Fenton method for treating sewage generally requires a reaction time of 4-6 hours.

[0009] Heterogeneous electrocatalytic oxidation for sewage treatment has the following disadvantages: the catalyst layer is easily clogged, causing short-flow of sewage in the electrolytic cell; due to the small particle size of the catalyst layer, in addition to catalyzing the electrolytic reaction, it can also filter the sewage. Therefore, after a long period of use, it is easy to cause the catalyst layer to be clogged and short-flow, which in turn causes the water quality of the effluent to deteriorate; and pressure water inlet is required: heterogeneous electrocatalytic oxidation generally adopts pressure water inlet and upward flow mode, and the energy consumption of sewage lifting is large; the equipment maintenance workload is large: since the catalyst layer and the electrode plate are in a state of mutual contact and compression, when the electrode plate needs to be replaced, the catalyst layer in the electrolytic cell needs to be completely cleared out before it can be carried out. Due to the small space in the electrolytic cell, it can usually only be cleaned manually, and the maintenance workload is large; when a good treatment effect is required, a multi-stage electrolytic cell series mode is usually required: if heterogeneous electrocatalytic oxidation needs to achieve a good removal effect of organic pollutants, a two-stage, three-stage or multi-stage series mode is usually required. This results in an increase in energy consumption and one-time equipment investment costs.

[0010] Based on this, an electro-Fenton device and method for pre-treating high-concentration difficult-to-degrade organic wastewater is now provided, which can eliminate the drawbacks of existing devices. Summary of the invention

[0011] The purpose of the present invention is to provide an electro-Fenton device and method for pre-treating high-concentration refractory organic wastewater, which solves the problem of poor treatment methods in the prior art.

[0012] To achieve the above object, the present invention provides the following technical solutions:

[0013] An electro-Fenton device for pre-treating high-concentration refractory organic wastewater comprises an electro-Fenton treatment box, wherein a partition partition is arranged at the center of the inner cavity of the electro-Fenton treatment box, and an inlet partition and an outlet partition are respectively arranged in the electro-Fenton treatment box on both sides of the partition partition, a first reaction zone is constructed between the inlet partition and the partition partition, and a second reaction zone is constructed between the outlet partition and the partition partition, the inlet partition and the inner wall of the electro-Fenton treatment box constitute an inlet distribution trough, and an inlet pipe for water inlet is arranged on the electro-Fenton treatment box at the end of the inlet distribution trough, and the inlet pipe is close to the bottom of the electro-Fenton treatment box. The electro-Fenton treatment box is provided with an electro-Fenton plate assembly at the top, an anode plate assembly is arranged in the water inlet distribution trough, the water outlet baffle and the inner wall of the electro-Fenton treatment box constitute a water outlet trough, a water outlet pipe for drainage is arranged on the side of the water outlet trough away from the water inlet pipe, the water outlet pipe is located at the top of the electro-Fenton treatment box, a cathode plate assembly is arranged at the water outlet trough, the cathode plate assembly and the anode plate assembly constitute an electrochemical treatment unit, the first reaction zone is filled with an iron-carbon catalyst, and the second reaction zone is filled with a Fenton-specific catalyst, the two catalysts act synergistically, and the effect is better, and a reactor cover is provided at the upper port of the electro-Fenton treatment box.

[0014] On the basis of the above technical solution, the present invention also provides the following optional technical solution:

[0015] In an optional scheme: a plurality of first reaction zone water guide and distribution plates arranged in parallel are arranged at the first reaction zone position, and a plurality of second reaction zone water guide and distribution plates arranged in parallel are arranged at the second reaction zone position. The arrangement of the first reaction zone water guide and distribution plates and the second reaction zone water guide and distribution plates divides and guides the reaction area.

[0016] In an optional solution: a water inlet baffle is provided at the water inlet baffle position to block the water flow, and a water outlet baffle is provided at the water outlet baffle position to block the water flow.

[0017] In an optional solution: an overflow pipe is also provided on the outside of the electro-Fenton treatment box.

[0018] In an optional scheme: the first reaction zone and the second reaction zone are also provided with an aeration assembly for blowing air into the interior thereof, the aeration assembly includes an aeration duct, the aeration duct is arranged at the bottom of the electric-Fenton treatment box where the first reaction zone and the second reaction zone are located, a plurality of compressed air releasers are distributed on the surface of the aeration duct located in the first reaction zone and the second reaction zone, the other end of the aeration duct extends to the outer end along the inner wall of the electric-Fenton treatment box, and the outer end of the aeration duct is connected to the air supply equipment through a compressed air inlet.

[0019] In an optional solution: the water inlet baffle, the water outlet baffle and the partition baffle are all grid plates with holes, covered with a small-pore plastic mesh.

[0020] In an optional solution: a vent pipe is also provided on one side of the bottom of the electro-Fenton treatment box.

[0021] In an optional scheme: the cathode plate group includes slots symmetrically arranged on both sides of the water outlet trough, and a cathode plate is arranged in the slot. The outside of the electro-Fenton treatment box is provided with cathode terminals corresponding to the position of the water outlet trough, and the inner end of the cathode terminal extends into the water outlet trough and is in sliding contact with the cathode plate.

[0022] In an optional scheme: the anode plate group includes slots symmetrically arranged on both sides of the water inlet distribution trough, an anode plate is arranged in the slot, and an anode terminal corresponding to the position of the water inlet distribution trough is provided on the outside of the electro-Fenton treatment box, and the inner end of the anode terminal extends into the water inlet distribution trough and is in sliding contact with the anode plate.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention overcomes the condition that traditional Fenton must react under pH 3 to 4, saving the addition of acid, alkali and other reagents. During the reaction process, no ferrous salt is added, only hydrogen peroxide is added, which reduces the amount of sludge, strengthens the sewage treatment effect and treatment speed, and improves the stability of the treatment effect, and has strong adaptability to water quality changes. The water inlet method is gravity water inlet and water distribution, which saves energy consumption. The catalyst is configured in combination, one is an iron-containing catalyst, and the other is a Fenton-specific catalyst. The two types of catalysts work synergistically to make the reaction effect better; the inlet water is treated with sedimentation to reduce the suspended matter entering the electrolytic cell. Combined with the multiple water distribution design in the electrolytic cell, it effectively solves the problems of catalyst blockage, compaction and sewage short-flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention.

[0026] Figure 2 For the present invention Figure 1 Schematic diagram of the BB structure.

[0027] Figure 3 It is a schematic structural diagram of the water guide and distribution plate in the first reaction zone of the present invention.

[0028] Figure 4 For the present invention Figure 1 Schematic diagram of the structure of AA.

[0029] Figure 5 The present invention is a flow chart of the electro-Fenton equipment used for pretreatment of high-concentration, difficult-to-degrade organic wastewater.

[0030] Notes on the figure numbers: 1-water inlet pipe; 2-water outlet pipe; 3-anode plate; 4-cathode plate; 5-anode terminal; 6-cathode terminal; 7-compressed air inlet; 8-compressed air releaser; 9-water inlet distribution trough; 10-water outlet collecting trough; 11-water inlet baffle; 12-water outlet baffle; 13-water inlet partition; 14-water outlet partition; 15-partition partition; 16-water guide and distribution plate for the first reaction zone; 17-water guide and distribution plate for the second reaction zone; 18-overflow pipe; 19-first reaction zone; 20-second reaction zone; 21-vent pipe; 22-reactor cover. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] like Figure 1-Figure 4 As shown, an embodiment of the present invention provides an electro-Fenton device for pre-treating high-concentration refractory organic wastewater, including an electro-Fenton treatment box, wherein a partition partition 15 is arranged at the center of the inner cavity of the electro-Fenton treatment box, and an inlet partition 13 and an outlet partition 14 are respectively arranged in the electro-Fenton treatment box on both sides of the partition partition 15, a first reaction zone 19 is constructed between the inlet partition 13 and the partition partition 15, and a second reaction zone 20 is constructed between the outlet partition 14 and the partition partition 15, the inlet partition 13 and the inner wall of the electro-Fenton treatment box constitute an inlet distribution trough 9, and an inlet pipe 1 for water inlet is arranged on the electro-Fenton treatment box at the end of the inlet distribution trough 9, and the inlet pipe 1 is close to the bottom of the electro-Fenton treatment box. An anode plate group is provided in the water distribution tank 9, and the water outlet baffle 14 and the inner wall of the electric Fenton treatment box constitute a water outlet trough 10. The side of the water outlet trough 10 away from the water inlet pipe 1 is provided with a water outlet pipe 2 for drainage, and the water outlet pipe 2 is located at the top of the electric Fenton treatment box, so that low water level enters and high water level is discharged, which helps to extend the purification path of sewage and improve the purification effect. A cathode plate group is provided at the position of the water outlet trough 10, and the cathode plate group and the anode plate group constitute an electrochemical treatment unit. The first reaction zone 19 is filled with an iron-carbon catalyst, and the second reaction zone 20 is filled with a Fenton-specific catalyst. The two catalysts work synergistically and the effect is better. The upper port of the electric Fenton treatment box is matched with a reactor cover plate 22;

[0033] The first reaction zone 19 is provided with a plurality of first reaction zone water guide and distribution plates 16 arranged in parallel, and the second reaction zone 20 is provided with a plurality of second reaction zone water guide and distribution plates 17 arranged in parallel. The first reaction zone water guide and distribution plates 16 and the second reaction zone water guide and distribution plates 17 are arranged to divide and guide the reaction zone, so that the water flows evenly through the reaction zone, which helps to ensure uniform and stable treatment effect.

[0034] The water inlet baffle 11 is provided at the position of the water inlet baffle 13 to block the water flow, and the water outlet baffle 12 is provided at the position of the water outlet baffle 14 to block the water flow. The water inlet baffle 11 and the water outlet baffle 12 are provided to prevent the sewage from short-circuiting during the process of flowing from the water inlet distribution tank 9 to the water outlet collection tank 10;

[0035] The outer side of the electro-Fenton treatment box is also provided with an overflow pipe 18, which can drain away excess water to prevent the water from overflowing the equipment.

[0036] The first reaction zone 19 and the second reaction zone 20 are also provided with an aeration assembly for blowing air into the interior thereof. The aeration assembly provides oxygen to the reaction area, and the sewage and the filler can be fully mixed, which helps to improve the purification effect. The aeration assembly includes an aeration conduit, which is arranged at the bottom of the electric-Fenton treatment box where the first reaction zone 19 and the second reaction zone 20 are located. A plurality of compressed air releasers 8 are distributed on the surface of the aeration conduit located in the first reaction zone 19 and the second reaction zone 20. The other end of the aeration conduit extends to the outer end along the inner wall of the electric-Fenton treatment box. The outer end of the aeration conduit is connected to the air supply device through the compressed air inlet 7. In this way, compressed gas is provided through the air supply device, and the gas enters the bottom of the electric-Fenton treatment box along the aeration conduit, and then is ejected along the compressed air releaser 8 to assist the sewage treatment at the first reaction zone 19 and the second reaction zone 20;

[0037] The water inlet baffle 13, the water outlet baffle 14, and the partition baffle 15 are all grid plates with holes, covered with a small-pore plastic mesh, so that the first reaction zone 19 and the second reaction zone 20 can be isolated from the electrode plate to avoid damage to the electrode plate and facilitate the removal, maintenance and replacement of the electrode plate;

[0038] A vent pipe 21 is also provided on one side of the bottom of the electro-Fenton treatment box for draining all the liquid;

[0039] The cathode plate group includes slots symmetrically arranged on both sides of the outlet water collecting tank 10, and a cathode plate 4 is matched in the slot. The outer side of the electro-Fenton treatment box is provided with a cathode terminal 6 corresponding to the position of the outlet water collecting tank 10. The inner end of the cathode terminal 6 extends into the outlet water collecting tank 10 and is in sliding contact with the cathode plate 4, so that the cathode plate 4 can be powered, and it is also convenient to replace and maintain the cathode plate 4 in the later stage;

[0040] The anode plate group includes slots symmetrically arranged on both sides of the water inlet distribution trough 9, and an anode plate 3 is arranged in the slot. The outer side of the electro-Fenton treatment box is provided with an anode terminal 5 corresponding to the position of the water inlet distribution trough 9. The inner end of the anode terminal 5 extends into the water inlet distribution trough 9 and is in sliding contact with the anode plate 3, so that the anode plate 3 can be powered, and it is also convenient to replace and maintain the anode plate 3 in the later stage.

[0041] Working principle: Sewage enters the water inlet distribution tank 9 of the electro-Fenton equipment through the water inlet pipe 1, and then enters the first reaction zone 19 through the water inlet baffle 11 and the water inlet partition 13. Then, the water is evenly distributed in the first reaction zone 19 through the first reaction zone water distribution plate 16. The sewage first undergoes an electrochemical reaction in the first reaction zone 19. After the reaction is completed, the sewage enters the second reaction zone 20 through the partition baffle 15, and then the water is evenly distributed in the second reaction zone 20 through the second reaction zone water distribution plate 17. The sewage undergoes an electrochemical reaction in the second reaction zone 20. After the reaction is completed, the sewage flows into the water outlet trough 10 through the water outlet baffle 14 and the water outlet baffle 12, and then is discharged from the electro-Fenton equipment through the water outlet pipe 2.

[0042] During the operation of the electro-Fenton equipment, compressed air enters from the compressed air inlet 7 and is released through the compressed air releaser 8. During the entire operation, the compressed air remains in an open state. The inlet baffle 11 and the outlet baffle 12 are set to prevent short-circuiting of sewage from flowing from the inlet distribution tank 9 to the outlet collection tank 10;

[0043] When the water level inside the electric Fenton equipment is high, water overflows from the overflow pipe 18 .

[0044] When the electro-Fenton equipment is used for the pretreatment of high-concentration, difficult-to-degrade organic wastewater, such as Figure 5 As shown;

[0045] Process description:

[0046] High-concentration, difficult-to-degrade organic wastewater first enters the regulating tank for water quality and water quality balance adjustment, and then is lifted to the 1# coagulation sedimentation tank by a water pump, where acid or alkali is added to adjust the pH to the range of 6~9, and then polyaluminum chloride and polyacrylamide are added to make the suspended matter and colloidal substances in the sewage form a Brahma with good precipitation performance, and then removed by precipitation. The effluent from the 1# coagulation sedimentation tank flows into the electro-Fenton equipment by gravity. Under the action of the electric field provided by direct current, the hydrogen peroxide input and the internal catalyst undergo electrolysis and catalytic reaction to generate ·OH with extremely strong oxidizing ability, which opens the loop and breaks the chain of complex organic pollutants in the sewage, achieving the purpose of detoxification and improving biodegradability. After being treated by the electro-Fenton equipment, a small amount of suspended matter will still be produced in the sewage, so a 2# coagulation sedimentation tank is set up to continue the precipitation treatment of the electro-Fenton effluent.

[0047] The effluent from the 2# coagulation sedimentation tank can enter the subsequent biochemical system for further treatment.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An electro-Fenton device for pre-treating high-concentration refractory organic wastewater, comprising an electro-Fenton treatment box, wherein a partitioning baffle (15) is arranged at the center of the inner cavity of the electro-Fenton treatment box, and an inlet baffle (13) and an outlet baffle (14) are respectively arranged in the electro-Fenton treatment box on both sides of the partitioning baffle (15); Features: A first reaction zone (19) is constructed between the water inlet baffle (13) and the partition baffle (15), a second reaction zone (20) is constructed between the water outlet baffle (14) and the partition baffle (15), the water inlet baffle (13) and the inner wall of the electro-Fenton treatment box form a water inlet distribution trough (9), an anode plate group is provided in the water inlet distribution trough (9), the water outlet baffle (14) and the inner wall of the electro-Fenton treatment box form a water outlet collection trough (10), a cathode plate group is provided at the position of the water outlet collection trough (10), and the cathode plate group and the anode plate group form an electrochemical treatment unit, the first reaction zone (19) is filled with an iron-carbon catalyst, and the second reaction zone (20) is filled with a Fenton-specific catalyst, and the upper port of the electro-Fenton treatment box is matched with a reactor cover plate (22).

2. The electro-Fenton equipment for pretreatment of high-concentration refractory organic wastewater according to claim 1 is characterized in that: The first reaction zone (19) is provided with a plurality of first reaction zone water guide and distribution plates (16) arranged in parallel, and the second reaction zone (20) is provided with a plurality of second reaction zone water guide and distribution plates (17) arranged in parallel. The arrangement of the first reaction zone water guide and distribution plates (16) and the second reaction zone water guide and distribution plates (17) divides and guides the reaction areas.

3. The electro-Fenton equipment for pretreatment of high-concentration refractory organic wastewater according to claim 1 is characterized in that: A water inlet baffle (11) for blocking water flow is provided at the position of the water inlet baffle (13), and a water outlet baffle (12) for blocking water flow is provided at the position of the water outlet baffle (14).

4. The electro-Fenton equipment for pretreatment of high-concentration refractory organic wastewater according to claim 1 is characterized in that: An overflow pipe (18) is also provided on the outside of the electro-Fenton treatment box.

5. The electro-Fenton equipment for pretreatment of high-concentration refractory organic wastewater according to claim 1 is characterized in that: The first reaction zone (19) and the second reaction zone (20) are also provided with an aeration assembly for blowing air into the interior thereof, the aeration assembly comprising an aeration duct, the aeration duct being arranged at the bottom of the electro-Fenton treatment box where the first reaction zone (19) and the second reaction zone (20) are located, a plurality of compressed air releasers (8) are distributed on the surface of the aeration duct located in the first reaction zone (19) and the second reaction zone (20), the other end of the aeration duct extending along the inner wall of the electro-Fenton treatment box to the outer end, the outer end of the aeration duct being connected to the air supply device via a compressed air inlet (7).

6. The electro-Fenton equipment for pretreatment of high-concentration refractory organic wastewater according to claim 1 is characterized in that: The water inlet baffle (13), the water outlet baffle (14), and the partition baffle (15) are all grid plates with holes and covered with a small-pore plastic mesh.

7. The electro-Fenton equipment for pretreatment of high-concentration refractory organic wastewater according to claim 1 is characterized in that: A vent pipe (21) is also provided on one side of the bottom of the electro-Fenton treatment box.

8. The electro-Fenton equipment for pretreatment of high-concentration refractory organic wastewater according to claim 1 is characterized in that: The cathode plate assembly comprises slots symmetrically arranged on both sides of the water outlet trough (10), wherein a cathode plate (4) is arranged in cooperation with the slots, and a cathode terminal post (6) corresponding to the position of the water outlet trough (10) is arranged on the outside of the electro-Fenton treatment box, wherein the inner end of the cathode terminal post (6) extends into the water outlet trough (10) and is in sliding contact with the cathode plate (4).

9. The electro-Fenton equipment for pretreatment of high-concentration refractory organic wastewater according to claim 1 is characterized in that: The anode plate assembly comprises slots symmetrically arranged on both sides of the water inlet distribution trough (9), an anode plate (3) being arranged in the slot, and an anode terminal (5) corresponding to the position of the water inlet distribution trough (9) is arranged on the outside of the electro-Fenton treatment box, and the inner end of the anode terminal (5) extends into the water inlet distribution trough (9) and is in sliding contact with the anode plate (3).

10. A method for pre-treating high-concentration refractory organic wastewater using an electro-Fenton device according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: The sewage enters the water inlet distribution tank (9) of the electro-Fenton equipment through the water inlet pipe (1), and then enters the first reaction zone (19) through the water inlet baffle (11) and the water inlet partition (13); and then the water is uniformly distributed in the first reaction zone (19) through the first reaction zone water guide plate (16); Step 2: The sewage first undergoes an electrochemical reaction in the first reaction zone (19). After the reaction is completed, the sewage enters the second reaction zone (20) through the partition plate (15), and then passes through the second reaction zone water distribution plate (17) to evenly distribute water into the second reaction zone (20); Step 3: The sewage undergoes an electrochemical reaction in the second reaction zone (20). After completion, the sewage passes through the outlet baffle (14) and the outlet baffle (12), flows into the outlet sump (10), and is then discharged through the outlet pipe (2).

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