Dynamic polar plate density electrochemical water treatment device and chromium-containing wastewater treatment method

Abstract

The invention discloses a dynamic polar plate density electrochemical water treatment device and a chromium-containing wastewater treatment method. The device comprises a reaction tank and an electrolytic adsorption module, and is characterized in that a water inlet and a water outlet are respectively formed in two ends of the reaction tank; the electrolytic adsorption module is mounted in the reaction tank and is positioned between the water inlet and the water outlet; the electrolytic adsorption module comprises an adjusting assembly and an electrolytic reaction module; the adjusting assembly comprises a fixed water baffle, a sliding water baffle, a first connecting piece and a second connecting piece. The fixed water baffle is fixed in the middle of one side wall of the reaction tank; the sliding water baffle and the fixed water baffle form a sliding pair sliding in the width direction of the flow channel. The electrolytic reaction module comprises a plurality of electrode plates, an X-shaped telescopic unit and a driving mechanism; an X-shaped telescopic unit is arranged between any two adjacent electrode plates; according to the invention, the density of the polar plate can be dynamically adjusted according to the concentration of input wastewater, so that the treatment efficiency is maximized under the condition of ensuring the treatment effect.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage purification, and in particular relates to a dynamic plate density electrochemical water treatment device and method. Background Art

[0002] During the process of electroplating and other processes, wastewater containing heavy metal ions will be generated, and there will be a large amount of hexavalent chromium ions in the wastewater. At present, the main method used is electrolysis to convert hexavalent chromium ions into trivalent chromium ions, and separate them from the wastewater through flocculation and precipitation. In the prior art, the electrolysis device usually immerses several energized electrode plates in the sewage, and the sewage is electrolyzed when it flows through the electrode plates. However, in actual use, the content of metal chromium ions in the sewage is changing, and the specifications of the electrolysis device are usually fixed. When the amount of heavy metal ions that need to be electrolyzed in the sewage is large, a strong electric field is required between the electrode plates to adsorb the metal chromium ions for reaction, and at the same time, the flow between the electrode plates needs to be reduced so that the sewage flowing through reacts more fully, and vice versa.

[0003] After long-term use, some impurities or polarization products will adhere to the electrode plates immersed in sewage, which will make the electrode plates passivated and the electrode efficiency decreased. Usually, they need to be taken out regularly for surface cleaning. When the distance between the electrode plates decreases and the area of ​​the electrode plates is larger, the liquid between the electrode plates will form a laminar flow when it flows naturally, which is not conducive to the full mixing of the liquid to form floccules, nor is it conducive to the uniformity of the liquid composition. Liquids with uneven composition in different places can easily lead to different electrolysis effects in different parts of the electrode plates, resulting in uneven reaction of the iron plates on the electrode plates, affecting the service life of the electrode plates and the effect of electrolysis. Stable laminar flow is also not conducive to full contact between the liquid and the electrode plates. Summary of the invention

[0004] The object of the present invention is to provide a dynamic plate density electrochemical water treatment device.

[0005] In a first aspect, the present invention provides a dynamic plate density electrochemical water treatment device, which includes a reaction tank and an electrolysis adsorption module, characterized in that: a water inlet and a water outlet are respectively provided at both ends of the reaction tank; the electrolysis adsorption module is installed in the reaction tank and is located between the water inlet and the water outlet.

[0006] The electrolysis adsorption module includes an adjustment component and an electrolysis reaction module; the adjustment component includes a fixed water baffle, a sliding water baffle, a first connecting piece and a second connecting piece; the fixed water baffle is fixed at the middle of one of the side walls of the reaction tank; the sliding water baffle and the fixed water baffle constitute a sliding pair that slides along the width direction of the flow channel; the width direction of the flow channel is perpendicular to the direction from the water inlet to the water outlet as the water flow direction; the fixed water baffle and the sliding water baffle can both block the flow of water; the position where the fixed water baffle and the sliding water baffle are located is the blocking area; the area between the sliding water baffle and the other side wall of the reaction tank is the flow area; by adjusting the position of the sliding water baffle, the width of the flow area can be changed, and then the flow size of the reaction tank can be changed under the same hydraulic retention time.

[0007] The first connecting member is fixed on the other side wall; the second connecting member is fixed on the sliding water retaining plate; the first connecting member and the second connecting member are opposite to each other; and the electrolytic reaction module is installed between the first connecting member and the second connecting member.

[0008] The electrolytic reaction module comprises a plurality of electrode plates, an X-shaped telescopic unit and a driving mechanism; the plurality of electrode plates are arranged in sequence along the width direction of the flow channel; each electrode plate forms a sliding pair with the bottom surface of the reaction tank that slides along the width direction of the flow channel; each electrode plate is slidably connected to a slider; the electrode plates arranged at both ends are fixed to the first connecting member and the second connecting member respectively.

[0009] An X-shaped telescopic unit is provided between any two adjacent electrode plates; the X-shaped telescopic unit comprises two driving rods; the middle parts of the two driving rods constitute a rotating pair; one end of the two driving rods and the corresponding two electrode plates respectively constitute a rotating pair; the sliders on the two electrode plates corresponding to the other ends of the two driving rods respectively constitute a rotating pair; the driving mechanism is used to drive two adjacent electrode plates to move closer to or away from each other.

[0010] Preferably, all the electrode plates are arranged vertically; the slider is slidably connected to the top edge of the electrode plate.

[0011] Preferably, the driving mechanism comprises a transmission member, a hydraulic cylinder and two pins; the driving mechanism corresponds to two adjacent electrode plates; the two pins are respectively fixed to the two electrode plates corresponding to the driving mechanism; a first slide groove is provided on the transmission member; the two pins are both slidably connected in the first slide groove; the hydraulic cylinder is fixed to the reaction pool; the transmission member is fixed to the output push rod of the hydraulic cylinder.

[0012] Preferably, two scrapers are fixed on the slider, and the two scrapers respectively abut against two side surfaces of the electrode plate, so that during the process of adjusting the width of the electrolytic reaction module, the scrapers automatically clean the two side surfaces of the electrode plate.

[0013] Preferably, each X-shaped telescopic unit corresponds to an aeration tube. The middle parts of the two driving rods in the same X-shaped telescopic unit are hinged by a hollow pin. The bottom opening of the hollow pin is fixed to the air inlet at the top of the aeration tube. The air inlet at the top of each hollow pin is connected to the air source. Each aeration tube can be moved closer or farther away from each other as the width of the electrolytic reaction module is adjusted.

[0014] Preferably, each electrode plate is divided into a plurality of anode plates and a plurality of cathode plates which are arranged alternately in sequence; the anode plates are all connected to the positive electrode interface of the power supply; and the cathode plates are all connected to the negative electrode interface of the power supply.

[0015] Preferably, a water quality detection device is provided at the water inlet of the reaction tank.

[0016] Preferably, the electrolytic reaction module further comprises a support beam, and a plurality of stirring modules corresponding to the X-shaped telescopic units one by one; the middle parts of the two driving rods in the same X-shaped telescopic unit are hinged by a pin. The two ends of the support beam and the two sides of the top of the reaction tank respectively constitute sliding pairs that slide along the direction of water flow; the stirring module comprises a sliding motor seat, a stirring rod, a rotating shaft and a stirring drive motor; the sliding motor seat is slidably connected to the support beam; the sliding motor seat is fixed on the sliding motor seat, and the output shaft is fixed to the top of the pin. The bottom end of the pin is fixed to the top of the vertically arranged stirring rod. Each stirring module can move closer to or farther away from each other as the width of the electrolytic reaction module is adjusted.

[0017] In a second aspect, the present invention provides a method for treating chromium-containing wastewater, which adopts the aforementioned dynamic plate density electrochemical water treatment device; the process of the method for treating chromium-containing wastewater is as follows: electricity is supplied to the electrode plates in the electrolysis reaction module; an iron plate is fixed on the electrode plates; wastewater containing hexavalent chromium ions is input into the reaction tank from the water inlet; an electrochemical reaction occurs when the wastewater passes through the electrolysis reaction module to produce chromium-containing precipitates.

[0018] The chromium ion concentration in the input wastewater is continuously detected, and the spacing between adjacent electrode plates in the electrolytic adsorption module and the wastewater input flow rate of the reaction tank are dynamically adjusted according to the chromium ion concentration. The greater the chromium ion concentration, the smaller the spacing between the electrode plates in the electrolytic adsorption module, the smaller the width of the flow area of ​​the reaction tank at the electrolytic adsorption module, and the smaller the wastewater input flow rate of the reaction tank; therefore, when the chromium ion concentration increases, the treatment speed decreases and the treatment effect improves. Conversely, when the chromium ion concentration decreases, the treatment speed increases and the treatment effect decreases, so as to maximize the comprehensive treatment efficiency.

[0019] Preferably, the wastewater input flow rate Q of the reaction tank is Q=v0·H·L; v0 is the wastewater flow rate in the flow area; H is the height difference between the outlet and the bottom of the reaction tank; L is the width of the flow area of ​​the reaction tank at the electrolysis adsorption module; the wastewater flow rate v0 in the flow area remains unchanged during the entire treatment process.

[0020] The present invention has the following beneficial effects: 1. The present invention sets an X-shaped telescopic unit on two electrode plates. During the movement of the two electrode plates, the distance between the two electrode plates is reduced by driving the two driving rods, thereby increasing the electric field strength between the two electrode plates and increasing the adsorption of heavy metal ions in the sewage by the electrode plates. Therefore, the present invention can dynamically adjust the electrode plate density according to the concentration of the input wastewater, thereby maximizing the treatment efficiency while ensuring the treatment effect.

[0021] 2. The present invention controls the distance between the two electrode plates through the X-shaped telescopic unit, thereby controlling the flow of sewage flowing through between the electrode plates, so that the heavy metal ions in the sewage can be fully reacted.

[0022] 3. The present invention provides an aeration tube. The gas outputted from the aeration tube pushes the flocculent precipitate generated by the reaction in the sewage to float, while preventing the flocculent precipitate from affecting the reaction on the electrode plate. The aeration tube also stirs the sewage during the gas output process, so that the heavy metal ions in the sewage react more fully. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic top view of Example 1 of the present invention.

[0024] Figure 2 It is a cross-sectional view along the AA direction in Example 1 of the present invention.

[0025] Figure 3 is a schematic diagram of the structure of the X-shaped telescopic unit in Example 1 of the present invention ( Figure 1 (partial enlarged view of part C in the figure).

[0026] Figure 4 Schematic diagram of the structure of the driving mechanism in Example 1 of the present invention ( Figure 1 (a partial enlarged view of part D in the figure).

[0027] Figure 5 This is a schematic diagram of the overall structure of Example 2 of the present invention.

[0028] Figure 6 It is a cross-sectional view along the BB direction in Example 2 of the present invention.

[0029] Among them: 1. reaction tank; 2. water inlet; 3. water outlet; 4. fixed water baffle; 5. first connecting piece; 6. second connecting piece; 7. sliding water baffle; 8. anode plate; 9. cathode plate; 10. X-shaped telescopic unit; 11. scraper; 12. aeration pipe; 13. support beam; 14. stirring rod; 15. motor; 16. mounting plate; 17. transmission part; 18. hydraulic cylinder; 19. slider. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] Example 1 like Figure 1 and 2 As shown, a dynamic plate density electrochemical water treatment device includes a reaction tank 1 and an electrolytic adsorption module. A water outlet 3 and a water inlet 2 are respectively provided at both ends of the reaction tank 1. A water quality detection device is provided at the water inlet of the reaction tank. The electrolytic adsorption module is installed in the reaction tank 1 and is located between the water inlet 2 and the water outlet 3. The direction from the water inlet 2 to the water outlet 3 in the reaction tank 1 is the water flow direction. The water quality detection device is used to detect the chromium ion concentration in the water body. The flow channel width direction perpendicular to the direction from the water inlet to the water outlet is set as the water flow direction.

[0032] The electrolysis adsorption module includes an adjustment component and an electrolysis reaction module. The adjustment component includes a sliding water baffle 7, two fixed water baffles 4 and two mutually parallel first and second connecting members 5 and 6. The two fixed water baffles 4 are fixed at intervals in the middle of one of the side walls of the reaction tank 1. The sliding water baffle 7 is arranged between the two fixed water baffles 4, and constitutes a sliding pair whose sliding direction is perpendicular to the direction of water flow. The bottom edges of the sliding water baffle 7 and the fixed water baffle 4 are both in contact with the reaction tank 1, which can block the water flow from passing through the sliding water baffle 7 and the fixed water baffle 4. The position where the fixed water baffle and the sliding water baffle are located is the blocking area; the area between the sliding water baffle and the other side wall of the reaction tank is the flow area; by adjusting the position of the sliding water baffle, the width of the flow area can be changed, and then the flow size of the reaction tank can be changed under the same hydraulic retention time.

[0033] The first connector 5 and the second connector 6 are arranged at intervals along the width direction of the flow channel; the first connector 5 is fixedly connected to the side wall of the reaction tank 1 without the fixed water baffle 4; the second connector 6 is fixed to the outer edge of the sliding water baffle 7. The electrolytic reaction module is installed between the two connectors. The sliding water baffle 7 is used to provide support force in the direction of the water flow to the second connector 6 when it slides, so as to prevent the second connector 6 from shaking due to the impact of the water flow.

[0034] The electrolytic reaction module includes a slide rail, an X-shaped telescopic unit 10, a driving mechanism, a plurality of anode plates 8 and a plurality of cathode plates 9, and a telescopic frame installed on the positive and negative plates 9. The slide rail is fixedly arranged in the reaction tank 1 along the width direction of the flow channel, and the anode plates 8 and the cathode plates 9 are alternately arranged on the slide rail, and the anode plates 8 and the cathode plates 9 are arranged at intervals. The anode plates 8 and the cathode plates 9 are both slidably connected to the slide rail. Iron plates are fixed on both sides of the anode plate 8. Two connecting pieces are fixedly connected to an anode plate 8 and a cathode plate 9 respectively. The iron plate is used to provide divalent iron ions in the electrolytic reaction.

[0035] The X-shaped telescopic unit 10 is arranged between any two electrode plates. The X-shaped telescopic unit 10 comprises two cross-hinged driving rods, an aeration pipe 12 and two scrapers 11. One end of the two driving rods is rotatably connected to the corresponding two electrode plates. The other ends of the two driving rods are slidably connected to the two electrode plates.

[0036] The driving mechanism includes a mounting plate 16, a transmission member 17, two pins, and a hydraulic cylinder 18 fixedly mounted on the mounting plate 16. The mounting plate 16 is fixedly mounted on the side wall of the reaction tank 1 and is on the same side wall as the first connecting member 5. The two pins are respectively fixedly connected to the sliding ends of the two driving rods. The transmission member 17 is fixedly connected to the output shaft of the hydraulic cylinder 18. The transmission member 17 is provided with a first slide groove, and the two pins are both extended into the first slide groove. By pushing the moving ends of the two driving rods in one of the X-type telescopic units 10 to move, the principle of the scissor structure having an amplified stroke is utilized to make each X-type telescopic unit 10 move synchronously, thereby gradually changing the distance between the anode plate 8 and the cathode plate 9 in each electrode plate group, thereby achieving the purpose of changing the electric field strength.

[0037] A slider 19 is fixed on the displacement end of the driving rod. The slider 19 is in an inverted U shape. Two scrapers 11 are fixed on both ends of the slider 19. The scrapers 11 are used to remove dirt attached to the two sides of the electrode plate. The aeration pipe 12 is fixed on the lower surface of a driving rod. The flocculent precipitate produced by the reaction is floated by the gas output from the aeration pipe 12; it does not affect the reaction of other heavy metal ions, thereby improving the overall reaction efficiency.

[0038] Working principle of the present invention: The industrial wastewater containing chromium ions is fed into the reaction tank from the water inlet. The anode plate and the cathode plate are energized. After the energization, Fe 2+ , Fe 2+ The hexavalent chromium is reduced to trivalent chromium. Hydrogen is released on the cathode to perform a reduction reaction. The reaction formula is as follows:

[0039] The reaction at the anode is: Fe-2e - →Fe 2+ Fe 2＋ The ions then undergo the following surface transformation reactions Cr2O7 2- +6Fe 2+ +14H + →2Cr 3+ +6Fe 3+ +7H2O CrO4 2- +3Fe 2+ +8H+ →Cr 3+ +3Fe 3+ +4H2O When the anode is passivated, H2O discharge will occur to release oxygen 2H2O-4e - =O2+4H + Cathode reaction: 2H + +2e - →H2↑ Cr2O7 2+ +6e - +14H + →2Cr 3+ +7H2O CrO4 2- +3e - +8H + →Cr 3+ +4H2O The amount of hexavalent chromium directly reduced in the cathode area is very small, only 4% in the anode area. It is mainly the ferrous ions dissolved on the anode that reduce the hexavalent chromium. As the electrolysis reaction proceeds, the hydrogen ions in the sewage are continuously consumed and the pH value continues to rise. When the pH value is >5, chromium hydroxide, ferrous oxide and ferric hydroxide are precipitated.

[0040] Cr 3+ +3OH - →Cr(OH)3↓ Fe 2+ +2OH - →Fe(OH)2↓ Fe 3+ +3OH - →Fe(OH)3↓ When the reaction produces precipitation, the aeration pipe 12 is started; the gas output from the aeration pipe 12 floats the flocculent precipitation produced by the reaction; it does not affect the reaction of the remaining metal chromium ions, thereby improving the reaction efficiency. At the same time, the gas output from the aeration pipe 12 will stir the wastewater, so that the metal chromium ions flowing between the two electrode plates contact and react with the iron plate, and the reaction is more complete.

[0041] When the concentration of hexavalent chromium ions in the wastewater increases, the electric telescopic rod is started, and the output shaft of the hydraulic cylinder 18 pushes the transmission member 17 to move. During the movement of the transmission member 17, the two pins will be driven to slide in the first slide groove. The two drive rod displacement ends in the reference module are moved by the two pins, and the scissor structure has the principle of amplifying the stroke, so that the telescopic frame moves synchronously as a whole, thereby gradually reducing the distance between the anode plate 8 and the cathode plate 9 in each electrode plate group, so that the electric field strength between the anode plate 8 and the cathode plate 9 is enhanced, and the attraction to the metal chromium ions is increased. Thereby, the metal chromium ions in the sewage react more fully.

[0042] During the dynamic adjustment of the plate spacing, the wastewater input flow Q of the reaction tank 1 is dynamically adjusted according to the following relationship: Q=v0·H·L Wherein, v0 is the wastewater flow rate; H is the height difference between the outlet (3) and the bottom of the reaction tank (1); L is the width of the flow area of ​​the reaction tank (1) at the electrolytic adsorption module; so that the wastewater flow rate v0 remains unchanged in the flow area during the entire treatment process.

[0043] Example 2 A dynamic plate density electrochemical water treatment device, the difference between this embodiment and embodiment 1 is that the multiple aeration tubes 12 in the electrolytic reaction module are replaced by a stirring module. The stirring module includes a support beam 13, a stirring rod 14, a rotating shaft, a sliding motor seat, and a stirring drive motor 15 fixedly connected to the sliding motor seat. The two ends of the support beam 13 are respectively fixedly connected to two connecting pieces, and a second slide groove is provided on the support beam 13, and the sliding motor seat is slidably arranged in the second slide groove. The rotating shaft passes through the hinge points of the two driving rods, and the two ends of the rotating shaft are respectively fixedly connected to the stirring rod 14 and the output shaft of the stirring drive motor 15. The stirring rod 14 is driven to move by the stirring drive motor 15 to stir the liquid flowing through, so that the laminar flow formed when the liquid flows naturally will be eliminated, thereby avoiding the uneven reaction of the iron sheet on the stirring drive motor 15 plate.

Claims

1. A dynamic plate density electrochemical water treatment device, comprising a reaction tank (1) and an electrolysis adsorption module, characterized in that: The reaction pool (1) is provided with a water inlet (2) and a water outlet (3) at both ends thereof; the electrolytic adsorption module is installed in the reaction pool (1) and is located between the water inlet (2) and the water outlet (3); The electrolysis adsorption module comprises an adjustment component and an electrolysis reaction module; the adjustment component comprises a fixed water baffle plate (4), a sliding water baffle plate (7), a first connecting member (5) and a second connecting member (6); the fixed water baffle plate (4) is fixed to the middle part of one of the side walls of the reaction tank (1); the sliding water baffle plate (7) and the fixed water baffle plate (4) form a sliding pair that slides along the width direction of the flow channel; The first connecting member (5) is fixed on the other side wall; the second connecting member (6) is fixed on the sliding water retaining plate (7); the first connecting member (5) and the second connecting member (6) are opposite to each other; the electrolytic reaction module is installed between the first connecting member (5) and the second connecting member (6); The electrolytic reaction module comprises a plurality of electrode plates, an X-shaped telescopic unit (10) and a driving mechanism; the plurality of electrode plates are arranged in sequence along the width direction of the flow channel; each electrode plate and the bottom surface of the reaction tank (1) form a sliding pair that slides along the width direction of the flow channel; each electrode plate is slidably connected to a slider; the electrode plates arranged at both ends are fixed to a first connecting member (5) and a second connecting member (6) respectively; An X-shaped telescopic unit (10) is provided between any two adjacent electrode plates; the X-shaped telescopic unit (10) comprises two driving rods; the middle parts of the two driving rods constitute a rotation pair; one end of the two driving rods and the corresponding two electrode plates respectively constitute a rotation pair; the other ends of the two driving rods and the sliders on the corresponding two electrode plates respectively constitute a rotation pair; the driving mechanism is used to drive two adjacent electrode plates to move closer to each other or farther away from each other.

2. A dynamic plate density electrochemical water treatment device according to claim 1, characterized in that: All the electrode plates are arranged vertically; the slider is slidably connected to the top edge of the electrode plate.

3. A dynamic plate density electrochemical water treatment device according to claim 1, characterized in that: The driving mechanism comprises a transmission member (17), a hydraulic cylinder (18) and two pins; the driving mechanism corresponds to two adjacent electrode plates; the two pins are respectively fixed to the two electrode plates corresponding to the driving mechanism; a first slide groove is provided on the transmission member (17); the two pins are slidably connected in the first slide groove; the hydraulic cylinder (18) is fixed to the reaction pool (1); and the transmission member (17) is fixed to an output push rod of the hydraulic cylinder (18).

4. The dynamic plate density electrochemical water treatment device according to claim 1, characterized in that: Two scrapers (11) are fixed on the sliding block; the two scrapers (11) respectively abut against two side surfaces of the electrode plate.

5. The dynamic plate density electrochemical water treatment device according to claim 1, characterized in that: Each X-shaped telescopic unit (10) corresponds to an aeration tube (12); the middle parts of two driving rods in the same X-shaped telescopic unit (10) are hinged via a hollow pin shaft; the bottom opening of the hollow pin shaft is fixed to the air inlet at the top end of the aeration tube (12); and the air inlet at the top end of each hollow pin shaft is connected to an air source.

6. The dynamic plate density electrochemical water treatment device according to claim 1, characterized in that: Each electrode plate is divided into a plurality of anode plates (8) and a plurality of cathode plates (9) which are arranged alternately in sequence; the anode plates (8) are all connected to the positive electrode interface of the power supply; and the cathode plates (9) are all connected to the negative electrode interface of the power supply.

7. The dynamic plate density electrochemical water treatment device according to claim 1, characterized in that: The water inlet (2) of the reaction tank (1) is provided with a water quality detection device.

8. The dynamic plate density electrochemical water treatment device according to claim 1, characterized in that: The electrolytic reaction module further comprises a support beam (13) and a plurality of stirring modules corresponding to the X-shaped telescopic units (10); the middle parts of the two driving rods in the same X-shaped telescopic unit (10) are hinged by a pin; the two ends of the support beam (13) and the two sides of the top of the reaction tank (1) respectively form a sliding pair that slides along the water flow direction; the stirring module comprises a sliding motor seat, a stirring rod (14), a rotating shaft and a stirring drive motor (15); the sliding motor seat is slidably connected to the support beam (13); the sliding motor seat is fixed to the sliding motor seat, and the output shaft is fixed to the top end of the pin; the bottom end of the pin is fixed to the top end of the vertically arranged stirring rod (14).

9. A method for treating chromium-containing wastewater, characterized in that: A dynamic plate density electrochemical water treatment device as claimed in claim 1 is used; the chromium-containing wastewater treatment method has the following process: the electrode plates in the electrolytic reaction module are energized; wastewater containing hexavalent chromium ions is input into the reaction tank (1) from the water inlet (2); an electrochemical reaction occurs when the wastewater passes through the electrolytic reaction module, generating chromium-containing precipitates; Continuously detecting the chromium ion concentration in the input wastewater, and dynamically adjusting the distance between adjacent electrode plates in the electrolytic adsorption module and the wastewater input flow rate of the reaction tank (1) according to the chromium ion concentration; The greater the chromium ion concentration, the smaller the spacing between the electrode plates in the electrolytic adsorption module, the smaller the width of the flow area of ​​the reaction tank (1) at the electrolytic adsorption module, and the smaller the wastewater input flow rate of the reaction tank (1).

10. A method for treating chromium-containing wastewater according to claim 9, characterized in that: The wastewater input flow rate Q of the reaction tank (1) is v0·H·L; v0 is the wastewater flow rate in the flow area; H is the height difference between the outlet (3) and the bottom of the reaction tank (1); L is the width of the flow area of ​​the reaction tank (1) at the electrolytic adsorption module; the wastewater flow rate v0 in the flow area remains unchanged during the entire treatment process.

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