CN115010320A

CN115010320A - high-COD wastewater treatment method and treatment device

Info

Publication number: CN115010320A
Application number: CN202210691828.0A
Authority: CN
Inventors: 李阳; 王建庆
Original assignee: Chongqing Manyi Environmental Protection Technology Co ltd
Current assignee: Chongqing Manyi Environmental Protection Technology Co ltd
Priority date: 2022-07-29
Filing date: 2022-07-29
Publication date: 2022-09-06

Abstract

The invention discloses a high COD wastewater treatment method, which comprises the following four steps: the device for implementing the method comprises a sludge pool, an anaerobic pool, an electrocatalytic oxidation, a clean water pool and an aerobic pool, wherein one end of the sludge pool is connected with a sludge pump, and the output end of the sludge pump is provided with a sludge discharge box; sewage is through coagulating sedimentation in proper order, indisputable carbon micro-electrolysis is handled, biochemical treatment and electrocatalytic oxidation treatment, can make sewage at physics through the pH value regulation to sewage in the processing procedure, chemistry, the processing speed increases in the biological treatment process, the equipment that is used for the method simultaneously is centralized distribution, the transport of the sewage of being convenient for, simultaneously at physics, chemistry, biological treatment pond bottom installs row's mud case structure additional, physics, chemistry, the biological treatment pond is when carrying out silt clearance, row's mud incasement portion drives the squeeze roll and extrudees silt, avoid the bottom of the pool foreign matter to block up the sludge pump, the user of being convenient for clears up pond mud.

Description

high-COD wastewater treatment method and treatment device

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a high-COD wastewater treatment method and a high-COD wastewater treatment device.

Background

When the sewage treatment plant carries out sewage treatment, all indexes in the sewage treatment tank need to be detected all the time, so that parameters such as sludge concentration, medicament adding amount and the like can be effectively adjusted according to the indexes in the sewage treatment tank in real time, and therefore energy conservation and emission reduction of the sewage treatment are achieved.

The sewage treatment method can be roughly divided into three types, namely physical treatment, chemical treatment and biological treatment: the physical sewage treatment method separates solid substances, suspended substances and the like in the sewage through a sedimentation tank; the chemical sewage treatment method uses a method of adding chemical agents to remove suspended particles, organic substances, metal ions and the like in water; the biological sewage treatment method mainly decomposes organic substances in the sewage by means of microorganisms;

the existing physical, chemical and biological treatment methods have corresponding known defects, and the physical sewage treatment cannot decompose organic substances in the sewage; the chemical sewage is poor in reactivity to small molecular organic substances after being treated; the biological treatment has high requirement on environment and operation time.

The single sewage treatment mode is not suitable for the relatively complicated industrial sewage treatment that discharges, and when the sewage treatment mode of adoption combined type, the sewage carries out the order of physics nature, chemistry and biological nature and processing time and all can influence sewage treatment's effect, consequently how to improve waste water COD clearance and reduce the waste water treatment time, makes sewage COD reach discharge standard and is very important to waste water treatment.

Disclosure of Invention

The invention aims to provide a high-COD wastewater treatment method and a high-COD wastewater treatment device, so as to solve the problems in the background technology.

A high COD wastewater treatment method comprises the following four steps:

the method comprises the following steps: coagulating sedimentation, namely injecting the wastewater into a primary sedimentation tank, adding sodium sulfide, sodium carbonate, PAC, PAM and a heavy metal trapping agent into the primary sedimentation tank, pretreating, and standing for 12 hours;

step two: performing iron-carbon micro-electrolysis treatment, namely allowing the wastewater after standing in the primary sedimentation tank to flow into an intermediate water tank, adding industrial hydrochloric acid into the intermediate water tank, injecting the solution in the intermediate water tank into an iron-carbon micro-electrolysis treatment tank, adjusting the pH value to 1.5-2.4, and standing for 2 hours;

step three: the biochemical treatment is carried out on the mixture,

a. conveying the waste liquid after standing in the intermediate water tank into a secondary sedimentation tank through a water pump, adding sodium hydroxide into the secondary sedimentation tank to adjust the pH value of the waste water to be between 8 and 9, then adding a PAC and PAM flocculating agent, stirring through stirring equipment, and standing for 12 hours after stirring;

b. pumping the waste liquid after standing in the anaerobic tank into the aerobic tank for aeration treatment, wherein the gas-water ratio is controlled at 10:1, and the waste liquid stays in the aerobic tank for 24 hours;

c. pumping the waste liquid after standing in the secondary sedimentation tank into an anaerobic tank for standing for 48 hours;

step four: and (3) performing electrocatalytic oxidation, namely introducing the waste liquid treated in the aerobic tank into the electrocatalytic oxidation, wherein the distance between electrode plates in the electrocatalytic oxidation is controlled to be 5-10cm, and the operating voltage is controlled to be 10-15V.

Preferably, the high COD wastewater treatment device comprises two groups of comprehensive reaction tanks; a comprehensive equipment room is arranged between the two groups of comprehensive reaction tanks, a dosing workshop and a sludge dewatering workshop are respectively arranged on the other two sides of the comprehensive equipment room, a water unloading tank is arranged below the comprehensive reaction tank on one side of the comprehensive equipment room, an accident tank is arranged on one side of the water unloading tank, and a waste gas centralized treatment device is arranged on one side of the accident tank;

the comprehensive reaction tank comprises an oil separation tank, a primary sedimentation tank, an adjusting tank, an intermediate water tank, a secondary sedimentation tank, a sludge tank, an anaerobic tank, an electrocatalytic oxidation tank, a clean water tank and an aerobic tank, wastewater sequentially flows through the oil separation tank, the adjusting tank, the primary sedimentation tank, the intermediate water tank, the secondary sedimentation tank, the aerobic tank, the anaerobic tank, the electrocatalytic oxidation tank and the clean water tank, six groups of sewage discharge pipes are arranged on the side wall of the sludge tank, one end of each sewage discharge pipe, which is far away from the sludge tank, is connected with a sludge pump, the output end of the sludge pump is provided with a valve, the top of the valve is provided with a sludge discharge box, two groups of squeeze rollers are rotatably arranged in the sludge discharge box, and the periphery of the extrusion roller is provided with a plurality of extrusion teeth, and the six groups of sludge discharge boxes are respectively communicated with the bottoms of the primary sedimentation tank, the middle water tank, the secondary sedimentation tank, the anaerobic tank, the electrocatalytic oxidation tank and the aerobic tank at the ends far away from the valve.

Preferably, after the wastewater in the primary sedimentation tank is precipitated, the upper clear water enters the middle water tank through an automatic overflow mode, the iron-carbon micro-electrolysis treatment tank needs to be filled with high-temperature sintered iron-carbon filler, the consumed iron-carbon filler is added periodically, and the addition amount is about-ton per month.

Preferably, an electrode plate is required to be installed inside the aerobic tank, the electrode plate is a metal oxide doped titanium-based dual-function electrode, one surface of the electrode is a multi-element metal oxide electrocatalytic anode surface added with rare earth metal, and the other surface of the electrode is a cathode surface.

Preferably, one side of second grade sedimentation tank bottom is equipped with the sludge impoundment, a through-hole has been seted up to the bottom of sludge impoundment and has been linked together with row's mud case, second grade sedimentation tank bottom is provided with the ground, one side that the ground is located row mud case is equipped with the sludge pump installing port. Preferably, a gear box is installed on one side of the sludge discharge box, the supporting shafts of the two groups of squeeze rollers extend to the inside of the gear box, transmission gears are installed outside the two groups of squeezing roller supporting shafts inside the gear box, and the two transmission gears are meshed with each other.

Preferably, a motor is installed on one side, away from the sludge discharge box, of the gear box, an output end of the motor extends to the inside of the gear box, a motor gear is installed inside the gear box, and the motor gear is meshed with one of the transmission gears.

Preferably, each water pool in the comprehensive reaction pool is provided with a pipeline which is communicated with the accident pool, and a water pump structure is arranged between the pipelines.

Preferably, set up the switch board between the comprehensive equipment to adopt PLC control system to carry out feedback control to water pump, motor and the corollary equipment of using in the device, inside placing industrial hydrochloric acid, sodium sulfide, sodium carbonate, PAC, PAM, the heavy metal trapping agent of dosing workshop, inside the sludge dewatering workshop possesses sludge dewatering equipment.

The invention has the beneficial effects that: sewage is in proper order through coagulating sedimentation, indisputable carbon micro-electrolysis is handled, biochemical treatment and electrocatalytic oxidation treatment, four process flows, can make sewage at physics through the pH value regulation to sewage in the course of the treatment, chemistry, the processing speed increases in the biological treatment process, the equipment that is used for the method simultaneously is centralized distribution, the transport of the sewage of being convenient for, simultaneously at physics, chemistry, biological treatment pond bottom installs row's mud case structure additional, physics, chemistry, biological treatment pond when carrying out silt clearance, row's mud incasement portion drives the squeeze roll and extrudees silt, avoid the bottom of the pool foreign matter to block up the sludge pump, the user of being convenient for clears up pond mud.

Drawings

FIG. 1 is a schematic flow diagram of the present invention;

FIG. 2 is a schematic plan view of the present invention;

FIG. 3 is a schematic partially cut-away view of a secondary sedimentation tank of the present invention;

FIG. 4 is a schematic view of a portion of a sludge pump of the present invention;

FIG. 5 is a schematic view of the inside of the sludge discharge box of the present invention;

fig. 6 is a partial schematic view of an extrusion roll of the present invention.

In the figure: 1. a comprehensive reaction tank; 2. a comprehensive equipment room; 3. a dosing workshop; 4. a sludge dewatering plant; 5. an oil separation tank; 6. a first-stage sedimentation tank; 7. a regulating tank; 8. a middle water tank; 9. a secondary sedimentation tank; 901. a sludge tank; 902. a sludge pump mounting port; 903. a foundation; 10. a sludge tank; 11. an anaerobic tank; 12. an electrocatalytic oxidation tank; 13. a clean water tank; 14. an aerobic tank; 15. a waste gas centralized treatment device; 16. an accident pool; 17. a water discharge tank; 18. a sludge discharge box; 1801. a squeeze roll; 1802. a transmission gear; 1803. extruding teeth; 19. a gear case; 1901. a motor gear; 20. a motor; 21. a valve; 22. a sludge pump; 2201. a sewage discharge pipe.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1-6, the present invention provides an embodiment: the high COD wastewater treatment method comprises the following four steps:

specifically, the wastewater after homogenizing and uniform quantity adjustment is lifted to enter a primary sedimentation tank, PAC and PAM flocculants are added, the wastewater is slowly stirred by a stirrer to enable suspended matters, colloid and emulsified oil in the wastewater to form floccules, sodium carbonate is added to remove the total hardness of Ca2+, Mg2+ and the like in the wastewater, sodium sulfate and Ba2+ in the wastewater are added to form barium sulfate sediment, and the wastewater is kept still for 12 hours to enable the generated floccules and barium sulfate to be completely precipitated.

Step two: performing iron-carbon micro-electrolysis treatment, namely allowing the wastewater after standing in the primary sedimentation tank to flow into an intermediate water tank, adding industrial hydrochloric acid into the intermediate water tank, conveying the solution in the intermediate water tank into an iron-carbon micro-electrolysis treatment tank, adjusting the pH value to 1.5-2.4, and standing for 2 hours;

specifically, the iron-carbon micro-electrolysis treatment tank is configured by a 4-way skid, the size of the iron-carbon micro-electrolysis treatment tank is 3 meters in diameter and 3.5 meters in height, an adjustable aeration device is additionally arranged in the iron-carbon micro-electrolysis treatment tank, an integrated high-temperature iron-carbon sintered filler is placed in the iron-carbon micro-electrolysis treatment tank, organic pollutants in sewage are removed through the advanced oxidation treatment effect of a Fe/C primary battery, and iron and ferrous ions in the sewage are reserved under the acidic condition that the pH value is 1.5-2.5.

Step three: the biochemical treatment is carried out on the mixture,

specifically, sodium hydroxide is used for adjusting the pH value of the wastewater to 8-9, then PAC and PAM flocculating agents are added, the mixture is slowly stirred by a stirrer, and flocculating agents formed by iron ions, ferrous ions and the flocculating agents are settled by gravity under the alkaline condition;

specifically, aerobic microorganisms are arranged inside the aerobic tank, the aerobic microorganisms thoroughly decompose organic matters to release CO2, the goal of removing BOD is achieved, meanwhile, nitrifying bacteria and organic ammonia are arranged inside the aerobic tank, and ammonia nitrogen in the wastewater is converted into nitrate or nitrite through biological nitrification.

specifically, anaerobic bacteria are arranged in the anaerobic tank, and convert nitrate or nitrite in the wastewater into nitrogen through nitrification and denitrification and discharge the nitrogen to the atmosphere, so that the aim of denitrification is fulfilled.

Step four: performing electrocatalytic oxidation, namely introducing the waste liquid treated in the aerobic tank into the electrocatalytic oxidation tank, wherein the distance between electrode plates in the electrocatalytic oxidation is controlled to be 5-10cm, and the operating voltage is controlled to be 10-15V;

specifically, a plurality of double electrode plates are arranged in the electrocatalytic oxidation tank through a support frame structure, and one side of each electrode plate is an anode, so that the electrocatalytic oxidation tank has a high-grade electrocatalytic oxidation activity function and can degrade and mineralize organic matters; the other side is an electrocatalytic cathode surface which has the function of electrochemical reduction activity and can remove heavy metal ions by electrodeposition.

The high COD wastewater treatment device for implementing the method comprises two groups of comprehensive reaction tanks 1; a comprehensive equipment room 2 is arranged between the two groups of comprehensive reaction tanks 1, the other two sides of the comprehensive equipment room 2 are respectively provided with a dosing workshop 3 and a sludge dewatering workshop 4, a water unloading tank 17 is arranged below the comprehensive reaction tank 1 at one side of the comprehensive equipment room 2, an accident pool 16 is arranged at one side of the water unloading tank 17, and a waste gas centralized treatment device 15 is arranged at one side of the accident pool 16;

the comprehensive reaction tank 1 comprises an oil separation tank 5, a primary sedimentation tank 6, an adjusting tank 7, an intermediate water tank 8, a secondary sedimentation tank 9, a sludge tank 10, an anaerobic tank 11, an electrocatalytic oxidation tank 12, a clean water tank 13 and an aerobic tank 14, wastewater sequentially flows through the oil separation tank 5, the adjusting tank 7, the primary sedimentation tank 6, the intermediate water tank 8, the secondary sedimentation tank 9, the aerobic tank 14, the anaerobic tank 11, the electrocatalytic oxidation tank 12 and the clean water tank 13, six groups of blow-off pipes 2201 are mounted on the side wall of the sludge tank 10, one ends of the blow-off pipes 2201 far away from the sludge tank 10 are connected with a sludge pump 22, a valve 21 is mounted at the output end of the sludge pump 22, a sludge discharge box 18 is mounted at the top of the valve 21, two groups of extrusion rollers 1801 are rotatably mounted inside the sludge discharge box 18, a plurality of extrusion teeth 1803 are arranged on the periphery of the extrusion rollers 1801, and one ends of the six groups of the sludge discharge box 18 far away from the valve 21 are respectively connected with the primary sedimentation tank 6, the intermediate water tank 8, the secondary sedimentation tank 8, the adjustment tank 7, the adjustment tank 10, the adjustment tank and the adjustment tank, the adjustment tank 6, The bottoms of the secondary sedimentation tank 9, the anaerobic tank 11, the electrocatalytic oxidation tank 12 and the aerobic tank 14 are communicated with each other.

Specifically, two groups of comprehensive reaction tanks 1 are symmetrically distributed at two sides of a comprehensive equipment room 2, a dosing workshop 3 and a sludge dewatering workshop 4, the two groups of comprehensive reaction tanks 1 can alternately work to facilitate maintenance personnel to clean all the tanks in the comprehensive reaction tanks 1, an oil separation tank 5, a primary sedimentation tank 6, an adjusting tank 7, a middle tank 8, a secondary sedimentation tank 9, a sludge tank 10, an anaerobic tank 11, an electrocatalytic oxidation tank 12, a clean water tank 13 and an aerobic tank 14 are formed by pouring concrete, the tanks are communicated with each other according to a wastewater treatment process and are provided with two groups of water pumps at positions needing to be lifted for water supply, one of the water pumps is a spare water pump, the bottoms of the tanks are provided with sludge grooves 901 which are in the same direction as the secondary sedimentation tank 9, the oil separation tank 5 floats on the top of water by utilizing the principle of different oil-water densities, the oil is pumped from the bottom of the oil separation tank 5 to enter the adjusting tank 7 to separate the oil in the wastewater, the adjusting tank 7 is convenient for a user to carry out homogenization and uniform amount adjustment on the wastewater and then inject the wastewater into a subsequent treatment tank;

one-level sedimentation tank 6, middle pond 8, second grade sedimentation tank 9, anaerobism pond 11, electrocatalytic oxidation pond 12 and good oxygen pond 14 are settling a large amount of mud to sewage treatment in-process bottom, debris such as flocculation thing, to mud, when debris such as flocculation thing are cleared up, open the valve 21 that each pond corresponds and make sludge pump 22's input, arrange the inside sedimentary silt of mud case 18 promptly and be discharged into sludge tank 10 by sludge pump 22 suction, at mud suction in-process starter motor 20, motor 20 passes through two sets of squeeze rollers 1801 of gear engagement transmission, the outside extrusion tooth 1803 of two sets of squeeze rollers 1801 can extrude the breakage with the debris that add greatly in the mud, prevent that great debris from entering into sludge pump 22 inside, avoid sludge pump 22 to be blockked up by the foreign matter.

Further, after the wastewater in the first-stage sedimentation tank 6 is sedimentated, the upper clear water enters the middle water tank 8 through an automatic overflow mode, high-temperature sintered iron-carbon filler needs to be filled in the iron-carbon micro-electrolysis treatment tank, the consumed iron-carbon filler is added periodically, and the addition amount is supplemented by about 2-3 tons every month.

Specifically, possess the difference in height between one-level sedimentation tank 6 and the middle pond 8, one-level sedimentation tank 6 is higher than middle pond 8 promptly, and 6 inside waste water of one-level sedimentation tank can get into overflow to middle pond 8 inside through depositing back top clear water part, avoids sucking through the water pump and supplies water in-process 6 bottoms sediments of one-level sedimentation tank and is carried inside middle pond 8.

Furthermore, an electrode plate is required to be installed inside the aerobic tank 14, the electrode plate is a metal oxide doped titanium-based dual-function electrode, one surface of the electrode is a multi-element metal oxide electrocatalytic anode surface added with rare earth metal, and the other surface of the electrode is a cathode surface.

Specifically, a plurality of electrode plates are arranged inside the aerobic tank 14 in a grid manner by using a steel frame.

Further, a sludge groove 901 is formed in one side of the bottom of the secondary sedimentation tank 9, a through hole is formed in the bottom end of the sludge groove 901 and communicated with the sludge discharge box 18, a foundation 903 is arranged at the bottom of the secondary sedimentation tank 9, and a sludge pump mounting opening 902 is formed in one side, located on the sludge discharge box 18, of the foundation 903; a gear box 19 is arranged on one side of the sludge discharge box 18, the supporting shafts of the two groups of squeezing rollers 1801 extend to the interior of the gear box 19, transmission gears 1802 are arranged outside the supporting shafts of the two groups of squeezing rollers 1801 in the gear box 19, and the two transmission gears 1802 are meshed with each other;

the side of the gear box 19 far away from the mud discharging box 18 is provided with a motor 20, the output end of the motor 20 extends to the inside of the gear box 19 and is provided with a motor gear 1901, and the motor gear 1901 is meshed with one of the transmission gears 1802.

Specifically, sludge tank 901 sets up in one side of second grade sedimentation tank 9 bottom, when carrying out the mud clearance, the user passes through the mud of scraper blade with second grade sedimentation tank 9 bottom and scrapes to one side of sludge tank 901, it is open structure to arrange mud case 18 top, mud directly enters into row mud case 18 inside, when motor 20 starts, can drive motor gear 1901 and rotate, motor gear 1901 can mesh rather than one of them drive gear 1802, then two sets of drive gear 1802 intermeshing, make two sets of squeeze rollers 1801 be opposite rotary motion, can be torn by extrusion tooth 1803 when large-scale filth enters into two sets of squeeze rollers 1801 inside, avoid inside large-scale filth enters into sludge pump 22, make sludge pump 22 block up.

Further, each pool in the comprehensive reaction tank 1 is provided with a pipeline which is communicated with the accident pool 16, and a water pump structure is arranged between the pipelines.

Specifically, the accident pool 16 is a middle buffer storage pool of the equipment, and when the sewage treatment process is unqualified or has misoperation, the sewage can be discharged into the accident pool 16 for buffer storage.

Further, synthesize the equipment room 2 and set up the switch board to adopt PLC control system to carry out feedback control to water pump, motor and corollary equipment of using in the device, add that 3 inside places industrial hydrochloric acid, sodium sulfide, sodium carbonate, PAC, PAM, heavy metal trapping agent in the workshop, 4 inside sludge dewatering equipment that possess in the sludge dewatering workshop.

Specifically, the comprehensive equipment room 2, the dosing workshop 3 and the sludge dewatering workshop 4 are auxiliary workshops equipped for sewage treatment equipment.

In summary, the following steps: a method for treating high-COD wastewater,

coagulating sedimentation, removing suspended matters, colloid and emulsified oil in the wastewater by gravity dust settling to form floccules, adding sodium carbonate to remove the total hardness of Ca2+, Mg2+ and the like in the wastewater, adding sodium sulfate and Ba2+ in the wastewater to form barium sulfate sediment, and standing for 12 hours to completely precipitate the generated floccules and the barium sulfate;

performing iron-carbon micro-electrolysis treatment, namely removing organic pollutants in the sewage through the advanced oxidation treatment effect of a Fe/C primary battery, and performing biochemical treatment;

biochemical treatment, wherein aerobic microorganisms decompose organic matters in the wastewater, nitrifying bacteria and organic ammonia convert ammonia nitrogen in the wastewater into nitrate or nitrite through biological nitrification, and anaerobic bacteria convert the nitrate or nitrite in the wastewater into nitrogen through nitrification and denitrification and discharge the nitrogen into the atmosphere;

the electrocatalytic oxidation leads organic matters in the wastewater to be degraded, mineralized and removed by heavy metal ion electrodeposition.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. A high COD wastewater treatment method comprises a primary sedimentation tank (6), an intermediate water tank (8), a secondary sedimentation tank (9), an anaerobic tank (11), an aerobic tank (14) and an electrocatalytic oxidation tank (12); the method is characterized in that: the method comprises the following four steps:

the method comprises the following steps: coagulating sedimentation, namely injecting the wastewater into a primary sedimentation tank (6), adding sodium sulfide, sodium carbonate, PAC, PAM and heavy metal trapping agent into the primary sedimentation tank (6), pretreating, and standing for 12 hours;

step two: performing iron-carbon micro-electrolysis treatment, namely enabling the wastewater after standing in the primary sedimentation tank (6) to flow into an intermediate water tank (8), adding industrial hydrochloric acid into the intermediate water tank (8), injecting the solution in the intermediate water tank (8) into an iron-carbon micro-electrolysis treatment tank, adjusting the pH value to be 1.5-2.4, and standing for 2 hours;

step three: the biochemical treatment is carried out on the mixture,

conveying the waste liquid after standing in the intermediate water tank (8) to the interior of a secondary sedimentation tank (9) through a water pump, adding sodium hydroxide into the secondary sedimentation tank (9) to adjust the pH value of the waste water to be between 8 and 9, then adding a PAC and PAM flocculating agent, stirring through stirring equipment, and standing for 12 hours after stirring;

step four: and (3) performing electrocatalytic oxidation, namely introducing the waste liquid treated in the aerobic tank (14) into the electrocatalytic oxidation tank (12), controlling the distance between electrode plates in the electrocatalytic oxidation tank (12) to be 5-10cm, and controlling the operating voltage to be 10-15V.

2. A high COD wastewater treatment device comprises two groups of comprehensive reaction tanks (1); the method is characterized in that: a comprehensive equipment room (2) is arranged between the two groups of comprehensive reaction tanks (1), the other two sides of the comprehensive equipment room (2) are respectively provided with a dosing workshop (3) and a sludge dewatering workshop (4), a water unloading tank (17) is arranged below the comprehensive reaction tank (1) at one side of the comprehensive equipment room (2), an accident tank (16) is arranged at one side of the water unloading tank (17), and a waste gas centralized treatment device (15) is arranged at one side of the accident tank (16);

the comprehensive reaction tank (1) comprises an oil separation tank (5), a primary sedimentation tank (6), an adjusting tank (7), a middle water tank (8), a secondary sedimentation tank (9), a sludge tank (10), an anaerobic tank (11), an electrocatalytic oxidation tank (12), a clean water tank (13) and an aerobic tank (14), wastewater sequentially flows through the oil separation tank (5), the adjusting tank (7), the primary sedimentation tank (6), the middle water tank (8), the secondary sedimentation tank (9), the aerobic tank (14), the anaerobic tank (11), the electrocatalytic oxidation tank (12) and the clean water tank (13), six groups of blow-off pipes (2201) are installed on the side wall of the sludge tank (10), one ends of the blow-off pipes (2201) far away from the sludge tank (10) are connected with a sludge pump (22), a valve (21) is installed at the output end of the sludge pump (22), and a sludge discharge tank (18) is installed at the top of the valve (21), the inside of mud discharging box (18) is rotated and is installed two sets of squeeze rolls (1801), and the periphery of squeeze roll (1801) is equipped with a plurality of extrusion teeth (1803), six groups the one end that valve (21) were kept away from in mud discharging box (18) communicates with the bottom of one-level sedimentation tank (6), middle pond (8), second grade sedimentation tank (9), anaerobism pond (11), electrocatalytic oxidation pond (12) and aerobic tank (14) each other respectively.

3. The high COD wastewater treatment device according to claim 2, characterized in that: after the wastewater in the primary sedimentation tank (6) is precipitated, the upper clear water enters the middle water tank (8) in an automatic overflow mode, high-temperature sintered iron-carbon fillers need to be filled in the iron-carbon micro-electrolysis treatment tank, the consumed iron-carbon fillers are added periodically, and the addition amount is supplemented by about 2-3 tons each month.

4. The high COD wastewater treatment device according to claim 2, characterized in that: an electrode plate is required to be installed inside the aerobic tank (14), the electrode plate is a metal oxide doped titanium-based dual-function electrode, one surface of the electrode is a multi-element metal oxide electrocatalytic anode surface added with rare earth metal, and the other surface of the electrode is a cathode surface.

5. The high COD wastewater treatment device according to claim 2, characterized in that: one side of the bottom of the secondary sedimentation tank (9) is provided with a sludge tank (901), the bottom of the sludge tank (901) is provided with a through hole communicated with the sludge discharge box (18), the bottom of the secondary sedimentation tank (9) is provided with a foundation (903), and one side of the foundation (903) positioned on the sludge discharge box (18) is provided with a sludge pump mounting opening (902).

6. The high COD wastewater treatment device according to claim 2, characterized in that: gear box (19) are installed to one side of row mud case (18), and two sets of the back shaft of squeeze roll (1801) extends to the inside of gear box (19), and the externally mounted of the inside two sets of back shafts of squeeze roll (1801) of gear box (19) has drive gear (1802), and two drive gear (1802) intermeshing.

7. The high COD wastewater treatment device of claim 6, wherein: the motor (20) is installed to one side of gear box (19) far away from mud discharging box (18), the output of motor (20) extends to the internally mounted of gear box (19) and is installed motor gear (1901), and motor gear (1901) and one of them drive gear (1802) meshing.

8. The high COD wastewater treatment device according to claim 2, characterized in that: synthesize inside each pond of reaction tank (1) and all possess pipeline and accident pond (16) intercommunication each other to possess the water pump structure between the pipeline.

9. The high COD wastewater treatment device according to claim 2, characterized in that: synthesize the plant room (2) and set up the switch board to adopt PLC control system to carry out feedback control to water pump, motor and corollary equipment of using in the device, add that industrial hydrochloric acid, sodium sulfide, sodium carbonate, PAC, PAM, heavy metal trapping agent are placed to medicine workshop (3) inside, sludge dewatering equipment is equipped with in sludge dewatering workshop (4) inside.