Device and method for treating cleaning waste liquid of oiling agent equipment

Abstract

The invention discloses an oiling agent equipment cleaning waste liquid treatment device and method, and relates to the field of oiling agent waste liquid treatment. The device comprises an electric field demulsification mechanism communicated with a waste liquid pipe, a pulse electrode is arranged in the electric field demulsification mechanism, a composite reactor is arranged on the downstream side of the electric field demulsification mechanism, an anaerobic bacterium area, a lower grating, a transverse partition plate, an upper grating and an aerobic bacterium area are arranged in the electric field demulsification mechanism from bottom to top, and an aeration assembly, a monitoring and shunting system and a gas collection mechanism are further arranged. The treatment method comprises the steps of electric field demulsification pretreatment, aeration, aerobic / anaerobic microbial degradation, multi-parameter monitoring, split-flow treatment and the like. Secondary pollution is avoided through pulsed electric field demulsification, graded degradation of pollutants is achieved through an anaerobic-aerobic linkage circulation structure, real-time monitoring and intelligent flow dividing are combined, the treatment efficiency is improved, and the operation cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of oil waste liquid treatment, and in particular to a device and method for treating oil equipment cleaning waste liquid. Background Art

[0002] In oil production and related chemical industries, equipment cleaning produces large amounts of wastewater containing high concentrations of grease, organic matter, and other pollutants. Direct discharge of this wastewater not only severely pollutes the environment but also poses a threat to ecosystems and human health. Therefore, effective treatment is essential.

[0003] Traditional oil wastewater treatment processes primarily rely on high-temperature demulsification and frequent dosing, resulting in high energy consumption and operating costs. To address these issues, existing approaches attempt to combine physical demulsification (such as ultrasonic demulsification) with chemical flocculation. While this approach reduces energy consumption to some extent, it still has significant drawbacks: the investment cost of ultrasonic equipment is high, the use of chemical flocculants can easily cause secondary pollution, and the treatment efficiency of highly concentrated oil wastewater is limited, resulting in insignificant reductions in overall operating costs.

[0004] In summary, how to reduce secondary pollution while ensuring the treatment efficiency of oil waste liquid and avoiding excessively high operating costs has become a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0005] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0006] The present invention provides a device for treating waste liquid from cleaning oil-agent equipment, comprising an electric field demulsification mechanism connected to a waste liquid pipe, wherein the electric field demulsification mechanism is equipped with a built-in pulse electrode for destroying the interface film of the oil droplets. A composite reactor is arranged on the downstream side of the electric field demulsification mechanism, and an anaerobic bacteria area, a lower grid, a transverse partition, an upper grid, and an aerobic bacteria area are arranged in sequence from bottom to top inside the composite reactor. The transverse partition is provided with a lower partition inserted downward into the anaerobic bacteria area and an upper partition inserted upward into the aerobic bacteria area. A first liquid inlet area is provided on one side of the lower partition and a first liquid outlet area is provided on the other side. A second liquid inlet area is provided on one side of the upper partition and a second liquid outlet area is provided on the other side. The downstream side of the electric field demulsification mechanism is connected to the second liquid inlet area through an injection pipe, and the second liquid inlet area is provided with an aeration component.

[0007] The composite reactor is equipped with a lower liquid supply pipe connecting the second liquid outlet area and the first liquid inlet area, and an upper liquid supply pipe connecting the first liquid outlet area and the second liquid inlet area. The lower liquid supply pipe is equipped with an oxygen sensor, a COD sensor, a grease sensor, a reflux pipe, and a discharge pipe in sequence. The end of the reflux pipe is connected to the second liquid inlet area. A gas collection mechanism is installed on the outside of the composite reactor. The gas collection mechanism is equipped with a gas collecting pipe connecting the top of the first liquid inlet area and the top of the first liquid outlet area.

[0008] As a preferred technical solution of the device of the present invention: the electric field demulsification mechanism is equipped with a pulse electric field generating module, and the liquid surface area inside the electric field demulsification mechanism is equipped with an oil scraper.

[0009] As a preferred technical solution of the device of the present invention, the first liquid inlet and first liquid outlet areas are located between the lower grille and the transverse partition, while the second liquid inlet and second liquid outlet areas are located between the upper grille and the transverse partition. The injection pipe and upper liquid supply pipe are equipped with a liquid pump that supplies liquid to the second liquid inlet area. The injection pipe, lower liquid supply pipe, return pipe, and discharge pipe are each independently equipped with an electrically controlled valve. The electrically controlled valve of the lower liquid supply pipe is located downstream of the return pipe and discharge pipe.

[0010] As a preferred technical solution of the device of the present invention, the aeration assembly includes an aeration pump connected to a main air pipe, which is connected to multiple aeration branch pipes. The outlet ends of the aeration branch pipes are inserted into the bottom of the second liquid inlet area. The connection between the injection pipe and the second liquid inlet area and the connection between the upper liquid supply pipe and the second liquid inlet area are both located higher than the outlet ends of the aeration branch pipes.

[0011] As an optimal technical solution of the device of the present invention: the lower liquid supply pipe and the upper liquid supply pipe are independently equipped with a one-way valve, the one-way valve of the lower liquid supply pipe flows toward the first liquid inlet area, and the one-way valve of the upper liquid supply pipe flows toward the second liquid inlet area.

[0012] As a preferred technical solution of the device of the present invention: the connection position of the reflux pipe and the second liquid inlet area is higher than the connection position of the injection pipe and the second liquid inlet area.

[0013] As a preferred technical solution of the device of the present invention: the gas collection mechanism is installed at a position higher than the top of the first liquid inlet area and the first liquid outlet area, and the connection port of the upper liquid supply pipe and the first liquid outlet area is located lower than the connection port of the gas collecting pipe and the first liquid outlet area.

[0014] The present invention also provides a method for treating waste liquid from cleaning oil equipment, comprising the following contents:

[0015] S1. Waste liquid enters the electric field demulsification mechanism through the waste liquid pipe. The pulse electrodes in the electric field demulsification mechanism destroy the oil droplet interface film through electrolysis, causing the oil and water to separate into layers. The upper floating oil is collected by the oil scraper, and the lower waste liquid is discharged from the electric field demulsification mechanism after treatment.

[0016] S2. The waste liquid treated by the electric field demulsification mechanism enters the second liquid inlet area of ​​the composite reactor through the injection pipe.

[0017] S3. In the second liquid inlet area, the aeration pump of the aeration assembly supplies air to the bottom through the main air pipe and multiple aeration branches to aerate the waste liquid.

[0018] S4. The waste liquid enters the aerobic bacteria area from the second liquid inlet area through the upper grille, and the microorganisms in the aerobic bacteria area degrade organic matter.

[0019] S5. The treated waste liquid enters the second liquid outlet area from the aerobic bacteria area and then flows into the lower liquid supply pipe. The lower liquid supply pipe monitors the oxygen content, COD concentration, and oil concentration of the waste liquid through an oxygen sensor, a COD sensor, and an oil sensor in sequence.

[0020] S6. Conduct triage based on monitoring results:

[0021] S6.1. If all three conditions are within the specified limits, the lower liquid supply pipe stops supplying liquid to the first liquid inlet area, the reflux pipe is closed, the discharge pipe is opened, and the waste liquid is discharged from the discharge pipe.

[0022] S6.2. If the oxygen content exceeds the standard, the lower liquid supply pipe stops supplying liquid to the first liquid inlet area, the discharge pipe is closed, the return pipe is opened, and the waste liquid is re-injected into the second liquid inlet area through the return pipe for another aerobic bacterial reaction.

[0023] S6.3. If the oxygen content is within the specified value but the concentration of either of the other two exceeds the specified value, the discharge pipe and the return pipe are closed, and the lower liquid supply pipe supplies liquid to the first liquid inlet area.

[0024] S7. The waste liquid enters the anaerobic bacteria zone through the first liquid inlet zone. The microorganisms in the anaerobic bacteria zone decompose the macromolecular organic matter. The waste liquid after the reaction enters the first liquid outlet zone from the anaerobic bacteria zone.

[0025] S8. The waste liquid from the first liquid outlet area flows back to the second liquid inlet area through the upper liquid supply pipe. At the same time, the N2 produced in the anaerobic bacteria area is concentrated at the top of the first liquid inlet area and the first liquid outlet area, and is discharged by the gas collection mechanism through the gas collecting pipe.

[0026] Compared with the existing technology, the beneficial effects of the present invention are:

[0027] In this invention, pulse electrodes generate a micro-electrolysis effect through a high-frequency pulsed electric field. This electric field disrupts the charge balance of the oil droplet interface film, causing the oil droplets to coalesce and float. This process eliminates the energy consumption of traditional high-temperature demulsification and avoids the secondary pollution caused by chemical demulsifiers. Simultaneously, the electrolysis process produces a small amount of oxygen, which is directly supplied to aerobic bacteria, precisely controlling byproducts and creating optimal conditions for subsequent anaerobic reactions.

[0028] In the present invention, anaerobic bacteria zones and aerobic bacteria zones are arranged in layers inside the composite reactor, and the graded degradation of pollutants such as organic matter, nitrogen, and phosphorus is achieved through an anaerobic-aerobic linkage circulation composite structure. In combination with real-time monitoring (oxygen sensor, COD sensor, grease sensor) and an intelligent diversion system (reflux pipe, discharge pipe, lower liquid supply pipe), it is ensured that the waste liquid subjected to circulating treatment is treated in a targeted manner, thereby guaranteeing the anaerobic-aerobic biochemical treatment environment and treatment efficiency, and achieving the goal of reducing costs and increasing efficiency in the process of treating oil waste liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1Schematic diagram of the overall structure of the device of the present invention.

[0030] Figure 2 It is a schematic diagram of the electric field demulsification mechanism, aeration assembly, upper liquid supply pipe and gas collection mechanism in the present invention.

[0031] Figure 3 It is a schematic diagram of the composite reactor and the waste liquid outlet and circulation pipeline in the present invention.

[0032] Figure 4 Schematic diagram of the internal structure of the composite reactor in the present invention.

[0033] Wherein: 1-composite reactor, 101-cross plate, 102-lower plate, 103-upper plate, 104-lower grid, 105-upper grid, 106-first liquid inlet area, 107-anaerobic bacteria area, 108-first liquid outlet area, 109-second liquid inlet area, 110-aerobic bacteria area, 111-second liquid outlet area; 2-electric field demulsification mechanism, 201-pulse electrode, 202-oil scraper; 3-waste liquid pipe; 4-injection pipe; 5-liquid pump; 6-electrically controlled valve; 7-lower liquid supply pipe; 8-oxygen sensor; 9-COD sensor; 10-grease sensor; 11-reflux pipe; 12-discharge pipe; 13-check valve; 14-upper liquid supply pipe; 15-gas collecting pipe; 16-gas collecting mechanism; 17-aeration pump; 18-main gas pipe; 19-aeration branch pipe. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] Example 1: The present invention designs a device for treating waste liquid from cleaning oil equipment, such as Figure 1 It mainly includes a composite reactor 1, an electric field demulsification mechanism 2, a lower liquid supply pipe 7, an upper liquid supply pipe 14, a gas collection mechanism 16, an aeration component, etc. The specific structural configuration is as follows:

[0036] like Figure 1 、 Figure 2 The electric field demulsification mechanism 2 includes a built-in pulse electrode 201 for disrupting the oil droplet interface film. An oil scraper 202 is located within the liquid surface area of ​​the mechanism 2 to collect the floating oil layer. The mechanism 2 is externally connected to a waste liquid pipe 3, which directs the waste liquid to be treated.

[0037] The pulse electrode 201 of the electric field demulsification mechanism 2 generates a micro-electrolysis effect using a high-frequency pulsed electric field. This electric field disrupts the charge balance of the oil droplet interface film, causing the oil droplets to coalesce and float upward. This electrolysis process produces a small amount of oxygen, which is not directly injected into the anaerobic bacteria zone 107. The oil scraper 202 continuously collects the floating oil layer above, and the waste liquid below is treated and discharged. In the electric field demulsification mechanism 2, the pulsed electric field generation module controls the electric field intensity, and the liquid level must be high enough to ensure the effective operation of the oil scraper 202.

[0038] like Figure 1 、 Figure 3 、 Figure 4 The composite reactor 1 is provided with an anaerobic bacteria area 107, a lower grid 104, a transverse partition 101, an upper grid 105, and an aerobic bacteria area 110 from bottom to top, as follows:

[0039] The anaerobic zone 107 is located at the bottom of the composite reactor 1 and is separated from the first liquid inlet zone 106 and the first liquid outlet zone 108 by a lower partition 102. It decomposes macromolecular organic matter (such as long-chain oils and cellulose), denitrifying bacteria remove nitrogen, and phosphate-accumulating bacteria release phosphorus. A lower screen 104, located above the anaerobic zone 107, limits the wastewater flow rate (≤ 0.1 m / s) to ensure sufficient contact with the anaerobic bacteria. The transverse partition 101 also includes a lower screen 102 that extends downward into the anaerobic zone 107 and an upper screen 103 that extends upward into the aerobic zone 110, dividing the composite reactor 1 into multiple zones. An upper screen 105, located below the aerobic zone 110, guides wastewater evenly into the zone. The aerobic zone 110, located at the top of the composite reactor 1, is isolated by the upper partition 103 to create an oxygen-rich environment. Aerobic bacteria degrade small organic matter, nitrifying bacteria oxidize NH3-N, and phosphate-accumulating bacteria absorb excess phosphorus.

[0040] The first liquid inlet area 106 is located on one side of the lower partition 102 and is connected to the lower liquid supply pipe 7. It receives the diverted waste liquid and feeds it into the anaerobic bacteria area 107. The first liquid outlet area 108 is located on the other side of the lower partition 102 and collects the waste liquid treated in the anaerobic bacteria area 107. The waste liquid is then returned to the second liquid inlet area 109 through the upper liquid supply pipe 14. The second liquid inlet area 109 is located on the side of the upper partition 103 and receives the waste liquid from the electric field demulsification mechanism 2 through the injection pipe 4.

[0041] The second liquid outlet area 111 is located on the other side of the upper partition 103 , and collects waste liquid treated by the aerobic bacteria area 110 and flows it into the lower liquid supply pipe 7 .

[0042] The injection pipe 4 connects the electric field demulsification mechanism 2 and the second liquid inlet area 109 , and is equipped with a liquid pump 5 and an electric control valve 6 . The connection port of the injection pipe 4 is higher than the gas outlet end of the aeration branch pipe 19 .

[0043] like Figure 1 、 Figure 3The lower liquid supply pipe 7 connects the second liquid outlet area 111 with the first liquid inlet area 106. It is equipped with an oxygen sensor 8, a COD sensor 9, and a grease sensor 10 (the three sensors comprehensively monitor waste liquid indicators), as well as a return pipe 11, a discharge pipe 12, and an electronically controlled valve 6. A one-way valve 13 directs the flow toward the first liquid inlet area 106 to prevent backflow.

[0044] The upper liquid supply pipe 14 connects the first liquid outlet area 108 and the second liquid inlet area 109, and is equipped with a liquid pump 5 and an electric control valve 6. The one-way valve 13 flows toward the second liquid inlet area 109. The connection port of the upper liquid supply pipe 14 is lower than the interface between the gas collecting pipe 15 and the first liquid outlet area 108.

[0045] The end of the return pipe 11 is connected to the second liquid inlet area 109. The interface of the return pipe 11 is higher than the interface of the injection pipe 4, so that the airflow injected by the aeration branch pipe 19 can first contact the waste liquid in the injection pipe 4. The waste liquid in the return pipe 11 has been aerated once before and is refluxed because the oxygen content exceeds the standard.

[0046] The discharge pipe 12 is used to discharge the waste liquid that meets the standards, is connected to the lower liquid supply pipe 7, and is equipped with an electric control valve 6.

[0047] Aeration components: Figure 2 、 Figure 4 The aeration pump 17, main air pipe 18, and multiple aeration branches 19 are installed at the outlet end of the second liquid inlet area 109. The aeration assembly supplies air to the bottom of the second liquid inlet area 109, forming a bottom-up gas-liquid mixed flow, improving aeration efficiency, providing oxygen for aerobic bacteria, and carrying oil droplets for aerobic bacteria to adsorb and degrade.

[0048] like Figure 2 、 Figure 3 The gas collection mechanism 16 connects the top of the first liquid inlet area 106 and the top of the first liquid outlet area 108 through the gas collecting pipe 15 and is installed above the top of both areas. The gas collection mechanism 16 collects N2 and trace methane produced by the anaerobic bacteria area 107 to prevent gas accumulation and potential safety hazards.

[0049] Example 2: In combination with the specific structural design in Example 1, the present invention designs a method for treating waste liquid from cleaning oil equipment, the specific contents of which are as follows:

[0050] Step 1: Electric Field Demulsification Pretreatment: Wastewater enters the electric field demulsification mechanism 2 through the wastewater pipe 3. Pulsed electrodes 201 electrolytically break down the interfacial film between oil droplets, separating the oil and water layers. The upper layer of floating oil is collected by the oil scraper 202, while the lower layer of wastewater is treated and discharged from the electric field demulsification mechanism 2. The pulsed electric field intensity must be adapted to the wastewater oil concentration, and the operating frequency of the oil scraper 202 is adjusted according to the rate of floating oil accumulation.

[0051] Step 2: Introducing waste liquid into the composite reactor: The waste liquid treated in step 1 is transported to the second liquid inlet area 109 of the composite reactor 1 through the injection pipe 4 and the liquid pump 5, and the electric control valve 6 controls the flow rate.

[0052] Step 3: Aeration treatment: The aeration pump 17 supplies air to the bottom of the second liquid inlet area 109 through the main air pipe 18 and the aeration branch pipe 19 to aerate the waste liquid, increase the dissolved oxygen concentration (for example, the target is 2-4 mg / L), provide oxygen for the subsequent microbial metabolism in the aerobic bacteria area 110, and promote the degradation of organic matter.

[0053] Step 4: Aerobic bacteria degrade organic matter: The wastewater enters the aerobic bacteria area 110 through the upper grille 105. Aerobic bacteria decompose organic matter, and nitrifying bacteria oxidize NH3-N into NO3 - , polyphosphate bacteria absorb excessive phosphorus.

[0054] Step 5: Multi-parameter monitoring: The treated waste liquid enters the second liquid outlet area 111 from the aerobic bacteria area 110, and passes through the lower liquid supply pipe 7 in turn through the oxygen sensor 8 (monitoring dissolved oxygen), COD sensor 9 (monitoring organic matter concentration), and grease sensor 10 (monitoring grease content).

[0055] Reference indicators for emission standards: dissolved oxygen ≤ 2.5 mg / L, COD ≤ 50 mg / L, oil ≤ 10 mg / L (can be adjusted according to emission standards).

[0056] Step 6: Diversion Decision-making Mechanism:

[0057] Situation 1: Direct discharge if the three indicators meet the standards: If the three indicators are within the standards, the lower liquid supply pipe 7 stops supplying liquid to the first liquid inlet area 106, the reflux pipe 11 is closed, the discharge pipe 12 is opened, and the waste liquid is directly discharged.

[0058] Situation 2: Excessive oxygen content: If the dissolved oxygen is greater than 2.5 mg / L, the aerobic reaction is determined to be insufficient, the discharge pipe 12 and the lower liquid supply pipe 7 are closed, the reflux pipe 11 is opened, and the waste liquid is returned to the second liquid inlet area 109 .

[0059] Situation 3: COD / grease exceeds the standard: If the dissolved oxygen does not exceed the standard but the COD or grease exceeds the standard, close the discharge pipe 12 and the return pipe 11, open the lower liquid supply pipe 7, and the waste liquid enters the first liquid inlet area 106 and is guided to the anaerobic bacteria area 107 for deep decomposition.

[0060] Step 7: Anaerobic decomposition: The wastewater enters the anaerobic bacteria zone 107 through the first liquid inlet zone 106. Anaerobic bacteria decompose macromolecular organic matter through hydrolysis and acidification. Denitrifying bacteria use organic matter to convert NO3 - The wastewater flows around the lower baffle 102 to form a "U-shaped" flow channel, which prolongs the residence time and ensures sufficient reaction.

[0061] Step 8: Waste Liquid Reflux and Gas Collection: Waste liquid from the first liquid outlet area 108 flows back to the second liquid inlet area 109 via the upper liquid supply pipe 14 and liquid pump 5. This utilizes the liquid level difference to achieve gravity circulation, reducing energy consumption by approximately 15%. Simultaneously, N₂ produced by the anaerobic bacteria area 107 accumulates at the top of the first liquid inlet area 106 and the first liquid outlet area 108, and is discharged through the gas collection pipe 15 and the gas collection mechanism 16, achieving safety, explosion protection, and resource recycling.

[0062] 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 and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for treating waste liquid from cleaning oil equipment, characterized by: The invention comprises an electric field demulsification mechanism (2) connected to a waste liquid pipe (3), wherein the electric field demulsification mechanism (2) has a built-in pulse electrode (201), and a composite reactor (1) is arranged on the downstream side of the electric field demulsification mechanism (2). The composite reactor (1) is provided with an anaerobic bacteria area (107), a lower grid (104), a transverse partition (101), an upper grid (105), and an aerobic bacteria area (110) in order from bottom to top. The transverse partition (101) is provided with a lower partition (102) inserted downward into the anaerobic bacteria area (107), and an upper partition (103) inserted upward into the aerobic bacteria area (110); a first liquid inlet area (106) is provided on one side of the lower partition (102), and a first liquid outlet area (108) is provided on the other side; a second liquid inlet area (109) is provided on one side of the upper partition (103), and a second liquid outlet area (111) is provided on the other side; The downstream side of the electric field demulsification mechanism (2) is connected to the second liquid inlet area (109) through an injection pipe (4), and the second liquid inlet area (109) is equipped with an aeration component; The composite reactor (1) is provided with a lower liquid supply pipe (7) connecting the second liquid outlet area (111) and the first liquid inlet area (106), and an upper liquid supply pipe (14) connecting the first liquid outlet area (108) and the second liquid inlet area (109) on the outside thereof. The lower liquid supply pipe (7) is provided with an oxygen sensor (8), a COD sensor (9), a grease sensor (10), a reflux pipe (11), and a discharge pipe (12) in sequence, wherein the end of the reflux pipe (11) is connected to the second liquid inlet area (109); A gas collecting mechanism (16) is arranged outside the composite reactor (1), and the gas collecting mechanism (16) is provided with a gas collecting pipe (15) connected to the top of the first liquid inlet area (106) and the top of the first liquid outlet area (108).

2. The oil equipment cleaning waste liquid treatment device according to claim 1, characterized in that: The electric field demulsification mechanism (2) is equipped with a pulse electric field generating module, and an oil scraper (202) is equipped in the liquid surface area inside the electric field demulsification mechanism (2).

3. The oil equipment cleaning waste liquid treatment device according to claim 1, characterized in that: The first liquid inlet area (106) and the first liquid outlet area (108) are located between the lower grid (104) and the transverse partition (101); the second liquid inlet area (109) and the second liquid outlet area (111) are located between the upper grid (105) and the transverse partition (101); The injection pipe (4) and the upper liquid supply pipe (14) are equipped with a liquid pump (5) for supplying liquid toward the second liquid inlet area (109); the injection pipe (4), the lower liquid supply pipe (7), the return pipe (11), and the discharge pipe (12) are all independently equipped with an electric control valve (6); The electric control valve (6) of the lower liquid supply pipe (7) is located on the downstream side of the return pipe (11) and the discharge pipe (12).

4. The oil equipment cleaning waste liquid treatment device according to claim 1, characterized in that: The aeration assembly includes an aeration pump (17), the aeration pump (17) is connected to a main air pipe (18), the main air pipe (18) is connected to a plurality of aeration branch pipes (19), and the outlet ends of the aeration branch pipes (19) are inserted into the bottom of the second liquid inlet area (109); The connection port between the injection pipe (4) and the second liquid inlet area (109), and the connection port between the upper liquid supply pipe (14) and the second liquid inlet area (109) are both located higher than the gas outlet end of the aeration branch pipe (19).

5. The oil equipment cleaning waste liquid treatment device according to claim 1, characterized in that: The lower liquid supply pipe (7) and the upper liquid supply pipe (14) are each independently provided with a one-way valve (13); the one-way valve (13) of the lower liquid supply pipe (7) flows in a direction toward the first liquid inlet area (106), and the one-way valve (13) of the upper liquid supply pipe (14) flows in a direction toward the second liquid inlet area (109).

6. The oil equipment cleaning waste liquid treatment device according to claim 1, characterized in that: The connection port of the reflux pipe (11) and the second liquid inlet area (109) is located higher than the connection port of the injection pipe (4) and the second liquid inlet area (109).

7. The oil equipment cleaning waste liquid treatment device according to claim 1, characterized in that: The gas collecting mechanism (16) is installed at a position higher than the top of the first liquid inlet area (106) and the first liquid outlet area (108), and the connection port of the upper liquid supply pipe (14) and the first liquid outlet area (108) is located lower than the connection port of the gas collecting pipe (15) and the first liquid outlet area (108).

8. A method for treating waste liquid from cleaning oil-containing equipment, applied to a waste liquid treatment device for cleaning oil-containing equipment according to any one of claims 1 to 7, characterized in that: Includes the following: S1. The waste liquid enters the electric field demulsification mechanism (2) through the waste liquid pipe (3). The pulse electrode (201) in the electric field demulsification mechanism (2) destroys the oil droplet interface film through electrolysis, causing the oil and water to separate. The upper floating oil is collected by the oil scraper (202), and the lower waste liquid is discharged from the electric field demulsification mechanism (2) after being treated. S2. The waste liquid treated by the electric field demulsification mechanism (2) enters the second liquid inlet zone (109) of the composite reactor (1) through the injection pipe (4); S3. In the second liquid inlet zone (109), the aeration pump (17) of the aeration assembly supplies air to the bottom through the main air pipe (18) and multiple aeration branches (19) to aerate the waste liquid; S4. The waste liquid enters the aerobic bacteria zone (110) from the second liquid inlet zone (109) through the upper grid (105), and the microorganisms in the aerobic bacteria zone (110) degrade organic matter; S5. The treated waste liquid enters the second liquid outlet area (111) from the aerobic bacteria area (110) and then flows into the lower liquid supply pipe (7). The lower liquid supply pipe (7) sequentially monitors the oxygen content, COD concentration, and oil concentration of the waste liquid through the oxygen sensor (8), COD sensor (9), and grease sensor (10); S6. Conduct triage based on monitoring results: S6.

1. If all three conditions are within the specified range, the lower liquid supply pipe (7) stops supplying liquid to the first liquid inlet area (106), the reflux pipe (11) is closed, the discharge pipe (12) is opened, and the waste liquid is discharged from the discharge pipe (12); S6.

2. If the oxygen content exceeds the standard, the lower liquid supply pipe (7) stops supplying liquid to the first liquid inlet area (106), the discharge pipe (12) is closed, the return pipe (11) is opened, and the waste liquid is re-injected into the second liquid inlet area (109) through the return pipe (11) for another aerobic bacterial reaction; S6.

3. If the oxygen content does not exceed the standard but any of the other two concentrations exceeds the standard, the discharge pipe (12) and the reflux pipe (11) are closed, and the lower liquid supply pipe (7) supplies liquid to the first liquid inlet area (106); S7. The waste liquid enters the anaerobic bacteria zone (107) through the first liquid inlet zone (106), and the microorganisms in the anaerobic bacteria zone (107) decompose the macromolecular organic matter. The waste liquid after the reaction enters the first liquid outlet zone (108) from the anaerobic bacteria zone (107); S8. The waste liquid from the first liquid outlet area (108) flows back to the second liquid inlet area (109) through the upper liquid supply pipe (14). At the same time, the N2 produced by the anaerobic bacteria area (107) is concentrated at the top of the first liquid inlet area (106) and the first liquid outlet area (108), and is discharged by the gas collection mechanism (16) through the gas collecting pipe (15).

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