A multi-stage modular oily wastewater purification device and purification method

Abstract

This invention discloses a multi-stage modular oily wastewater purification device and method, comprising an initial sedimentation tank, an oil separator, a cyclone dissolved air flotation mechanism, a dual-membrane separation mechanism, a biological treatment mechanism, and an end filter connected in sequence. The cyclone dissolved air flotation mechanism includes a flotation treatment tank, with a hollow air delivery ring fixed at the bottom and multiple air delivery nozzles connected to its interior fixed at the top. The dual-membrane separation mechanism includes paired, vertically extending dual-membrane separation storage cylinders, with a horizontally extending dual-membrane separation receiving cylinder fixed near the lower end between the two cylinders. An oil phase separation baffle and a water phase separation baffle are fixed inside the dual-membrane separation receiving cylinder. The device possesses high-efficiency oil removal performance, with multiple treatment stages. Through multi-stage treatment, it can effectively remove oil droplets of various particle sizes from oily wastewater and is adaptable to treating various types of oil and water quality.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a multi-stage modular oily wastewater purification device and purification method. Background Technology

[0002] Oily wastewater mainly originates from industries such as petroleum, petrochemicals, steel, coking, gasification, machinery processing, and shipbuilding. Oily wastewater causes multifaceted pollution to the environment and water bodies. Oil pollutants often contain aromatic hydrocarbons, which are carcinogenic. The harm caused by oil pollutants to oceans and rivers includes disrupting ecological balance, polluting water sources for domestic and industrial use, and damaging coastal landscapes. Soil pollution manifests as soil compaction and damage to the growth environment of soil microorganisms. Each drop of oil can form a 0.25 square meter oil film, isolating the atmosphere from water, disrupting normal reoxygenation conditions, affecting the self-purification capacity of water bodies, and damaging the ecological environment of aquatic plants and animals, potentially causing death in severe cases.

[0003] Existing technologies for purifying oily wastewater still suffer from incomplete oil phase removal, and the purification equipment needs further improvement and optimization. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-stage modular oily wastewater purification device and method, which can more thoroughly and effectively remove the oil phase from oily wastewater.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A multi-stage modular oily wastewater purification device includes an initial sedimentation tank, an oil separator, a cyclone dissolved air flotation mechanism, a dual-membrane separation mechanism, a biological treatment mechanism, and an end filter connected in sequence.

[0007] The swirl dissolved air flotation mechanism includes a flotation treatment tank, a hollow air delivery ring shell fixed at the bottom of the flotation treatment tank, and multiple air delivery nozzles connected to the inside of the air delivery ring shell fixed at the top of the air delivery ring shell.

[0008] The top of the flotation treatment tank is equipped with an oil flotation discharge pipe, which has an oil flotation discharge control valve.

[0009] The dual-membrane separation mechanism includes a pair of vertically extending dual-membrane separation storage cylinders, and a horizontally extending dual-membrane separation receiving cylinder is fixed between the dual-membrane separation storage cylinders near the lower end. An oil phase separation baffle and an aqueous phase separation baffle are fixed inside the dual-membrane separation receiving cylinder.

[0010] Multiple hydrophobic membranes for oil phase separation are fixed on the oil phase separation partition, and multiple hydrophilic membranes for water phase separation are fixed on the water phase separation partition.

[0011] The portion of the dual-membrane separation container between the oil phase separation plate and the water phase separation plate forms a mixing input space. The side of the oil phase separation plate away from the water phase separation plate forms an oil phase separation space, and the side of the water phase separation plate away from the oil phase separation plate forms a water phase separation space.

[0012] The mixed input space is connected to the interior of the dual-membrane separation temporary storage cylinder via a mixed input tube;

[0013] The biological treatment mechanism includes a vertically placed outer biological treatment shell, an inner biological treatment shell fixed inside the outer biological treatment shell and arranged coaxially therewith, an aerobic treatment space is formed between the inner side wall of the outer biological treatment shell and the outer side wall of the inner biological treatment shell, and an anaerobic treatment space is formed inside the inner biological treatment shell.

[0014] An aeration conveying ring is fixed at the bottom of the aerobic treatment space, and multiple aeration conveying nozzles connected to the inside of the aeration conveying ring are fixed at the top of the aeration conveying ring.

[0015] Preferably, a pressure reduction control mechanism is provided connected to the air flotation treatment tank. The pressure reduction control mechanism includes a pressure reduction control vacuum tank connected to the air flotation treatment tank through a pressure reduction control connecting pipe. The pressure reduction control connecting pipe has a pressure reduction control valve. The pressure reduction control vacuum tank is connected to a pressure reduction control vacuum pump through a vacuum extraction pipe. The vacuum extraction pipe has a vacuum extraction control valve.

[0016] Note: Microbubbles generated by depressurization can be more evenly dispersed and filled in oily wastewater, which helps to improve the removal rate of the oil phase.

[0017] Preferably, there are multiple pressure-reducing control vacuum tanks, and each pressure-reducing control vacuum tank is connected to the inside of the air flotation treatment tank through an independent pressure-reducing control connecting pipe. Each pressure-reducing control vacuum tank is also connected to a pressure-reducing control vacuum pump through a separate vacuum extraction pipe.

[0018] Explanation: Setting up multiple vacuum tanks with reduced pressure control enables stepped cyclone dissolved air treatment, causing a large number of microbubbles to precipitate in batches from the oily wastewater. These microbubbles are evenly dispersed and fill the oily wastewater. The suspended oil droplets in the oily wastewater can adhere to the microbubbles, and under the action of buoyancy, the microbubbles will carry the oil droplets to float up and gather on the surface of the oily wastewater, which can more thoroughly separate the oil droplets from the oily wastewater.

[0019] Preferably, the bottom of the air flotation treatment tank is provided with a low-speed stirring mechanism, which includes a low-speed stirring drive shaft that is rotatably connected to the bottom of the air flotation treatment tank and extends vertically. The low-speed stirring drive shaft is fixedly connected to a low-speed stirring drive ring through multiple stirring drive connecting rods. Multiple vertically extending low-speed stirring drive plates are fixed to the upper end of the low-speed stirring drive ring.

[0020] The lower end of the air flotation treatment tank is fixed with a stirring drive housing, and the lower end of the low-speed stirring drive shaft extends into the stirring drive housing. A low-speed stirring drive motor for driving the low-speed stirring drive shaft to rotate is fixed inside the stirring drive housing.

[0021] Explanation: A low-speed stirring mechanism is used to drive and stir the oily wastewater in the flotation treatment tank, causing the oily wastewater to rotate around the vertical axis of the flotation treatment tank and generate a swirling flow. Since water is denser than oil, under centrifugal force, the suspended oil droplets in the oily wastewater will concentrate at the vertical axis of the flotation treatment tank, making it easier to separate the collected oil droplets.

[0022] Preferably, the flotation oil mist discharge pipe is connected to the top of the flotation treatment tank through a discharge lifting mechanism. The top of the flotation treatment tank has a vertically penetrating sealed sliding hole. The flotation oil mist discharge pipe is slidably connected in the sealed sliding hole. The discharge lifting mechanism includes a discharge lifting fixed cylinder fixed to the top of the flotation treatment tank with its opening facing upward. A discharge lifting sliding cylinder with its opening facing downward is slidably connected to the outside of the discharge lifting fixed cylinder. The discharge lifting sliding cylinder is fixedly connected to the flotation oil mist discharge pipe.

[0023] The outer discharge lifting fixed cylinder is equipped with an outer discharge lifting drive rod for driving the outer discharge lifting sliding cylinder to move up and down.

[0024] Explanation: The lower end of the air flotation oil flake discharge pipe is always in contact with the liquid surface through the external discharge lifting mechanism, so as to effectively discharge the oil droplets that accumulate on the surface of the oily wastewater.

[0025] Preferably, the top of the flotation treatment tank is fixed with a flotation pressure relief pipe that communicates with its interior, and the flotation pressure relief pipe is equipped with a flotation pressure relief control valve.

[0026] Note: After the phase of work is completed, the air flotation treatment tank can be balanced with the external atmospheric pressure through the air flotation pressure relief pipe to avoid knocking caused by pressure imbalance.

[0027] Preferably, the dual-membrane separation storage cylinder is provided with an auxiliary pressurization separation mechanism. The auxiliary pressurization separation mechanism includes an auxiliary pressurization piston that is slidably connected inside the dual-membrane separation storage cylinder. A vertically extending pressurization piston drive rod is fixed to the top of the auxiliary pressurization piston, and the upper end of the pressurization piston drive rod extends upward to the outside of the dual-membrane separation storage cylinder.

[0028] A pressure-boosting drive fixed cylinder with its opening facing upward is fixed on the outside of the dual-membrane separation temporary storage cylinder. A pressure-boosting drive sliding cylinder is slidably connected inside the pressure-boosting drive fixed cylinder. The top of the pressure-boosting drive sliding cylinder is fixedly connected to the upper end of the pressure-boosting piston drive rod.

[0029] The booster drive fixed cylinder is equipped with an auxiliary booster drive rod for driving the booster drive sliding cylinder to move up and down.

[0030] Note: The auxiliary pressurization separation mechanism helps to force the oily wastewater in the dual-membrane separation temporary storage tank to flow more smoothly into the mixing input space.

[0031] Preferably, the auxiliary booster piston has multiple forced flow holes that run parallel to its axis, and the lower end of the auxiliary booster piston has a downward-facing shaft connection hole. An opening and closing disc shaft is rotatably connected in the shaft connection hole, and an opening and closing control disc is fixed at the lower end of the opening and closing disc shaft. The top of the opening and closing control disc is in pressure contact with the lower end of the auxiliary booster piston, and the opening and closing control disc has multiple forced flow mating holes that run parallel to the axis of the auxiliary booster piston.

[0032] A drive motor for the opening and closing disc is fixed in the shaft connection hole.

[0033] Explanation: The auxiliary method forces the suspended oil droplets in the oily wastewater in the dual-membrane separation temporary storage tank to merge together, forming larger oil droplets, which then aggregate and float to the surface of the oily wastewater. This helps to pre-separate part of the oil phase, thereby reducing the workload of the hydrophobic membrane in the oil phase separation process.

[0034] Preferably, a dual-membrane separation back pressure mechanism is provided on the outside of the dual-membrane separation container. The dual-membrane separation back pressure mechanism includes a back pressure flow ring shell fixed on the outside of the dual-membrane separation container. The mixing input space is connected to the inside of the back pressure flow ring shell through multiple back pressure flow holes.

[0035] A back pressure discharge pipe is fixed on the outside of the back pressure flow ring shell and is connected to its interior. The back pressure discharge pipe is equipped with a separation back pressure control valve.

[0036] The other end of the back pressure drain pipe is connected to a reflux storage tank, which is equipped with a conventional transfer pump. The transfer pump is used to transfer the wastewater stored in the reflux storage tank back to the dual membrane separation storage cylinder for reflux treatment.

[0037] Note: The dual-membrane separation back pressure mechanism helps to make the oily wastewater flow more smoothly in the mixing input space, and avoids the formation of stagnant water in the mixing input space due to excessive workload, which would affect the overall working efficiency.

[0038] Preferably, a multi-stage modular oily wastewater purification method, based on the above-mentioned multi-stage modular oily wastewater purification equipment, includes the following steps:

[0039] S1. Precipitation treatment:

[0040] The oily wastewater to be treated is transported to the initial sedimentation tank and allowed to settle for 2 to 6 hours.

[0041] S2, Oil separation treatment:

[0042] The oily wastewater after sedimentation is transported to an oil separator for oil separation at a flow rate of 2-5 mm / s.

[0043] S3, Air flotation treatment:

[0044] The oily wastewater after oil separation is transported into the flotation treatment tank and the process is stopped when the tank is filled to 70% of its volume.

[0045] The oily wastewater in the flotation treatment tank is aerated. High-pressure air is delivered into the air delivery ring using an air delivery pump. The air pressure is set to 1 MPa. The high-pressure air is discharged through each air delivery nozzle to form microbubbles. The microbubbles flow from bottom to top in the oily wastewater. Oil droplets can adhere to the microbubbles and float up with them to the surface of the oily wastewater.

[0046] Meanwhile, some air will dissolve in the oily wastewater. When the air pressure in the flotation tank reaches 1 MPa, aeration will be stopped.

[0047] At this time, the oily wastewater in the flotation tank is in a dissolved air saturation state.

[0048] Open the oil foam discharge control valve and control its opening degree. Under the high pressure of the air flotation treatment tank, the oil droplets that accumulate on the surface of the oily wastewater are discharged through the air flotation oil foam discharge pipe.

[0049] When the lower end of the air flotation oil mist discharge pipe is equipped with a liquid level sensor, the lower end of the air flotation oil mist discharge pipe is always in contact with the liquid surface. During the process of high-pressure air being discharged through the air flotation oil mist discharge pipe, the oil droplets that accumulate on the surface of the oily wastewater can be discharged along with the airflow through the air flotation oil mist discharge pipe. After the oil droplets that accumulate on the surface of the oily wastewater are discharged, the oil mist discharge control valve is closed.

[0050] S4, Cyclone dissolved gas treatment:

[0051] Under the pressure reduction action of the pressure reduction control mechanism, a large number of microbubbles will be released from the oily wastewater in the dissolved gas saturation state. These microbubbles are evenly dispersed and fill the oily wastewater. The suspended oil droplets in the oily wastewater can adhere to the microbubbles, and under the action of buoyancy, the microbubbles will carry the oil droplets to float up and gather on the surface of the oily wastewater.

[0052] At the same time, the low-speed stirring mechanism drives and stirs the oily wastewater in the flotation tank, causing the oily wastewater to rotate around the vertical axis of the flotation tank to generate swirling flow.

[0053] Because water is denser than oil, under centrifugal force, suspended oil droplets in oily wastewater will concentrate at the vertical axis of the flotation tank. Open the oil flake discharge control valve and control its opening degree to discharge the oil droplets concentrated at the vertical axis of the flotation tank through the flotation oil flake discharge pipe.

[0054] Open the flotation wastewater output control valve, and the oily wastewater after cyclone dissolved air treatment will be discharged through the flotation wastewater output pipe.

[0055] S5, membrane separation treatment;

[0056] The oily wastewater after cyclone dissolved air treatment is fed into a pair of dual-membrane separation storage cylinders. Under the action of its own weight pressure, the oily wastewater in the dual-membrane separation storage cylinders enters the mixing input space through the mixing input pipe.

[0057] The distance between the oil phase separation baffle and the water phase separation baffle is 5mm;

[0058] When oily wastewater flows through the slits in the mixing input space, the hydrophilic membrane selectively removes the aqueous phase from the oily wastewater, allowing the aqueous phase to pass through the membrane and enter the aqueous phase separation space. This results in an increase in the relative concentration of the oil phase in the oily wastewater in the mixing input space, which further intensifies the collision, coalescence, and demulsification between oil droplets, thereby increasing the permeation flux of the oil phase. The oil phase in the oily wastewater will then pass through the hydrophobic membrane and enter the oil phase separation space.

[0059] This allows the oil phase in the aqueous phase of oily wastewater to be separated;

[0060] S6. Biological treatment:

[0061] The oily wastewater is then fed into the aerobic treatment space for aerobic fermentation treatment;

[0062] Oily wastewater that has undergone aerobic fermentation treatment in the aerobic treatment space then enters the anaerobic treatment space for anaerobic fermentation treatment.

[0063] S7. Filtration treatment:

[0064] The end filter is an activated carbon filter. It is used to filter the oily wastewater after biological treatment, and completely remove the small amount of oil droplets remaining in the wastewater.

[0065] Compared with the prior art, the beneficial effects of the present invention are reflected in the following aspects:

[0066] 1. This invention has a reasonable structural design, possesses highly efficient oil removal performance, and is equipped with multiple treatment stages. Through multi-stage treatment, it can effectively remove oil droplets of various particle sizes from oily wastewater.

[0067] 2. This invention has good adaptability and can be adapted to treat a variety of oils and water qualities. It can effectively treat wastewater containing mechanical oil, animal and vegetable oils or emulsified oil, and has good adaptability to various water qualities with different acidity, alkalinity and salinity, and can effectively treat them.

[0068] 3. This invention has excellent deep purification performance. Multi-stage treatment can deeply purify oily wastewater, removing not only oil but also suspended solids, some dissolved organic matter, and other pollutants, which helps to improve the wastewater reuse rate.

[0069] 4. The vortex dissolved air flotation mechanism of the present invention can perform stepped vortex dissolved air treatment, so that a large number of microbubbles are released in batches from the oily wastewater. These microbubbles are evenly dispersed and fill the oily wastewater. The suspended oil droplets in the oily wastewater can adhere to the microbubbles, and under the action of buoyancy, the microbubbles will carry the oil droplets to float up and gather on the surface of the oily wastewater, which can more thoroughly separate the oil droplets from the oily wastewater.

[0070] 5. In the dual-membrane separation mechanism of the present invention, when oily wastewater flows in the slit in the mixing input space, the hydrophilic membrane of the aqueous phase separation selectively removes the aqueous phase in the oily wastewater, allowing the aqueous phase to pass through the hydrophilic membrane into the aqueous phase separation space, resulting in an increase in the relative concentration of the oil phase in the oily wastewater in the mixing input space. This further intensifies the collision, coalescence and demulsification between oil droplets, thereby increasing the permeation flux of the oil phase.

[0071] 6. The auxiliary pressurization separation mechanism of the present invention can not only force the oily wastewater in the dual-membrane separation storage cylinder to flow more smoothly into the mixing input space, but also help force the suspended oil droplets in the oily wastewater in the dual-membrane separation storage cylinder to merge together to form larger oil droplets and gather together to float to the surface of the oily wastewater, thus pre-separating part of the oil phase to reduce the workload of the hydrophobic membrane of oil phase separation. Attached Figure Description

[0072] Figure 1 This is a schematic diagram of the overall layout of the present invention;

[0073] Figure 2 This is a schematic diagram of the swirl dissolved air flotation mechanism of the present invention;

[0074] Figure 3 This is a schematic diagram of the dual-membrane separation mechanism of the present invention;

[0075] Figure 4 This is a schematic diagram of the structure of the dual-membrane separation container of the present invention;

[0076] Figure 5 This is a schematic diagram of the auxiliary booster piston of the present invention;

[0077] Figure 6 This is a schematic diagram of the biological treatment mechanism of the present invention;

[0078] Figure 7 This is a schematic diagram of the spatially separated annular shell structure of the present invention.

[0079] In the diagram, 10-initial sedimentation tank, 11-oil separator, 20-cyclone dissolved air flotation mechanism, 21-flotation treatment tank, 211-flotation wastewater inlet pipe, 2110-flotation wastewater inlet control valve, 212-flotation wastewater outlet pipe, 2120-flotation wastewater outlet control valve, 213-flotation pressure relief pipe, 2130-flotation pressure relief control valve, 22-air conveying ring, 221-air conveying nozzle, 23-flotation oil foam discharge pipe, 230-oil foam discharge control valve, 231-sealed sliding hole, 24-pressure reduction control mechanism, 241-pressure reduction control connecting pipe, 2410-pressure reduction control valve, 240-pressure reduction control vacuum tank, 242-vacuum extraction pipe, 2420-vacuum extraction control valve, 2 43-Reduced pressure control vacuum pump, 25-Low-speed stirring mechanism, 251-Low-speed stirring drive shaft, 252-Stirring drive connecting rod, 253-Low-speed stirring drive ring, 254-Low-speed stirring drive plate, 255-Stirring drive housing, 256-Low-speed stirring drive motor, 26-External discharge lifting mechanism, 261-External discharge lifting fixed cylinder, 262-External discharge lifting sliding cylinder, 263-External discharge lifting drive rod, 30-Dual membrane separation mechanism, 31-Dual membrane separation temporary storage cylinder, 311-Dual membrane separation input pipe, 3110-Separation input control valve, 312-Floating oil auxiliary external discharge pipe, 3120-Auxiliary external discharge control valve, 32-Dual membrane separation housing, 321-Oil phase separation space, 3210-Oil phase separation outer... Piping, 322-Mixing Input Space, 323-Aqueous Phase Separation Space, 3230-Aqueous Phase Separation External Pipe, 33-Oil Phase Separation Baffle, 330-Oil Phase Separation Hydrophobic Membrane, 34-Aqueous Phase Separation Baffle, 340-Aqueous Phase Separation Hydrophilic Membrane, 35-Auxiliary Pressure-Boosting Separation Mechanism, 351-Auxiliary Pressure-Boosting Piston, 3510-Forced Flow Hole, 352-Pressure-Boosting Piston Drive Rod, 353-Pressure-Boosting Drive Fixed Cylinder, 354-Pressure-Boosting Drive Sliding Cylinder, 355-Auxiliary Pressure-Boosting Drive Rod, 356-Rotary Shaft Connection Hole, 357-Opening / Closing Disc Rotary Shaft, 358-Opening / Closing Control Disc, 3580-Forced Flow Fitting Hole, 359-Opening / Closing Disc Drive Motor, 36-Dual Membrane Separation Back Pressure Mechanism, 361-Back Pressure Flow Ring Shell 3610-Back pressure flow hole, 362-Back pressure discharge pipe, 3620-Separation back pressure control valve, 363-Return storage tank, 40-Biological treatment mechanism, 41-Biological treatment outer shell, 410-Aerobic treatment space, 411-Aerobic treatment input pipe, 42-Biological treatment inner shell, 421-Anaerobic treatment output pipe, 420-Anaerobic treatment space, 43-Aeration conveying ring shell, 431-Aeration conveying nozzle, 432-Aeration overflow vent pipe, 44-Space separation ring shell, 440-Treatment exchange filter, 441-Treatment exchange through hole, 45-Exchange barrier ring shell, 451-Treatment exchange mating hole, 452-Exchange opening and closing support ring rail, 453-Exchange opening and closing drive ring, 50-End filter. Detailed Implementation

[0080] The following is combined Figures 1 to 7 The present invention will be described in detail. For ease of description, the orientations mentioned below are defined as follows: The directions of up, down, left, right, front, and back mentioned below are consistent with the directions of up, down, left, right, front, and back in the projection relationship of the respective main view or structural schematic diagram.

[0081] Example 1:

[0082] A multi-stage modular oily wastewater purification device, such as Figure 1 As shown, it includes an initial sedimentation tank 10, an oil separator 11, a vortex dissolved air flotation mechanism 20, a dual membrane separation mechanism 30, a biological treatment mechanism 40, and an end filter 50 that are connected in sequence.

[0083] The initial sedimentation tank 10 is a sedimentation tank of the prior art, and the oil separator 11 is an oil separator of the prior art with inclined plate.

[0084] The output end of the initial sedimentation tank 10 is connected to the input end of the oil separator 11 via a pipeline;

[0085] like Figure 2 As shown, the swirling dissolved air flotation mechanism 20 includes an air flotation tank 21, a hollow air delivery ring shell 22 is fixed at the bottom of the air flotation tank 21, and a plurality of air delivery nozzles 221 connected to the inside of the air delivery ring shell 22 are fixed at the top of the air delivery ring shell 22.

[0086] The air delivery ring 22 is connected to an existing air delivery pump via a pipe, and the air delivery pump delivers high-pressure air into the air delivery ring 22.

[0087] The air flotation treatment tank 21 has an air flotation wastewater inlet pipe 211 fixed on the outside and connected to the inside, and an air flotation wastewater outlet pipe 212 fixed at the bottom and connected to the inside.

[0088] The air flotation wastewater inlet pipe 211 is equipped with an air flotation wastewater inlet control valve 2110, and the air flotation wastewater outlet pipe 212 is equipped with an air flotation wastewater outlet control valve 2120.

[0089] The air flotation wastewater inlet pipe 211 is connected to the outlet end of the oil separator 11 via a pipeline;

[0090] The top of the flotation treatment tank 21 is fixed with a flotation pressure relief pipe 213 that is connected to its interior, and the flotation pressure relief pipe 213 has a flotation pressure relief control valve 2130.

[0091] The top of the flotation treatment tank 21 is equipped with a flotation oil foam discharge pipe 23, and the flotation oil foam discharge pipe 23 is equipped with an oil foam discharge control valve 230.

[0092] like Figure 2As shown, a pressure reduction control mechanism 24 is connected to the air flotation treatment tank 21. The pressure reduction control mechanism 24 includes a pressure reduction control vacuum tank 240 connected to the air flotation treatment tank 21 through a pressure reduction control connecting pipe 241. A pressure reduction control valve 2410 is provided on the pressure reduction control connecting pipe 241. A pressure reduction control vacuum pump 243 is connected to the pressure reduction control vacuum tank 240 through a vacuum extraction pipe 242. A vacuum extraction control valve 2420 is provided on the vacuum extraction pipe 242.

[0093] like Figure 2 As shown, the bottom of the air flotation treatment tank 21 is provided with a low-speed stirring mechanism 25. The low-speed stirring mechanism 25 includes a low-speed stirring drive shaft 251 that is rotatably connected to the bottom of the air flotation treatment tank 21 and extends vertically. The low-speed stirring drive shaft 251 is fixedly connected to a low-speed stirring drive ring 253 through multiple stirring drive connecting rods 252. Multiple vertically extending low-speed stirring drive plates 254 are fixed to the upper end of the low-speed stirring drive ring 253.

[0094] The lower end of the air flotation treatment tank 21 is fixed with a stirring drive housing 255, the lower end of the low-speed stirring drive shaft 251 extends into the stirring drive housing 255, and a low-speed stirring drive motor 256 for driving the low-speed stirring drive shaft 251 to rotate is fixed inside the stirring drive housing 255.

[0095] The low-speed stirring drive motor 256 is a motor of the prior art, and the low-speed stirring drive motor 256 drives the low-speed stirring drive shaft 251 to rotate through gear transmission.

[0096] like Figure 2 As shown, the flotation oil foam discharge pipe 23 is connected to the top of the flotation treatment tank 21 through the discharge lifting mechanism 26. The top of the flotation treatment tank 21 has a vertically penetrating sealed sliding hole 231. The flotation oil foam discharge pipe 23 is slidably connected in the sealed sliding hole 231. The discharge lifting mechanism 26 includes a discharge lifting fixed cylinder 261 fixed to the top of the flotation treatment tank 21 with the opening facing upward. A discharge lifting sliding cylinder 262 with the opening facing downward is slidably connected to the outside of the discharge lifting fixed cylinder 261. The discharge lifting sliding cylinder 262 is fixedly connected to the flotation oil foam discharge pipe 23.

[0097] The outer discharge lifting fixed cylinder 261 is provided with an outer discharge lifting drive rod 263 for driving the outer discharge lifting sliding cylinder 262 to move up and down. The outer discharge lifting drive rod 263 is an existing electric control telescopic rod driven by a servo motor. The outer rod end of the outer discharge lifting drive rod 263 is fixedly connected to the bottom of the outer discharge lifting fixed cylinder 261, and the inner rod end of the outer discharge lifting drive rod 263 is fixedly connected to the top of the outer discharge lifting sliding cylinder 262.

[0098] like Figure 3As shown, the dual-membrane separation mechanism 30 includes a pair of vertically extending dual-membrane separation storage cylinders 31, and a horizontally extending dual-membrane separation receiving cylinder 32 is fixed between the dual-membrane separation storage cylinders 31 near their lower ends, as shown. Figure 4 As shown, an oil phase separation baffle 33 and an aqueous phase separation baffle 34 are fixed inside the dual-membrane separation container 32;

[0099] Both the oil phase separation baffle 33 and the water phase separation baffle 34 are arranged perpendicular to the axis of the double membrane separation container 32;

[0100] like Figure 4 As shown, both the oil phase separation partition 33 and the water phase separation partition 34 are porous hollow structures with two sides. Multiple oil phase separation hydrophobic membranes 330 are fixed on the side of the oil phase separation partition 33 that are close to each other, and multiple water phase separation hydrophilic membranes 340 are fixed on the side of the water phase separation partition 34 that are close to each other.

[0101] The oil phase separation hydrophobic membrane 330 is a prior art selective permeable membrane that only allows the oil phase containing wastewater to pass through. The aqueous phase separation hydrophilic membrane 340 is a prior art selective permeable membrane that only allows the aqueous phase containing wastewater to pass through. Both the oil phase separation hydrophobic membrane 330 and the aqueous phase separation hydrophilic membrane 340 are commercially available products, and those skilled in the art can choose according to their actual needs.

[0102] The portion of the double-membrane separation container 32 between the oil phase separation partition 33 and the water phase separation partition 34 forms a mixing input space 322. The side of the oil phase separation partition 33 away from the water phase separation partition 34 forms an oil phase separation space 321, and the side of the water phase separation partition 34 away from the oil phase separation partition 33 forms a water phase separation space 323.

[0103] The mixed input space 322 is connected to the interior of the dual-membrane separation temporary storage cylinder 31 through the mixed input tube 320;

[0104] like Figure 3 As shown, a dual-membrane separation temporary storage cylinder 31 is fixed on the outside of the cylinder and a dual-membrane separation input pipe 311 and an oil floating auxiliary discharge pipe 312 that are connected to the inside of the cylinder, and the oil floating auxiliary discharge pipe 312 is located above the dual-membrane separation input pipe 311.

[0105] The dual-membrane separation input pipe 311 has a separation input control valve 3110, and the floating oil auxiliary discharge pipe 312 has an auxiliary discharge control valve 3120;

[0106] The dual-membrane separation input pipe 311 is connected to the air flotation wastewater output pipe 212 via a pipeline;

[0107] An oil phase separation drain pipe 3210 connected to the oil phase separation space 321 is fixed on the outside of the dual-membrane separation container 32, and an aqueous phase separation drain pipe 3230 connected to the aqueous phase separation space 323 is fixed on the outside of the dual-membrane separation container 32.

[0108] like Figure 6 As shown, the biological treatment mechanism 40 includes a vertically placed biological treatment outer shell 41, and a biological treatment inner shell 42 coaxially arranged inside the biological treatment outer shell 41. An aerobic treatment space 410 is formed between the inner side wall of the biological treatment outer shell 41 and the outer side wall of the biological treatment inner shell 42, and an anaerobic treatment space 420 is formed inside the biological treatment inner shell 42.

[0109] Multiple aerobic treatment input pipes 411 connected to the aerobic treatment space 410 are fixed on the outside of the biological treatment outer shell 41, and an anaerobic treatment output pipe 421 that extends vertically and is connected to the anaerobic treatment space 420 is fixed on the top of the biological treatment outer shell 41.

[0110] The anaerobic treatment output pipe 421 is connected to the input end of the terminal filter 50 via a pipe;

[0111] An aeration conveying ring shell 43 is fixed at the bottom of the aerobic treatment space 410, and multiple aeration conveying nozzles 431 connected to the inside of the aeration conveying ring shell 43 are fixed at the top of the aeration conveying ring shell 43.

[0112] The top of the outer shell 41 of the biological treatment is fixed with an aeration overflow pipe 432 that is connected to the aerobic treatment space 410;

[0113] The aeration conveying ring shell 43 is connected to an existing air conveying pump through a pipeline, and the air conveying pump is used to deliver air into the aeration conveying ring shell 43.

[0114] like Figure 7 As shown, a space-separating ring shell 44 is fixed inside the outer shell 41 of the biological treatment and is coaxial with it. The space-separating ring shell 44 is located outside the inner shell 42 of the biological treatment. The side wall of the space-separating ring shell 44 has a plurality of treatment exchange through holes 441 that are radially through it. A layer of treatment exchange filter screen 440 is fixed on the outside of the space-separating ring shell 44. An exchange barrier ring shell 45 is rotatably connected to the inner side of the space-separating ring shell 44 and is coaxial with it. The side wall of the exchange barrier ring shell 45 has a plurality of treatment exchange mating holes 451 that are radially through it.

[0115] The processing exchange filter 440 is a commercially available 400-mesh filter of the prior art;

[0116] The top of the outer shell 41 of the biological treatment is fixed with an exchange opening and closing support ring rail 452 arranged coaxially thereon. An exchange opening and closing drive ring 453 is rotatably connected to the exchange opening and closing support ring rail 452, and the exchange opening and closing drive ring 453 is fixedly connected to the upper end of the exchange barrier ring shell 45.

[0117] The exchange opening and closing drive ring 453 is driven by a prior art servo motor fixed to the top of the inner shell 41 of the biological treatment via gear transmission to rotate around the axis of the exchange opening and closing support ring rail 452.

[0118] Example 2:

[0119] This embodiment describes a multi-stage modular oily wastewater purification method, based on the multi-stage modular oily wastewater purification equipment of Embodiment 1 above, including the following steps:

[0120] S1. Precipitation treatment:

[0121] The oily wastewater to be treated is transported to the initial sedimentation tank 10 and allowed to settle for 2 to 6 hours.

[0122] Removes larger suspended solids from oily wastewater;

[0123] S2, Oil separation treatment:

[0124] The oily wastewater after sedimentation is transported to the oil separator 11 and oil separation is carried out at a flow rate of 2-5 mm / s.

[0125] Removes larger suspended and floating oil droplets from oily wastewater;

[0126] S3, Air flotation treatment:

[0127] The oily wastewater after oil separation is transported into the flotation treatment tank 21 through the flotation wastewater inlet pipe 211, and the process is stopped after the tank is filled to 70% of its volume.

[0128] The oily wastewater in the flotation treatment tank 21 is aerated. High-pressure air is delivered into the air delivery ring 22 by an air delivery pump. The air pressure is set to 1 MPa. The high-pressure air is discharged through each air delivery nozzle 221 to form microbubbles. The microbubbles flow from bottom to top in the oily wastewater. Oil droplets can adhere to the microbubbles and float up and gather on the surface of the oily wastewater together with the microbubbles.

[0129] Meanwhile, some air will dissolve in the oily wastewater. When the air pressure in the flotation tank 21 reaches 1 MPa, aeration will stop.

[0130] At this time, the oily wastewater in the flotation tank 21 is in a dissolved air saturation state.

[0131] Open the oil foam discharge control valve 230 and control its opening degree. Under the high pressure of the air flotation treatment tank 21, the oil droplets that accumulate on the surface of the oily wastewater are discharged through the air flotation oil foam discharge pipe 23.

[0132] When the lower end of the air flotation oil mist discharge pipe 23 is equipped with a liquid level sensor, it is easy to control the lower end of the air flotation oil mist discharge pipe 23 to always be in contact with the liquid surface through the discharge lifting mechanism 26. During the discharge of high pressure air through the air flotation oil mist discharge pipe 23, the oil droplets that accumulate on the surface of the oily wastewater can be discharged through the air flotation oil mist discharge pipe 23 along with the air flow. After the oil droplets that accumulate on the surface of the oily wastewater are discharged, the oil mist discharge control valve 230 is closed.

[0133] In the external discharge lifting mechanism 26, the external discharge lifting drive rod 263 is an existing electrically controlled telescopic rod driven by a servo motor. When the inner rod of the external discharge lifting drive rod 263 extends, it can drive the external discharge lifting sliding cylinder 262 and the air flotation oil flotation external discharge pipe 23 to move upward together. When the inner rod of the external discharge lifting drive rod 263 retracts, it can drive the external discharge lifting sliding cylinder 262 and the air flotation oil flotation external discharge pipe 23 to move downward together. The signal from the liquid level sensor at the lower end of the air flotation oil flotation external discharge pipe 23 will provide feedback to limit the drive of the external discharge lifting drive rod 263, so that the lower end of the air flotation oil flotation external discharge pipe 23 is always in contact with the liquid surface.

[0134] S4, Cyclone dissolved gas treatment:

[0135] The vacuum pump 243 is used to evacuate the inside of the vacuum tank 240, so that the inside of the vacuum tank 240 is in a vacuum state. Then the evacuation is stopped and the vacuum pumping control valve 2420 is closed.

[0136] Then, the pressure reducing control valve 2410 is opened to connect the pressure reducing control vacuum tank 240 and the air flotation treatment tank 21 through the pressure reducing control connecting pipe 241. Due to the pressure difference, the high-pressure air in the air flotation treatment tank 21 will quickly enter the pressure reducing control vacuum tank 240 through the pressure reducing control connecting pipe 241, so that the air pressure in the pressure reducing control vacuum tank 240 is balanced with the air pressure in the air flotation treatment tank 21.

[0137] Under decompression, a large number of microbubbles will be released from the oily wastewater in the dissolved gas saturation state. These microbubbles are evenly dispersed and fill the oily wastewater. The suspended oil droplets in the oily wastewater can adhere to the microbubbles, and under the action of buoyancy, the microbubbles will carry the oil droplets to float up and gather on the surface of the oily wastewater.

[0138] Meanwhile, the low-speed stirring drive motor 256 drives the low-speed stirring drive shaft 251 to rotate through gear transmission. The low-speed stirring drive shaft 251 drives the low-speed stirring drive ring 253 and multiple low-speed stirring drive plates 254 to rotate together through multiple stirring drive connecting rods 252. The multiple low-speed stirring drive plates 254 drive and stir the oily wastewater in the flotation treatment tank 21, so that the oily wastewater rotates around the vertical axis of the flotation treatment tank 21 to generate swirling flow. The rotation speed of the low-speed stirring drive shaft 251 is 30 rad / min.

[0139] Because water is denser than oil, under centrifugal force, suspended oil droplets in oily wastewater will concentrate at the vertical axis of the flotation treatment tank 21. Open the oil foam discharge control valve 230 and control its opening degree so that the oil droplets concentrated at the vertical axis of the flotation treatment tank 21 are discharged through the flotation oil foam discharge pipe 23.

[0140] Open the flotation wastewater output control valve 2120, and the oily wastewater after the cyclone dissolved air treatment will be discharged through the flotation wastewater output pipe 212.

[0141] S5, membrane separation treatment;

[0142] The oily wastewater after cyclone dissolved air treatment is fed into a pair of dual-membrane separation storage cylinders 31. Under the action of its own weight pressure, the oily wastewater in the dual-membrane separation storage cylinders 31 enters the mixing input space 322 through the mixing input pipe 320.

[0143] The distance between the oil phase separation partition 33 and the water phase separation partition 34 is 5 mm;

[0144] Both the oil-phase separation hydrophobic membrane 330 and the aqueous-phase separation hydrophilic membrane 340 are selectively permeable membranes in the prior art.

[0145] When oily wastewater flows through the slits in the mixing input space 322, the hydrophilic membrane 340 selectively removes the aqueous phase from the oily wastewater, allowing the aqueous phase to pass through the hydrophilic membrane 340 into the aqueous phase separation space 323. This results in an increase in the relative concentration of the oil phase in the oily wastewater in the mixing input space 322, which further intensifies the collision, coalescence, and demulsification between oil droplets, thereby increasing the permeation flux of the oil phase. The oil phase in the oily wastewater will then pass through the hydrophobic membrane 330 into the oil phase separation space 321.

[0146] This allows the oil phase in the aqueous phase of oily wastewater to be separated;

[0147] The oil phase separated from the oily wastewater is discharged through the oil phase separation drain pipe 3210, and the aqueous phase separated from the oily wastewater is discharged through the aqueous phase separation drain pipe 3230.

[0148] S6. Biological treatment:

[0149] Oily wastewater is fed into the aerobic treatment space 410 through multiple aerobic treatment input pipes 411 for aerobic fermentation treatment;

[0150] Air is supplied to the interior of the aeration conveying ring 43 by an air delivery pump, and the air is discharged from each aeration conveying nozzle 431 to provide oxygen dissolved in the oily wastewater in the aerobic treatment space 410.

[0151] The aerobic treatment space 410 contains Pseudomonas polyphaga, Pseudomonas aeruginosa, Pseudomonas fluorescens, Flavobacterium breve, Bacillus subtilis, Bacillus licheniformis, and Bacillus breve.

[0152] Aerobic fermentation was carried out at 40℃ for 72 hours;

[0153] Next, the exchange opening and closing drive ring 453 is driven by a servo motor fixed inside the top of the biological treatment outer shell 41 to rotate around the axis of the exchange opening and closing support ring rail 452 through gear transmission. The exchange opening and closing drive ring 453 drives the exchange blocking ring shell 45 to rotate together, so that each processing exchange mating hole 451 and each processing exchange through hole 441 are connected one by one.

[0154] Oily wastewater in aerobic treatment space 410 enters anaerobic treatment space 420 through treatment exchange through hole 441 and treatment exchange matching hole 451 for anaerobic fermentation treatment.

[0155] The anaerobic treatment space 420 contains Clostridium acetonebutanol, Clostridium beyerii, Vibrio butyrica, Methanobacterium formate, thermoautotrophic methanobacterium, Methanococcus martensii, and methanogenic filamentous bacteria.

[0156] Aerobic fermentation was carried out at 40℃ for 72 hours;

[0157] The treated oily wastewater is discharged through anaerobic treatment outlet pipe 421;

[0158] S7. Filtration treatment:

[0159] The end filter 50 is an activated carbon filter. It is used to filter the oily wastewater after biological treatment, and completely remove the small amount of oil droplets remaining in the wastewater.

[0160] Example 3:

[0161] Based on Example 1, multiple pressure-reducing vacuum tanks 240 are provided, and each pressure-reducing vacuum tank 240 is connected to the interior of the air flotation treatment tank 21 through an independent pressure-reducing control connecting pipe 241. Each pressure-reducing vacuum tank 240 is connected to a pressure-reducing vacuum pump 243 through a separate vacuum extraction pipe 242.

[0162] The pressure-reducing control vacuum pump 243 is a vacuum pump of the prior art.

[0163] Example 4:

[0164] This embodiment describes a multi-stage modular oily wastewater purification method, based on the multi-stage modular oily wastewater purification equipment of Embodiment 3 above. The difference from Embodiment 2 is that a stepped cyclone dissolved air treatment is performed in step S4. When the air flotation treatment tank 21 is connected to a pressure reduction control vacuum tank 240, the pressure reduction control vacuum tank 240 is numbered Z1, Z2, Z3, and the corresponding pressure reduction control connecting pipe 241 and pressure reduction control valve 2410 are numbered G1, G2, G3 and F1, F2, F3, respectively.

[0165] Open pressure reducing control valve 2410 (number F1) to connect pressure reducing control vacuum tank 240 (number Z1) and air flotation treatment tank 21 through pressure reducing control connecting pipe 241 (number G1). After the air pressure in pressure reducing control vacuum tank 240 (number Z1) is balanced with the air pressure in air flotation treatment tank 21, close pressure reducing control valve 2410 (number F1).

[0166] Next, open pressure reducing control valve 2410 (number F2) to connect pressure reducing control vacuum tank 240 (number Z2) and air flotation treatment tank 21 through pressure reducing control connecting pipe 241 (number G2). After the air pressure in pressure reducing control vacuum tank 240 (number Z2) is balanced with the air pressure in air flotation treatment tank 21, close pressure reducing control valve 2410 (number F2).

[0167] Next, open pressure reducing control valve 2410 (number F3) to connect pressure reducing control vacuum tank 240 (number Z3) and air flotation treatment tank 21 through pressure reducing control connecting pipe 241 (number G3). After the air pressure in pressure reducing control vacuum tank 240 (number Z3) is balanced with the air pressure in air flotation treatment tank 21, close pressure reducing control valve 2410 (number F3).

[0168] The air flotation treatment tank 21 is subjected to step-by-step decompression, which causes a large number of microbubbles to precipitate out of the oily wastewater in batches. These microbubbles are evenly dispersed and fill the oily wastewater. The suspended oil droplets in the oily wastewater can adhere to the microbubbles, and under the action of buoyancy, the microbubbles will carry the oil droplets to float up and gather on the surface of the oily wastewater, which can more thoroughly separate the oil droplets in the oily wastewater.

[0169] Example 5:

[0170] Based on Example 3, such as Figure 3As shown, the dual-membrane separation storage cylinder 31 is provided with an auxiliary pressurization separation mechanism 35. The auxiliary pressurization separation mechanism 35 includes an auxiliary pressurization piston 351 that is slidably connected inside the dual-membrane separation storage cylinder 31. A vertically extending pressurization piston drive rod 352 is fixed to the top of the auxiliary pressurization piston 351. The upper end of the pressurization piston drive rod 352 extends upward to the outside of the dual-membrane separation storage cylinder 31.

[0171] A pressure-boosting drive fixed cylinder 353 with an upward opening is fixed on the outside of the dual-membrane separation temporary storage cylinder 31. A pressure-boosting drive sliding cylinder 354 is slidably connected inside the pressure-boosting drive fixed cylinder 353. The top of the pressure-boosting drive sliding cylinder 354 is fixedly connected to the upper end of the pressure-boosting piston drive rod 352.

[0172] The booster drive fixed cylinder 353 is provided with an auxiliary booster drive rod 355 for driving the booster drive sliding cylinder 354 to move up and down. The auxiliary booster drive rod 355 is an existing electrically controlled telescopic rod driven by a servo motor. The outer end of the auxiliary booster drive rod 355 is fixedly connected to the bottom of the booster drive fixed cylinder 353, and the inner end of the auxiliary booster drive rod 355 is fixedly connected to the top of the booster drive sliding cylinder 354.

[0173] like Figure 5 As shown, the auxiliary booster piston 351 has multiple forced flow holes 3510 that pass through it parallel to its axis. The lower end of the auxiliary booster piston 351 has a downward-facing shaft connection hole 356. An opening and closing disc shaft 357 is rotatably connected in the shaft connection hole 356. An opening and closing control disc 358 is fixed at the lower end of the opening and closing disc shaft 357. The top of the opening and closing control disc 358 is in a pressing contact with the lower end of the auxiliary booster piston 351. The opening and closing control disc 358 has multiple forced flow mating holes 3580 that pass through it parallel to the axis of the auxiliary booster piston 351.

[0174] An opening and closing disk drive motor 359 for driving the opening and closing disk shaft 357 to rotate is fixed in the shaft connection hole 356. The opening and closing disk drive motor 359 is a servo motor of the prior art. The output shaft of the opening and closing disk drive motor 359 drives the opening and closing disk shaft 357 to rotate through a planetary reducer of the prior art.

[0175] Example 6:

[0176] This embodiment describes a multi-stage modular oily wastewater purification method, based on a multi-stage modular oily wastewater purification device of embodiment 5 above. The difference from embodiment 4 is that in step S5, the auxiliary pressurization separation mechanism 35 is used to drive the oily wastewater in the double membrane separation temporary storage cylinder 31 to flow to the mixing input space 322.

[0177] The inner rod of the auxiliary booster drive rod 355 retracts, causing the booster drive sliding cylinder 354, together with the booster piston drive rod 352 and the auxiliary booster piston 351, to move downwards. The auxiliary booster piston 351 is used to compress the volume of the dual-membrane separation temporary storage cylinder 31, forcing the oily wastewater in the dual-membrane separation temporary storage cylinder 31 to flow more smoothly into the mixing input space 322.

[0178] The output shaft of the opening and closing disc drive motor 359 drives the opening and closing disc rotating shaft 357 to rotate through the existing planetary reducer transmission. The opening and closing disc rotating shaft 357 drives the opening and closing control disc 358 to rotate, controlling each forced flow mating hole 3580 to be connected to each forced flow hole 3510 in a one-to-one correspondence, or controlling each forced flow mating hole 3580 to be staggered and isolated from each forced flow hole 3510.

[0179] During the downward movement of the auxiliary booster piston 351, the forced flow mating holes 3580 and the forced flow holes 3510 are in a mutually misaligned and isolated state. During the upward movement of the auxiliary booster piston 351, the forced flow mating holes 3580 and the forced flow holes 3510 are in a connected state.

[0180] The auxiliary booster piston 351 reciprocates within the dual-membrane separation storage cylinder 31. During the upward return process of the auxiliary booster piston 351, it also forces the newly input oily wastewater through the forced flow mating hole 3580 and the forced flow hole 3510, which helps the suspended oil droplets in the oily wastewater to merge together to form larger oil droplets and gather together to float to the surface of the oily wastewater. The dual-membrane separation storage cylinder 31 is equipped with a liquid level sensor of the prior art. The feedback control input to the surface of the oily wastewater in the dual-membrane separation storage cylinder 31 is always just above the floating oil auxiliary drain pipe 312. The floating oil auxiliary drain pipe 312 is opened to discharge the oil droplets gathered on the surface of the oily wastewater, thereby reducing the workload of the oil phase separation hydrophobic membrane 330.

[0181] Example 7:

[0182] Based on Example 5, such as Figure 4 As shown, a double membrane separation back pressure mechanism 36 is provided on the outside of the double membrane separation container 32. The double membrane separation back pressure mechanism 36 includes a back pressure flow ring shell 361 fixed on the outside of the double membrane separation container 32. The mixing input space 322 is connected to the inside of the back pressure flow ring shell 361 through multiple back pressure flow holes 3610.

[0183] A back pressure flow ring shell 361 is fixed on the outside of which a back pressure discharge pipe 362 is connected to the inside. The back pressure discharge pipe 362 has a separation back pressure control valve 3620, which is an existing electric regulating valve driven and controlled by a servo motor.

[0184] The aerobic treatment input pipe 411 is connected to the return storage tank 363 via a pipeline;

[0185] The other end of the back pressure drain pipe 362 is connected to a reflux storage tank 363. The reflux storage tank 363 is equipped with a prior art transfer pump. The transfer pump is used to transfer the wastewater stored in the reflux storage tank 363 back to the dual membrane separation storage cylinder 31 for reflux treatment.

[0186] Example 8:

[0187] This embodiment describes a multi-stage modular oily wastewater purification method, based on the multi-stage modular oily wastewater purification equipment of Embodiment 7 above. The difference from Embodiment 6 is that, in step S5, during the flow of oily wastewater in the mixing input space 322, part of the oily wastewater enters the back pressure flow ring shell 361 through the back pressure flow hole 3610, and the opening of the separation back pressure control valve 3620 is controlled so that the flow rate into the back pressure flow ring shell 361 is 20% of the flow rate input into the mixing input space 322.

[0188] The oily wastewater in the back pressure flow ring shell 361 then enters the return storage tank 363 through the back pressure discharge pipe 362. The wastewater in the return storage tank 363 is then transported back to the dual membrane separation storage cylinder 31 for return treatment. The amount of wastewater in the return storage tank 363 is 20% of the total amount input into the dual membrane separation storage cylinder 31.

[0189] In step S6, the oily wastewater discharged from the back pressure drain pipe 362 is fed into the aerobic treatment space 410 through multiple aerobic treatment input pipes 411 for aerobic fermentation treatment.

Claims

1. A multi-stage modular oily wastewater purification device, characterized in that, It includes an initial sedimentation tank (10), an oil separator (11), a vortex dissolved air flotation mechanism (20), a dual membrane separation mechanism (30), a biological treatment mechanism (40), and an end filter (50) that are connected in sequence. The swirling dissolved air flotation mechanism (20) includes an air flotation treatment tank (21), with a hollow air delivery ring shell (22) fixed at the bottom of the air flotation treatment tank (21), and multiple air delivery nozzles (221) connected to the inside of the air delivery ring shell (22) fixed at the top. The top of the flotation treatment tank (21) is provided with a flotation oil foam discharge pipe (23), and the flotation oil foam discharge pipe (23) is provided with an oil foam discharge control valve (230). A pressure reduction control mechanism (24) is provided connected to the air flotation treatment tank (21). The pressure reduction control mechanism (24) includes a pressure reduction control vacuum tank (240) connected to the air flotation treatment tank (21) through a pressure reduction control connecting pipe (241). The pressure reduction control connecting pipe (241) has a pressure reduction control valve (2410). The pressure reduction control vacuum tank (240) is connected to a pressure reduction control vacuum pump (243) through a vacuum extraction pipe (242). The vacuum extraction pipe (242) has a vacuum extraction control valve (2420). Multiple pressure-reducing vacuum tanks (240) are provided, and each pressure-reducing vacuum tank (240) is connected to the interior of the air flotation treatment tank (21) through an independent pressure-reducing control connecting pipe (241). Each pressure-reducing vacuum tank (240) is connected to a pressure-reducing vacuum pump (243) through a separate vacuum extraction pipe (242). The air flotation treatment tank (21) is provided with a low-speed stirring mechanism (25) at the bottom. The low-speed stirring mechanism (25) includes a low-speed stirring drive shaft (251) that is rotatably connected to the bottom of the air flotation treatment tank (21) and extends vertically. The low-speed stirring drive shaft (251) is fixedly connected to a low-speed stirring drive ring (253) through multiple stirring drive connecting rods (252). Multiple vertically extending low-speed stirring drive plates (254) are fixed at the upper end of the low-speed stirring drive ring (253). The lower end of the air flotation tank (21) is fixed with a stirring drive housing (255), and the lower end of the low-speed stirring drive shaft (251) extends into the stirring drive housing (255). A low-speed stirring drive motor (256) for driving the low-speed stirring drive shaft (251) to rotate is fixed inside the stirring drive housing (255). The air flotation oil mist discharge pipe (23) is connected to the top of the air flotation treatment tank (21) through the discharge lifting mechanism (26). The top of the air flotation treatment tank (21) has a vertically penetrating sealed sliding hole (231). The air flotation oil mist discharge pipe (23) is slidably connected in the sealed sliding hole (231). The discharge lifting mechanism (26) includes a discharge lifting fixed cylinder (261) fixed on the top of the air flotation treatment tank (21) with its opening facing upward. A discharge lifting sliding cylinder (262) with its opening facing downward is slidably connected to the outside of the discharge lifting fixed cylinder (261). The discharge lifting sliding cylinder (262) is fixedly connected to the air flotation oil mist discharge pipe (23). The lower end of the air flotation oil mist discharge pipe (23) has a liquid level sensor. The outer discharge lifting fixed cylinder (261) is provided with an outer discharge lifting drive rod (263) for driving the outer discharge lifting sliding cylinder (262) to move up and down. The dual-membrane separation mechanism (30) includes a pair of vertically extending dual-membrane separation storage cylinders (31), and a horizontally extending dual-membrane separation receiving cylinder (32) is fixed between the dual-membrane separation storage cylinders (31) near the lower end. An oil phase separation partition (33) and an aqueous phase separation partition (34) are fixed inside the dual-membrane separation receiving cylinder (32). Multiple oil phase separation hydrophobic membranes (330) are fixed on the oil phase separation partition (33), and multiple water phase separation hydrophilic membranes (340) are fixed on the water phase separation partition (34). The portion of the dual-membrane separation container (32) between the oil phase separation partition (33) and the water phase separation partition (34) forms a mixing input space (322). The side of the oil phase separation partition (33) away from the water phase separation partition (34) forms an oil phase separation space (321), and the side of the water phase separation partition (34) away from the oil phase separation partition (33) forms a water phase separation space (323). The mixing input space (322) is connected to the interior of the dual-membrane separation storage cylinder (31) through the mixing input tube (320); The biological treatment mechanism (40) includes a vertically placed outer biological treatment shell (41), and a coaxially arranged inner biological treatment shell (42) is fixed inside the outer biological treatment shell (41). An aerobic treatment space (410) is formed between the inner side wall of the outer biological treatment shell (41) and the outer side wall of the inner biological treatment shell (42), and an anaerobic treatment space (420) is formed inside the inner biological treatment shell (42). The aerobic treatment space (410) has an aeration conveying ring shell (43) fixed at the bottom, and a plurality of aeration conveying nozzles (431) connected to the inside of the aeration conveying ring shell (43) are fixed at the top.

2. The multi-stage modular oily wastewater purification equipment according to claim 1, characterized in that, The top of the air flotation treatment tank (21) is fixed with an air flotation pressure relief pipe (213) that communicates with its interior, and the air flotation pressure relief pipe (213) has an air flotation pressure relief control valve (2130).

3. The multi-stage modular oily wastewater purification equipment according to claim 1, characterized in that, The dual-membrane separation storage cylinder (31) is provided with an auxiliary pressurization separation mechanism (35). The auxiliary pressurization separation mechanism (35) includes an auxiliary pressurization piston (351) slidably connected inside the dual-membrane separation storage cylinder (31). A vertically extending pressurization piston drive rod (352) is fixed at the top of the auxiliary pressurization piston (351). The upper end of the pressurization piston drive rod (352) extends upward to the outside of the dual-membrane separation storage cylinder (31). The outside of the dual-membrane separation temporary storage cylinder (31) is fixed with an upward-facing pressure-boosting drive fixed cylinder (353), and a pressure-boosting drive sliding cylinder (354) is slidably connected inside the pressure-boosting drive fixed cylinder (353). The top of the pressure-boosting drive sliding cylinder (354) is fixedly connected to the upper end of the pressure-boosting piston drive rod (352). The booster drive fixed cylinder (353) is provided with an auxiliary booster drive rod (355) for driving the booster drive sliding cylinder (354) to move up and down.

4. The multi-stage modular oily wastewater purification equipment according to claim 3, characterized in that, The auxiliary booster piston (351) has multiple forced flow holes (3510) that pass through it parallel to its axis. The lower end of the auxiliary booster piston (351) has a downward-facing shaft connection hole (356). A rotating shaft (357) of a start / stop disc is rotatably connected in the rotating shaft connection hole (356). A start / stop control disc (358) is fixed at the lower end of the start / stop disc (357). The top of the start / stop control disc (358) is in a pressing contact with the lower end of the auxiliary booster piston (351). The start / stop control disc (358) has multiple forced flow mating holes (3580) that pass through it parallel to the axis of the auxiliary booster piston (351). An opening and closing disk drive motor (359) for driving the opening and closing disk shaft (357) to rotate is fixed in the shaft connection hole (356).

5. The multi-stage modular oily wastewater purification equipment according to claim 1, characterized in that, The double membrane separation container (32) is provided with a double membrane separation back pressure mechanism (36) on the outside. The double membrane separation back pressure mechanism (36) includes a back pressure flow ring shell (361) fixed on the outside of the double membrane separation container (32). The mixing input space (322) is connected to the inside of the back pressure flow ring shell (361) through multiple back pressure flow holes (3610). The back pressure flow ring shell (361) is fixed with a back pressure drain pipe (362) that communicates with its interior. The back pressure drain pipe (362) has a separation back pressure control valve (3620). The other end of the back pressure drain pipe (362) is connected to a reflux storage tank (363).

6. A multi-stage modular oily wastewater purification method, based on the multi-stage modular oily wastewater purification equipment described in claim 1, characterized in that, Includes the following steps: S1. Precipitation treatment: The oily wastewater to be treated is transported to the initial sedimentation tank (10) and allowed to settle for 2 to 6 hours; S2, Oil separation treatment: The oily wastewater after sedimentation is transported to the oil separator (11) and oil separation is performed at a flow rate of 2~5 mm / s. S3, Air flotation treatment: The oily wastewater after oil separation is transported into the flotation tank (21) and the flow is stopped after it reaches 70% of the volume. Aeration is performed on the oily wastewater in the flotation treatment tank (21). High-pressure air is delivered to the air delivery ring (22) using an air delivery pump. The air pressure is set to 1 MPa. The high-pressure air is discharged through each air delivery nozzle (221) to form microbubbles. The microbubbles flow from bottom to top in the oily wastewater. Oil droplets can adhere to the microbubbles and float up and gather on the surface of the oily wastewater together with the microbubbles. Meanwhile, some air will dissolve in the oily wastewater. When the air pressure in the flotation tank (21) reaches 1 MPa, aeration will stop. At this time, the oily wastewater in the flotation tank (21) is in a dissolved air saturation state; Open the oil foam discharge control valve (230) and control its opening degree. Under the high pressure of the air flotation treatment tank (21), the oil droplets that accumulate on the surface of the oily wastewater are discharged through the air flotation oil foam discharge pipe (23). When the lower end of the air flotation oil droplet discharge pipe (23) is equipped with a liquid level sensor, the lower end of the air flotation oil droplet discharge pipe (23) is always in contact with the liquid surface. During the process of high pressure air being discharged through the air flotation oil droplet discharge pipe (23), the oil droplets that accumulate on the surface of the oily wastewater can be discharged through the air flotation oil droplet discharge pipe (23) along with the air flow. After the oil droplets that accumulate on the surface of the oily wastewater are discharged, the oil droplet discharge control valve (230) is closed. S4, Cyclone dissolved gas treatment: Under the pressure reduction action of the pressure reduction control mechanism (24), a large number of microbubbles will be released in the oily wastewater in the dissolved gas saturation state. These microbubbles are evenly dispersed and filled in the oily wastewater. The suspended oil droplets in the oily wastewater can adhere to the microbubbles, and under the action of buoyancy, the microbubbles will carry the oil droplets to float up and gather on the surface of the oily wastewater. At the same time, the low-speed stirring mechanism (25) drives the oily wastewater in the flotation treatment tank (21) to stir, so that the oily wastewater rotates around the vertical axis of the flotation treatment tank (21) to generate swirling flow. Since water is denser than oil, under centrifugal force, the suspended oil droplets in the oily wastewater will be concentrated at the vertical axis of the flotation treatment tank (21). Open the oil foam discharge control valve (230) and control its opening degree so that the oil droplets concentrated at the vertical axis of the flotation treatment tank (21) can be discharged through the flotation oil foam discharge pipe (23). Open the flotation wastewater output control valve (2120), and the oily wastewater after cyclone dissolved air treatment is discharged through the flotation wastewater output pipe (212); S5, membrane separation treatment; The oily wastewater after cyclone dissolved air treatment is fed into a pair of double membrane separation storage cylinders (31). Under the action of its own weight pressure, the oily wastewater in the double membrane separation storage cylinders (31) enters the mixing input space (322) through the mixing input pipe (320). The distance between the oil phase separation partition (33) and the water phase separation partition (34) is 5 mm; When oily wastewater flows through the slits in the mixing input space (322), the hydrophilic membrane (340) selectively removes the aqueous phase from the oily wastewater, allowing the aqueous phase to pass through the hydrophilic membrane (340) into the aqueous phase separation space (323). This results in an increase in the relative concentration of the oil phase in the oily wastewater in the mixing input space (322), which further intensifies the collision, coalescence, and demulsification between oil droplets, thereby increasing the permeation flux of the oil phase. The oil phase in the oily wastewater will then pass through the hydrophobic membrane (330) into the oil phase separation space (321). This allows the oil phase in the aqueous phase of oily wastewater to be separated; S6. Biological treatment: The oily wastewater is then fed into the aerobic treatment space (410) for aerobic fermentation treatment; Oily wastewater that has undergone aerobic fermentation treatment in the aerobic treatment space (410) then enters the anaerobic treatment space (420) for anaerobic fermentation treatment. S7. Filtration treatment: The end filter (50) is an activated carbon filter. The end filter (50) is used to filter the oily wastewater after biological treatment, and to completely remove the small amount of oil droplets remaining in the oily wastewater at this time.

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