A device of a two-way multi-stage rotary shearing high-speed multiphase flow hydraulic cavitation combined with a venturi pipe applied to landfill leachate treatment

Abstract

The application relates to a device of a two-way multi-stage rotary shearing high-speed multiphase flow hydraulic cavitation combined with a Venturi tube applied to landfill leachate treatment, and relates to the technical field of landfill leachate treatment. The device comprises a two-way high-speed shearing wheel set and a Venturi tube array. Waste water flows through the reverse series wheel set, the connecting section and the forward series wheel set in sequence, cavitation occurs at the wheel set outlet to generate free radicals, and the shearing structure is used to improve the mass transfer effect. The high-speed multiphase flow formed at the wheel set outlet passes through the flow body in the connecting section to form vortex flow, collides with the fluid sprayed by the Venturi tube array, strengthens the uniformity of the free radicals in the waste water, improves the dissolution amount of the gas treatment agent, and improves the cavitation effect of the subsequent wheel set. The total amount of free radicals at the outlet of the forward series wheel set is large and uniformly distributed, the free radical density at the outlet of the reverse series wheel set is large and the energy is high, and the two can be used to cooperatively remove ammonia nitrogen, chemical oxygen demand and other high-concentration organic pollutants in the leachate, as well as difficult-to-degrade trace new pollutants such as perfluoro / polyfluorinated compounds and microplastics.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of landfill leachate treatment, in particular to a device for landfill leachate treatment by using a two-way multi-stage rotating shearing high-speed multiphase flow hydraulic cavitation combined with a Venturi tube. BACKGROUND

[0002] Landfill leachate is a kind of complex wastewater with high pollution, and its treatment is very challenging. The organic pollutants in landfill leachate are of various types, and the content of organic pollutants is usually high, with large values of chemical oxygen demand (COD) and biochemical oxygen demand (BOD). In addition, it also contains new pollutants such as perfluorinated polyfluorinated compounds (PFAS) and microplastics, which are difficult to degrade and have low concentrations. The composition and concentration of organic pollutants change significantly with factors such as the age of the landfill site, climate conditions, and garbage composition. As the landfill time extends, the organic pollutants in the leachate become more difficult to biodegrade, leading to increased treatment difficulty. Some organic pollutants have strong toxicity and can cause serious harm to the ecological environment and human health.

[0003] The main methods for treating landfill leachate at home and abroad include physicochemical treatment, biological treatment, and land treatment. Hydraulic cavitation oxidation technology utilizes the high temperature, high pressure, and strong shock waves generated by hydraulic cavitation to produce strong oxidative hydroxyl radicals and other active oxygen species, thereby oxidizing and decomposing organic pollutants in water. Hydraulic cavitation technology has strong oxidation ability and rapid reaction, and can oxidize and decompose organic pollutants in a short time without secondary pollution and the need for additional chemical reagents, thus avoiding additional energy consumption. It is an energy-saving water treatment technology.

[0004] The hydraulic cavitation device directly affects the cavitation effect and water treatment effect. The hydraulic cavitation device can be divided into a Venturi tube cavitation generator, a orifice plate type cavitation generator, a rotating type cavitation generator and a vortex type cavitation generator, and the cavitation effects of different structures of cavitation generators are quite different. The patent No. ZL201210040830.8 proposes a combined hydraulic cavitation device for degrading organic matter in wastewater, which realizes a COD removal rate of 21.2% by connecting the Venturi tube assembly and the sieve plate in series. The patent No. 202410474247.0 proposes a wastewater treatment method combining oxidation and hydraulic cavitation, which realizes a COD conversion rate of 96% by connecting the cavitation generator and the wet oxidation reactor in series, which is improved from 85% when only hydraulic cavitation is used. The reported hydraulic cavitation oxidation technology and its combination technology mainly report the removal effect of conventional organic matters such as COD and ammonia nitrogen, and the removal effect of trace and refractory new pollutants is limited. Therefore, it is necessary to develop a hydraulic cavitation device for the simultaneous treatment of new pollutants such as perfluorinated polyfluorinated compounds and microplastics in landfill leachate, and ammonia nitrogen, COD, BOD and other organic matters. SUMMARY

[0005] The purpose of the present application is to provide a device for the treatment of landfill leachate by using a two-way multi-stage rotary shear high-speed multiphase flow hydraulic cavitation combined with a Venturi tube. The device is aimed at various organic pollutants in landfill leachate and leachate concentrate. The high-density hydroxyl radicals generated by the reverse series wheel set are used to remove trace pollutants, and the large number of uniformly distributed hydroxyl radicals generated by the forward series wheel set are used to remove high-concentration organic pollutants, so as to realize the removal of various organic pollutants in landfill leachate.

[0006] In order to achieve the above purpose, the present application provides a device for the treatment of landfill leachate by using a two-way multi-stage rotary shear high-speed multiphase flow hydraulic cavitation combined with a Venturi tube. The device comprises a motor, a shaft assembly, a housing, a reverse series wheel set, a forward series wheel set, a Venturi tube, a flow body and a shaft coupling. The reverse series wheel set and the forward series wheel set are installed at opposite ends of the housing and are connected by the shaft assembly. The motor is installed at the end of the housing and is connected to the shaft assembly. The housing is provided with a water inlet near one end of the reverse series wheel set, and is provided with a water outlet near one end of the forward series wheel set.

[0007] The leachate of the landfill to be treated enters the reverse series wheel set along the radial direction through the water inlet, and then enters the forward series wheel set through the connecting section of the housing. The connecting section is provided with a Venturi tube and a flow body. The flow body is arranged upstream of the Venturi tube, and the Venturi tube is used to supplement gas or liquid into the leachate.

[0008] In an optional embodiment, the installation direction of the reverse rotation series wheel set on the shaft assembly is opposite to that of the forward rotation series wheel set, the reverse rotation series wheel set and the forward rotation series wheel set comprise 1-5 stages of shearing wheel sets, and the shearing wheel sets comprised by the reverse rotation series wheel set and the forward rotation series wheel set can be inconsistent.

[0009] In an optional embodiment, the shaft assembly comprises a transmission shaft, a bearing and a protective sleeve, the bearing is sleeved on the transmission shaft, the protective sleeve is sleeved on the bearing, the diameter d of the transmission shaft and the diameter D of the connecting section have a ratio of 0.1-0.4, and the diameter d of the transmission shaft is positively correlated with the rotational speed.

[0010] In an optional embodiment, the reverse rotation series wheel set comprises a plurality of reverse rotation shearing wheel sets arranged in sequence, and each reverse rotation shearing wheel set comprises a fixed shearing wheel, a rotating wheel and a movable shearing wheel arranged in sequence, wherein the fixed shearing wheel is provided with bolt holes and flow guide grooves, the fixed shearing wheel is connected to the shell through the bolt holes, the movable shearing wheel is provided with shearing blocks, and the movable shearing wheel and the rotating wheel are driven by the shaft assembly.

[0011] In an optional embodiment, the movable shearing wheel is close to the water inlet relative to the fixed shearing wheel, the diameter of the movable shearing wheel is smaller than the inner diameter of the shell, and a channel for percolate passing is formed between the edge of the movable shearing wheel and the inner surface of the shell.

[0012] In an optional embodiment, the central hole of the fixed shearing wheel and the central hole of the rotating wheel are in communication to form a water flow channel, when the reverse rotation series wheel set rotates, the flow guide grooves on the edge of the fixed shearing wheel and the shearing blocks on the edge of the rotating movable shearing wheel form a shearing action, which intensifies the cavitation phenomenon of the percolate and forms asymmetric cavitation bubbles.

[0013] In an optional embodiment, a plurality of flow guide grooves are uniformly arranged on the edge of the fixed shearing wheel, a plurality of shearing blocks are uniformly arranged on the edge of the movable shearing wheel, the number of the flow guide grooves and the number of the shearing blocks are consistent, and the number is 6-12.

[0014] In an optional embodiment, the number of the flow guide grooves in the reverse rotation series wheel set is smaller than the number of the flow guide grooves in the forward rotation series wheel set.

[0015] In an optional embodiment, the inlet flow of the reverse rotation series wheel set is 20-200 kg / min, the inlet pressure is 0.5-5 MPa, the rotational speed is 1000-8000 rpm, and the rotational speed is inversely proportional to the inlet flow and the inlet pressure.

[0016] In an optional embodiment, the Venturi tube and the flow-around body are arranged in groups, the flow passes through the flow-around body to form a vortex downstream, and the collision effect of the fluid at the outlet of the Venturi tube is improved.

[0017] In an optional embodiment, the number of Venturi tubes and the number of flow-around bodies is 4-10, the installation angle of the Venturi tubes relative to the flow direction in the connecting section is 0-30°, the ratio of the diameter dw of the Venturi tube to the diameter D of the connecting section is 0.1-0.3, dw is inversely proportional to the diameter d of the transmission shaft, the installation height of the Venturi tube is 0.1-0.2D from the pipe wall of the connecting section, and the jet flow cross section of the outlet of the Venturi tube fully covers the cross section of the connecting section.

[0018] In an optional embodiment, the gas or liquid jetted by the Venturi tube includes at least one of air, oxygen, ozone and recycled treated effluent.

[0019] In an optional embodiment, the Venturi tubes and flow-around bodies are arranged at the outlet of the reverse rotation series wheel set and the inlet of the positive rotation series wheel set, and the Venturi tubes with the same flow direction as the water flow in the connecting section will work when the device is running, and the Venturi tubes with the opposite flow direction will be in a closed state.

[0020] Through the above technical solution, the leachate to be treated enters the reverse rotation series wheel set along the radial direction through the water inlet, and then enters the positive rotation series wheel set through the connecting section. The connecting section is provided with Venturi tubes at both ends, which are used to supplement gas or liquid into the leachate. The gas or liquid is accelerated and jetted out through the Venturi tube, mixed with the incoming leachate to form a high-speed multiphase flow, thereby improving the cavitation effect in the wheel set. The hydroxyl radical density is high and the energy is high at the outlet of the shear wheel set of the reverse rotation series wheel set, which can be used for the removal of refractory and trace organic pollutants. The total amount of hydroxyl radicals is large and the distribution is uniform at the outlet of the shear wheel set of the positive rotation series wheel set, which can be used for the removal of high-concentration organic pollutants such as ammonia nitrogen and chemical oxygen demand (COD). The effluent that does not meet the standard at the outlet is introduced into the device through the water inlet for further treatment, or discharged after meeting the standard, thereby realizing the removal of various organic pollutants in the landfill leachate. The device provided in the embodiment has the advantages of strong applicability, good cavitation effect, reliable structure and the like.

[0021] Other features and advantages of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 The structural schematic diagram of the device for landfill leachate treatment provided by the bidirectional multi-stage rotary shear high-speed multiphase flow hydraulic cavitation combined with Venturi tube of the embodiments of the present application;

[0024] Figure 2 For Figure 1 Structure diagram of reverse series wheel group in the middle;

[0025] Figure 3 Structure diagram of reverse series wheel group in the middle;

[0026] Figure 4 Structure diagram of reverse series wheel group in the middle;

[0027] Figure 5 Structure diagram of reverse series wheel group in the middle;

[0028] Figure 6 Structure diagram of reverse series wheel group in the middle;

[0029] Figure 7 Structure diagram of reverse series wheel group in the middle;

[0030] Figure 8 Structure diagram of reverse series wheel group in the middle;

[0031] Figure 9 Structure diagram of reverse series wheel group in the middle;

[0032] Figure 10 Structure diagram of reverse series wheel group in the middle;

[0033] Figure: 1-motor; 2-axis assembly; 21-transmission shaft; 22-bearing; 23-protective sleeve; 3-housing; 31-water inlet; 32-water outlet; 4-reverse series wheel group; 41-first stage reverse shear wheel group; 42-second stage reverse shear wheel group; 43-third stage reverse shear wheel group; 411-fixed shear wheel; 412-rotary wheel; 413-moving shear wheel; 4111-bolt hole; 4112-flow guide groove; 4131-shear block; 5-forward series wheel group; 51-first stage forward shear wheel group; 52-second stage forward shear wheel group; 53-third stage forward shear wheel group; 6-venturi tube; 7-flowing body; 8-coupling. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] In the description of the present application, it should be pointed out that the positions or location relationships indicated by the terms "in", "out" and the like are based on the positions or location relationships shown in the drawings, or the positions or location relationships commonly placed when the products of the present application are used, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used for differentiation in description and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present application, it should be pointed out that unless otherwise explicitly specified and limited, the terms "provided", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0037] Please refer to Figure 1 The embodiment provides a device for applying a two-way multi-stage rotary shear high-speed multiphase flow hydraulic cavitation combined Venturi tube to landfill leachate treatment (hereinafter referred to as: device), which uses high-speed multiphase flow coupling Venturi effect. Specifically, the device comprises a two-way high-speed shear wheel set and a Venturi tube array, wherein the two-way high-speed shear wheel set comprises a motor 1, a shaft assembly 2, a shell 3, a reverse rotation tandem wheel set 4, a forward rotation tandem wheel set 5, a flow body 7 and a shaft coupling 8, and the Venturi tube array comprises a plurality of Venturi tubes 6.

[0038] The reverse rotation tandem wheel set 4 and the forward rotation tandem wheel set 5 are installed at opposite ends in the shell 3 and are connected through the shaft assembly 2, and the installation direction of the reverse rotation tandem wheel set 4 and the forward rotation tandem wheel set 5 on the shaft assembly 2 is opposite. The motor 1 is installed at one end of the shell 3 and is connected to one end of the shaft assembly 2, and the shell 3 is provided with a shaft coupling 8 at both ends and is connected to both ends of the shaft assembly 2. In the embodiment, the reverse rotation tandem wheel set 4 is arranged close to the motor 1 compared with the forward rotation tandem wheel set 5.

[0039] Please refer to Figures 5 to 7 The shaft assembly 2 comprises a transmission shaft 21, a bearing 22 and a protective sleeve 23, the bearing 22 is sleeved on the transmission shaft 21, and the protective sleeve 23 is sleeved on the bearing 22, the ratio of the diameter d of the transmission shaft 21 to the diameter D of the connecting section is 0.1-0.4, and the value of the diameter d of the transmission shaft 21 is positively correlated with the rotational speed. The number of Venturi tubes 6 and flow bodies 7 is 4-10 groups (please refer to Figure 7 , Figure 7A Venturi tube 6 and a structure of 4 groups of fluid 7 around the flow are shown, and a structure of 10 groups of fluid 7 around the flow is also shown, the installation angle a of the Venturi tube 6 relative to the flow direction in the connecting section is 0-30°, the included angle of the adjacent two Venturi tubes 6 can also be a, the ratio of the diameter dw of the Venturi tube 6 to the diameter D of the connecting section is 0.1-0.3, the value of dw is inversely proportional to the diameter d of the transmission shaft 21, the installation height of the Venturi tube 6 is 0.1-0.2D away from the pipe wall of the connecting section, which ensures that the fluid injection cross section of the outlet of the Venturi tube 6 fully covers the cross section of the connecting section.

[0040] The water inlet 31 is arranged on the shell 3 near one end of the reverse series wheel set 4, and the water outlet 32 is arranged on the shell 3 near one end of the positive series wheel set 5; the leachate of the waste to be treated enters the reverse series wheel set 4 along the radial direction through the water inlet 31, and then enters the positive series wheel set 5 through the connecting section of the shell 3, the connecting section is provided with a Venturi tube 6 and a fluid 7 around the flow, and the fluid 7 around the flow is arranged upstream of the Venturi tube 6. The Venturi tube 6 and the fluid 7 around the flow are arranged in groups, and the flow passing through the fluid 7 around the flow forms a vortex downstream, which enhances the collision effect of the fluid at the outlet of the Venturi tube 6.

[0041] The Venturi tube 6 is used to supplement gas or liquid to the leachate, and the gas or liquid is accelerated and sprayed out through the Venturi tube 6, mixed with the incoming leachate to form a high-speed multiphase flow. The shear wheel set outlet of the reverse series wheel set 4 has high hydroxyl radical density and high energy, which can be used for the removal of difficult-to-degrade and trace organic pollutants (such as new pollutants of perfluoro / polyfluoro compounds), the shear wheel set outlet of the positive series wheel set 5 has large total amount of hydroxyl radicals and uniform distribution, which can be used for the removal of high-concentration organic pollutants such as ammonia nitrogen and chemical oxygen demand (COD), and the non-compliant leachate at the water outlet 32 is introduced into the device through the water inlet 31 for further treatment, or discharged after reaching the standard, so as to realize the removal of various organic pollutants in the leachate.

[0042] The reverse series wheel set 4 and the positive series wheel set 5 are respectively composed of a plurality of shear wheel sets in series, and the number of shear wheel sets contained in the reverse series wheel set 4 and the positive series wheel set 5 can be inconsistent, and the number of wheel sets can be increased or decreased according to the treatment effect.

[0043] In this embodiment, the reverse series wheel group 4 includes three reverse shearing wheel groups arranged in sequence. The water flow in the reverse series wheel group 4 flows in from the edge of the first-stage reverse shearing wheel group 41 in the radial direction, and flows out from the center hole of the first-stage reverse shearing wheel group 41, and then flows through the second-stage reverse shearing wheel group 42 and the third-stage reverse shearing wheel group 43 in sequence. The high-speed multiphase flow then enters the forward series wheel group 5 through the connecting section, and the water flow in the first-stage forward shearing wheel group 51 flows in in the axial direction, and flows out in the radial direction from the edge of the forward shearing wheel group, and then flows through the second-stage forward shearing wheel group 52 and the third-stage forward shearing wheel group 53 in sequence. Downstream of the water flow flowing through the shearing wheel groups, due to the huge pressure difference between the inlet and outlet, the leachate to be treated will cavitate near the center hole of the reverse shearing wheel group and in the edge area of the forward shearing wheel group. In addition, due to the layer-by-layer pressurization of the leachate to be treated through the shearing wheel groups, the liquid flow rate at the outlet of the shearing wheel groups gradually increases, the pressure difference between the inlet and outlet of the shearing wheel groups increases, and the cavitation phenomenon will intensify.

[0044] The number of shearing wheel groups in the forward series wheel group 5 and the reverse series wheel group 4 can be increased or decreased according to the treatment effect. When the concentration of difficult-to-treat micro-pollutants is high, the number of stages of the reverse series wheel group 4 can be appropriately increased. When the concentration of conventional pollutants such as ammonia nitrogen and COD is high, the number of stages of the forward series wheel group 5 can be appropriately increased. In addition, the forward series wheel group 5 and the reverse series wheel group 4 can be switched by changing the direction of the motor 1. This operation can effectively solve the problem of shearing wheel group blockage.

[0045] The Venturi tube 6 includes two groups, each group containing 4-10 pipes, and being uniformly arranged on the circumference of the connecting section. When the device is running, the Venturi tube 6 in the same direction as the water flow will work, and at least one of air, oxygen, ozone, and recycled treated water is injected by the Venturi tube 6. A high-speed airflow is formed at the outlet of the Venturi tube 6, and after the leachate flows through the flow body 7, a vortex is formed downstream. The fluid injected by the Venturi tube 6 collides and mixes with the leachate vortex, improving the solubility of the gas in the leachate, and further improving the cavitation effect in the subsequent wheel groups. In addition, according to the treatment effect of the leachate, a portion of the outlet water of the device can also be introduced into the Venturi tube 6 to complete the collision and mixing with the wastewater to be treated, thereby improving the recycling treatment effect of the wastewater to be treated.

[0046] The Venturi tube 6 and the flow body 7 are arranged at the outlet of the reverse series wheel group 4 and the inlet of the forward series wheel group 5. When the device is running, the Venturi tube 6 in the same direction as the water flow in the connecting section will work, and the Venturi tube 6 in the opposite direction will be in a closed state.

[0047] Please refer to Figures 2 to 4, the reverse shear wheel group comprises, which are sequentially stacked, a fixed shear wheel 411, a rotating wheel 412 and a movable shear wheel 413, wherein the movable shear wheel 413 is close to the water inlet 31 relative to the fixed shear wheel 411, the fixed shear wheel 411 is provided with bolt holes 4111 and flow guide grooves 4112, the fixed shear wheel 411 is connected to the shell 3 through the bolt holes 4111, and the movable shear wheel 413 is provided with shear blocks 4131, and the movable shear wheel 413 and the rotating wheel 412 are driven by the shaft assembly 2.

[0048] The diameter of the movable shear wheel 413 is smaller than the inner diameter of the shell 3, and a channel for percolate passing is formed between the edge of the movable shear wheel 413 and the inner surface of the shell 3. The central hole of the fixed shear wheel 411 and the central hole of the rotating wheel 412 are communicated to form a water flow channel, when the reverse series wheel group 4 rotates, the flow guide grooves 4112 on the edge of the fixed shear wheel 411 and the shear blocks 4131 on the edge of the rotating movable shear wheel 413 form a shearing action, which intensifies the cavitation phenomenon of the percolate and forms an asymmetric cavity, thereby improving the mass transfer rate.

[0049] A plurality of flow guide grooves 4112 are uniformly arranged on the edge of the fixed shear wheel 411, a plurality of shear blocks 4131 are uniformly arranged on the edge of the movable shear wheel 413, the number of the flow guide grooves 4112 and the shear blocks 4131 is consistent, and the number is 6-12. The number of the flow guide grooves 4112 in the reverse series wheel group 4 is less than the number of the flow guide grooves 4112 in the forward series wheel group 5, so as to weaken the inlet resistance, and the number of the flow guide grooves 4112 in the forward series wheel group 5 is taken as a large value, so as to improve the shearing action.

[0050] The inlet flow of the reverse series wheel group 4 is 20kg / min-200kg / min, the inlet pressure is 0.5-5MPa, the rotating speed is 1000r / min-8000r / min, and the rotating speed and the inlet flow are inversely proportional, and the required pressure difference between the inlet and the outlet of the shear wheel group for cavitation is realized by adjusting the rotating speed, the inlet pressure or the flow. When the number of shear wheel groups increases, the inlet flow / pressure or the rotating speed can be appropriately reduced.

[0051] Embodiment 1

[0052] The device provided in the specific embodiment is used, ANSYS software is used for fluid mechanics calculation of the device, the simulation part is the forward series wheel group 5, the number of the flow guide grooves 4112 and the shear blocks 4131 is 10, the inlet flow is 180kg / min, and the rotating speed is forward 6000r / min, and the bubble rate, the hydroxyl radical distribution and the volume fraction flow line in the single-stage shear wheel group are as follows: Figures 8 to 10The maximum cavitation rate in the forward rotating shear wheel group is 86.33%, and the average cavitation rate is 25.36%. The hydroxyl radicals are mainly distributed at the radial outlet of the shear wheel group. The local maximum volume fraction of the hydroxyl radicals is 16.1%. The hydroxyl radicals are uniformly distributed along the circumference of the shear wheel group. The maximum flow rate through the outlet of the shear wheel group is about 0.83 / s.

[0053] Example 2

[0054] The other conditions are the same as in Example 1. The rotation direction of the shear wheel group is changed. The rotation speed of the shear wheel group is 6000 rpm in the reverse direction. The cavitation rate, the distribution of the hydroxyl radicals, and the flow rate of the volume fraction of the hydroxyl radicals in the single-stage shear wheel group in the reverse direction are shown in Table 2. Figures 8 to 10 The maximum cavitation rate in the reverse rotating shear wheel group is 54.86%, and the average cavitation rate is 1.55%. The hydroxyl radicals are mainly concentrated at the center outlet. The maximum volume fraction of the hydroxyl radicals is about 8.40%. The hydroxyl radicals are concentrated in the outlet pipeline in the reverse direction. The maximum flow rate is about 337 / s.

[0055] It can be seen that the volume fraction of the hydroxyl radicals at the outlet of the shear wheel group is large in the forward direction, but the maximum flow rate is much smaller. The hydroxyl radicals are relatively uniformly distributed at the outlet of the shear wheel group, which can be used for the removal of a large amount of conventional organic matter. In the reverse direction, although the maximum volume fraction of the hydroxyl radicals is 8.4%, the maximum flow rate reaches 337 / s. The hydroxyl radicals are concentrated in the outlet pipeline, and the energy density is high, which can be used for the removal of residual and trace organic pollutants. The leachate is treated by circulating through the forward rotating shear wheel group 5 and the reverse rotating shear wheel group 4 until it meets the discharge standard.

[0056] The device provided by the embodiment of the bidirectional multi-stage rotating shear high-speed multiphase flow hydraulic cavitation combined with a Venturi tube for treating landfill leachate has the following beneficial effects:

[0057] The leachate of the landfill to be treated enters the reverse rotating shear wheel group 4 from the water inlet 31 in the radial direction, and then enters the forward rotating shear wheel group 5 through the connecting section. The connecting section is provided with a Venturi tube 6 at both ends, which is used to supplement gas or liquid into the leachate. The gas or liquid is sprayed out after being accelerated through the Venturi tube 6, mixed with the incoming leachate to form a high-speed multiphase flow, thereby improving the cavitation effect in the shear wheel group.

[0058] The hydroxyl radical density is high and the energy is high at the outlet of the reverse rotating shear wheel group 4, which can be used for the removal of difficult-to-degrade and trace organic pollutants. The total amount of hydroxyl radicals is large and uniformly distributed at the outlet of the forward rotating shear wheel group 5, which can be used for the removal of high-concentration organic pollutants such as ammonia nitrogen and chemical oxygen demand (COD). The non-compliant leachate at the water outlet 32 is introduced into the device through the water inlet 31 for further treatment, or discharged after meeting the standard, thereby realizing the removal of various organic pollutants in the landfill leachate.

[0059] The device provided by the embodiment has the advantages of strong applicability, good cavitation effect and reliable structure.

[0060] It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0061] The above is only the preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A device for landfill leachate treatment by using a two-way multi-stage rotary shear high-speed multiphase flow hydraulic cavitation combined with a Venturi tube, characterized in that, The device comprises a motor (1), a shaft assembly (2), a shell (3), a reverse tandem wheel set (4), a forward tandem wheel set (5), a Venturi tube (6), a flow body (7) and a shaft coupling (8), the reverse tandem wheel set (4) and the forward tandem wheel set (5) are installed at opposite ends of the shell (3) and connected by the shaft assembly (2), the motor (1) is installed at the end of the shell (3) and connects the shaft assembly (2) through the shaft coupling (8), a water inlet (31) is arranged on the shell (3) near one end of the reverse tandem wheel set (4), and a water outlet (32) is arranged on the shell (3) near one end of the forward tandem wheel set (5); The leachate of the garbage to be treated enters the reverse tandem wheel set (4) from the water inlet (31) in the radial direction, and then enters the forward tandem wheel set (5) through the connecting section of the shell (3), the connecting section is provided with the Venturi tube (6) and the flow body (7), the flow body (7) is arranged upstream of the Venturi tube (6), and the Venturi tube (6) is used for supplementing gas or liquid into the leachate.

2. The device according to claim 1, wherein the device is used for treatment of landfill leachate. The installation direction of the reverse tandem wheel set (4) and the forward tandem wheel set (5) on the shaft assembly (2) is opposite.

3. The device according to claim 1, wherein the device is used for treatment of landfill leachate. The shaft assembly (2) comprises a transmission shaft (21), a bearing (22) and a protective sleeve (23), the bearing (22) is sleeved on the transmission shaft (21), the protective sleeve (23) is sleeved on the bearing (22), the diameter d of the transmission shaft (21) and the diameter D of the connecting section have a ratio of 0.1-0.4, and the diameter d of the transmission shaft (21) is positively correlated with the rotational speed.

4. The device according to claim 1, wherein the device is used for treatment of landfill leachate. The reverse tandem wheel set (4) comprises a plurality of reverse shear wheel sets arranged at intervals, the reverse shear wheel set comprises a fixed shear wheel (411), a rotating wheel (412) and a movable shear wheel (413) arranged in layers, the fixed shear wheel (411) is provided with a bolt hole (4111) and a flow guide groove (4112), the fixed shear wheel (411) is connected to the shell (3) through the bolt hole (4111), the movable shear wheel (413) is provided with a shear block (4131), and the movable shear wheel (413) and the rotating wheel (412) are driven by the shaft assembly (2).

5. The device according to claim 4, wherein the device is used for treatment of landfill leachate. The movable shear wheel (413) is close to the water inlet (31) relative to the fixed shear wheel (411), the diameter of the movable shear wheel (413) is smaller than the inner diameter of the shell (3), and the edge of the movable shear wheel (413) and the inner surface of the shell (3) form a channel for the leachate to pass through.

6. The device according to claim 5, wherein the device is used for treatment of landfill leachate. The central hole of the fixed shear wheel (411) and the central hole of the rotating wheel (412) are communicated to form a water flow channel, when the reverse tandem wheel set (4) rotates, the driving flow guide groove (4112) at the edge of the fixed shear wheel (411) and the shear block (4131) at the edge of the rotating movable shear wheel (413) form a shearing action, which intensifies the cavitation phenomenon of the leachate and forms an asymmetric cavity.

7. The device according to claim 6, wherein the device is used for treatment of landfill leachate. A plurality of the guide grooves (4112) are uniformly arranged on the edge of the fixed shearing wheel (411), and a plurality of the shearing blocks (4131) are uniformly arranged on the edge of the movable shearing wheel (413), the number of the guide grooves (4112) and the shearing blocks (4131) is consistent, and the number is 6-12.

8. The device according to claim 7, wherein the device is used for treatment of landfill leachate. The number of the guide grooves (4112) in the reverse rotation series wheel group (4) is less than the number of the guide grooves (4112) in the forward rotation series wheel group (5), so as to weaken the inlet resistance of the reverse rotation series wheel group (4).

9. The device according to claim 1, wherein the device is used for treatment of landfill leachate. The inlet flow of the reverse rotation series wheel group (4) is 20-200 kg / min, the inlet pressure is 0.5-5 MPa, the rotating speed is 1000-8000 rpm, and the rotating speed is inversely proportional to the inlet flow and pressure.

10. The device according to claim 3, wherein the device is used for treatment of landfill leachate. The venturi (6) and the flow-around body (7) are arranged in groups, and the flow around the flow-around body (7) forms a vortex downstream to improve the collision effect with the fluid at the outlet of the venturi (6).

11. The device according to claim 10, wherein the device is used for treatment of landfill leachate. The gas or liquid injected by the venturi (6) includes at least one of air, oxygen, ozone and recycled treated water.

12. The device according to claim 10, wherein the device is used for treatment of landfill leachate. The number of the venturi (6) and the flow-around body (7) is 4-10 groups, the installation angle α of the venturi (6) relative to the flow direction in the connecting section is 0-30°, the ratio of the diameter dw of the venturi (6) to the diameter D of the connecting section is 0.1-0.3, the value of dw is inversely proportional to the diameter d of the transmission shaft (21), the installation height of the venturi (6) is 0.1-0.2D away from the pipe wall of the connecting section, so as to ensure that the fluid injection cross section of the venturi (6) outlet fully covers the cross section of the connecting section.

13. The device according to claim 10, wherein the device is used for treatment of landfill leachate. The venturi (6) and the flow-around body (7) are arranged at the outlet of the reverse rotation series wheel group (4) and the inlet of the forward rotation series wheel group (5), and the venturi (6) with the same flow direction as the water flow direction in the connecting section will work during the operation of the device, and the venturi (6) with the opposite direction will be in a closed state.

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