A wastewater deep treatment process using an ejector and ozone catalytic oxidation

Abstract

The present invention relates to an ejector and an ozone catalytic oxidation wastewater deep treatment process. The present invention discloses an ejector design, an ozone catalytic oxidation and a residual ozone treatment process. Through reasonable settings, the added ozone is effectively utilized. The cavitation number and the cavitation starting point are optimized by designing the shape of the ejector's gradually shortened nozzle, and the ozone mass transfer coefficient is improved by combining ultrasonic cavitation. The influence of the non-steady-state magnetic field generated by the optimized magnetic shear on the water molecule clusters is combined to balance the contradiction between the magnetic field and the cavitation bubble, improve the efficiency of free radical generation, stabilize the number of free radicals, and improve the ozone solubility and catalytic oxidation capabilities. The residual ozone treatment process is adopted, and an activated carbon-loaded manganese dioxide catalyst is used as the filler of the fluidized bed. An ultraviolet or near-infrared irradiation device is provided to coordinate with activated carbon and electromagnetic waves to treat residual ozone. The synergistic effect of manganese dioxide, activated carbon and electromagnetic waves can significantly improve the treatment efficiency of residual ozone and enhance the stability and water resistance of the catalyst. The invention solves the problems in the existing ozone catalytic oxidation process, such as low ozone dissolution efficiency in water, unstable number of free radicals, low ozone utilization rate, and influence of residual ozone on subsequent units.

Description

Technical Field

[0001] The invention relates to the field of sewage treatment, and in particular to an ejector and an ozone catalytic oxidation wastewater deep treatment process. Background Art

[0002] With the rapid development of my country's industry and the acceleration of the industrialization process, a large number of difficult-to-degrade organic pollutants are discharged into water bodies. These pollutants have low concentrations in water, are difficult to degrade, are highly toxic and persistent, and pose a potential threat to human health and ecosystems. The shortage of water resources has become increasingly prominent, and zero-discharge technology for wastewater has therefore become the focus of the wastewater treatment industry. Traditional water treatment technologies are often difficult to effectively remove these highly stable organic pollutants. In the process of achieving zero discharge of industrial wastewater and improving the treatment standards of sewage treatment plants, how to effectively remove difficult-to-degrade organic matter has become a major challenge. The notable characteristics of these difficult-to-degrade organic matter include long molecular chains, high chemical bond energies and stable chemical structures, which make them difficult to be directly decomposed by biochemical methods.

[0003] Ozone catalytic oxidation, as an advanced oxidation process (AOPs), shows great potential in water treatment due to its high efficiency and environmental friendliness. The core of the advanced oxidation process is to eliminate refractory organic matter in wastewater by using the strong oxidizing properties of hydroxyl radicals. Hydroxyl radicals have a redox potential of up to 2.8 electron volts, which allows most refractory organic matter to undergo chain breaking reactions under this high potential and be converted into shorter-chain organic matter, or directly oxidized into carbon dioxide and water. Whether hydroxyl radicals can be generated efficiently and in large quantities has become a key criterion for measuring the effectiveness of advanced oxidation technology.

[0004] Compared with homogeneous catalytic ozonation technology, heterogeneous catalytic ozonation technology has the advantages of easy recycling, low water treatment cost, high activity, and improved organic matter mineralization rate. In heterogeneous catalytic ozone oxidation, the surface hydroxyl groups, Lewis acid sites, redox cycles and structural defects of the catalyst can serve as active sites, effectively promoting the ozone decomposition reaction and generating reactive oxygen species (ROS), enhancing the degradation of organic pollutants. Through active site engineering, both metal-based catalysts and non-metallic catalysts can significantly improve the efficiency of ozonation reactions.

[0005] Ozone residue in treated wastewater may have some impacts, mainly in the following aspects:

[0006] Effect on microbial activity, low residual ozone can improve the COD removal rate in the biological process, increase the amount of tightly bound extracellular polymers (EPS) in activated sludge, and improve the biological activity of activated sludge. However, high residual ozone concentrations may have a negative impact on microbial activity and reduce COD removal efficiency. Ozone residues may affect subsequent biological treatment processes. Some studies have shown that the chemical form distribution of heavy metals in sewage sludge after ozone treatment changes, affecting the subsequent biological leaching process. As a strong oxidant, ozone residues may have a certain impact on the water environment, especially in sensitive aquatic ecosystems.

[0007] Therefore, the ozone catalytic oxidation method has problems such as low ozone dissolution efficiency in water, unstable number of free radicals, low ozone utilization rate, and the impact of residual ozone on subsequent units. Summary of the invention

[0008] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0009] The purpose of the present invention is to propose an ejector and an ozone catalytic oxidation wastewater deep treatment process. The system can stabilize the number of hydroxyl radicals, improve the utilization rate of ozone, improve the ozone catalytic oxidation effect, reduce the amount of ozone added, enhance the mass transfer efficiency, reduce the residence time, and reduce the impact of residual ozone on subsequent units.

[0010] To achieve the above-mentioned purpose, the present invention proposes an ejector, comprising a sewage inlet, a gradually shortened nozzle, a throat, an ozone suction chamber, a diffusion section, an electromagnetic coil, a power supply, an ultrasonic transducer, and an ultrasonic generator, wherein sewage enters into the gradually shortened nozzle through the sewage inlet, the gradually shortened nozzle penetrates into the ozone suction chamber, and corresponds to the interval of the throat, ozone is mixed with sewage passing through the gradually shortened nozzle through the ozone suction chamber and enters the throat, and the mixed ozone and sewage are discharged from the ejector through the diffusion section; the gradually shortened nozzle, the throat, the ozone suction chamber, and the outer walls of the diffusion section are provided with an electromagnetic coil and an ultrasonic transducer, and the above-mentioned electromagnetic coil and ultrasonic transducer are arranged at intervals.

[0011] In addition, the ejector according to the above embodiment of the present invention may also have the following additional technical features:

[0012] Furthermore, the electromagnetic coil is connected to a power source, and the power source provides a power signal to the electromagnetic coil for forming a stable or changing magnetic field.

[0013] Furthermore, the ultrasonic transducer is connected to an ultrasonic generator, and the ultrasonic generator provides the ultrasonic transducer with an ultrasonic signal for forming stable or changing ultrasonic waves.

[0014] Furthermore, the shape of the tapered shortening nozzle satisfies y=1+e^(-a(xb)))^-1+c,{x,-1,0}, where a ranges from 1-5, b ranges from 0-5, and c ranges from 0.1-3.

[0015] Furthermore, the power supply is a signal for supplying power to the electromagnetic coil to form a magnetic field whose strength satisfies H(t)=max{e^(-t 2 / 2σ 2 ), H min}.

[0016] Furthermore, the frequency range of the ultrasonic wave is 50kHz-8.5MHz, preferably 3MHz, 5MHz.

[0017] Furthermore, the electromagnetic coil and the ultrasonic transducer are arranged at intervals.

[0018] The present invention optimizes the cavitation number and the cavitation starting point by designing the shape of the ejector's gradually shortened nozzle, and combines ultrasonic cavitation. The combined use of hydraulic cavitation and ultrasonic cavitation can improve the ozone mass transfer coefficient. Since the formation of bubbles leads to an increase in the mass transfer area, the hydraulic cavitation coefficient is about 1.5 times higher.

[0019] The present invention combines the magnetochemical effect, ultrasonic cavitation effect and hydraulic cavitation effect, and uses an optimized ejector for hydraulic cavitation. The sewage formed by ultrasonic cavitation by the ultrasonic transducer enters the ejector, and further reaches the hydraulic cavitation of the ejector structure. The hydraulic cavitation produces cavitation by changing the pressure fluctuation caused by the flow rate of the liquid medium, while the ultrasonic cavitation uses ultrasonic waves to produce the cavitation effect in the liquid. The combination of the two can produce a large number of cavitation bubbles, enhance the oxidation reaction and physical fragmentation effect. The number and intensity of the generated cavitation bubbles are increased, and the influence of the non-steady-state magnetic field generated by the optimized magnetic shear on the water molecule clusters is combined to balance the contradiction between the magnetic field and the cavitation bubbles, improve the efficiency of free radical generation, stabilize the number of free radicals, and improve the ozone dissolution capacity and catalytic oxidation capacity.

[0020] To achieve the above-mentioned purpose, the present invention proposes a wastewater deep treatment process of ozone catalytic oxidation, firstly, the sewage is mixed with ozone, and the wastewater is transported to the ozone catalytic oxidation tank by using the ejector designed by the present invention, and ozone is added in sections in the tank. A centrifugal pump is arranged in each section, and the pump takes sewage from a specific position in the tank and pumps it into the sewage inlet of the ejector. The ozone suction chamber in the ejector forms a negative pressure to suck the ozone, and the ozone and sewage are mixed;

[0021] Then, ozone catalytic oxidation is carried out, and the mixed sewage is put into the ozone catalytic oxidation tank to carry out catalytic oxidation reaction under the action of ozone and multi-element palladium catalyst;

[0022] Finally, the residual ozone is treated, and the effluent from the ozone catalytic oxidation system enters the activated carbon degassing fluidized bed reactor to decompose the residual ozone.

[0023] In addition, the wastewater advanced treatment process of ozone catalytic oxidation according to the above embodiment of the present invention may also have the following additional technical features:

[0024] Furthermore, an irradiation device is arranged in the middle of the activated carbon degassing fluidized bed reactor.

[0025] Furthermore, the diameter of the irradiation device is 0.1-1 m, preferably 0.5 m.

[0026] Furthermore, the irradiation device uses ultraviolet rays or near-infrared rays for irradiation.

[0027] Furthermore, the near infrared ray has a wavelength range of 1000-1500 nm, preferably 1200-1300 nm.

[0028] Furthermore, the activated carbon degassing fluidized bed reactor has a diameter of 3.8 meters, a height of 10 meters, and a circulation pump flow rate of 400 cubic meters per hour.

[0029] Furthermore, the hydraulic retention time of the residual ozone treatment is 0.2-3 hours, preferably 0.5 hours.

[0030] Furthermore, the reaction temperature of the residual ozone treatment is 4°C-80°C, preferably 20-60°C, and more preferably 40°C, 48°C, and 50°C.

[0031] Furthermore, the activated carbon degassing fluidized bed reactor uses activated carbon loaded with manganese dioxide as filler.

[0032] Furthermore, the activated carbon degassing fluidized bed reactor preferably uses a filler with a specific surface area of ​​400-800m 2 / g, preferably 600m 2 / g.

[0033] Furthermore, the loading amount of manganese dioxide on the activated carbon is 5-20%, preferably 13%.

[0034] The present invention adopts the form of a fluidized bed, and uses an activated carbon-supported manganese dioxide catalyst as the filler of the fluidized bed. At the same time, an ultraviolet or near-infrared irradiation device is provided in the activated carbon degassing system, and the residual ozone is treated in coordination with the activated carbon and electromagnetic waves. By introducing oxygen vacancies, the ozone decomposition activity of the catalyst can be improved. The regeneration performance and service life of the catalyst are improved. Electromagnetic wave radiation can be combined with the catalyst, and the catalyst can be excited by light to enhance its catalytic activity, thereby more effectively decomposing ozone. The synergistic effect of manganese dioxide, activated carbon and electromagnetic waves can significantly improve the treatment efficiency of residual ozone, enhance the stability and water resistance of the catalyst, which is of great significance for improving the practical application value of ozone treatment technology.

[0035] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of an ejector provided by the present invention;

[0037] Figure 2 It is a schematic diagram of the wastewater deep treatment process by ozone catalytic oxidation provided by the present invention.

[0038] Among them, 1. sewage inlet; 2. gradually shortened nozzle; 3. throat; 4. ozone suction chamber; 5. diffusion section; 6. electromagnetic coil; 7. ultrasonic transducer; 8. ejector; 9. ozone generator; 10. ozone catalytic oxidation tank; 11. activated carbon degassing fluidized bed reactor; 12. irradiation device; 13. circulation pump; 14. separator outlet. DETAILED DESCRIPTION

[0039] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0040] The technical solution of the present application will be described in detail below with reference to the accompanying drawings and in combination with the implementation modes.

[0041] like Figure 1As shown, the ejector of the present application includes: a sewage inlet 1, a gradually shortened nozzle 2, a throat 3, an ozone suction chamber 4, a diffusion section 5, an electromagnetic coil 6, and an ultrasonic transducer. The sewage enters the gradually shortened nozzle 2 through the sewage inlet 1, and the gradually shortened nozzle 2 goes deep into the ozone suction chamber 4, corresponding to the interval of the throat 3. Ozone is mixed with the sewage passing through the gradually shortened nozzle 2 through the ozone suction chamber 4 and enters the throat 3. The mixed ozone and sewage are discharged from the ejector through the diffusion section 5; the gradually shortened nozzle, the throat, the ozone suction chamber, and the outer wall of the diffusion section are provided with an electromagnetic coil and an ultrasonic transducer, and the above-mentioned electromagnetic coil and ultrasonic transducer are arranged at intervals. The electromagnetic coil is connected to a power supply, and the power supply is used to form a stable or changing magnetic field for the electromagnetic coil. The ultrasonic transducer is connected to an ultrasonic generator, and the ultrasonic generator is used to provide an ultrasonic signal for the ultrasonic transducer to form a stable or changing ultrasonic wave.

[0042] Cavitation technology is known as "green technology" because of its non-secondary pollution characteristics. Hydraulic cavitation is to use the principles of fluid mechanics to artificially form numerous cavitation bubbles in the water jet ejected from the nozzle. These cavitation bubbles are formed and grow in low-pressure areas (pressure lower than the saturated vapor pressure of water), and then collapse in high-pressure areas (pressure greater than the saturated vapor pressure of water), which is the so-called "implosion". The instantaneous high temperature and high pressure generated in this process cause water molecules to decompose to generate hydroxyl and hydrogen free radicals, triggering a series of complex chemical reactions. This extreme environment provides special physical conditions for chemical reactions that are difficult to carry out under conventional conditions and opens up new reaction pathways. Hydraulic cavitation technology has shown broad application prospects with its advantages of large processing capacity and low energy consumption. Ultrasonic cavitation technology is based on the propagation of ultrasonic waves in the medium. When the negative pressure phase of the sound wave arrives, tiny cavitation bubbles (cavitation nuclei) are formed in the liquid. These cavitation bubbles quickly collapse under the subsequent positive pressure phase, producing extreme physical conditions, such as local high temperature (up to thousands of Kelvin) and high pressure (up to hundreds of atmospheres). This phenomenon is called cavitation collapse. Under high temperature and high pressure conditions, water molecules decompose to produce hydroxyl radicals (·OH), which have strong oxidizing properties.

[0043] The present invention designs the shape of the gradually shortened nozzle of the ejector to enhance the fluid mixing effect and improve the ejection efficiency. The gradually shortened nozzle can induce the generation of a flow vortex, thereby improving the ejection efficiency of the ejector. The inner cone angle of the nozzle and the nozzle slit length are optimized, and different streamline fields are formed at the nozzle outlet. The nozzle slit length is optimized by optimizing the range of c. When the nozzle slit length is 2mm, a flow vortex is formed in a specific section, and the vortex intensity begins to decay in other sections until it disappears. When the slit length is 3mm or 5mm, multiple sections form a flow vortex, and the continuous distance is longer than that of other slit lengths. By optimizing the nozzle shape, the fluid dynamics performance can be improved, the mixing effect can be enhanced, the energy consumption can be reduced, and the overall injection efficiency can be improved.

[0044] When the ultrasonic wave is at low frequency, the cavitation bubbles are few but large in diameter, and the cavitation bubbles have obvious growth and collapse processes. When the cavitation nucleus reaches the resonance radius in the rarefaction stage, it first oscillates strongly, and then collapses instantly, so the explosion is more violent; at high frequencies, the formation and collapse of cavitation bubbles become faster, and the generated free radicals are more likely to enter the liquid phase, but the acoustic period is short, the cavitation bubble diameter is small, the cavitation limit is large but the intensity is weak. Therefore, when treating different pollutants, the selected ultrasonic frequency is quite different. For degradation reactions dominated by free radical oxidation, when the ultrasonic frequency is high, the cavitation bubble particle size is small, the cavitation intensity is weakened, and the sonolysis efficiency is reduced. Therefore, it is particularly important to select a suitable ultrasonic frequency for ozone catalytic oxidation reactions. The present invention optimizes the effect of ultrasonic cavitation composite hydraulic cavitation by optimizing the frequency range of ultrasonic waves to 50kHz-8.5MHz, preferably 3MHz and 5MHz, thereby enhancing the generation efficiency of cavitation bubbles, stabilizing the number of free radicals, and enhancing the catalytic ability of ozone oxidation.

[0045] Based on the electromagnetic shear theory, the cluster structure of water molecules, organic molecules and ions in sewage can be quickly sheared by high-frequency electromagnetic fields, which can destroy the original microstructure in sewage and weaken the hydration and association between water molecules and organic molecules and ions, thereby changing the physical, chemical and molecular mechanical properties of sewage. This change is mainly manifested in: (1) the size of water molecule clusters is reduced, the tension is increased, the viscosity is reduced, the permeability is improved, and the fluidity is enhanced, which is conducive to the dissolution of gas molecules; (2) the size of the association clusters formed by organic matter and ions with water molecules is reduced, making it easier for organic molecules to contact with oxidants. At the same time, polar organic molecules are stretched and the charge distribution of the molecules is readjusted, which is conducive to the subsequent reaction with oxidants; (3) the adsorption capacity of organic molecules and ions on the surface of solid-phase catalysts is reduced, and the efficiency of solid-phase catalytic interface reactions is improved.

[0046] The present invention uses a high-frequency electromagnetic field to quickly shear the cluster structure of water molecules, organic molecules and ions in sewage, thereby increasing the ozone dissolving capacity. However, the presence of the magnetic field will affect the expansion of cavitation bubbles, and then affect the number of OH free radicals generated by the collapse of the cavitation bubbles, thereby affecting the effect of cavitation degradation of organic pollutants. Therefore, it is necessary to finely set the intensity of the magnetic field to balance the contradiction between the magnetic field and the cavitation bubbles. The present invention optimizes the magnetic field intensity to balance the contradiction between cavitation bubbles and the magnetochemical effect. The power supply is the electromagnetic coil power supply signal used to form a magnetic field intensity that satisfies H(t)=max{e^(-t 2 / 2σ 2 ), H minBy alternately arranging the ultrasonic transducer and the electromagnetic coil on the outer wall of the ejector, a changing magnetic field and ultrasonic waves are formed inside the ejector, and the cavitation effect of the ultrasonic wave is combined with the hydraulic cavitation effect of the ejector nozzle. Through the optimized magnetic field, the efficiency of cavitation bubble generation is improved, the mass transfer coefficient is enhanced, the dissolution rate of ozone is enhanced, the generation of free radicals is enhanced, the number of free radicals is stabilized, and the efficiency of ozone catalytic oxidation is enhanced.

[0047] The wastewater deep treatment process by ozone catalytic oxidation will be further described below with reference to the accompanying drawings.

[0048] In one embodiment of the present invention, sewage enters into the gradually shortened nozzle 2 through the sewage inlet 1, and the gradually shortened nozzle 2 goes deep into the ozone suction chamber 4, corresponding to the interval of the throat section 3, and the ozone is mixed with the sewage passing through the gradually shortened nozzle 2 through the ozone suction chamber 4 and enters the throat section 3, and the mixed ozone and sewage are discharged from the ejector 8 through the diffusion section 5. The sewage is sucked into the ozone suction chamber 4 by the ozone generator 8 through the ejector 8, and is mixed with the sewage through the gradually shortened nozzle 2, especially the ejector 8 adopts the hydraulic cavitation combined with ultrasonic cavitation, under the action of the ultrasonic wave generated by the ultrasonic transducer, the cavitation effect is strengthened, the mass transfer coefficient is strengthened, the ozone and sewage are mixed more fully, sufficient free radicals are generated, and the catalytic oxidation effect of ozone is better. In addition, an electromagnetic coil is arranged on the outer wall of the ejector, and the ultrasonic transducer and the electromagnetic coil are arranged alternately, forming a changing magnetic field inside the ejector. The magnetochemical effect is used to cut the agglomeration of water molecules, thereby enhancing the contact effect between ozone and pollutant molecules in sewage. At the same time, the designed magnetic field balances the destruction of the cavitation effect by the magnetochemical effect, so that the magnetochemical effect and the cavitation effect act together in the ozone catalytic oxidation reaction. The sewage treated by the ejector 8 flows into the ozone catalytic oxidation tank 9, and catalytic oxidation reaction is carried out under the action of ozone and multi-element palladium catalyst; the effluent of the ejector 8 is a gas-liquid mixture, and its density is lower than that of the reflux water. The existence of the density difference increases the circulation power of the reflux water. The internal reflux cycle increases the relative flow rate of solid and liquid and improves the mass transfer rate. After the sewage is catalytically oxidized, it flows into the ozone catalytic oxidation tank 9 for residual ozone treatment. The effluent of the ozone catalytic oxidation system flows into the activated carbon degassing fluidized bed reactor 11 to decompose the residual ozone. An irradiation device 12 is arranged in the middle of the activated carbon degassing fluidized bed reactor. The activated carbon degassing fluidized bed reactor 11 is also provided with a circulating water device, and the sewage is circulated in the activated carbon degassing fluidized bed reactor 11 through a circulating pump 13. The treated sewage is discharged through the separator outlet 14 provided at the top of the activated carbon degassing fluidized bed reactor 11. The one-hour average value of the treated ozone emission is less than 0.16 mg / m 3 .

[0049] The activated carbon degassing fluidized bed reactor uses activated carbon loaded with manganese dioxide as filler. By introducing oxygen vacancies, the ozone decomposition activity of the catalyst can be improved. The regeneration performance and service life of the catalyst are improved. It can quickly and efficiently decompose medium and low concentration ozone into oxygen at room temperature. The activated carbon degassing fluidized bed reactor 11 is equipped with an irradiation device, which uses ultraviolet rays or near infrared rays of 1200-1300nm to irradiate ozone. Under light excitation, ozone is first converted into singlet O 2 , and then converted to the ground state O 2 Electromagnetic wave radiation can work synergistically with the catalyst to enhance its catalytic activity by photoexciting the catalyst, thereby decomposing ozone more effectively. This method can improve decomposition efficiency, reduce energy consumption, and reduce the risk of secondary pollution. The synergistic effect of manganese dioxide, activated carbon and electromagnetic waves can significantly improve the treatment efficiency of residual ozone and enhance the stability and water resistance of the catalyst.

[0050] Embodiment 1:

[0051] An industrial wastewater plant in Inner Mongolia adopts the wastewater deep treatment process of ozone catalytic oxidation of the present invention. The design scale of the process section is: Q = 11040m 3 / d, design hourly flow rate Q = 460.0m 3 / h. Experimental research was carried out at the pilot site. The specific implementation process is as follows: (1) The sewage first enters the regulating water tank, where the water volume and water quality are balanced, and then the water is pumped into the ejector by the lifting pump. (2) The ejector forms a negative pressure to suck ozone, and the sewage enters the ozone oxidation tank 9 through the ejector, where a catalytic oxidation reaction is carried out under the action of ozone and a multi-element palladium catalyst; the sewage and ozone are efficiently mixed and fully contacted with the catalyst, and hydroxyl free radicals are stimulated to be produced under the action of the active components of the catalyst. Under the strong oxidizing action of hydroxyl free radicals, most of the difficult-to-degrade organic matter undergoes a chain breaking reaction to form short-chain organic matter or is directly oxidized to CO 2 and H 2 O. (3) The effluent from the ozone catalytic oxidation tank flows into the activated carbon degassing fluidized bed reactor by gravity for degassing to prevent the safe operation of the subsequent treatment system to protect ozone.

[0052] The pilot test of this project adopted a water volume of 500L / h, an ozone dosage of 170.0mg / L, an OC ratio of 2.6, and a total residence time of 120min. The ejector designed in this application was used, and the shape of the gradually shortened nozzle of the ejector satisfied y=1+e^(-1.5(x-3.1)))^-1+1.5,{x,-1,0}. The frequency range of ultrasound is 5MHz. The power supply is the electromagnetic coil power supply signal used to form a magnetic field strength that satisfies H(t)=max{e^(-t 2 / 2σ 2), 250mT}. The diameter of the activated carbon degassing fluidized bed reactor is 3.8 meters, the height is 10 meters, and the circulation pump flow rate is 400 cubic meters / hour. Activated carbon loaded with manganese dioxide is used as filler, and the loading amount of manganese dioxide on the activated carbon is 13%; the specific surface area of ​​the filler is preferably 600m 2 / g; the hydraulic retention time of residual ozone treatment is 0.8 hours; the reaction temperature is 38°C; the diameter of the irradiation device is 0.5m. The irradiation device uses near-infrared rays for irradiation. The wavelength range of near-infrared rays is 1200-1300nm.

[0053] It can be seen from the pilot test data that the combined process of ozone catalytic oxidation and activated carbon degassing technology of the present invention has a significant effect on removing COD in this type of sewage. The ozone catalytic oxidation and activated carbon degassing unit facilities operate stably, with good treatment effects, and the effluent water quality meets the design standards. The original design of the inlet and outlet water quality indicators and operation results of the project are shown in Tables 1 and 2.

[0054] Table 1 Designed inlet and outlet water quality of this project (unit: mg / L)

[0055]

[0056] Table 2 Actual inlet and outlet water quality of the pilot test of this project (unit: mg / L)

[0057]

[0058] In summary, due to the adoption of the above technical scheme, the wastewater deep treatment process of the ejector and ozone catalytic oxidation proposed in the embodiment of the present invention solves the problems of low ozone dissolution efficiency in water, unstable number of free radicals, low ozone utilization rate, and residual ozone affecting subsequent units in the existing ozone catalytic oxidation process. The technology disclosed in the present invention combines the ejector design, ozone catalytic oxidation and residual ozone treatment process, and effectively utilizes the added ozone through reasonable settings. The cavitation number and cavitation starting point are optimized by designing the shape of the ejector's gradually shortened nozzle, and combined with ultrasonic cavitation, the combination of hydraulic cavitation and ultrasonic cavitation can improve the ozone mass transfer coefficient. The influence of the non-steady-state magnetic field generated by the optimized magnetic shear on the water molecule clusters is balanced to balance the contradiction between the magnetic field and the cavitation bubble, improve the efficiency of free radical generation, stabilize the number of free radicals, and improve the ozone solubility and catalytic oxidation capabilities. The residual ozone treatment process is adopted in the form of a fluidized bed, and the activated carbon-loaded manganese dioxide catalyst is used as the filler of the fluidized bed. At the same time, an ultraviolet or near-infrared irradiation device is installed in the activated carbon degassing system to cooperate with the activated carbon and electromagnetic waves to treat the residual ozone. The synergistic effect of manganese dioxide, activated carbon and electromagnetic waves can significantly improve the treatment efficiency of residual ozone and enhance the stability and water resistance of the catalyst, which is of great significance for improving the practical application value of ozone treatment technology.

[0059] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0060] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0061] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An ejector, characterized in that: It includes a sewage inlet, a gradually shortened nozzle, a throat, an ozone suction chamber, a diffusion section, an electromagnetic coil, a power supply, an ultrasonic transducer, and an ultrasonic generator, wherein sewage enters into the gradually shortened nozzle through the sewage inlet, the gradually shortened nozzle goes deep into the ozone suction chamber, and corresponds to the interval of the throat, ozone is mixed with sewage passing through the gradually shortened nozzle through the ozone suction chamber and enters the throat, and the mixed ozone and sewage are discharged from the ejector through the diffusion section; the outer walls of the gradually shortened nozzle, the throat, the ozone suction chamber, and the diffusion section are provided with an electromagnetic coil and an ultrasonic transducer, and the above-mentioned electromagnetic coil and ultrasonic transducer are arranged at intervals.

2. An ejector according to claim 1, characterized in that: The electromagnetic coil is connected to a power source, and the power source provides a power signal to the electromagnetic coil for forming a stable or changing magnetic field.

3. An ejector according to claim 1, characterized in that: The ultrasonic transducer is connected to an ultrasonic generator, and the ultrasonic generator provides the ultrasonic transducer with an ultrasonic signal for forming a stable or changing ultrasonic wave.

4. An ejector according to claim 1, characterized in that: The shape of the gradually shortened nozzle satisfies y=1+e^(-a(xb)))^-1+c,{x,-1,0}, where a ranges from 1-5, b ranges from 0-5, and c ranges from 0.1-3.

5. The ejector according to claim 1, characterized in that: The power supply is a signal for supplying power to the electromagnetic coil to form a magnetic field strength that satisfies H(t)=max{e^(-t 2 / 2σ 2 ), H min }.

6. An ejector according to claim 1, characterized in that: The frequency range of ultrasound is 50kHz-8.5MHz.

7. An ejector according to claim 6, characterized in that: The frequency range of ultrasound is 3MHz or 5MHz.

8. A wastewater deep treatment process by ozone catalytic oxidation, characterized in that: The ejector as claimed in claim 1 is used to first mix sewage with ozone, and then the ejector designed by the present invention is used to transport wastewater to an ozone catalytic oxidation tank, and ozone is added in sections in the tank. A centrifugal pump is provided in each section, and the pump takes sewage from a specific position in the tank and pumps it into the sewage inlet of the ejector. The ozone suction chamber in the ejector forms a negative pressure to suck ozone, and the ozone and sewage are mixed; Then, ozone catalytic oxidation is carried out, and the mixed sewage is put into the ozone catalytic oxidation tank to carry out catalytic oxidation reaction under the action of ozone and multi-element palladium catalyst; Finally, the residual ozone is treated, and the effluent from the ozone catalytic oxidation system enters the activated carbon degassing fluidized bed reactor to decompose the residual ozone.

9. The wastewater deep treatment process by ozone catalytic oxidation according to claim 8, characterized in that: An irradiation device is arranged in the middle of the activated carbon degassing fluidized bed reactor. The diameter of the irradiation device is 0.1-1m. The irradiation device uses ultraviolet rays or near-infrared rays for irradiation. The diameter of the activated carbon degassing fluidized bed reactor is 3.8 meters, the height is 10 meters, and the flow rate of the circulating pump is 400 cubic meters / hour. The hydraulic retention time of the residual ozone treatment is 0.2-3 hours, and the reaction temperature of the residual ozone treatment is 4°C-80°C. The activated carbon degassing fluidized bed reactor uses activated carbon loaded with manganese dioxide as filler, and the filler specific surface area is preferably 400-800m 2 / g, and the loading amount of manganese dioxide on activated carbon is 5-20%.

10. The wastewater deep treatment process by ozone catalytic oxidation according to claim 9, characterized in that: The irradiation device uses near-infrared rays with a wavelength range of 1000-1500nm for irradiation; the hydraulic retention time of the residual ozone treatment is 0.5 hours, and the reaction temperature of the residual ozone treatment is 48°C; the specific surface area of ​​the filler is preferably 600m 2 / g, and the loading amount of manganese dioxide on activated carbon is 13%.

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