Enhanced Fenton integrated wastewater purification system

Abstract

The invention relates to an enhanced Fenton integrated wastewater purification system. The enhanced Fenton integrated wastewater purification system comprises an ultrasonic device, and a mixing region, an integrated purification device and a neutralization and precipitation region which are connected in sequence, the ultrasonic device is used for providing ultrasonic waves for the integrated purification device; the mixing area is used for adding an agent into to-be-treated wastewater so as to adjust the to-be-treated wastewater; the integrated purification device comprises a first reaction zone, a second reaction zone, a third reaction zone, a fourth reaction zone, a fifth reaction zone and a sixth reaction zone which are arranged in sequence so as to remove pollutants in wastewater, and a neutralization precipitation zone which is used for adding chemicals and precipitating iron mud into the wastewater treated by the sixth reaction zone, so that the wastewater is discharged after reaching the standard. The method solves the problems of high pH value limitation requirement, high iron mud yield and difficulty in subsequent treatment in the existing ultrasonic and Fenton combined wastewater treatment process.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and particularly relates to an enhanced Fenton integrated wastewater purification system. Background Art

[0002] Fenton technology, as an efficient advanced oxidation process, is widely used in the treatment of organic wastewater that is difficult to biodegrade. This technology uses Fenton reagent (the main components include Fe2 + and H 2 O 2 ) to generate strongly oxidizing hydroxyl radicals (·OH) in an acidic environment, thereby effectively decomposing organic substances. Nevertheless, traditional Fenton technology has limitations such as low treatment efficiency, slow reaction rate, and sensitivity to pH value changes. In addition, in order to further improve the wastewater treatment effect, additional biological treatment or physicochemical treatment is usually required after Fenton treatment. To break through these limitations, researchers have begun to focus on the improvement and enhancement of Fenton technology. Among them, ultrasonic technology enhances the mixing and mass transfer efficiency of Fenton reagent by generating cavitation effects, and has been proven to significantly improve the treatment efficiency and reduce the operating cost. However, there are still the following problems when only ultrasonic and Fenton reagent are combined to treat wastewater: 1) Although ultrasonic can accelerate the decomposition of H 2 O 2 , its effect on expanding the applicable range of the pH value of the Fenton reaction is limited, and an acidic environment still needs to be maintained, resulting in the complexity of the process not being significantly reduced; 2) The problem of iron sludge has not been fundamentally solved. Ultrasonic technology has limited influence on the generation amount of iron sludge, and the treatment pressure of iron sludge in the existing ultrasonic-Fenton process is still relatively large, seriously restricting its operability and environmental protection in industrial applications; 3) High energy consumption and poor economy. Ultrasonic technology requires continuous energy supply, and its economy is limited by high energy consumption. In addition, the improvement effect of the utilization efficiency of H 2 O 2 is not significant, and a large amount of reagents still need to be added, further increasing the operating cost. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide an enhanced Fenton integrated wastewater purification system to solve the problems of high pH value limitation requirements, large iron sludge production, and difficult subsequent treatment in the existing combination of ultrasonic and Fenton for wastewater treatment.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] An enhanced Fenton integrated wastewater purification system includes an ultrasonic device, and a mixing zone, an integrated purification device, and a neutralization precipitation zone connected in sequence;

[0006] The ultrasonic device is used to provide ultrasonic waves for the integrated purification device;

[0007] The mixing zone is used to add chemicals to the wastewater to be treated to adjust the wastewater to be treated;

[0008] The integrated purification device includes, arranged in sequence:

[0009] The first reaction zone is provided with a light source and a heterogeneous catalytic device, and is used to synergistically strengthen Fenton by light, heterogeneous catalyst and ultrasound to achieve preliminary removal of pollutants in the wastewater to be treated; wherein, in the first reaction zone, the heterogeneous catalyst is catalytically excited by light and ultrasound to rapidly generate strongly oxidizing hydroxyl radicals (·OH), and the hydroxyl radicals (·OH) oxidize the organic pollutants in the wastewater to be treated to preliminarily remove organic solvents, pesticide chemicals, dyes and pigments, petroleum pollutants, plastics and their additives, etc. in the wastewater to be treated;

[0010] The second reaction zone is provided with a reflux device, and is used to increase the contact probability between the remaining pollutants and the remaining chemicals in the wastewater treated by the first reaction zone through hydraulic turbulence and mixing, and to achieve secondary removal of the remaining pollutants in the wastewater treated by the first reaction zone; thereby ensuring sufficient mixing of the pollutants and the chemicals in the wastewater treated by the first reaction zone, improving the removal efficiency of the pollutants, and achieving secondary removal of the remaining pollutants in the wastewater treated by the first reaction zone;

[0011] The third reaction zone is provided with a light source and a heterogeneous catalytic device, and is used to synergistically strengthen Fenton by light, heterogeneous catalyst and ultrasound to achieve tertiary removal of the remaining pollutants in the wastewater treated by the second reaction zone, thereby further removing organic intermediate products, chloride compounds, nitrogen oxides, acidic substances and dissolved organic matters in the wastewater;

[0012] The fourth reaction zone is provided with a reflux device, and is used to increase the contact probability between the remaining pollutants and the remaining chemicals in the wastewater treated by the third reaction zone through hydraulic turbulence and mixing, buffer the load difference of the previous reaction zone, confirm sufficient mixing of the pollutants and the chemicals in the wastewater, ensure the removal efficiency of the pollutants, and achieve quaternary removal of the remaining pollutants in the wastewater treated by the third reaction zone;

[0013] The fifth reaction zone is provided with a light source and a heterogeneous catalytic device, and is used to synergistically strengthen Fenton by light, heterogeneous catalyst and ultrasound to achieve quinary removal of the remaining pollutants in the wastewater treated by the fourth reaction zone; thereby intensively treating the deeply degraded wastewater and further degrading trace and refractory pollutants such as residual COD, organic acids, phenols, pesticides, chlorinated organic compounds, and some heavy metal ions;

[0014] The sixth reaction zone is equipped with a reflux device, which is used to adjust the pH value of the wastewater through hydraulic turbulence and mixing, as well as chemical dosing, so as to stably precipitate the remaining iron ions and remaining inorganic substances in the wastewater treated by the fifth reaction zone.

[0015] The neutralization and precipitation zone is used to add chemicals and precipitate iron sludge to the wastewater treated by the sixth reaction zone, so that the COD, total carbon, total ammonia nitrogen, pH value, chromaticity and suspended solids in the treated wastewater meet the standards and are discharged.

[0016] According to the above technical means, through the synergistic effect of ultraviolet light, ultrasonic wave and heterogeneous catalyst, the existing wastewater treatment process is optimized from multiple aspects, specifically including: 1) Introducing ultraviolet light, which can activate H 2 O 2 and promote the reduction of Fe 3+ to Fe 2+ , thereby enhancing the generation efficiency of hydroxyl radicals (·OH). This photoreaction reduces the dependence on a strong acid environment, enables the reaction to operate effectively within a wider pH range, reduces the demand for acid-base adjustment in wastewater pretreatment, and thus effectively expands the applicable pH range; 2) Using a heterogeneous catalyst to reduce the production of iron sludge. The heterogeneous catalyst provides stable catalytic active sites for the reaction and enables the recovery and reuse of the catalyst, significantly reducing the generation amount of iron sludge and fundamentally reducing the burden of solid waste treatment; 3) The synergistic effect of ultraviolet and ultrasonic improves the reaction efficiency. Ultraviolet light promotes the generation of ·OH by activating the catalyst and H 2 O 2 , and ultrasonic wave improves the mass transfer efficiency of reactants through the cavitation effect. The two cooperate with each other to effectively enhance the oxidation ability of the Fenton reaction, while reducing the usage amount of H 2 O 2 , optimizing the economy and environmental protection of the system; 4) Modular design to achieve efficient operation. This system integrates ultraviolet light sources, ultrasonic devices and heterogeneous catalysts into a multi-stage reaction zone, effectively achieving deep removal of pollutants in wastewater, ensuring that the multi-stage reaction zone forms a compact integrated structure, with good treatment efficiency and operation flexibility, and is particularly suitable for the deep treatment of high-concentration organic wastewater.

[0017] Preferably, a tube mixer is provided at the water inlet end of the mixing zone. The tube mixer is provided with at least a wastewater inlet and three chemical dosing ports, which are respectively used to introduce the wastewater to be treated and add sulfuric acid, ferrous sulfate solution and hydrogen peroxide.

[0018] Preferably, the tube mixer is designed as a spiral structure to enhance the mixing effect of wastewater and chemicals.

[0019] Preferably, the chemical addition port is connected to a liquid medicine tank through a pipeline, and a metering pump is provided on the pipeline to accurately control the dosage of the Fenton reagent and achieve accurate control of the chemical agent dosage.

[0020] Preferably, the heterogeneous catalytic device includes a fixing plate and a heterogeneous catalytic fiber membrane provided on the fixing plate.

[0021] Preferably, the fixing plate is a steel plate, and the heterogeneous catalytic fiber membrane is detachably installed on the surface of the steel plate to increase the contact area between the heterogeneous catalyst and the reactants, facilitate disassembly and recycling, and the surface of the steel plate can also reflect the light emitted by the ultraviolet lamp, making the reaction area full of ultraviolet light, so that a better reaction effect can be achieved with fewer ultraviolet lamp groups. Openings are provided on the fixing plate to balance the internal pressure of the reaction area.

[0022] Preferably, the heterogeneous catalytic fiber membrane includes a fiber membrane and a heterogeneous catalyst loaded on the fiber membrane.

[0023] Preferably, the heterogeneous catalyst is selected from a composite catalyst, and the composite catalyst is a nano-composite catalyst (TiO 2 / Fe 3 O 4 ) obtained by the sol-gel method and doped with each other by titanium dioxide and iron trioxide.

[0024] By selecting a nano-composite catalyst doped with each other by titanium dioxide and iron trioxide as the heterogeneous catalyst, the separation of electron-hole pairs is excited by ultraviolet light, and the characteristics of titanium dioxide and iron trioxide are combined, effectively realizing the generation of hydroxyl radicals and the reduction of Fe 3+ , improving the efficiency of the photocatalytic reaction, effectively reducing the dosage of medicine and the output of iron mud. And iron trioxide has good stability and can maintain stable catalytic performance under different reaction conditions. After being mixed with titanium dioxide, a more stable composite catalyst can be formed, reducing the interference of external factors, extending the service life, reducing the frequency and cost of catalyst replacement. At the same time, as a magnetic material, iron trioxide enables the mixture of titanium dioxide and iron trioxide to be separated and recovered by an external magnetic field. After the photocatalytic reaction is completed, the catalyst can be easily separated by an external magnetic field, and after removing the external magnetic field, the catalyst can be reused after stirring and rinsing. This characteristic reduces the loss of the catalyst, improves its reuse rate, and thus reduces the cost.

[0025] Among them, TiO 2 is combined with Fe 2+ (or Fe 3+ ) and H 2 O 2 to form Fe-TiO2 -H 2 O 2 system. Fe 3+ As an electron acceptor, it promotes the transfer of photo-generated electrons in TiO 2 , reduces the recombination of electron-hole pairs, thereby improving the generation efficiency of hydroxyl radicals, and realizes the conversion of Fe 3+ to Fe 2+ . This not only improves the removal efficiency but also reduces the cost input.

[0026] Preferably, the preparation method of the nano-composite catalyst includes the following steps:

[0027] S1. Mix an iron source and a titanium source into a mixed solution;

[0028] S2. Adjust the pH value of the mixed solution to 4.5 - 6 to obtain a sol;

[0029] S3. Subject the sol to a gelation reaction to obtain a precipitate;

[0030] S4. Dry and calcine the precipitate to obtain the nano-composite catalyst.

[0031] Preferably, the iron source is selected from one or both of iron nitrate and iron nitrate hexahydrate.

[0032] Preferably, the titanium source is selected from titanium chloride.

[0033] Preferably, the mass ratio of titanium dioxide to iron tetroxide in the nano-composite catalyst is 1:1 - 3:1.

[0034] Preferably, the mass ratio of titanium dioxide to iron tetroxide and the dosage of the nano-composite catalyst in the heterogeneous catalytic devices in the first reaction zone, the third reaction zone, and the fifth reaction zone are different to remove different pollutants in the wastewater.

[0035] Among them, the mass ratio of titanium dioxide to iron tetroxide in the nano-composite catalyst located in the first reaction zone is 1:1; the mass ratio of titanium dioxide to iron tetroxide in the nano-composite catalyst located in the second reaction zone is 2:1; the mass ratio of titanium dioxide to iron tetroxide in the nano-composite catalyst located in the third reaction zone is 3:1.

[0036] Preferably, the drying temperature is 60 - 120 °C.

[0037] Preferably, the calcination temperature is 300 - 500 °C.

[0038] Preferably, the calcination time is 2 - 4 h.

[0039] Preferably, the heterogeneous catalytic device is provided on the partition plates of the first reaction zone, the third reaction zone and the fifth reaction zone.

[0040] Preferably, ultrasonic vibration plates are installed on the two side walls of the first reaction zone, the third reaction zone and the fifth reaction zone at the water inlet end, and the ultrasonic vibration plates are connected to the ultrasonic device.

[0041] Preferably, the ultrasonic waves provided by the ultrasonic device are transverse impacts.

[0042] Preferably, the ultrasonic device is arranged beside the integrated purification device. The ultrasonic device is selected from an ultrasonic generator box, and an ultrasonic generator is installed in the ultrasonic generator box. The ultrasonic generator is connected to the ultrasonic vibration plate, so as to provide ultrasonic waves for the first reaction zone, the third reaction zone and the fifth reaction zone through the ultrasonic generator.

[0043] Preferably, the ultrasonic frequencies, powers and times of the first reaction zone, the third reaction zone and the fifth reaction zone are different to remove different pollutants in the wastewater.

[0044] Preferably, the light source is an ultraviolet light source, and the wavelengths of the ultraviolet light in the first reaction zone, the third reaction zone and the fifth reaction zone are different to remove different pollutants in the wastewater.

[0045] Preferably, the wavelength of the ultraviolet light in the first reaction zone is set to 185 nm; the wavelength of the ultraviolet light in the third reaction zone is set to 254 nm; the wavelength of the ultraviolet light in the fifth reaction zone is set to 365 nm.

[0046] Preferably, multiple groups of ultraviolet lamps are installed in the first reaction zone, the third reaction zone and the fifth reaction zone to serve as the ultraviolet light source and improve the efficiency of the photocatalytic Fenton reaction.

[0047] Preferably, multiple groups of ultraviolet lamps are arranged in parallel along the vertical direction of the first reaction zone, the third reaction zone and the fifth reaction zone.

[0048] Preferably, an ultraviolet lamp fixed mounting plate is provided at the top of the first reaction zone, the third reaction zone and the fifth reaction zone, and each reaction zone is equipped with an ultraviolet lamp. The power of the ultraviolet lamp is 220 W, and the length of the ultraviolet lamp is 1.6 m. A quartz sleeve is sleeved on the ultraviolet lamp.

[0049] Preferably, the neutralization and precipitation zone includes a tubular mixer provided at the water inlet end for adding medicaments and an inclined plate sedimentation tank provided at the outlet of the tubular mixer for precipitating iron sludge and discharging the supernatant.

[0050] Preferably, the system further includes a control system, which includes a sensor, an execution module and a central control unit connected to each other to monitor and adjust the parameters of the wastewater in the mixing zone, the first reaction zone, the second reaction zone, the third reaction zone, the fourth reaction zone, the fifth reaction zone, the sixth reaction zone and the neutralization precipitation zone in real time. Among them, the parameters include pH value, temperature, flow rate and chemical oxygen demand.

[0051] By introducing an automated control system to automatically monitor and adjust key parameters such as pH value, temperature, flow rate and chemical oxygen demand (COD), the optimal operating state of the equipment is ensured, manual operation is greatly reduced, and the reliability and safety of the equipment are improved.

[0052] Preferably, the upper part of the neutralization sedimentation tank is provided with a supernatant outlet, and the bottom is provided with a sludge outlet.

[0053] Preferably, the sensor includes a flow sensor arranged in the mixing zone, and the execution module includes a metering pump arranged in the mixing zone, so that the wastewater flow rate monitored by the flow sensor is fed back to the central control unit, and the central control unit controls the metering pump to adjust the dosing amounts of sulfuric acid, ferrous sulfate and hydrogen peroxide. Thereby ensuring that the dosing amount of the reagent matches the wastewater flow rate, and the pH value and the oxidant concentration reach the optimized range.

[0054] Preferably, the sensor includes pH sensors arranged in the first reaction zone, the second reaction zone, the third reaction zone, the fourth reaction zone and the fifth reaction zone, and the pH values of the wastewater in the first reaction zone, the second reaction zone, the third reaction zone, the fourth reaction zone and the fifth reaction zone are detected by the pH sensors. Thereby controlling the acidity and alkalinity within the optimal range of the Fenton reaction.

[0055] Preferably, the optimal range of the pH in the first reaction zone, the second reaction zone, the third reaction zone, the fourth reaction zone and the fifth reaction zone is 2.5 - 3.5.

[0056] Preferably, the central control unit is also connected to an ultrasonic device to control the frequency and power of the ultrasonic wave. Thereby ensuring the stability of the cavitation effect, adjusting the power and operating state of the ultraviolet lamp, and optimizing the photocatalytic reaction efficiency.

[0057] Preferably, the sensor includes a COD sensor arranged in the sixth reaction zone, and the execution module includes a flowmeter arranged in the sixth reaction zone, so that the effluent COD monitored by the COD sensor is fed back to the central control unit, and the central control unit controls the flow rate of the flowmeter to adjust the flow rate of the wastewater flowing through the sixth reaction zone. To ensure sufficient reaction and the effluent chemical oxygen demand (COD) reaches the discharge standard.

[0058] Preferably, the sensor includes a pH sensor disposed in the neutralization precipitation zone, and the execution module includes a metering pump disposed in the neutralization precipitation zone to monitor the pH value of the wastewater through the pH sensor and feedback it to the central control unit, and control the metering pump through the central control unit to adjust the dosage of the acid-base regulator and the flocculant.

[0059] Preferably, the optimal range of the pH in the neutralization precipitation zone is 6.5 - 8.5.

[0060] Preferably, the mixing zone is equipped with same - wave baffle plates, so that the wastewater flows in from the middle bottom of the same - wave baffle plates, and the wastewater after mixing with the reagent flows into the integrated purification device from the top of both ends of the same - wave baffle plates.

[0061] By installing same - wave baffle plates in the mixing zone and setting the water flow mode as middle - inlet and two - end - outlet, the mixing efficiency is effectively improved.

[0062] Preferably, the spacing of the same - wave baffle plates gradually increases from the middle to both ends, by gradually reducing the velocity gradient to increase the contact time between the wastewater and the reagent, so as to achieve better mixing of the reagent.

[0063] Preferably, the reflux device includes a cross - shaped water distribution pipe and a reflux pump arranged on the water distribution pipe to achieve hydraulic turbulence and mixing effects.

[0064] Preferably, the bottom of the first reaction zone, the third reaction zone and the fifth reaction zone is provided with a water distribution pipe to achieve the circulation treatment of the wastewater.

[0065] Preferably, an overflow channel is provided between adjacent reaction zones among the first reaction zone, the second reaction zone, the third reaction zone, the fourth reaction zone, the fifth reaction zone and the sixth reaction zone, so that the wastewater flows downwards.

[0066] Preferably, the first reaction zone, the third reaction zone and the fifth reaction zone adopt a baffle - plate type design, so that the wastewater continuously changes direction during the flowing process, which helps to increase the turbulence degree and mixing effect of the wastewater, improve the mixing effect of the wastewater and the reagent, ensure the full treatment of the wastewater, and create good conditions for the subsequent treatment links.

[0067] Preferably, air holes are opened above the overflow channel.

[0068] Preferably, the mixing zone is connected to the first reaction zone through a channel.

[0069] The beneficial effects of the present invention:

[0070] The integrated wastewater purification system with enhanced Fenton combines photo-Fenton and heterogeneous catalysis ingeniously. Through the separation of photo-excited electron-hole pairs, the generation of hydroxyl radicals and the reduction of Fe 3+ are realized. At the same time, the cavitation effect of ultrasonic waves is combined to directly generate hydroxyl radicals and promote the uniform dispersion of reagents, thereby not only improving the reaction efficiency and effluent quality, but also effectively reducing the dosage of chemicals and the sludge production. The integrated wastewater purification system of the present invention integrates a variety of advanced oxidation technologies. Through different operating conditions selection, the treatment efficiency of refractory organic pollutants in industrial wastewater is improved, and the deep purification of water quality is realized. It integrates multiple functions, including pretreatment, mixing, reaction, circulation and precipitation, which can reduce the floor area and does not require on-site splicing and assembly, and is convenient and flexible to use in the process. At the same time, it has important practical significance for improving the treatment efficiency of refractory organic wastewater, reducing the operating cost and reducing the chemical sludge production. It has a modular design, which is convenient for transportation and installation, the equipment is easy to operate, easy to maintain, has a low operating cost, good environmental protection performance, no secondary pollution and meets the requirements of green environmental protection. It realizes the miniaturization, high efficiency and automation of the equipment. This device belongs to the field of industrial water treatment technology, and is particularly suitable for removing industrial water with high concentration of COD to meet the increasingly high industrial standards. In the field of wastewater treatment technology, it has the value of popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 is a schematic structural diagram of the integrated wastewater purification system with enhanced Fenton;

[0072] Figure 2 is a top view of the integrated wastewater purification system with enhanced Fenton (excluding the neutralization and precipitation area);

[0073] Figure 3 is a schematic structural diagram of the mixing area;

[0074] Among them, 1 - ultrasonic device, 11 - ultrasonic vibrating plate; 2 - mixing area, 21 - corrugated plate, 22 - wastewater inlet, 23 - wastewater outlet; 3 - integrated purification device, 31 - first reaction area, 32 - second reaction area, 33 - third reaction area, 34 - fourth reaction area, 35 - fifth reaction area, 36 - sixth reaction area, 37 - light source, 38 - heterogeneous catalytic device, 39 - reflux device, 310 - water distribution pipe; 4 - neutralization and precipitation area, 41 - tubular mixer, 42 - inclined plate sedimentation tank. DETAILED DESCRIPTION OF THE INVENTION

[0075] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for explaining the present invention, rather than for limiting the protection scope of the present invention.

[0076] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0077] The present invention aims to publicly provide an integrated enhanced Fenton wastewater purification system to solve the problems of high pH value limitation requirements, large iron sludge production, and difficult subsequent treatment in the existing combination of ultrasonic and Fenton for wastewater treatment.

[0078] Among them, as Figures 1 to 3 shown, an integrated enhanced Fenton wastewater purification system includes an ultrasonic device 1, and a mixing zone 2, an integrated purification device 3, and a neutralization precipitation zone 4 that are connected in sequence;

[0079] The ultrasonic device 1 is used to provide ultrasonic waves for the integrated purification device 3;

[0080] The mixing zone 2 is used to add reagents to the wastewater to be treated to adjust the wastewater to be treated, and the adjusted wastewater to be treated flows into the integrated purification device 3;

[0081] The integrated purification device 3 includes the following arranged in sequence:

[0082] The first reaction zone 31 is provided with a light source 37 and a heterogeneous catalytic device 38, and is used to synergistically enhance Fenton through light, heterogeneous catalyst, and ultrasonic waves to achieve preliminary removal of pollutants in the wastewater to be treated adjusted by the mixing zone 2; The first reaction zone 31 synergistically excites the heterogeneous catalyst through light and ultrasonic waves to catalyze the Fenton reagent to rapidly generate strongly oxidizing hydroxyl radicals (·OH), and the hydroxyl radicals (·OH) oxidize the organic pollutants in the wastewater to be treated to preliminarily remove organic solvents, pesticide chemicals, dyes and pigments, petroleum pollutants, plastics and their additives, etc. in the wastewater to be treated;

[0083] The second reaction zone 32 is provided with a reflux device 39, which is used to increase the contact probability between the remaining pollutants and the remaining chemicals in the wastewater treated by the first reaction zone 31 through hydraulic turbulence and mixing, and to achieve the secondary removal of the remaining pollutants in the wastewater treated by the first reaction zone 31; ensure the full mixing of the pollutants and the chemicals in the wastewater treated by the first reaction zone, improve the removal efficiency of the pollutants, and achieve the secondary removal of the remaining pollutants in the wastewater treated by the first reaction zone;

[0084] The third reaction zone 33 is provided with a light source 37 and a heterogeneous catalytic device 38, which are used to synergistically strengthen Fenton by light, heterogeneous catalyst and ultrasound to achieve the tertiary removal of the remaining pollutants in the wastewater treated by the second reaction zone 32; further remove organic intermediates, chlorides, nitrogen oxides, acidic substances and dissolved organic matters in the wastewater;

[0085] The fourth reaction zone 34 is provided with a reflux device 39, which is used to increase the contact probability between the remaining pollutants and the remaining chemicals in the wastewater treated by the third reaction zone 33 through hydraulic turbulence and mixing, buffer the load difference of the previous reaction zone, confirm the full mixing of the pollutants and the chemicals in the wastewater, ensure the removal efficiency of the pollutants, and achieve the quaternary removal of the remaining pollutants in the wastewater treated by the third reaction zone 33;

[0086] The fifth reaction zone 35 is provided with a light source 37 and a heterogeneous catalytic device 38, which are used to synergistically strengthen Fenton by light, heterogeneous catalyst and ultrasound to achieve the fifth removal of the remaining pollutants in the wastewater treated by the fourth reaction zone 34; intensively treat the wastewater after deep degradation, and further degrade residual COD and trace refractory pollutants such as organic acids, phenols, pesticides, chlorinated organic compounds, and some heavy metal ions;

[0087] The sixth reaction zone 36 is provided with a reflux device 39, which is used to adjust the pH value of the wastewater through hydraulic turbulence and mixing, and the addition of chemicals, to achieve the precipitation of the remaining iron ions and remaining inorganic substances in the wastewater treated by the fifth reaction zone 35; ensure the stable precipitation of the remaining iron ions and other inorganic substances, while reducing the amount of iron sludge;

[0088] The neutralization and precipitation zone 4 is connected to the sixth reaction zone 36, and is used to add chemicals to the wastewater treated by the sixth reaction zone 36 and precipitate iron sludge, so that the wastewater is discharged after reaching the standard.

[0089] The above-mentioned integrated Fenton wastewater purification system combines photo-Fenton and heterogeneous catalysis skillfully. Through the separation of photo-excited electron-hole pairs, the generation of hydroxyl radicals and Fe 3+Reduction, meanwhile, the cavitation effect of ultrasonic waves directly generates hydroxyl radicals and promotes the uniform dispersion of the reagent, enhancing the oxidation ability of the Fenton reagent. As a result, not only the reaction efficiency and the effluent quality are improved, but also the dosage of the medicine and the sludge production are effectively reduced. The integrated wastewater purification system of the present invention ingeniously combines a variety of advanced oxidation technologies, including photo-Fenton, ultrasonic enhanced oxidation, heterogeneous catalytic oxidation, and ultraviolet photocatalytic oxidation, etc. Through the separation of photo-excited electron-hole pairs, the efficient generation of hydroxyl radicals (·OH) and the reduction of Fe3+ are achieved. At the same time, the cavitation effect of ultrasonic waves directly generates hydroxyl radicals and promotes the uniform dispersion of the Fenton reagent and reactants, thus significantly enhancing the oxidation ability of the Fenton reagent, not only improving the reaction efficiency and the effluent quality, but also effectively reducing the reagent consumption and the iron sludge production. The efficient treatment of refractory organic pollutants in wastewater is realized through different operating conditions. The specific operating conditions include: 1) Light source condition: Adjust the wavelength of the ultraviolet lamp to optimize the photocatalytic efficiency. Among them, the first reaction zone 31: is mainly used to excite the catalyst TiO 2 , generate ·OH radicals through ultraviolet light, and treat high-concentration organic pollutants. The wavelength of the ultraviolet light source in this area is set to 185 nm because this wavelength can effectively excite the heterogeneous catalyst and enhance its catalytic effect. Strong light source and high light intensity can accelerate the reaction. The third reaction zone 33: This area combines photocatalysis and Fenton reaction to degrade secondary pollutants. The ultraviolet light wavelength is set to 254 nm to help excite the photocatalyst and cooperate with the Fenton reagent to remove organic matter. The fifth reaction zone 35: is the enhanced treatment stage, using ultraviolet light of 365 nm, which is suitable for the further degradation of more complex or low-concentration organic pollutants; 2) Ultrasonic condition: Adjust the ultrasonic frequency, power and action time to improve the efficiency of the cavitation effect. Among them, the ultrasonic frequency in the first reaction zone 31 is 40 kHz, the ultrasonic power is 200 W / m 3 , and the ultrasonic action time is 15 - 20 minutes. It mainly treats high-concentration organic pollutants and uses the ·OH radicals generated by ultrasonic waves to promote the degradation of organic pollutants. The ultrasonic frequency in the third reaction zone 33 is 80 kHz, the ultrasonic power is 300 W / m 3 , further enhancing the cavitation effect and helping the photocatalysis and Fenton reaction to synergistically degrade secondary pollutants. The ultrasonic frequency in the fifth reaction zone 35 is 120 kHz, the ultrasonic power is 300 W / m 3 , which is used in the enhanced treatment stage to further decompose the refractory residual COD and trace pollutants; 3) Heterogeneous catalyst condition: By adjusting the dosage of the catalyst and the mass ratio of titanium dioxide to iron tetroxide in the catalyst, the oxidation ability and the stability of the catalyst are optimized. Among them, the first reaction zone 31: The organic matter concentration in this reaction zone is the highest, so control TiO 2 and Fe 3 O 4The mass ratio is 1:1, and the dosage is generally set at 1 - 2 g / L. TiO 2 The photocatalytic effect of 3 O 4 and the Fenton reaction of Fe 3 O 4 act together to remove high - concentration organic pollutants. The third reaction zone 33: In this area, Fe 2 is mainly used to participate in the Fenton reaction. The mass ratio of TiO 3 O 4 to Fe 2 is 2:1, and the dosage is set at 0.5 - 1 g / L to further remove secondary pollutants. The fifth reaction zone 35: The mass ratio of TiO 3 O 4 to Fe 2 O 2 is 3:1, and the dosage can be adjusted according to the previous degradation effect, generally maintained in the range of 1 - 2 g / L, which is used to enhance the degradation of residual pollutants; 4) Fenton reagent dosing conditions: Adjust the concentrations and dosing ratios of H 2+ O 2 and Fe 2 O 2 O 2 :COD and H 2+ O

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[0090] [[ID=The reaction module of this system achieves efficient treatment of wastewater through multiple reaction zones, specifically including: 1) Photocatalytic reaction: Under the irradiation of an ultraviolet light source, heterogeneous catalysts are excited to generate electron-hole pairs, producing hydroxyl radicals (·OH) to effectively decompose refractory organic matter in wastewater. 2) Ultrasonic cavitation reaction: Utilize the cavitation effect of ultrasonic waves to enhance the mixing and mass transfer effects of Fenton's reagent (Fe 2+ and H 2 O 2 ). 3) Fenton reaction: Under acidic conditions, hydrogen peroxide reacts with Fe 2+ to generate ·OH, rapidly oxidizing organic matter. Combining with the strengthening effect of ultraviolet light, the generation rate of ·OH is increased, and at the same time, the reduction cycle of Fe 3+ to Fe 2+ is promoted. 4) Combined oxidation reaction: Through the synergistic effect of the above-mentioned multiple advanced oxidation reactions, complex organic matter is further decomposed, and refractory pollutants are converted into easily degradable small molecule intermediate products.

[0091] The advantages of this system are that it can reduce the floor area and there is no need for on-site splicing and assembly, and it is convenient and flexible to use during the process. At the same time, it improves the treatment efficiency of refractory organic wastewater, which has important practical significance for reducing operating costs and chemical sludge production. It has a modular design, is convenient for transportation and installation, the equipment is easy to operate, easy to maintain, has low operating costs, good environmental protection performance, no secondary pollution and meets the requirements of green environmental protection, realizing the miniaturization, high efficiency and automation of the equipment. This device belongs to the field of industrial water treatment technology and is especially suitable for removing industrial water with high concentration of COD to meet the increasingly high industrial standards. Its application scope includes but is not limited to the following types of industrial wastewater: chemical wastewater, pharmaceutical wastewater, printing and dyeing wastewater, coking wastewater, leather wastewater, landfill leachate, petrochemical wastewater.

[0092] Exemplarily, a tubular mixer is provided at the water inlet end of the mixing zone 2. The tubular mixer is provided with at least a wastewater inlet and three chemical addition ports, which are respectively used for introducing the wastewater to be treated and adding sulfuric acid, ferrous sulfate solution and hydrogen peroxide.

[0093] Exemplarily, the tubular mixer is designed as a spiral structure to enhance the mixing effect of wastewater and chemicals.

[0094] Exemplarily, the chemical addition port is connected to a chemical liquid tank through a pipeline, and a metering pump is provided on the pipeline, so as to accurately control the dosage of Fenton's reagent and achieve accurate control of chemical dosing.

[0095] In some embodiments, the heterogeneous catalytic device 38 includes a fixing plate and a heterogeneous catalytic fiber membrane provided on the fixing plate.

[0096] Exemplarily, the fixing plate is a steel plate, and the heterogeneous catalytic fiber membrane is detachably installed on the surface of the steel plate to increase the contact area between the heterogeneous catalyst and the reactants, while facilitating disassembly and recycling. Moreover, the surface of the steel plate can also reflect the light emitted by the ultraviolet lamp, making the reaction zone filled with ultraviolet light, so that a better reaction effect can be achieved with fewer ultraviolet lamp groups.

[0097] Exemplarily, the fixing plate is provided with openings for balancing the internal pressure of the reaction zone.

[0098] In some embodiments, the heterogeneous catalytic fiber membrane comprises a fiber membrane and a heterogeneous catalyst loaded on the fiber membrane.

[0099] In some embodiments, the heterogeneous catalyst is selected from composite catalysts, and the composite catalyst is a nano-composite catalyst (TiO 2 / Fe 3 O 4 ) obtained by doping titanium dioxide and iron trioxide with each other by the sol-gel method.

[0100] By selecting a mixture of titanium dioxide and iron trioxide doped with each other as the heterogeneous catalyst, the separation of electron-hole pairs is excited by ultraviolet light, thereby realizing the generation of hydroxyl radicals and the reduction of Fe 3+ , improving the reaction efficiency, reducing the dosage of medicine and the sludge production.

[0101] In some embodiments, the preparation method of the nano-composite catalyst comprises the following steps:

[0102] S1. Mix an iron source and a titanium source into a mixed solution;

[0103] S2. Adjust the pH value of the mixed solution to 4.5 - 6 to obtain a sol;

[0104] S3. Subject the sol to a gelation reaction to obtain a precipitate;

[0105] S4. Dry and calcine the precipitate to obtain the nano-composite catalyst.

[0106] Exemplarily, the iron source is selected from one or both of iron nitrate and ferric nitrate hexahydrate; the titanium source is selected from titanium chloride;

[0107] The mass ratio of titanium dioxide to iron trioxide in the nano-composite catalyst is 1:1 - 3:1;

[0108] The drying temperature is 60 - 120 °C;

[0109] The calcination temperature is 300 - 500 °C;

[0110] The calcination time is 2 - 4 h.

[0111] In some embodiments, the heterogeneous catalytic device 38 is provided on the partition plates of the first reaction zone 31, the third reaction zone 33, and the fifth reaction zone 35.

[0112] In some embodiments, ultrasonic vibration plates 11 are installed on the two side walls of the first reaction zone 31, the third reaction zone 33, and the fifth reaction zone 35 at the water inlet end, and the ultrasonic vibration plates 11 are connected to the ultrasonic device 1;

[0113] Exemplarily, the ultrasonic waves provided by the ultrasonic device 1 are lateral impacts.

[0114] In some embodiments, the ultrasonic device 1 is arranged beside the integrated purification device 3. The ultrasonic device 1 is selected from an ultrasonic generator box, and an ultrasonic generator is installed in the ultrasonic generator box. The ultrasonic generator is connected to the ultrasonic vibration plates 11, so as to provide ultrasonic waves for the first reaction zone 31, the third reaction zone 33, and the fifth reaction zone 35 through the ultrasonic generator.

[0115] In some embodiments, multiple groups of ultraviolet lamps are installed in the first reaction zone 31, the third reaction zone 33, and the fifth reaction zone 35 to serve as ultraviolet light sources and improve the efficiency of the photocatalytic Fenton reaction.

[0116] In some embodiments, multiple groups of ultraviolet lamps are arranged in parallel along the vertical direction of the first reaction zone 31, the third reaction zone 33, and the fifth reaction zone 35.

[0117] Exemplarily, ultraviolet lamp fixed mounting plates are provided at the tops of the first reaction zone 31, the third reaction zone 33, and the fifth reaction zone 35. 12 ultraviolet lamps are installed in each reaction zone. The power of the ultraviolet lamp is 220W, and the length of the ultraviolet lamp is 1.6m. A quartz sleeve is sleeved on the ultraviolet lamp.

[0118] In some embodiments, the neutralization precipitation zone 4 includes a tubular mixer 41 provided at the water inlet end for adding chemicals and an inclined plate sedimentation tank 42 provided at the outlet of the tubular mixer 41 for precipitating iron mud and discharging the supernatant.

[0119] In some embodiments, the system further includes a control system. The control system includes a connected sensor, an execution module, and a central control unit to monitor and adjust the wastewater in the mixing zone 2, the first reaction zone 31, the second reaction zone 32, the third reaction zone 33, the fourth reaction zone 34, the fifth reaction zone 35, the sixth reaction zone 36, and the neutralization precipitation zone 4 in real time. By introducing an automated control system, manual operation is greatly reduced, and the reliability and safety of the equipment are improved.

[0120] Exemplarily, the sensor includes a flow sensor disposed in the mixing zone 2, and the execution module includes a metering pump disposed in the mixing zone 2, so as to feed the wastewater flow rate monitored by the flow sensor back to the central control unit, and control the metering pump through the central control unit to adjust the dosing amounts of sulfuric acid, ferrous sulfate and hydrogen peroxide;

[0121] Exemplarily, the sensor includes pH sensors disposed in the first reaction zone 31, the second reaction zone 32, the third reaction zone 33, the fourth reaction zone 34 and the fifth reaction zone 35, and the pH values of the wastewater in the first reaction zone 31, the second reaction zone 32, the third reaction zone 33, the fourth reaction zone 34 and the fifth reaction zone 35 are detected through the pH sensors;

[0122] Exemplarily, the central control unit is further connected to the ultrasonic device 1 to control the frequency and power of the ultrasonic wave;

[0123] Exemplarily, the sensor includes a COD sensor disposed in the sixth reaction zone 36, and the execution module includes a flowmeter disposed in the sixth reaction zone 36, so as to feed the effluent COD monitored by the COD sensor back to the central control unit, and control the flow rate of the flowmeter through the central control unit to adjust the flow rate of the wastewater flowing through the sixth reaction zone 36;

[0124] And / or, the sensor includes a pH sensor disposed in the neutralization and precipitation zone 4, and the execution module includes a metering pump disposed in the neutralization and precipitation zone 4, so as to feed the wastewater pH value monitored by the pH sensor back to the central control unit, and control the metering pump through the central control unit to adjust the dosing amounts of the acid-base regulator and the flocculant.

[0125] Exemplarily, the upper part of the neutralization sedimentation tank is provided with a supernatant outlet, and the bottom is provided with a sludge outlet.

[0126] In some embodiments, the mixing zone 2 is installed with a same-wave corrugated plate 21, so that the wastewater flows in from the wastewater inlet 22 at the middle bottom of the same-wave corrugated plate 21, and the wastewater after mixing with the reagent flows into the integrated purification device 3 from the wastewater outlets 23 at the two ends of the same-wave corrugated plate 21.

[0127] By installing a same-wave corrugated plate in the mixing zone and setting the water flow mode as middle inlet and two-end outlet, the mixing efficiency is effectively improved.

[0128] Exemplarily, the spacing of the same-wave corrugated plate gradually increases from the middle to the two ends, and by gradually reducing the velocity gradient, the contact time between the wastewater and the reagent is increased to achieve better mixing of the reagent.

[0129] Exemplarily, the reflux device 39 includes a cross-shaped water distribution pipe and a reflux pump arranged on the water distribution pipe to achieve hydraulic turbulence and mixing effects.

[0130] In some embodiments, a water distribution pipe 310 is provided at the bottom of the first reaction zone 31, the third reaction zone 33, and the fifth reaction zone 35 to achieve wastewater circulation treatment.

[0131] Exemplarily, an overflow channel is provided between adjacent reaction zones in the first reaction zone 31, the third reaction zone 33, and the fifth reaction zone 35, so that the wastewater is guided from top to bottom.

[0132] In some embodiments, the first reaction zone 31, the third reaction zone 33, and the fifth reaction zone 35 adopt a baffle plate type design, so that the wastewater continuously changes direction during the flow process, which helps to increase the turbulence degree and mixing effect of the wastewater, improve the mixing effect of the wastewater and the medicament, ensure the full treatment of the wastewater, and create good conditions for the subsequent treatment link.

[0133] Exemplarily, air holes are provided above the overflow channel.

[0134] Exemplarily, the mixing zone 2 is connected to the first reaction zone 31 through a channel.

[0135] Exemplarily, the water distribution pipe 310 is a cross-shaped water distribution pipe, and a reflux pump is provided on the water distribution pipe 310 to ensure that the wastewater can be fully and evenly treated.

[0136] The working principle of the above enhanced Fenton integrated wastewater purification system is as follows: The wastewater first enters the tubular mixer, and sulfuric acid, hydrogen peroxide, and ferrous sulfate solution are sequentially added through the dosing system for preliminary mixing. After mixing, the wastewater enters the mixing zone 1 from the middle bottom, and further mixes through the baffle plates in the mixing zone 1 and flows through the first reaction zone 31, the second reaction zone 32, the third reaction zone 33, the fourth reaction zone 34, the fifth reaction zone 35, and the sixth reaction zone 36 of the integrated purification device 3 in sequence. During the flow process, ultrasonic and heterogeneous catalytic photo-Fenton reactions are carried out. At the same time, the return water pipe uses the reflux pump to evenly distribute water through the cross-shaped water distribution pipes provided at the bottom of each reaction zone to achieve internal circulation. Ensure that the organic matter in the wastewater is completely oxidized, and the oxidized wastewater is discharged from the drain pipe, enters the tubular mixer, and the pH value of the wastewater is adjusted to neutral through the sodium hydroxide dosing system. The neutralized wastewater is connected to an inclined plate sedimentation tank for solid-liquid separation, and the separated particulate matter precipitates and the sludge enters the sewage collection well for regular discharge.

[0137] Detection and analysis

[0138] Taking a certain chemical wastewater as an example, the water quality of the wastewater to be treated and the effluent water quality after being treated by the enhanced Fenton integrated wastewater purification system of the present invention are shown in Table 1 and Table 2.

[0139] Table 1 Water quality characteristics of the wastewater to be treated before treatment

[0140]

[0141]

[0142] Table 2 shows the effluent water quality after being treated by the system of the present invention

[0143] Parameter Processed value Removal rate Unit Chemical Oxygen Demand (COD) ≤50 ≥95％ mg / L Total Organic Carbon (TOC) ≤10 ≥95％ mg / L Ammonia nitrogen (NH-N) ≤10 ≥90％ mg / L pH 6-8 Adjusted to neutral Chromaticity (chromaticity unit, CU) ≤30 ≥98％ CU Suspended solids (SS) ≤10 ≥90％ mg / L

[0144] In summary, the enhanced Fenton integrated wastewater purification system of the present invention cleverly combines photo-Fenton and heterogeneous catalysis. Through photoexcitation to separate electron-hole pairs, the generation of hydroxyl radicals and the reduction of Fe 3+ are realized. At the same time, the cavitation effect of ultrasonic waves is combined to directly generate hydroxyl radicals and promote the uniform dispersion of the medicament, thereby not only improving the reaction efficiency and effluent water quality, but also effectively reducing the dosage of the medicament and the sludge production. The enhanced Fenton integrated wastewater purification system of the present invention integrates a variety of advanced oxidation technologies. Through different working condition selections, the treatment efficiency of refractory organic pollutants in industrial wastewater is improved, the deep purification of water quality is realized, and it integrates multiple functions, including pretreatment, mixing, reaction, circulation and precipitation, which can reduce the floor area and there is no need to splice and assemble on site, and the use process is convenient and flexible. At the same time, it improves the treatment efficiency of refractory organic wastewater, reduces the operation cost and the chemical sludge production, which has important practical significance. It has a modular design, is convenient for transportation and installation, the equipment is easy to operate, easy to maintain, has a low operation cost, good environmental protection performance, no secondary pollution and meets the requirements of green environmental protection. It realizes the miniaturization, high efficiency and automation of the equipment. This device belongs to the technical field of industrial water treatment, and is particularly suitable for removing industrial water with high concentration of COD to meet the increasingly high industrial standards. In the field of wastewater treatment technology, it has the value of popularization and application.

[0145] The above embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention.

Claims

1. An enhanced Fenton integrated wastewater purification system, characterized in that: It comprises an ultrasonic device (1), and a mixing zone (2), an integrated purification device (3) and a neutralization precipitation zone (4) which are connected in sequence; The ultrasonic device (1) is used to provide ultrasonic waves for the integrated purification device (3); The mixing zone (2) is used to add a reagent to the wastewater to be treated to adjust the wastewater to be treated; The integrated purification device (3) comprises: The first reaction zone (31) is provided with a light source (37) and a heterogeneous catalytic device (38) for achieving preliminary removal of pollutants in the wastewater to be treated by synergistically enhancing Fenton reaction through light, heterogeneous catalyst and ultrasound; The second reaction zone (32) is provided with a reflux device (39) for increasing the contact probability between the remaining pollutants in the wastewater treated by the first reaction zone (31) and the remaining reagents through hydraulic turbulence and mixing, and realizing secondary removal of the remaining pollutants in the wastewater treated by the first reaction zone (31); The third reaction zone (33) is provided with a light source (37) and a heterogeneous catalytic device (38) for achieving tertiary removal of residual pollutants in the wastewater treated by the second reaction zone (32) by synergistically enhancing Fenton through light, heterogeneous catalyst and ultrasound; The fourth reaction zone (34) is provided with a reflux device (39) for increasing the contact probability between the remaining pollutants in the wastewater treated by the third reaction zone (33) and the remaining reagents through hydraulic turbulence and mixing, and achieving a fourth removal of the remaining pollutants in the wastewater treated by the third reaction zone (33); The fifth reaction zone (35) is provided with a light source (37) and a heterogeneous catalytic device (38) for achieving five-fold removal of the remaining pollutants in the wastewater treated by the fourth reaction zone (34) through synergistic Fenton enhancement by light, heterogeneous catalyst and ultrasound; The sixth reaction zone (36) is provided with a reflux device (39) for adjusting the pH value of the wastewater through hydraulic turbulence and mixing, as well as adding a reagent, so as to achieve the precipitation of residual iron ions and residual inorganic substances in the wastewater treated by the fifth reaction zone (35); The neutralization and precipitation zone (4) is used to add reagents and precipitate iron sludge to the wastewater treated by the sixth reaction zone (36), so that the wastewater meets the standards before being discharged.

2. The enhanced Fenton integrated wastewater purification system according to claim 1, characterized in that: The heterogeneous catalytic device (38) comprises a fixed plate and a heterogeneous catalytic fiber membrane arranged on the fixed plate; The heterogeneous catalytic fiber membrane comprises a fiber membrane and a heterogeneous catalyst loaded on the fiber membrane.

3. The enhanced Fenton integrated wastewater purification system according to claim 2, characterized in that: The heterogeneous catalyst is selected from a composite catalyst; The composite catalyst is a nano composite catalyst prepared by a sol-gel method and is formed by doping titanium dioxide and ferrosoferric oxide.

4. The enhanced Fenton integrated wastewater purification system according to claim 3, characterized in that: The method for preparing the nanocomposite catalyst comprises the following steps: S1, mixing an iron source and a titanium source into a mixed solution; S2, adjusting the pH value of the mixed solution to 4.5-6 to obtain a sol; S3, subjecting the sol to a gelling reaction to obtain a precipitate; S4, drying and calcining the precipitate to obtain a nanocomposite catalyst.

5. The enhanced Fenton integrated wastewater purification system according to claim 4, characterized in that: The iron source is selected from one or both of ferric nitrate and ferric nitrate hexahydrate; and / or, the titanium source is selected from titanium chloride; And / or, the mass ratio of titanium dioxide to ferrosoferric oxide in the nanocomposite catalyst is 1:1 to 3:1; And / or, the drying temperature is 60-120°C; And / or, the calcination temperature is 300-500°C; And / or, the calcination time is 2 to 4 hours.

6. The enhanced Fenton integrated wastewater purification system according to claim 1, characterized in that: The heterogeneous catalytic device (38) is provided on the partitions of the first reaction zone (31), the third reaction zone (33) and the fifth reaction zone (35); and / or, the first reaction zone (31), the third reaction zone (33) and the fifth reaction zone (35) are provided with ultrasonic vibration plates (11) installed on the two side walls located at the water inlet end, and the ultrasonic vibration plates (11) are connected to the ultrasonic device (1); And / or, the ultrasonic wave provided by the ultrasonic device (1) is a transverse impact; and / or, the ultrasonic frequency, power and time of the first reaction zone (31), the third reaction zone (33) and the fifth reaction zone (35) are different; And / or, the light source (37) is an ultraviolet light source, and the wavelengths of the ultraviolet lights in the first reaction zone (31), the third reaction zone (33) and the fifth reaction zone (35) are different; And / or, the neutralization sedimentation zone (4) comprises a tubular mixer (41) provided at the water inlet end and used for adding reagents, and an inclined plate sedimentation tank (42) provided at the outlet of the tubular mixer (41) and used for precipitating iron mud and removing supernatant.

7. The enhanced Fenton integrated wastewater purification system according to claim 1, characterized in that: The system also includes a control system, which includes connected sensors, execution modules and a central control unit to monitor and adjust the wastewater in the mixing zone (2), the first reaction zone (31), the second reaction zone (32), the third reaction zone (33), the fourth reaction zone (34), the fifth reaction zone (35), the sixth reaction zone (36) and the neutralization and sedimentation zone (4) in real time.

8. The enhanced Fenton integrated wastewater purification system according to claim 7, characterized in that: The sensor comprises a flow sensor arranged in the mixing zone (2), and the execution module comprises a metering pump arranged in the mixing zone (2), so as to feed back the wastewater flow monitored by the flow sensor to the central control unit, and the metering pump is controlled by the central control unit to adjust the dosage of sulfuric acid, ferrous sulfate and hydrogen peroxide; And / or, the sensor comprises a pH sensor disposed in the first reaction zone (31), the second reaction zone (32), the third reaction zone (33), the fourth reaction zone (34) and the fifth reaction zone (35), and the pH value of the wastewater in the first reaction zone (31), the second reaction zone (32), the third reaction zone (33), the fourth reaction zone (34) and the fifth reaction zone (35) is detected by the pH sensor; And / or, the central control unit is also connected to the ultrasonic device (1) to control the frequency and power of the ultrasound; And / or, the sensor includes a COD sensor provided in the sixth reaction zone (36), the execution module includes a flow meter provided in the sixth reaction zone (36), so as to feed back the effluent COD monitored by the COD sensor to the central control unit, and the central control unit controls the flow rate of the flow meter to adjust the speed of the wastewater flowing through the sixth reaction zone (36); And / or, the sensor includes a pH sensor arranged in the neutralization sedimentation zone (4), and the execution module includes a metering pump arranged in the neutralization sedimentation zone (4), so as to monitor the pH value of the wastewater through the pH sensor and feed it back to the central control unit, and the metering pump is controlled by the central control unit to adjust the dosage of the acid-base regulator and the flocculant.

9. The enhanced Fenton integrated wastewater purification system according to claim 1, characterized in that: The mixing zone (2) is equipped with a folding plate, so that wastewater flows in from the middle bottom of the folding plate, and the wastewater mixed with the reagent flows into the integrated purification device (3) from the tops of both ends of the folding plate.

10. The enhanced Fenton integrated wastewater purification system according to claim 1, characterized in that: A water distribution pipe (310) is provided at the bottom of the first reaction zone (31), the second reaction zone (32), the third reaction zone (33), the fourth reaction zone (34), the fifth reaction zone (35) and the sixth reaction zone (36) to realize wastewater recycling treatment.

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