Wastewater treatment device based on persulfate advanced oxidation method

Abstract

A wastewater treatment device based on a persulfate advanced oxidation process comprises a persulfate advanced oxidation reactor, a persulfate adding device and a catalyst adding device, and is characterized in that the persulfate advanced oxidation reactor adopts a structural design of a cylinder at the upper part and a cone at the lower part; an anchor-paddle composite water impeller, a filler layer, a persulfate distributor and a catalyst distributor are arranged in the reactor, an overflow weir, an ultrasonic device, a chemical oxygen demand (COD) on-line analyzer and an oxidation-reduction potential (ORP) on-line analyzer are arranged on the outer wall of the reactor, an anchor stirrer is matched with the conical bottom of the reactor, and through the synergistic effect of mechanical stirring and the ultrasonic device, the persulphate on-line analyzer and the persulphate on-line analyzer are analyzed. A strong shear flow field and an ultrasonic cavitation field are constructed, efficient activation of persulfate and a catalyst is achieved, and the effluent quality is improved. The method has the advantages of high solid-liquid mass transfer efficiency, high catalyst utilization rate, low operation energy consumption, remarkable sludge reduction effect and the like, and is particularly suitable for treating refractory organic wastewater generated in the industries of pharmacy, pesticide and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and specifically relates to a wastewater treatment device based on a persulfate advanced oxidation process, which is particularly suitable for treating refractory organic wastewater generated in the pharmaceutical, pesticide and other industries. Background Art

[0002] At present, the treatment technologies for wastewater containing difficult-to-degrade organic pollutants such as antibiotics generated by the pharmaceutical and pesticide industries mainly include physical and chemical methods and biological treatment methods. The commonly used physical and chemical methods include adsorption, coagulation, and chemical oxidation. The adsorbent in water treatment technology is usually activated carbon, but whether it is powdered activated carbon or granular activated carbon, its adsorption effect is closely related to factors such as pollutant concentration and water quality background conditions. Although the coagulation method is simple to operate, the removal effect of the coagulant on the target pollutant is very unsatisfactory, and the amount of coagulant used is large, resulting in a large amount of sludge. Although adsorption and coagulation methods can remove some pollutants to a certain extent, they only transfer them and do not completely degrade them. Therefore, it is still necessary to completely degrade and remove the target pollutants through chemical oxidation.

[0003] Advanced oxidation processes can attack target pollutants through a series of chain reactions triggered by free radicals, degrading them into H2O and CO2, thereby reducing secondary pollution. Advanced oxidation methods also have great application prospects due to their high efficiency, rapidity, and thorough oxidation reactions. In recent years, persulfate-based advanced oxidation technologies have received increasing attention. Compared with traditional advanced oxidation technologies, they have the following advantages: higher free radical production, a wider range of activation methods, better adaptability to operating parameters (such as peroxide dosage) and water background (such as pH, coexisting ions, etc.), and easier transportation and storage of persulfate. Therefore, persulfate-based advanced oxidation technologies have broader application prospects in wastewater treatment.

[0004] Existing persulfate advanced oxidation reactors have a stirring dead zone (accounting for approximately 15-20% of the total volume), which leads to severe catalyst deposition and a catalyst utilization rate of less than 60%. Alternatively, they use a simple ultrasonic activation method, resulting in excessive energy consumption (2.5-3.8 kWh per ton of water) and a sharp drop in the treatment effect on high-concentration wastewater (COD>2000 mg / L). Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention designs an anchor-propeller composite flow-pushing device and an ultrasonic device to work together to construct a strong shear flow field and an ultrasonic cavitation field, thereby achieving efficient activation of persulfate and catalyst, thereby improving the treatment efficiency of wastewater containing difficult-to-degrade organic matter and improving the effluent water quality.

[0006] The present invention adopts the following technical solution: a wastewater treatment device based on a persulfate advanced oxidation method, comprising a persulfate advanced oxidation reactor, a persulfate adding device, and a catalyst adding device, characterized in that: the persulfate advanced oxidation reactor comprises a reactor tank body, a top cover, a water inlet, a motor, an anchor propeller composite flow pusher, a packing layer, a persulfate distributor, a catalyst distributor, an overflow weir, an ultrasonic device, a COD online analyzer, an ORP online analyzer, a mud discharge port, and a support leg; the persulfate adding device comprises a persulfate storage tank and a persulfate metering pump; and the catalyst adding device comprises a catalyst storage tank and a catalyst metering pump.

[0007] Furthermore, the upper part of the reactor tank is cylindrical with a height-to-diameter ratio of 2:1-4:1, the lower part is conical with a cone angle of 45-75°, and a polytetrafluoroethylene anti-corrosion layer is provided on the inner wall.

[0008] Furthermore, the anchor-propeller composite flowmaker is driven by a motor, the lower layer is an anchor stirrer, and the upper layer is a three-blade propeller stirrer, with a rotation speed of 30-200 rp / min.

[0009] Furthermore, the anchor agitator is adapted to the conical structure at the bottom of the reactor tank, the gap between the anchor blade and the cone wall is 10-20 mm, the height of the anchor blade is 0.1-0.15 times the diameter of the cylindrical section of the reactor tank, and the blade diameter of the three-blade agitator is 0.3-0.5 times the diameter of the cylindrical section of the reactor tank.

[0010] Furthermore, the filler layer is filled with ceramsite with a diameter of 5-10 mm and a filling height of 3-50 cm.

[0011] Furthermore, the ultrasonic devices are arranged in a circular matrix along the outer wall of the reactor tank at equal intervals, with 3-6 groups arranged in each layer, and the spacing between adjacent layers is 0.2-0.4 times the diameter of the cylindrical section of the reactor tank. The operating frequency of the ultrasonic devices is 20-100 kHz, and the power density is 0.1-1.0 W / cm 3 .

[0012] Furthermore, the inlet end of the persulfate metering pump is connected to the persulfate storage tank, and the outlet end is connected to the persulfate distributor; the inlet end of the catalyst metering pump is connected to the catalyst storage tank, and the outlet end is connected to the catalyst distributor; the persulfate distributor and the catalyst distributor adopt an annular porous water distribution pipe.

[0013] Furthermore, the persulfate is one or more mixtures of sodium persulfate, sodium persulfate, potassium persulfate, potassium persulfate, ammonium persulfate, and ammonium persulfate, and the catalyst is one or more mixtures of metal oxides, hydroxides, or sulfides of iron, cobalt, nickel, manganese, copper, and zinc.

[0014] Furthermore, the COD online analyzer and the ORP online analyzer are controlled in linkage with the persulfate metering pump and the catalyst metering pump through a relay to maintain the redox potential of the reaction zone ≥400 mV.

[0015] The beneficial effects of the present invention are as follows: (1) The present invention forms a strong shear flow field by designing a conical bottom of the reactor and cooperating with an anchor agitator, which has high solid-liquid mass transfer efficiency, can effectively prevent catalyst deposition, and improve catalyst utilization.

[0016] (2) The present invention constructs a strong shear flow field and an ultrasonic cavitation field by designing an anchor propeller composite flow and an ultrasonic device to promote the generation of more free radicals, thereby improving the efficiency of treating wastewater containing difficult-to-degrade organic matter and reducing operating energy consumption.

[0017] (3) The present invention generates less oxidation by-products and has a significant sludge reduction effect, which is beneficial to controlling secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a process flow chart of the present invention.

[0019] Figure 2 Schematic diagram of fluid flow in the persulfate advanced oxidation reactor of the present invention.

[0020] In the figure: 1. Reactor body, 2. Top cover, 3. Water inlet, 4. Motor, 5. Anchor-propeller composite flowmaker, 6. Anchor agitator, 7. Three-blade paddle agitator, 8. Packing layer, 9. Persulfate distributor, 10. Catalyst distributor, 11. Overflow weir, 12. Ultrasonic device, 13. COD online analyzer, 14. ORP online analyzer, 15. Mud discharge port, 16. Support leg, 17. Persulfate storage tank, 18. Persulfate metering pump, 19. Catalyst storage tank, 20. Catalyst metering pump. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the embodiments and accompanying drawings.

[0022] like Figure 1As shown, a wastewater treatment device based on a persulfate advanced oxidation process comprises a persulfate advanced oxidation reactor, a persulfate adding device, and a catalyst adding device, characterized in that: the persulfate advanced oxidation reactor comprises a reactor tank body 1, a top cover 2, a water inlet 3, a motor 4, an anchor-propeller composite flow propeller 5, a packing layer 8, a persulfate distributor 9, a catalyst distributor 10, an overflow weir 11, an ultrasonic device 12, a COD online analyzer 13, an ORP online analyzer 14, a mud outlet 15, and a support leg 16; the persulfate adding device comprises a persulfate storage tank 17 and a persulfate metering pump 18; and the catalyst adding device comprises a catalyst storage tank 19 and a catalyst metering pump 20.

[0023] Among them, the upper part of the reactor tank body 1 is a cylinder with a height-to-diameter ratio of 2:1-4:1, the lower part is a cone with a cone angle of 45-75°, and a polytetrafluoroethylene anti-corrosion layer is provided on the inner wall; the reactor tank body 1 is equipped with an anchor-propeller composite flow producer 5 consisting of an anchor stirrer 6 and a three-blade paddle stirrer 7. The anchor-propeller composite flow producer 5 is driven by a motor 4 with a rotation speed of 30-200 rp / min. The anchor stirrer 6 is adapted to the conical structure of the lower part of the reactor tank body 1. The gap between the anchor paddle and the cone wall is 10-20 mm. The height of the anchor paddle is 0.1-0.15 times the diameter of the cylindrical section of the reactor tank body 1. The blade diameter of the three-blade paddle stirrer 7 is 0.3-0.5 times the diameter of the cylindrical section of the reactor tank body 1. The upper part of the reactor tank 1 is filled with ceramsite with a diameter of 5-10 mm to form a packing layer 8, and the filling height of the packing layer 8 is 3-50 cm. A persulfate distributor 9 and a catalyst distributor 10 are provided below the packing layer 8. Both the persulfate distributor 9 and the catalyst distributor 10 use an annular porous water distribution pipe. The outer wall of the reactor tank 1 is provided with an overflow weir 11, an ultrasonic device 12, a COD online analyzer 13, and an ORP online analyzer 14. The ultrasonic devices 12 are arranged in an annular matrix with equal spacing along the axial direction of the reactor tank 1, with 3-6 groups arranged in each layer. The distance between adjacent layers is 0.2-0.4 times the diameter of the cylindrical section of the reactor tank 1. The operating frequency of the ultrasonic device 12 is 20-100 kHz, and the power density is 0.1-1.0 W / cm 3 The probes of the COD online analyzer 13 and the ORP online analyzer 14 are immersed in the wastewater of the reactor tank 1, and the start and stop of the persulfate metering pump 18 and the catalyst metering pump 20 are controlled by the relay linkage in the COD online analyzer 13 and the ORP online analyzer 14, respectively, to maintain the redox potential of the reaction zone ≥400 mV.

[0024] In the persulfate addition unit, the inlet end of the persulfate metering pump 18 is connected to the persulfate storage tank 17, and the outlet end is connected to the persulfate distributor 9. The persulfate is one or more mixtures of sodium persulfate, sodium persulfate, potassium persulfate, potassium persulfate, ammonium persulfate, and ammonium persulfate. In the catalyst addition unit, the inlet end of the catalyst metering pump 20 is connected to the catalyst storage tank 19, and the outlet end is connected to the catalyst distributor 10. The catalyst is one or more mixtures of metal oxides, hydroxides or sulfides of iron, cobalt, nickel, manganese, copper, and zinc.

[0025] During operation, the wastewater to be treated enters the reactor from the water inlet 3. Under the control of the COD online analyzer 13 and the ORP online analyzer 14, the persulfate oxidant in the persulfate storage tank 17 is added to the reactor by the persulfate metering pump 18 through the persulfate distributor 9, and the catalyst in the catalyst storage tank 19 is added to the reactor by the catalyst metering pump 20 through the catalyst distributor 10. Under the stirring and cavitation action of the anchor propeller composite flow propeller 5 and the ultrasonic device 12, the wastewater, persulfate and catalyst are uniformly mixed and fully reacted. The supernatant of the wastewater after the reaction flows into the subsequent treatment unit through the filler layer 8 and the overflow weir 11 by gravity. The wastewater flow diagram is shown in FIG. Figure 2 As shown, the packing layer 8 acts as a buffer and barrier, and the ceramsite contained therein intercepts some suspended matter, particulate matter, sediment, and other impurities in the water. The sludge produced in the reactor is discharged from the sludge outlet 15, dehydrated by the sludge treatment unit, and then transported for harmless disposal.

[0026] The above content describes the technical solution of the present invention in detail, but does not limit the scope of protection of the present invention. Ordinary technicians in this technical field can also make improvements and modifications on this basis, but these improvements and modifications are within the scope of protection of the claims of the present invention.

Claims

1. A wastewater treatment device based on a persulfate advanced oxidation process, comprising a persulfate advanced oxidation reactor, a persulfate addition device, and a catalyst addition device, characterized in that: The persulfate advanced oxidation reactor includes a reactor tank body, a top cover, a water inlet, a motor, an anchor propeller composite flow propeller, a packing layer, a persulfate distributor, a catalyst distributor, an overflow weir, an ultrasonic device, a COD online analyzer, an ORP online analyzer, a mud outlet, and support legs. The persulfate addition device includes a persulfate storage tank and a persulfate metering pump. The catalyst addition device includes a catalyst storage tank and a catalyst metering pump.

2. A wastewater treatment device based on persulfate advanced oxidation process according to claim 1, characterized in that: The upper part of the reactor tank is cylindrical with a height-to-diameter ratio of 2:1-4:1, the lower part is conical with a cone angle of 45-75 degrees, and a polytetrafluoroethylene anti-corrosion layer is provided on the inner wall.

3. The wastewater treatment device based on persulfate advanced oxidation process according to claim 1, characterized in that: The anchor-propeller composite flow-maker is driven by a motor, the lower layer is an anchor-type agitator, and the upper layer is a three-blade paddle-type agitator, with a rotation speed of 30-200 rp / min.

4. A wastewater treatment device based on persulfate advanced oxidation process according to claim 3, characterized in that: The anchor agitator is adapted to the conical structure at the bottom of the reactor tank body. The gap between the anchor blade and the cone wall is 10-20 mm. The height of the anchor blade is 0.1-0.15 times the diameter of the cylindrical section of the reactor tank body. The blade diameter of the three-blade agitator is 0.3-0.5 times the diameter of the cylindrical section of the reactor tank body.

5. The wastewater treatment device based on persulfate advanced oxidation process according to claim 1, characterized in that: The packing layer is filled with ceramsite with a diameter of 5-10 mm and a filling height of 3-50 cm.

6. The wastewater treatment device based on persulfate advanced oxidation process according to claim 1, characterized in that: The ultrasonic devices are arranged in a circular matrix along the outer wall of the reactor tank at equal intervals, with 3-6 groups arranged in each layer, and the spacing between adjacent layers is 0.2-0.4 times the diameter of the cylindrical section of the reactor tank. The operating frequency of the ultrasonic devices is 20-100 kHz, and the power density is 0.1-1.0 W / cm 3 .

7. A wastewater treatment device based on persulfate advanced oxidation process according to claim 1, characterized in that: The inlet end of the persulfate metering pump is connected to the persulfate storage tank, and the outlet end is connected to the persulfate distributor. The inlet end of the catalyst metering pump is connected to the catalyst storage tank, and the outlet end is connected to the catalyst distributor. The persulfate distributor and the catalyst distributor adopt an annular porous water distribution pipe.

8. The wastewater treatment device based on persulfate advanced oxidation process according to claim 1, characterized in that: The persulfate is one or more mixtures of sodium persulfate, sodium hydrogen persulfate, potassium persulfate, potassium hydrogen persulfate, ammonium persulfate, and ammonium hydrogen persulfate; the catalyst is one or more mixtures of metal oxides, hydroxides, or sulfides of iron, cobalt, nickel, manganese, copper, and zinc.

9. The wastewater treatment device based on persulfate advanced oxidation process according to claim 1, characterized in that: The COD online analyzer and the ORP online analyzer are linked and controlled with the persulfate metering pump and the catalyst metering pump through a relay to maintain the redox potential of the reaction zone ≥400 mV.

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