Iron catalysis advanced oxidation synergistic phosphorus removal device for wastewater treatment

Abstract

The utility model discloses an iron catalysis advanced oxidation synergetic phosphorus removal device for wastewater treatment. The iron catalysis advanced oxidation synergetic phosphorus removal device comprises an oxidation zone, a neutralization zone, a flocculation zone and a settling zone, the oxidation zone is provided with a water inlet pipe, an acid dosing pipe, a ferrous dosing pipe, a Venturi mixer, an oxidant dosing pipe, an energy dissipation mixing paddle and a first guide cylinder; the neutralization area is provided with a lime milk dosing pipe; the flocculation zone is provided with a second guide cylinder and a PAM dosing pipe; the settling zone is provided with an inclined tube filler, a sludge scraper, a sludge hopper, a sludge discharge pump, an effluent weir and a water collecting tank; and the iron powder catalyst recycling machine is arranged above the first guide cylinder. According to the utility model, the problems that the traditional Fenton technology is large in medicament dosage and low in catalytic oxidation efficiency are solved; by adopting a lime milk solution dosing scheme, the method has the effects of adjusting the pH value, removing phosphorus and enhancing flocculation, and solves the problems that a catalyst cannot be recycled, the medicament utilization efficiency is low, the medicament cost is high and the iron sludge flocculation effect is poor in a traditional scheme.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment, in particular to an iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment.

Background Art

[0002] Taking industries such as chemical industry, electroplating, medicine, and electric power as examples, the production wastewater contains refractory organic matters such as benzene series, environmental endocrine disruptors and antibiotics, and organic phosphorus, which are difficult to effectively remove by traditional biochemical treatment methods.

[0003] For the treatment of such wastewater, the currently common technologies include: physical adsorption, chemical precipitation, and advanced oxidation processes, etc. For the advanced oxidation method, the current research and application mainly include photocatalytic oxidation, ozone oxidation, electrochemistry, Fenton oxidation, etc. The technology closest to the utility model is the Fenton oxidation technology. The traditional homogeneous Fenton oxidation technology is to add ferrous sulfate solution as a catalyst under acidic conditions to catalyze H2O2 to generate hydroxyl radicals with strong oxidation ability, oxidize refractory organic matters and organic phosphorus into CO2, H2O, and phosphate. In this process, Fe 2+ is converted into Fe 3+ , and phosphate reacts with Fe 3+ to form ferric phosphate precipitation, which is removed by flocculation precipitation separation.

[0004] The Fenton oxidation method has the advantages of easy availability of materials, convenient operation, and low cost compared with other oxidation methods. However, in actual engineering practice, due to the inevitable existence of mixing dead zones in the point-like dosing reactor, it is necessary to use an excessive amount of ferrous solution catalyst and the unreacted catalyst cannot be recovered. Therefore, there are problems such as low actual utilization rate of the ferrous catalyst, large dosing amount, and a lot of iron mud. To solve this problem, the technologies of Fenton fixed bed and Fenton fluidized bed are formed by introducing solid catalyst fillers. However, the Fenton fixed bed technology has problems such as easy blockage of solid catalyst fillers, easy deactivation of the active surface, and difficult replacement; the Fenton fluidized bed technology has problems such as relatively high fluidization energy consumption, serious catalyst loss, or relatively large particle size of the solid catalyst, small catalytic specific surface area, and low catalytic efficiency; in addition, the above-mentioned Fenton oxidation technology has problems such as poor sedimentation of iron mud, large precipitation area required for iron mud precipitation or low separation efficiency, and high suspended solids in the effluent.

[0005] In view of this, it is necessary to provide an iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment to overcome the above defects.

Content of the Utility Model

[0006] The object of the utility model is to provide an iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment, which is used for the efficient treatment of industrial wastewater, aiming to solve the problems existing in the homogeneous ferrous-catalyzed Fenton oxidation technology, such as excessive dosing of ferrous catalysts and inability to recycle, resulting in low catalyst utilization efficiency, large output of end iron sludge, low precipitation efficiency, large floor area, etc., and the problems existing in the heterogeneous Fenton fluidized bed technology, such as easy blockage of solid catalyst fillers, easy inactivation of active surfaces, difficult replacement, relatively high fluidization energy consumption of the fluidized bed, high effluent turbidity, etc., so as to improve the use efficiency of chemicals, precipitation efficiency, thereby reducing chemical costs, reducing floor area, and improving the removal efficiency of refractory organic compounds and phosphorus-containing pollutants in wastewater.

[0007] To achieve the above object, the utility model provides an iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment, comprising: an oxidation zone, a neutralization zone, a flocculation zone, and a precipitation zone through which wastewater flows in sequence;

[0008] The oxidation zone is provided with: a water inlet pipe having a water inlet pump, an acid dosing pipe and a ferrous dosing pipe both connected to the middle of the water inlet pipe, a Venturi mixer installed at the outlet of the water inlet pipe, an oxidant dosing pipe provided above the outlet of the Venturi mixer, and a first draft tube provided above the oxidant dosing pipe;

[0009] The neutralization zone is provided with: a lime milk dosing pipe extending into the inner part of the tank body; the neutralization zone is used to adjust the pH of the final effluent of the device to a preset pH value, and also to make the phosphates flowing into the oxidation zone react with Ca(OH)2 in the lime milk to form phosphate precipitates respectively; 3+ and Ca(OH)2 in the lime milk react to form phosphate precipitates;

[0010] The flocculation zone is provided with: a second draft tube, a PAM dosing pipe provided below the second draft tube, and a mechanical stirrer provided above the PAM dosing pipe and inside the second draft tube; the PAM solution added through the PAM dosing pipe is mixed inside the second draft tube and then overflows from the top of the second draft tube to flocculate and form flocs wrapping the phosphate precipitates and the iron powder catalyst;

[0011] The precipitation zone is provided with: inclined tube fillers, a sludge scraper and a sludge hopper both installed at the bottom of the tank body, a sludge discharge pump connected to the sludge hopper, an effluent weir and a water collection tank both provided on the upper side of the tank body; the outlet of the sludge discharge pump is sequentially connected to a sludge deflocculator and an iron powder catalyst recovery machine, and the iron powder catalyst recovery machine is provided above the first draft tube;

[0012] The Venturi mixer is used to mix the acid input through the acid dosing pipe and the ferrous catalyst input through the ferrous iron dosing pipe, and then mix it with the oxidant input through the oxidant dosing pipe and the iron powder catalyst falling from the iron powder catalyst recovery machine at the top to carry out a catalytic oxidation reaction, so that the refractory organic matter and organic phosphorus in the wastewater are oxidized into CO2, H2O and phosphate;

[0013] The inclined tube packing is used for mud-water separation, so that the sludge wrapped with the iron powder catalyst settles to the bottom of the pool body and is scraped into the sludge hopper by the sludge scraper; the sludge deflocculator is used to expose the iron powder catalyst wrapped in the sludge, and the iron powder catalyst recovery machine is used to magnetically attract the exposed iron powder catalyst under the action of magnetism and drop it into the first draft tube.

[0014] In a preferred embodiment, an energy dissipation mixing paddle is provided in the first draft tube through a rotating shaft; the energy dissipation mixing paddle is used to rotate driven by the liquid ejected from the Venturi mixer, so as to stir and dissipate energy from the liquid ejected from the Venturi mixer.

[0015] In a preferred embodiment, the neutralization zone is provided with a first baffle and a second baffle arranged at intervals; the number of the first baffles is two, and they are respectively connected to the top and bottom of the pool body in the neutralization zone; the number of the second baffles is two, and they are respectively connected to the top and bottom of the pool body in the neutralization zone.

[0016] In a preferred embodiment, the neutralization zone is connected to a gas stirring device; the gas stirring device includes an air diffuser pipe arranged at the bottom of the pool body in the neutralization zone and an air blower arranged outside the pool and communicated with the air diffuser pipe; the air diffuser pipe is provided with a perforated pipe structure or an air diffuser head structure on both sides of the first baffle.

[0017] In a preferred embodiment, the oxidation zone is communicated with the neutralization zone through a water passing hole, the outlet of the second baffle is communicated with the flocculation zone through a connecting pipe, and the water outlet side of the flocculation zone is communicated with the sedimentation zone through a third baffle.

[0018] In a preferred embodiment, the sludge hopper is further connected with a sludge reflux pump, and the outlet pipe of the sludge reflux pump extends to the inlet of the Venturi mixer.

[0019] In a preferred embodiment, the particle size of the iron powder catalyst is 100 mesh - 200 mesh, and the dosing amount is 0.1% - 1% of the influent water volume.

[0020] In a preferred embodiment, a first pH meter is provided outside the first draft tube. The first pH meter is used to interlock with the acid dosing device corresponding to the acid dosing pipe to adjust the pH value in the oxidation zone to the optimal pH value range required by the oxidant.

[0021] When the oxidant added through the oxidant dosing pipe is H2O2 or NaClO, the pH value in the oxidation zone is adjusted to 3-4.

[0022] When the oxidant added through the oxidant dosing pipe is percarbonate or persulfate, the pH value in the oxidation zone is adjusted to 6-9.

[0023] In a preferred embodiment, a COD detector is provided in the collection tank. The COD detector is used to interlock with the oxidant dosing device corresponding to the oxidant dosing pipe to adjust the dosage of the oxidant to degrade the COD in the wastewater to the required range.

[0024] In a preferred embodiment, a second pH meter is provided outside the second draft tube, and a TP detector is provided in the collection tank. The lime milk dosing device corresponding to the lime milk dosing pipe is interlocked with the second pH meter and the TP detector respectively, and the larger value of the lime milk dosage required to adjust the pH value of the wastewater to the preset pH value detected by the second pH meter and the lime milk dosage required to make the TP value less than the preset value detected by the TP detector is used to determine the lime milk dosage added through the lime milk dosing pipe.

[0025] The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment provided by the present utility model has at least the following beneficial effects:

[0026] (1) By using a Venturi mixer, enhanced mass transfer mixing with acid, ferrous catalyst, oxidant, iron powder catalyst, and reflux mixture is achieved in sequence, solving the problems of uneven mixing of the water distribution structure in traditional Fenton technology, large dosage of chemicals, low catalytic oxidation efficiency, and premature generation of hydroxyl radicals causing oxidation corrosion of pipelines, pipe fittings, and equipment.

[0027] (2) By using a sludge deflocculator and an iron powder catalyst recovery machine, the recovery efficiency of micron-sized iron powder catalyst can reach more than 99%, realizing the reuse of the catalyst. In addition, a sludge reflux pump is used to reflux sludge to recover iron ion catalyst, improving the utilization efficiency of the catalyst and solving the problems of catalyst loss, inability to recycle, and low utilization efficiency in traditional solutions.

[0028] (3) By adopting the lime milk solution dosing scheme, it has the functions of callback pH, phosphorus removal, and enhanced flocculation, solving the problems of many types of chemicals added, high chemical cost, and poor iron sludge flocculation effect in traditional solutions.

[0029] (4) In the preferred embodiment, by adopting the energy dissipation mixing blade, the energy at the outlet of the Venturi mixer is fully utilized to rotate the energy dissipation mixing blade to strengthen the stirring, solving the problems of high fluidization energy consumption and poor mixing effect in the traditional Fenton fluidized bed technology;

[0030] (5) In the preferred embodiment, by introducing a catalyst with a smaller particle size (micron-sized iron powder) than the traditional Fenton fluidized bed technology as the catalyst, the catalytic efficiency is further improved; at the same time, the micron-sized iron powder also serves as the crystal nucleus for iron sludge flocculation, increasing the specific gravity of the iron sludge flocs, thereby improving the efficiency of iron sludge precipitation and solving the problems of difficult iron sludge sedimentation, large sedimentation area, high SS and high chromaticity in the effluent in the traditional solution.

Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0032] Figure 1 It is a schematic structural diagram of the iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment provided by the present invention.

[0033] 1. Oxidation zone; 10. Inlet pipe; 11. Venturi mixer; 12. Energy dissipation mixing blade; 13. Rotating shaft; 14. First draft tube; 15. First pH meter; 16. Acid dosing pipe; 17. Ferrous iron dosing pipe; 18. Oxidant dosing pipe;

[0034] 2. Neutralization zone; 21. Water passing holes; 22. First baffle; 23. Second baffle; 24. Lime milk dosing pipe;

[0035] 3. Flocculation zone; 31. Connecting pipe; 32. Mechanical stirrer; 33. Second draft tube; 34. PAM dosing pipe; 35. Second pH meter; 36. Third baffle;

[0036] 4. Sedimentation zone; 41. Inclined tube packing; 42. Scraper; 43. Effluent weir; 44. Collection tank; 45. Outlet pipe; 46. TP detector; 47. COD detector; 48. Sludge hopper; 51. Sludge discharge pump; 52. Sludge reflux pump; 53. Sludge deflocculator; 54. Iron powder catalyst recovery machine; 55. Sludge discharge pipe;

[0037] 6. Gas stirring device; 61. Aeration pipe; 62. Aeration pump.

Detailed Embodiments

[0038] In order to make the purpose, technical solution and beneficial technical effects of the present utility model clearer and more understandable, the present utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described in this specification are only for explaining the present utility model and are not intended to limit the present utility model.

[0039] It should also be understood that the terms used in this specification of the present utility model are only for the purpose of describing specific embodiments and are not intended to limit the present utility model. As used in this specification of the present utility model and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0040] It should be further understood that the term "and / or" used in this specification of the present utility model and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0041] In an embodiment of the present utility model, there is provided an iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment, which is used for the efficient treatment of industrial wastewater, oxidizing refractory organic matter and organic phosphorus into CO2, H2O and phosphate, and the phosphate reacts with Fe 3+ to form iron phosphate precipitate, and then is removed by flocculation precipitation separation.

[0042] As Figure 1 shown, the iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment includes: an oxidation zone 1, a neutralization zone 2, a flocculation zone 3 and a precipitation zone 4 through which wastewater flows in sequence.

[0043] Specifically, the oxidation zone 1 is provided with: a water inlet pipe 10 having a water inlet pump, an acid dosing pipe 16 and a ferrous ion dosing pipe 17 both connected to the middle of the water inlet pipe 10, a Venturi mixer 11 installed at the outlet of the water inlet pipe 10, an oxidant dosing pipe 18 provided above the outlet of the Venturi mixer 11, and a first draft tube 14 provided above the oxidant dosing pipe 18.

[0044] Among them, the acid dosing pipe 16 is correspondingly connected to an acid dosing device, the ferrous ion dosing pipe 17 is correspondingly connected to a ferrous ion dosing device, the oxidant dosing pipe 18 is correspondingly connected to an oxidant dosing device, and the water inlet pump is used to pump untreated wastewater from the inlet of the water inlet pipe 10 into the oxidation zone 1.

[0045] The Venturi mixer 11 is used to mix the acid (for providing an acidic environment) introduced through the acid dosing pipe 16 and the ferrous catalyst (such as ferrous sulfate) introduced through the ferrous dosing pipe 17, and then mix with the oxidant (such as H2O2, NaClO, percarbonate, persulfate, etc.) introduced through the oxidant dosing pipe 18 and the iron powder catalyst falling from the top to carry out a catalytic oxidation reaction, so that the refractory organic matter and organic phosphorus in the wastewater are oxidized to CO2, H2O and phosphate. In this process, Fe 2+ is oxidized to Fe 3+ .

[0046] The upper part of the first draft tube 14 is cylindrical and the lower part is a flared mouth. The wastewater is mixed at the flared mouth part and then overflows upward from the cylindrical part. Further, an energy dissipation mixing blade 12 is provided in the first draft tube 14 through a rotating shaft 13. The energy dissipation mixing blade 12 is used to rotate driven by the liquid ejected from the Venturi mixer 11, so as to stir and dissipate energy from the liquid ejected from the Venturi mixer 11 and the iron powder catalyst recovered by the iron powder catalyst recovery machine 54 at the top of the first draft tube 14. That is, the hydraulic flow rate of the liquid at the water outlet of the Venturi mixer 11 causes the energy dissipation mixing blade 12 to rotate, playing a stirring role and an energy dissipation role, so that the liquid at the water outlet of the Venturi mixer 11 will not rush out of the oxidation zone 1.

[0047] In addition, an iron powder catalyst is also added into the oxidation zone 1. The iron powder catalyst can be zero-valent iron powder or magnetite powder, which can be obtained by recycling in the subsequent pool or newly added manually from the pool top. Among them, the particle size of the iron powder catalyst is 100 mesh - 200 mesh, and the dosing amount is 0.1% - 1% of the wastewater inflow. After the energy dissipation and stirring by the energy dissipation mixing blade 12, the liquid is mixed with the iron powder catalyst recovered by the iron powder catalyst recovery machine 54 or the newly added iron powder catalyst to further carry out a catalytic oxidation reaction.

[0048] Further, a first pH meter 15 is arranged outside the first draft tube 14. The first pH meter 15 is used to be interlocked with the acid dosing device corresponding to the acid dosing pipe 16 to adjust the pH value in the oxidation zone 1 to the optimal pH value range required by the oxidant. That is, the acid dosing amount of the acid dosing device is adjusted according to the pH value in the oxidation zone 1, so that the oxidant is in the most suitable acidic environment.

[0049] Among them, when the oxidant added through the oxidant dosing pipe 18 is H2O2 or NaClO, the pH value in the oxidation zone 1 is adjusted to 3 - 4; when the oxidant added through the oxidant dosing pipe 18 is percarbonate or persulfate, the pH value in the oxidation zone 1 is adjusted to 6 - 9.

[0050] In an embodiment of the present utility model, the oxidation zone 1 communicates with the neutralization zone 2 through the water passing holes 21. The neutralization zone 2 is provided with: a lime milk dosing pipe 24 extending into the interior of the tank body. The lime milk dosing pipe 24 is correspondingly connected to a lime milk dosing device, and the concentration of the dosed lime milk solution is 5%-10%. The neutralization zone 2 is used to adjust the pH of the final effluent of the device to a preset pH value (i.e., the pH required for discharge or the next treatment process), and is also used to enable the phosphorus-containing pollutants flowing into the oxidation zone 1 to react with Fe 3+ and Ca(OH)2 in the lime milk to generate phosphate precipitates and be removed. Among them, the phosphorus-containing pollutants in the reaction liquid flowing into the oxidation zone 1 react with Fe 3+ in the neutralization zone 2 to generate iron phosphate precipitates and react with Ca(OH)2 in the lime milk to generate Ca 10 (PO4)6(OH)2 precipitates.

[0051] Furthermore, the neutralization zone 2 is provided with a first baffle 22 and a second baffle 23 arranged at intervals. The number of the first baffles 22 is two, and they are respectively connected to the top and bottom of the tank body of the neutralization zone 2; the number of the second baffles 23 is two, and they are respectively connected to the top and bottom of the tank body of the neutralization zone 2.

[0052] Even further, the neutralization zone 2 is connected to a gas stirring device 6. The gas stirring device 6 includes an air diffuser pipe 61 arranged at the bottom of the tank body of the neutralization zone 2 and an air pump 62 arranged outside the tank and communicated with the air diffuser pipe 61. The air diffuser pipe 61 is provided with a perforated pipe structure or an air diffuser head structure on both sides of the first baffle 22 to provide sufficient gas to the neutralization zone 2 for mixing the added lime milk and removing the unreacted oxidant. Among them, the channels between the two first baffles 22 and between the two second baffles 23 are not provided with a perforated pipe structure and an air diffuser head structure.

[0053] In an embodiment of the present utility model, the outlet of the second baffle 23 is communicated with the flocculation zone 3 through a connecting pipe 31. The flocculation zone 3 is provided with: a second draft tube 33, a PAM dosing pipe 34 arranged below the second draft tube 33, and a mechanical stirrer 32 arranged above the PAM dosing pipe 34 and inside the second draft tube 33. The PAM (Polyacrylamide) solution added through the PAM dosing pipe 34 is mixed with the liquid flowing into the neutralization zone 2 under the stirring of the mechanical stirrer 32 and then overflows from the second draft tube 33 to flocculate to form flocs wrapping the phosphate precipitates and the iron powder catalyst. In this embodiment, the concentration of the PAM solution is 0.1%-0.3%.

[0054] Among them, the second draft tube 33 has a cylindrical upper part and a flared lower part. In addition, a mechanical stirrer 32 is provided inside the second draft tube 33. In this embodiment, the mechanical stirrer 32 adopts a low-speed and large-flow lifting stirring paddle. The PAM dosing pipe 34 is arranged below the stirring paddle of the mechanical stirrer 32.

[0055] In the embodiment of the present utility model, the water outlet side of the flocculation zone 3 is communicated with the sedimentation zone 4 by arranging a third baffle 36. The sedimentation zone 4 is provided with: inclined tube fillers 41, a sludge scraper 42 and a sludge hopper 48 both installed at the bottom of the pool body, a sludge discharge pump 51 connected to the sludge hopper 48, a water outlet weir 43 and a water collecting tank 44 both arranged on the upper side of the pool body. The outlet of the sludge discharge pump 51 is successively connected to a sludge deflocculator 53 and an iron powder catalyst recovery machine 54, and the iron powder catalyst recovery machine 54 is arranged above the first draft tube 14.

[0056] Specifically, the flocculated liquid mixture entering the sedimentation zone 4 is subjected to solid-liquid separation by the inclined tube fillers 41, so that the sludge wrapped with the iron powder catalyst settles to the bottom of the pool body and is scraped into the sludge hopper 48 by the sludge scraper 42. The clear liquid after solid-liquid separation by the inclined tube fillers 41 flows upward, overflows through the water outlet weir 43 to the water collecting tank 44 and is then discharged through the water outlet pipe 45. In this embodiment, the sedimentation surface load of the sedimentation zone 4 is 10m 3 / m 2 ·h - 20m 3 / m 2 ·h.

[0057] Among them, the sludge deflocculator 53 is used to expose the iron powder catalyst wrapped in the sludge, and the iron powder catalyst recovery machine 54 is used to magnetically attract the exposed iron powder catalyst under the action of electromagnetic force and drop it into the first draft tube 14 to play an oxidation catalytic role again.

[0058] Furthermore, in some embodiments, the bottom of the sludge hopper 48 is also connected with a sludge reflux pump 52, and the outlet pipe of the sludge reflux pump 52 extends to the inlet of the Venturi mixer 11. Specifically, a part of the sludge flows into the 55 sludge discharge pipe by gravity and is pumped into the sludge deflocculator 53 and the iron powder catalyst recovery machine 54 by the sludge discharge pump 51. After separating the iron powder catalyst, it is transported to the sludge treatment system for dehydration and then transported out for disposal. Another part of the sludge is refluxed to the inlet of the Venturi mixer 11 through the sludge reflux pump 52. In this embodiment, the reflux flow of the sludge reflux pump 52 is 5% - 10% of the influent flow. Therefore, after the liquid is dissipated energy and stirred by the energy dissipation mixing blades 12, it is mixed with the iron powder catalyst recovered by the iron powder catalyst recovery machine 54 or the newly added iron powder catalyst, and further undergoes a catalytic oxidation reaction. The mixed liquid overflows from the top of the first draft tube 14. A part of the reaction liquid and the sludge refluxed by the sludge reflux pump 52 are sucked into the Venturi mixer 11 to be mixed with the newly incoming wastewater for another catalytic oxidation reaction, forming an internal circulation.

[0059] Further, a COD detector 47 is provided in the water collecting tank 44. The COD detector 47 is used to sample the clear liquid in the water collecting tank 44 to detect the COD (Chemical Oxygen Demand) concentration in the clear liquid. The COD detector 47 is interlocked with the oxidant dosing device corresponding to the oxidant dosing pipe 18 to adjust the oxidant dosing amount to degrade the COD in the wastewater to the required range.

[0060] Further, a second pH meter 35 is provided outside the second draft tube 33. A TP detector 46 is provided in the water collecting tank 44. The TP detector 46 is used to sample the clear liquid in the water collecting tank 44 to detect the TP (Total Phosphorus) concentration in the clear liquid. The lime milk dosing device corresponding to the lime milk dosing pipe 24 is interlocked with the second pH meter 35 and the TP detector 46 respectively to determine the lime milk dosing amount added through the lime milk dosing pipe 24 according to the larger value of the lime milk dosing amount required to adjust the pH value of the wastewater to the preset pH value detected by the second pH meter 35 and the lime milk dosing amount required to make the TP value less than the preset value detected by the TP detector 46.

[0061] In order to make the above objects, features, and advantages of the present utility model more obvious and understandable, the effects of the present technical solution will be described in detail below with reference to an exemplary specific embodiment.

[0062] Taking the sewage discharged from the circulating cooling system of a certain gas-fired power plant with municipal reclaimed water as the water source as the treatment object, the sewage has a CODcr of 80 - 150 mg / L, a TP of 3 - 5 mg / L, a chromaticity of 100 - 200, and a pH of 7 - 9. The existing Fenton oxidation method and the iron-catalyzed advanced oxidation phosphorus removal device described in the present utility model are respectively used for treatment.

[0063] Comparative example: The Fenton oxidation method is used to treat this wastewater. The wastewater is pumped to the Fenton oxidation device and concentrated sulfuric acid, ferrous sulfate, and hydrogen peroxide are added in sequence. The pH is adjusted to 3 - 4, the dosing amount of concentrated sulfuric acid is 75 mg / L; ferrous sulfate heptahydrate is 2085 mg / L; hydrogen peroxide (27.5%) is 764 mg / L, the oxidation time is 3 h, and after the reaction, sodium hydroxide (30%) 133 mg / L and PAC (PolyAluminum Chloride) dosing amount 120 mg / L and PAM dosing amount 8 mg / L are added for coagulation and precipitation, and the precipitation load is 0.5 m 3 / m 2 ·h. After treatment, the produced water has a COD of 45 mg / L, a TP of 0.4 mg / L, a chromaticity of 25, and a pH of 7 - 9. Among them, the chemical agent cost of the traditional Fenton oxidation process is 2.87 yuan / ton of wastewater.

[0064] This embodiment: The iron-catalyzed advanced oxidation and phosphorus removal device disclosed by the present utility model is used to treat this wastewater. The wastewater is mixed with concentrated sulfuric acid and ferrous sulfate by a feed water pump and then injected into the iron-catalyzed advanced oxidation and phosphorus removal device. After being hydraulically mixed with hydrogen peroxide, it is further stirred by the energy dissipation mixing blade 12 to strengthen the mixing. Supplementary iron powder catalyst is added above the energy dissipation mixing blade 12 or the iron powder catalyst recovered by the iron powder catalyst recovery machine 54 is mixed to occur catalytic oxidation reaction. The dosage of the reagent is 75 mg / L of concentrated sulfuric acid to adjust the pH to 3-4, 294 mg / L of ferrous sulfate heptahydrate; 1 mg / L of supplementary iron powder catalyst, 530 mg / L of hydrogen peroxide (27.5%), the oxidation time is 2 h, and 1360 mg / L of calcium hydroxide (90%) is added after the reaction. The dosage of PAM is 8 mg / L for coagulation precipitation, and the precipitation load is 10 m 3 / m 2 ·h. After treatment, the produced water has a COD of 45 mg / L, a TP of 0.3 mg / L, a chromaticity of 10, and a pH of 7-9. Among them, the reagent cost of the iron-catalyzed advanced oxidation and phosphorus removal process of the present utility model is 2.35 yuan / ton of wastewater.

[0065] It can be seen from the above two cases that the removal rates of organic matter and TP of this device are the same as those of the traditional Fenton oxidation process, but the reagent cost is much lower than that of the traditional Fenton process, and the effluent chromaticity is lower and the sludge yield is less.

[0066] To sum up, the iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment provided by the present utility model has at least the following beneficial effects:

[0067] (1) By adopting a Venturi mixer, enhanced mass transfer mixing with acid, ferrous catalyst, oxidant, iron powder catalyst and reflux mixing liquid is achieved in sequence, solving the problems of large reagent dosage, low catalytic oxidation efficiency and premature generation of hydroxyl radicals causing oxidation corrosion to pipelines, pipe fittings and equipment due to uneven mixing of the water distribution structure in traditional Fenton technology;

[0068] (2) By adopting a sludge deflocculator and an iron powder catalyst recovery machine, the recovery efficiency of micron-sized iron powder catalyst can reach more than 99%, realizing the reuse of the catalyst. In addition, a sludge reflux pump is also used to reflux the sludge to recover the iron ion catalyst, improving the utilization efficiency of the catalyst and solving the problems of catalyst loss, inability to be recycled and low utilization efficiency in the traditional scheme;

[0069] (3) By adopting the dosing scheme of lime milk solution, it has the functions of adjusting the pH, removing phosphorus and strengthening flocculation at the same time, and there is no need to add a coagulant additionally, solving the problems of many types of dosing, high reagent cost and poor iron sludge flocculation effect in the traditional scheme;

[0070] (4) In a preferred embodiment, by adopting an energy dissipation mixing blade to fully utilize the energy at the outlet of the Venturi mixer to rotate the energy dissipation mixing blade and strengthen stirring, the problems of high fluidization energy consumption and poor mixing effect in the traditional Fenton fluidized bed technology are solved;

[0071] (5) In a preferred embodiment, by introducing a catalyst with a smaller particle size (micron-sized iron powder) than that in the traditional Fenton fluidized bed technology as the catalyst, the catalytic efficiency is further improved; at the same time, the micron-sized iron powder also serves as the crystal nucleus for iron sludge flocculation, increasing the proportion of iron sludge flocs, thereby improving the efficiency of iron sludge precipitation, and solving the problems of difficult iron sludge settlement, large precipitation area, high effluent SS (Suspended Solids), high chromaticity, etc. in the traditional scheme.

[0072] The present utility model is not limited solely to what is described in the specification and embodiments. Therefore, for those skilled in the art, additional advantages and modifications can be easily achieved. Thus, without departing from the spirit and scope of the general concept defined by the claims and the equivalent scope, the present utility model is not limited to specific details, representative devices, and the illustrated examples shown and described herein.

Claims

1. An iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment, characterized in that, Comprising: An oxidation zone, a neutralization zone, a flocculation zone, and a sedimentation zone through which the wastewater flows successively; The oxidation zone is provided with: a water inlet pipe having a water inlet pump, an acid dosing pipe and a ferrous catalyst dosing pipe both connected to the middle of the water inlet pipe, a Venturi mixer installed at the outlet of the water inlet pipe, an oxidant dosing pipe provided above the outlet of the Venturi mixer, and a first draft tube provided above the oxidant dosing pipe; The neutralization zone is provided with: a lime milk dosing pipe extending into the interior of the tank body; the neutralization zone is used to adjust the pH of the final effluent of the device to a preset pH value, and is also used to react the phosphate flowing into the oxidation zone with Fe 3+ , Ca(OH)2 in the lime milk to form phosphate precipitates; The flocculation zone is provided with: a second draft tube, a PAM dosing pipe provided below the second draft tube, and a mechanical stirrer provided above the PAM dosing pipe and inside the second draft tube; the PAM solution added through the PAM dosing pipe is mixed inside the second draft tube and overflows from the top of the second draft tube to form flocs that wrap the phosphate precipitate and the iron powder catalyst. The sedimentation zone is provided with: inclined tube fillers, a sludge scraper and a sludge hopper both installed at the bottom of the tank body, a sludge discharge pump connected to the sludge hopper, a water outlet weir and a water collection tank both provided on the upper side of the tank body; the outlet of the sludge discharge pump is successively connected to a sludge deflocculator and an iron powder catalyst recovery machine, and the iron powder catalyst recovery machine is provided above the first draft tube; The Venturi mixer is used to mix the acid input through the acid dosing pipe and the ferrous catalyst input through the ferrous catalyst dosing pipe, and then mix with the oxidant input through the oxidant dosing pipe and the iron powder catalyst falling from the iron powder catalyst recovery machine above to carry out a catalytic oxidation reaction, so that the refractory organic matter and organic phosphorus in the wastewater are oxidized into CO2, H2O and phosphate; The inclined tube fillers are used for solid-liquid separation, so that the sludge wrapped with the iron powder catalyst settles to the bottom of the tank body and is scraped into the sludge hopper by the sludge scraper; the sludge deflocculator is used to expose the iron powder catalyst wrapped in the sludge, and the iron powder catalyst recovery machine is used to magnetically attract the exposed iron powder catalyst under the action of magnetism and drop it into the first draft tube.

2. The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment according to claim 1, characterized in that, An energy dissipation mixing blade is provided in the first draft tube through a rotating shaft; the energy dissipation mixing blade is used to rotate driven by the liquid ejected from the Venturi mixer, so as to stir and dissipate the energy of the liquid ejected from the Venturi mixer.

3. The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment according to claim 1, characterized in that, The neutralization zone is provided with a first baffle plate and a second baffle plate arranged at intervals; the number of the first baffle plates is two, and they are respectively connected to the top and bottom of the tank body of the neutralization zone; the number of the second baffle plates is two, and they are respectively connected to the top and bottom of the tank body of the neutralization zone.

4. The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment according to claim 3, wherein, The neutralization zone is connected to a gas stirring device; the gas stirring device includes an air distribution pipe arranged at the bottom of the tank body of the neutralization zone and an air blower arranged outside the tank and communicated with the air distribution pipe; the air distribution pipe is provided with a perforated pipe structure or an air diffuser structure on both sides of the first baffle plate.

5. The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment according to claim 4, characterized in that, The oxidation zone is communicated with the neutralization zone through a water passing hole, the outlet of the second baffle plate is communicated with the flocculation zone through a connecting pipe, and the water outlet side of the flocculation zone is communicated with the sedimentation zone through the arrangement of a third baffle plate.

6. The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment according to claim 1, characterized in that, The sludge hopper is further connected with a sludge return pump, and the outlet pipe of the sludge return pump extends to the inlet of the Venturi mixer.

7. The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment according to claim 1, wherein The particle size of the iron powder catalyst is 100 mesh - 200 mesh, and the dosage is 0.1% - 1% of the influent water volume.

8. The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment according to claim 1, characterized in that, A first pH meter is arranged outside the first draft tube, and the first pH meter is used to be interlocked with the acid dosing device corresponding to the acid dosing pipe to adjust the pH value in the oxidation zone to the optimal pH value range required by the oxidant. When the oxidant added through the oxidant dosing pipe is H2O2 or NaClO, the pH value in the oxidation zone is adjusted to 3 - 4. When the oxidant added through the oxidant dosing pipe is percarbonate or persulfate, the pH value in the oxidation zone is adjusted to 6 - 9.

9. The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment according to claim 1, characterized in that The water collecting tank is equipped with a COD detector, and the COD detector is used to be interlocked with the oxidant dosing device corresponding to the oxidant dosing pipe to adjust the oxidant dosage to degrade the COD in the wastewater to the required range.

10. The iron-catalyzed advanced oxidation and phosphorus removal device for wastewater treatment according to claim 1, characterized in that, A second pH meter is arranged outside the second draft tube, and the water collecting tank is equipped with a TP detector; the lime milk dosing devices corresponding to the lime milk dosing pipes are respectively interlocked with the second pH meter and the TP detector to determine the lime milk dosage added through the lime milk dosing pipe according to the larger value of the lime milk dosage required to adjust the pH value of the wastewater to the preset pH value detected by the second pH meter and the lime milk dosage required to make the TP value less than the preset value detected by the TP detector.

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