Apparatus and Method for Coupled Ferric Ammonium Oxidation and Anaerobic Ammonium Oxidation of Fenton Residual Iron Sludge

Abstract

This invention discloses an apparatus and method for coupling ferroammonia oxidation and anaerobic ammonia oxidation of Fenton waste sludge, comprising an influent tank, a five-stage reactor, a secondary sedimentation tank, and a Fenton reactor connected in sequence. This invention enriches the ferroammonia-oxidizing bacteria in the activated sludge by recirculating the sludge (containing ferric iron) produced in the Fenton reactor to the five-stage reactor. The nitrite and nitrate nitrogen produced by ferroammonia oxidation are directly or indirectly utilized by anaerobic ammonia-oxidizing bacteria on the packing material for anaerobic ammonia oxidation. The nitrate nitrogen produced in the aerobic zone can be denitrified using carbon sources and ammonia nitrogen in the influent through short-cut denitrification anaerobic ammonia oxidation. This invention achieves volume reduction and harmless treatment of Fenton waste sludge, achieving high nitrogen and phosphorus removal efficiency in industrial wastewater while removing recalcitrant organic matter.

Description

Technical Field

[0001] This invention belongs to the field of wastewater purification technology, and relates to nitrogen and phosphorus removal from municipal wastewater. In particular, it relates to an apparatus and method for achieving nitrogen and phosphorus removal from industrial wastewater or industrial wastewater containing part of municipal wastewater by coupling Fenton residual iron sludge with iron ammonia oxidation or anaerobic ammonia oxidation. Background Technology

[0002] The Fenton reaction is an advanced oxidation technology used in wastewater treatment. It utilizes the strong oxidizing power of hydroxyl radicals to degrade and remove organic pollutants from water. This reaction typically proceeds under acidic conditions, involving the reaction of hydrogen peroxide with ferrous ions (Fe²⁺). 2+ ) reaction.

[0003] In the Fenton reaction, hydrogen peroxide reacts with ferrous ions to generate hydroxyl radicals. These hydroxyl radicals can oxidize organic pollutants, breaking them down into smaller inorganic compounds. This advanced oxidation process is characterized by high efficiency, speed, broad spectrum, and environmental friendliness, making it suitable for treating a variety of organic substances, including wastewater containing benzene, phenols, and / or formaldehyde.

[0004] The Fenton reaction is commonly used in industrial wastewater treatment and environmental remediation, and can effectively degrade and remove recalcitrant organic pollutants.

[0005] Feammox technology is a newly discovered autotrophic biological nitrogen removal technology. This technology offers advantages such as requiring no organic carbon source, low sludge production, and low greenhouse gas emissions, providing a novel nitrogen removal pathway for wastewater treatment systems. The Feammox reaction converts ferric salts and ammonia nitrogen into ferrous ions, nitrite, and nitrate. It also removes a portion of the ammonia nitrogen, converting it into nitrite and nitrate.

[0006] Ammonium oxidase can convert ammonia nitrogen and nitrite into nitrogen gas in the presence of anaerobic ammonia oxidizing bacteria. The reaction does not require an organic carbon source, and its application in wastewater treatment is a research hotspot in the environmental field.

[0007] The iron sludge produced by the Fenton reaction serves as a medium, providing iron salts and ammonia nitrogen from the influent as substrates for the ferroammonia oxidation (FAO). The products of FAO, nitrite, can provide one of the substrates for the anaerobic ammonia oxidation (AMO) reaction, and react with the remaining ammonia nitrogen in the influent. The ferrous ions generated during FAO can react with phosphate ions, simultaneously removing phosphorus from the system.

[0008] In industrial wastewater treatment, recalcitrant organic matter is often treated using advanced oxidation technologies such as Fenton oxidation. However, the Fenton process generates iron sludge, a hazardous waste that is both expensive and difficult to treat. Ferric ammonia oxidation technology can reduce and neutralize this Fenton iron sludge, achieving stable removal of recalcitrant organic matter from industrial wastewater while ensuring effective nitrogen and phosphorus removal. Summary of the Invention

[0009] To address the challenges of unstable substrate sources for anaerobic ammonia oxidation bacteria in continuous flow five-stage water treatment processes, the difficulty in treating iron sludge produced by Fenton treatment of organic matter in industrial wastewater, and the difficulty in maintaining ferroaming oxidation (FMO) in the system, this invention combines FMO with anaerobic ammonia oxidation processes and the waste generated by Fenton technology. By adding iron sludge produced by the Fenton reaction to the biological reaction tank, the functional effects of FMO and anaerobic ammonia oxidation are enhanced, further providing a stable nitrite substrate for anaerobic ammonia oxidation bacteria, increasing the nitrogen removal contribution rate of anaerobic ammonia oxidation in industrial wastewater treatment, and simultaneously achieving good phosphorus removal. This provides a stable and efficient new technology for industrial wastewater treatment, promotes the widespread application of anaerobic ammonia oxidation technology in wastewater treatment, and reduces hazardous waste such as iron sludge. This invention provides a theoretical basis and technical support for advanced industrial wastewater treatment, energy conservation and emission reduction, and iron sludge treatment and disposal, and has significant application value.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] This invention first provides an apparatus for coupling iron ammonia oxidation and anaerobic ammonia oxidation of Fenton residual iron sludge. The apparatus includes an inlet tank, a five-stage reactor, a secondary sedimentation tank, and a Fenton reactor connected in sequence. The five-stage reactor includes an anaerobic zone, an anoxic zone 1, an aerobic zone 1, an aerobic zone 2, an anoxic zone 2, an anoxic zone 3, and an aerobic zone 3. The iron sludge produced by the Fenton reactor is returned to the anaerobic zone and the anoxic zone 2 via pipelines. The sludge from the secondary sedimentation tank is returned to the anaerobic zone. The aerobic zone 2 and the anoxic zone 1 are also recirculated.

[0012] As a preferred embodiment of the present invention, aerators are provided at the bottom of the aerobic zone 1, aerobic zone 2 and aerobic zone 3; it also includes a blower system, and the aerobic zone 1, aerobic zone 2 and aerobic zone 3 are respectively connected to the blower system, and aeration control valves and rotor flow meters are respectively provided on the connecting pipes.

[0013] As a preferred embodiment of the present invention, the anaerobic zone, anoxic zone 1, anoxic zone 2 and anoxic zone 3 are respectively provided with anaerobic ammonia oxidation packing.

[0014] As a preferred embodiment of the present invention, an anaerobic zone stirrer is provided in the anaerobic zone, an anoxic zone one stirrer is provided in the anoxic zone one, an anoxic zone two stirrer is provided in the anoxic zone two, and an anoxic zone three stirrer is provided in the anoxic zone three.

[0015] As a preferred embodiment of the present invention, the effluent from the anoxic zone 3 enters the Fenton reactor after passing through a secondary sedimentation tank.

[0016] As a preferred embodiment of the present invention, the pipeline between the secondary sedimentation tank and the anaerobic zone is equipped with a sludge return pump and a sludge return control valve, and the secondary sedimentation tank is also equipped with a sludge discharge control valve for external sludge discharge; the pipeline between the Fenton reactor and the anaerobic zone and the anoxic zone is equipped with a Fenton iron sludge return pump.

[0017] As a preferred embodiment of the present invention, the reflux pipelines of the aerobic zone 2 and the anoxic zone 1 are equipped with a nitrification liquid reflux pump and a nitrification liquid reflux control valve.

[0018] The present invention also provides a method for coupling ferroammonia oxidation and anaerobic ammonia oxidation using the above-described apparatus for Fenton residual iron sludge, comprising the following steps:

[0019] 1) The excess sludge from ordinary urban sewage treatment plants is added to the five-stage reactor, and anaerobic ammonia oxidation packing material that has been inoculated with anaerobic ammonia oxidation biofilm is added to the anaerobic zone, anoxic zone 1, anoxic zone 2 and anoxic zone 3 of the five-stage reactor.

[0020] 2) Industrial wastewater or industrial wastewater containing some municipal sewage enters the anaerobic zone from the inlet tank. The sludge from the secondary sedimentation tank is also returned to the anaerobic zone via the sludge return pump. The nitrification liquid is returned from the aerobic zone 2 to the anoxic zone 1 via the nitrification liquid return pump. The wastewater flows from the anaerobic zone to the anoxic zone 1 in the five-stage reactor, and then flows through the aerobic zone 1, aerobic zone 2, anoxic zone 2, anoxic zone 3 and aerobic zone 3 in sequence. Sludge-water separation is achieved in the secondary sedimentation tank. The effluent enters the Fenton reactor via the Fenton reactor inlet pump. After removing the recalcitrant organic matter, the effluent is discharged.

[0021] 3) The iron sludge produced by the Fenton reactor is fed into the anaerobic zone and anoxic zone II of the five-stage reactor via the Fenton iron sludge reflux pump.

[0022] 4) Control the blower to regulate the aeration rate in the aerobic zone, so that the dissolved oxygen concentration in the aerobic zone is about 0.5 mg / L-2.5 mg / L;

[0023] 5) Control the hydraulic retention time of the five-stage reactor and discharge excess sludge through the sludge discharge control valve;

[0024] 6) The Fenton reactor, a non-biochemical reaction method, is used to remove recalcitrant organic matter from industrial wastewater, ensuring that the overall effluent consistently meets standards.

[0025] As a preferred embodiment of the present invention, in step 1), the sludge concentration in the reactor is maintained at 2000-3000 mg / L, and the filling ratio of the anaerobic ammonia oxidation packing is 15%-30%.

[0026] As a preferred embodiment of the present invention, in step 5), the hydraulic retention time of the five-stage reactor is controlled at 12-18h, and the remaining sludge is discharged through the sludge discharge control valve, so that the sludge age of the flocculent sludge in the system is 15-20d.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1) This invention utilizes a coupling of ferroammonia oxidation and anaerobic ammonia oxidation processes to treat industrial wastewater or industrial wastewater containing a small amount of municipal wastewater. Anaerobic ammonia oxidizing bacteria are retained by packing material, and the ferroammonia oxidation effect is enhanced by the continuous reflux of Fenton iron sludge. Under the synergistic effect of the ferroammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria, the coupling of ferroammonia oxidation and short-cut denitrification anaerobic ammonia oxidation can simultaneously remove ammonia nitrogen and nitrates, as well as easily degradable organic matter.

[0029] 2) This invention can reduce aeration, save on the addition of external carbon sources such as sodium acetate and methanol, and reduce operating costs.

[0030] 3) Iron salt is a commonly used phosphorus removal agent. The iron ions generated by the dissolution of the returned iron sludge can form precipitates with the phosphate in the system, thereby enhancing the phosphorus removal effect of the system.

[0031] 4) The method of the present invention can reduce the volume and harmlessly treat the iron sludge produced by Fenton, reduce the amount of hazardous waste in the process of industrial wastewater treatment, is highly operable, and is suitable for upgrading and transforming existing industrial wastewater treatment plants (containing a large amount of industrial wastewater), and is also suitable for newly built wastewater treatment plants with low carbon-nitrogen ratio influent water quality. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the device of the present invention.

[0033] In the diagram, 1-Inlet tank; 2-Raw water inlet pump; 3-Anaerobic zone; 4-Anoxic zone 1; 5-Aerobic zone 1; 6-Aerobic zone 2; 7-Anoxic zone 2; 8-Anoxic zone 3; 9-Aerobic zone 3; 10-Five-stage reactor; 11-Secondary sedimentation tank; 12-Fenton reactor inlet pump; 13-Fenton reactor; 14-Outlet pipe; 15-Anaerobic zone agitator; 16-Anoxic zone 1 agitator; 17-Anoxic zone 2 agitator; 18-Anoxic zone 3 agitator; 19-Blower; 20-Aeration control valve; 21-Rotameter; 22-Aerator; 23-Nitrification liquor return pump; 24-Nitrification liquor return control valve; 25-Sludge discharge control valve; 26-Sludge return pump; 27-Sludge return control valve; 28-Fenton iron sludge return pump; 29-Anaerobic ammonia oxidation packing. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] See Figure 1 The present invention provides a method and apparatus for coupled iron ammonia oxidation and anaerobic ammonia oxidation of Fenton residual iron sludge, including an inlet tank 1, a five-stage reactor 10, a secondary sedimentation tank 11 and a Fenton reactor 13.

[0037] The water inlet tank 1 is equipped with a raw water inlet pump 2.

[0038] The five-stage reactor 10 includes an anaerobic zone and two alternating anoxic and aerobic zones, namely anaerobic zone 3, anoxic zone 1 4, aerobic zone 1 5, aerobic zone 2 6, anoxic zone 2 7, anoxic zone 3 8, and aerobic zone 3 9.

[0039] The secondary sedimentation tank 11 is equipped with a sludge discharge control valve 25, a sludge return pump 26, and a sludge return control valve 27.

[0040] The Fenton reactor 13 is equipped with a Fenton reactor inlet pump 12, a Fenton iron sludge reflux pump 28 and an outlet pipe 14.

[0041] The dissolved oxygen in aerobic zone 5, aerobic zone 6 and aerobic zone 9 is controlled by blower 19, aeration control valve 20 and rotor flow meter 21, and the activated sludge in the five-stage reactor 10 is aerated by aerator 22.

[0042] Anaerobic zone 3, anoxic zone 1 4, anoxic zone 2 7, and anoxic zone 3 8 are equipped with anaerobic ammonia oxidation packing material 29 with biofilm attached, with a filling ratio of 15%-30%.

[0043] Anaerobic zone 3, anoxic zone 1 4, anoxic zone 2 7, and anoxic zone 3 8 are respectively equipped with an anaerobic zone stirrer 15, anoxic zone 1 16, anoxic zone 2 17, and anoxic zone 3 stirrer 18.

[0044] The reflux pipelines of aerobic zone 2 (6) and anoxic zone 1 (4) are equipped with a nitrification liquid reflux pump 23 and a nitrification liquid reflux control valve 24.

[0045] Industrial wastewater or industrial wastewater containing some municipal sewage from inlet tank 1 enters anaerobic zone 3 through raw water inlet pump 2. Different reaction zones of the five-stage reactor 10 are connected by short pipes. The effluent passes through secondary sedimentation tank 11 and is then pumped into Fenton reactor 13 by Fenton reactor inlet pump 12. Sludge discharge from secondary sedimentation tank 11 is controlled by sludge discharge control valve 25. Sludge return from secondary sedimentation tank 11 is regulated by sludge return pump 26 and sludge return control valve 27, and sludge is returned to anaerobic zone 3. Iron sludge produced in Fenton reactor 3 is returned to anaerobic zone 3 and anoxic zone 7 of the five-stage reactor 10 through pipeline via Fenton iron sludge return pump 28.

[0046] Example 2

[0047] This embodiment provides a method for coupling Fenton residual iron sludge oxidation with anaerobic ammonium oxidation using the apparatus of Embodiment 1, including the following steps:

[0048] 1) The excess sludge from ordinary urban sewage treatment plants is added to the five-stage reactor 10 to maintain the sludge concentration in the reactor at 2000-3000 mg / L. Then, anaerobic ammonia oxidation packing material 29, which has been inoculated with anaerobic ammonia oxidation biofilm, is added to the anaerobic zone 3, anoxic zone 1 4, anoxic zone 2 (7) and anoxic zone 3 8 in the five-stage reactor 10, with a filling ratio of 15%-30%.

[0049] 2) Industrial wastewater or industrial wastewater containing some municipal sewage enters the anaerobic zone 3 through the raw water inlet pump 2 from the inlet tank 1. The sludge from the secondary sedimentation tank 11 is also returned to the anaerobic zone 3 through the sludge return pump 26. In this zone, polyphosphate-accumulating bacteria absorb small molecule organic matter in the inlet water and carry out phosphorus release reaction. The nitrate nitrogen carried in the sludge return uses the organic matter and ammonia nitrogen in the inlet water to carry out short-cut denitrification anaerobic ammonia oxidation denitrification, while denitrification denitrification also occurs. The sludge return ratio is controlled at 50%-100%; the nitrified liquor is returned from aerobic zone 2 6 to anoxic zone 1 4 via nitrified liquor return pump 23. Nitrate nitrogen in the nitrified liquor can be denitrified through short-cut denitrification, anaerobic ammonia oxidation and denitrification. The nitrified liquor return ratio is controlled at 150%-300%; the wastewater flows from anaerobic zone 3 to anoxic zone 1 4 in the five-stage reactor 10, and then flows sequentially through aerobic zone 1 5, aerobic zone 2 6, anoxic zone 2 7, anoxic zone 3 8 and aerobic zone 3 9. Sludge-water separation is achieved in the secondary sedimentation tank 11. The effluent enters Fenton reactor 13 through Fenton reactor inlet pump 12. After removing the recalcitrant organic matter, the effluent is discharged.

[0050] 3) The iron sludge produced by Fenton reactor 13 enters the anaerobic zone 3 and anoxic zone 2 7 of the five-stage reactor 10 through Fenton iron sludge return pump 28, providing iron salts (ferric iron) for the biochemical reaction system. The return of iron salts continuously enriches the iron ammonia oxidizing bacteria in the five-stage reactor 10. In anaerobic zone 3 and anoxic zone 1 4, the nitrite and nitrate nitrogen produced by the iron ammonia oxidation reaction are utilized by anaerobic ammonia oxidizing bacteria and denitrifying bacteria for denitrification. In this process, ferric iron is reduced to ferrous iron. In the following aerobic zone 1 5 and aerobic zone 2 6, some ferrous iron is oxidized to ferric iron, and together with the returned iron salts, it undergoes iron ammonia oxidation reaction in anoxic zone 2 7 and anoxic zone 3 8. At the same time, it is coupled with anaerobic ammonia oxidation and denitrification reactions to remove nitrogen, reducing the production of iron sludge while utilizing the flocculation effect of iron salts and phosphates in the water to achieve simultaneous removal of nitrogen and phosphorus from wastewater.

[0051] 4) Control the blower 19 to regulate the aeration rate of the aerobic zone, so that the dissolved oxygen concentration in the aerobic zone is about 0.5mg / L-2.5mg / L.

[0052] 5) The hydraulic retention time (HRT) of the five-stage reactor 10 is controlled at 12-18h. The excess sludge is discharged through the sludge discharge control valve 25, so that the sludge age (SRT) of the flocculent sludge in the system is 15-20d, and the anaerobic ammonia oxidizing bacteria on the packing maintain a long sludge age.

[0053] 6) The Fenton reactor 13, a non-biochemical reaction, is used to remove recalcitrant organic matter from industrial wastewater, ensuring that the overall effluent meets the standards.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A device for coupling Fenton residual iron sludge with iron-ammonia oxidation and anaerobic ammonia oxidation, characterized in that, The device includes an inlet tank, a five-stage reactor, a secondary sedimentation tank, and a Fenton reactor connected in sequence. The five-stage reactor includes an anaerobic zone, an anoxic zone 1, an aerobic zone 1, an aerobic zone 2, an anoxic zone 2, an anoxic zone 3, and an aerobic zone 3. The iron sludge containing ferric iron produced by the Fenton reactor is returned to the anaerobic zone and the anoxic zone 2 of the five-stage reactor through pipelines to provide a source of ferric iron for the iron-ammonia-oxidizing bacteria therein. The sludge from the secondary sedimentation tank is returned to the anaerobic zone, and the nitrified liquid is returned from the aerobic zone 2 to the anoxic zone 1.

2. The device for Fenton residual iron sludge coupled with iron-ammonia oxidation and anaerobic ammonia oxidation according to claim 1, characterized in that, Aerators are installed at the bottom of aerobic zone 1, aerobic zone 2, and aerobic zone 3; a blower system is also included, and aerobic zone 1, aerobic zone 2, and aerobic zone 3 are respectively connected to the blower system, with aeration control valves and rotor flow meters respectively installed on the connecting pipes.

3. The apparatus for coupling Fenton residual iron sludge oxidation and anaerobic ammonium oxidation according to claim 1, characterized in that, The anaerobic zone, anoxic zone 1, anoxic zone 2, and anoxic zone 3 are each equipped with anaerobic ammonia oxidation packing material.

4. The apparatus for coupling Fenton residual iron sludge oxidation and anaerobic ammonium oxidation according to claim 1, characterized in that, The anaerobic zone is equipped with an anaerobic zone stirrer, the anoxic zone 1 is equipped with an anoxic zone 1 stirrer, the anoxic zone 2 is equipped with an anoxic zone 2 stirrer, and the anoxic zone 3 is equipped with an anoxic zone 3 stirrer.

5. The apparatus for coupling Fenton residual iron sludge oxidation and anaerobic ammonium oxidation according to claim 1, characterized in that, The effluent from the anoxic zone 3 enters the Fenton reactor after passing through a secondary sedimentation tank.

6. The apparatus for coupling Fenton residual iron sludge oxidation and anaerobic ammonium oxidation according to claim 1, characterized in that, The pipeline between the secondary sedimentation tank and the anaerobic zone is equipped with a sludge return pump and a sludge return control valve. The secondary sedimentation tank is also equipped with a sludge discharge control valve for external sludge discharge. The pipeline between the Fenton reactor and the anaerobic zone and the anoxic zone is equipped with a Fenton iron sludge return pump.

7. The apparatus for coupling Fenton residual iron sludge oxidation and anaerobic ammonium oxidation according to claim 1, characterized in that, The reflux pipelines of the aerobic zone 2 and the anoxic zone 1 are equipped with nitrification liquid reflux pumps and nitrification liquid reflux control valves.

8. A method for coupling ferroammonia oxidation and anaerobic ammonia oxidation of Fenton residual iron sludge, characterized in that, The method, employing the apparatus according to any one of claims 1-7, comprises the following steps: 1) The excess sludge from ordinary urban sewage treatment plants is added to the five-stage reactor, and anaerobic ammonia oxidation packing material that has been inoculated with anaerobic ammonia oxidation biofilm is added to the anaerobic zone, anoxic zone 1, anoxic zone 2 and anoxic zone 3 of the five-stage reactor. 2) Industrial wastewater or industrial wastewater containing some municipal sewage enters the anaerobic zone from the inlet tank. The sludge from the secondary sedimentation tank is also returned to the anaerobic zone via the sludge return pump. The nitrification liquid is returned from the aerobic zone 2 to the anoxic zone 1 via the nitrification liquid return pump. The wastewater flows from the anaerobic zone to the anoxic zone 1 in the five-stage reactor, and then flows through the aerobic zone 1, aerobic zone 2, anoxic zone 2, anoxic zone 3 and aerobic zone 3 in sequence. Sludge-water separation is achieved in the secondary sedimentation tank. The effluent enters the Fenton reactor via the Fenton reactor inlet pump. After removing the recalcitrant organic matter, the effluent is discharged. 3) The iron sludge containing ferric iron produced by the Fenton reactor is fed into the anaerobic zone and anoxic zone II of the five-stage reactor through the Fenton iron sludge reflux pump, providing a source of ferric iron for the iron ammonia oxidation reaction. 4) Control the blower to regulate the aeration rate in the aerobic zone, so that the dissolved oxygen concentration in the aerobic zone is 0.5 mg / L to 2.5 mg / L; 5) Control the hydraulic retention time of the five-stage reactor and discharge excess sludge through the sludge discharge control valve; 6) The Fenton reactor, a non-biochemical reaction method, is used to remove recalcitrant organic matter from industrial wastewater, ensuring that the overall effluent consistently meets standards.

9. The method for coupling ferroammonia oxidation and anaerobic ammonia oxidation of Fenton residual iron sludge according to claim 8, characterized in that, In step 1), the sludge concentration in the reactor is maintained at 2000-3000 mg / L, and the filling ratio of the anaerobic ammonia oxidation packing is 15%-30%.

10. The method for coupling ferroammonia oxidation and anaerobic ammonia oxidation of Fenton residual iron sludge according to claim 8, characterized in that, In step 5), the hydraulic retention time of the five-stage reactor is controlled at 12-18 hours, and the remaining sludge is discharged through the sludge discharge control valve, so that the sludge age of the flocculent sludge in the system is 15-20 days.

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