Denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matters

Abstract

The utility model discloses a denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organics, and belongs to the technical field of wastewater treatment. The system comprises a coarse / fine grid, an adjusting tank, an anaerobic reaction tank, an anaerobic sedimentation tank, a Fenton reaction tank, an iron ammoxidation adjusting tank, an iron ammoxidation reaction tank, an iron ammoxidation sedimentation tank, a liquid alkali sedimentation tank, a sulfur autotrophic adjusting tank and a sulfur autotrophic tank which are sequentially communicated along the wastewater treatment direction, at least part of sludge in the anaerobic sedimentation tank flows back to the anaerobic reaction tank, at least part of sludge in the iron ammonia oxidation sedimentation tank flows back to the iron ammonia oxidation reaction tank, and at least part of sludge in the liquid caustic soda sedimentation tank flows back to the Fenton reaction tank; and residual sludge in the anaerobic sedimentation tank, the iron ammonia oxidation sedimentation tank, the liquid caustic soda sedimentation tank and the sulfur autotrophic tank sequentially enters a sludge concentration tank and sludge dewatering equipment. On the premise of meeting the production and environmental protection requirements, the operation and sludge treatment cost is reduced, and the operation stability of the treatment system is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment, in particular to a wastewater denitrification treatment system containing high ammonia nitrogen and refractory organic matter. Background Art

[0002] A large amount of nitrogen compounds entering the water body will cause water quality deterioration, leading to eutrophication and other problems, posing serious risks to the ecological environment and human health. Commonly used nitrogen-containing wastewater treatment processes include: nitrification and denitrification process, anaerobic ammonia oxidation process, iron ammonia oxidation process and sulfur autotrophic process.

[0003] Although the traditional nitrification and denitrification process can remove total nitrogen from wastewater, aeration is required during the reaction, and carbon sources need to be added when there is insufficient carbon source available for biological use in the wastewater. At the same time, most industrial wastewater contains difficult-to-degrade organic matter, and there is a need to supplement alkalinity to ensure that the pH is suitable for the survival of microorganisms. These situations have led to the problem of huge cost consumption when treating wastewater containing high ammonia nitrogen and difficult-to-degrade organic matter with traditional processes.

[0004] The reaction equation of the anaerobic ammonium oxidation process is as follows:

[0005] 1NH4 + +1.32NO 2- +0.066HCO 3- +0.13H + →1.02N2+0.26NO 3- +0.066CH2O 0.5 N 0.15 +2.03H2O

[0006] When using the anaerobic ammonium oxidation process for denitrification, it is necessary to couple the anaerobic ammonium oxidation process with the nitrification process, while the nitrification process still requires aeration. In addition, some wastewater to be treated (such as landfill leachate) has a heavy metal imbalance problem, which will have an impact on the stability of the anaerobic ammonium oxidation process.

[0007] The reaction equation of the iron ammonia oxidation process is as follows:

[0008] 3Fe(OH)3+5H + +NH4 + →3Fe 2+ +9H2O+0.5N2

[0009] 6Fe(OH)3+10H + +NH4 + →6Fe 2+ +16H2O+NO 2−

[0010] 8Fe(OH)3+14H + +NH4 + →8Fe 2+ +21H2O+NO 3−

[0011] The existing iron-ammonia oxidation reaction pool mainly contains a large number of iron-ammonia oxidizing bacteria, a small number of dissimilatory iron-reducing bacteria and a small number of iron-autotrophic bacteria; iron-ammonia oxidizing bacteria use ammonia nitrogen to reduce iron mud (Fe(Ⅲ)) to Fe(Ⅱ) and generate nitrogen, nitrous acid and nitrate nitrogen; dissimilatory iron-reducing bacteria use a small amount of degradable organic pollutants remaining in the water after Fenton to convert Fe(Ⅲ) into Fe(Ⅱ); the iron-autotrophic bacteria use Fe(Ⅱ) to convert nitrous acid and nitrate nitrogen into nitrogen and generate Fe(Ⅲ), and its effluent mainly contains Fe(Ⅱ). As shown in the above reaction equation, it can use iron mud after Fenton reaction as an iron source, and can convert ammonia nitrogen into nitrogen, nitrate nitrogen and nitrous acid nitrogen without aeration. And compared with anaerobic ammonia oxidation, iron-ammonia oxidation has a stronger resistance to heavy metals. However, iron-ammonia oxidation requires a large amount of Fe(Ⅲ) as an electron acceptor.

[0012] Sulfur autotrophic process is often used for deep denitrification of wastewater. Elemental sulfur is easy to transport and is often used in sulfur autotrophic process. The reaction equation of sulfur autotrophic denitrification is as follows:

[0013] S 0 +0.876NO3 − +0.379HCO3 − +0.23CO2+0.080NH4 + →SO4 2− +0.44N2+0.824H + +0.080C5H7O2N

[0014] It can be seen that H is produced during sulfur autotrophic denitrification. + This may destroy the most suitable reaction environment for microorganisms. In addition, sulfur autotrophy has sulfur disproportionation, which will also produce sulfate ions in addition to the reaction.

[0015] Advanced oxidation processes are often used to remove difficult-to-degrade organic matter in water. The Fenton process is simple to operate, but it has problems such as excessive iron sludge, the Fe(II) generation rate is much lower than the Fe(III) generation rate, making it difficult to carry out Fe(II) / Fe(III) circulation, and a low reaction pH. Utility Model Content

[0016] In view of the deficiencies in the prior art, the utility model provides a denitrification treatment system for wastewater containing high ammonia nitrogen and difficult-to-degrade organic matter.

[0017] The utility model discloses a wastewater denitrification treatment system containing high ammonia nitrogen and refractory organic matter, comprising: a coarse / fine grid, a regulating tank, an anaerobic reaction tank, an anaerobic sedimentation tank, a Fenton reaction tank, an iron ammonia oxidation regulating tank, an iron ammonia oxidation reaction tank, an iron ammonia oxidation sedimentation tank, a liquid alkali sedimentation tank, a sulfur autotrophic regulating tank and a sulfur autotrophic tank, the effluent of the sulfur autotrophic tank enters a subsequent treatment system or is discharged in compliance with the standards;

[0018] At least part of the sludge in the anaerobic sedimentation tank is returned to the anaerobic reaction tank, at least part of the sludge in the iron ammonia oxidation sedimentation tank is returned to the iron ammonia oxidation reaction tank, at least part of the sludge in the liquid alkali sedimentation tank is returned to the Fenton reaction tank, and the remaining sludge in the anaerobic sedimentation tank, the iron ammonia oxidation sedimentation tank, the liquid alkali sedimentation tank and the sulfur autotrophic tank enters the sludge thickening tank and the sludge dewatering equipment in turn.

[0019] As a further improvement of the utility model, the coarse / fine grid includes a coarse grid and a fine grid sequentially arranged along the treatment direction of the wastewater, and is used to remove large pieces of suspended matter in the wastewater.

[0020] As a further improvement of the present invention, the regulating tank is used to regulate the water quality, water quantity and pH of the wastewater; the regulating tank is equipped with a pH meter, a sulfuric acid dosing system and / or a liquid alkali dosing system, and based on the pH meter, the pH of the wastewater in the regulating tank is monitored and maintained at 7~8; the sulfuric acid dosing system and the liquid alkali dosing system are both connected by a dissolving tank, an agitator, a dosing metering pump and a drug delivery pipe, the agitator is placed in the dissolving tank, one end of the drug delivery pipe is connected to the dissolving tank, and the other end is connected to the dosing port of the regulating tank, and the dosing metering pump is installed on the drug delivery pipe.

[0021] As a further improvement of the utility model, the anaerobic reaction tank is used to remove most of the biodegradable organic matter in the wastewater; the anaerobic reaction tank is equipped with an anaerobic sedimentation tank sludge return pipe, and the anaerobic sedimentation tank sludge return pipe consists of a return pipe, a sludge return pump and a flow meter. One end of the return pipe is connected to the anaerobic sedimentation tank and the other end is connected to the anaerobic reaction tank. The sludge return pump and the flow meter are installed on the return pipe.

[0022] As a further improvement of the utility model, the Fenton reaction tank is used to remove most of the organic pollutants in the anaerobic wastewater; wherein the Fenton reaction tank is equipped with a pH meter, a stirring device, a ferrous sulfate dosing system, a sulfuric acid dosing system, a hydrogen peroxide dosing system and a sludge return pipe of the liquid alkali precipitation tank;

[0023] Based on the pH meter, the pH of the wastewater in the Fenton reaction tank is monitored and maintained at 3-4, preferably 3.5; the stirring device is placed in the Fenton reaction tank for stirring and mixing; the ferrous sulfate dosing system, the sulfuric acid dosing system and the hydrogen peroxide dosing system are all connected by a dissolving tank, a stirrer, a dosing metering pump and a drug delivery tube, the stirrer is placed in the dissolving tank, one end of the drug delivery tube is connected to the dissolving tank, and the other end is connected to the dosing port of the Fenton reaction tank, and the dosing metering pump is installed on the drug delivery tube; the sludge return pipe of the liquid alkali sedimentation tank is composed of a return pipe, a sludge return pump and a flow meter, one end of the return pipe is connected to the liquid alkali sedimentation tank, and the other end is connected to the Fenton reaction tank, and the sludge return pump and the flow meter are installed on the return pipe.

[0024] As a further improvement of the present invention, the iron ammonia oxidation regulating tank is equipped with a pH meter, a liquid alkali dosing system and a stirring device. Based on the pH meter, the pH of the iron ammonia oxidation regulating tank is monitored and maintained at 6.5~7.5, preferably 7.0; the stirring device is placed in the iron ammonia oxidation regulating tank for stirring and mixing, and the iron mud (mainly Fe(III)) and water directly enter the iron ammonia oxidation reaction zone; the liquid alkali dosing system is composed of a dissolving drug tank, an agitator, and a dosing metering pump. The agitator is placed in the dissolving drug tank, one end of the drug delivery tube is connected to the dissolving drug tank, and the other end is connected to the dosing port of the iron ammonia oxidation regulating tank, and the dosing metering pump is installed on the drug delivery tube.

[0025] As a further improvement of the utility model, the iron-ammonia oxidation reaction tank is the core of ammonia nitrogen removal. The iron-ammonia oxidation reaction tank is an existing conventional reaction tank. There are mainly a large number of iron-ammonia oxidizing bacteria, a small amount of dissimilatory iron-reducing bacteria and a small amount of iron-autotrophic bacteria in the iron-ammonia oxidation reaction tank; the iron-ammonia oxidizing bacteria use ammonia nitrogen to reduce iron sludge (Fe(III)) to Fe(II) and generate nitrogen, nitrous acid and nitric nitrogen; the dissimilatory iron-reducing bacteria use a small amount of degradable organic pollutants remaining in the water after Fenton to convert Fe(III) into Fe(II); the iron-autotrophic bacteria use Fe(II) to convert nitrous acid and nitric nitrogen into nitrogen and generate Fe(III), and its effluent mainly contains Fe(II); the iron-ammonia oxidation reaction tank is equipped with a sludge return pipe of the iron-ammonia oxidation sedimentation tank, and the sludge return pipe of the iron-ammonia oxidation sedimentation tank is composed of a return pipe, a sludge return pump and a flow meter, one end of the return pipe is connected to the iron-ammonia oxidation sedimentation tank, and the other end is connected to the iron-ammonia oxidation reaction tank, and the sludge return pump and the flow meter are installed on the return pipe.

[0026] As a further improvement of the utility model, the liquid alkali precipitation tank is provided with a reaction zone and a precipitation zone, the reaction zone is provided with a pH meter and a liquid alkali dosing system, and at least part of the chemical sludge in the precipitation zone is returned to the Fenton reaction tank through a sludge return pipe of the liquid alkali precipitation tank;

[0027] Based on a pH meter, the pH of the reaction zone is monitored and maintained at 9-10 to ensure that a large amount of Fe(II) can be precipitated; the liquid alkali dosing system consists of a dissolving drug tank, an agitator, and a dosing metering pump, the agitator is placed in the dissolving drug tank, one end of the drug delivery tube is connected to the dissolving drug tank, and the other end is connected to the dosing port of the reaction zone, and the dosing metering pump is installed on the drug delivery tube.

[0028] As a further improvement of the utility model, the sulfur autotrophic regulating tank is equipped with a pH meter, a sulfuric acid dosing system and a stirring device;

[0029] Based on a pH meter, the pH of the sulfur autotrophic regulating tank is monitored and maintained at 7-8. A stirring device is placed in the sulfur autotrophic regulating tank for stirring and mixing. The sulfuric acid dosing system consists of a dissolving tank, a stirrer, and a dosing metering pump. The stirrer is placed in the dissolving tank. One end of the drug delivery tube is connected to the dissolving tank and the other end is connected to the dosing port of the sulfur autotrophic regulating tank. The dosing metering pump is installed on the drug delivery tube.

[0030] As a further improvement of the utility model, a sulfur autotrophic filler layer is provided in the sulfur autotrophic tank, which is used to remove nitrous acid and nitric nitrogen generated in the iron ammonia oxidation reaction tank; further, the sulfur autotrophic filler layer contains a slow-release carbon source (such as sawdust, etc.) and an alkaline substance that can buffer the pH (such as shells, etc.), which is used to reduce sulfate in the effluent of the sulfur autotrophic tank and maintain the stability of the reaction pH.

[0031] As a further improvement of the utility model, the anaerobic sedimentation tank, the iron ammonia oxidation sedimentation tank, the liquid alkali sedimentation tank and the sulfur autotrophic tank are also equipped with a sludge conveying pipe, one end of the sludge conveying pipe is connected to the anaerobic sedimentation tank, the iron ammonia oxidation sedimentation tank, the liquid alkali sedimentation tank and the sulfur autotrophic tank, and the other end is connected to the sludge concentration tank, and a sludge pump is installed on the sludge conveying pipe; the sludge outlet of the sludge concentration tank is connected to the feed port of the sludge dewatering equipment, the sludge dewatered by the sludge dewatering equipment is disposed of, and the dehydrated filtrate can be returned to the Fenton reaction tank or enter the subsequent treatment system.

[0032] Compared with the prior art, the beneficial effects of the utility model are:

[0033] The utility model can effectively remove organic pollutants and total nitrogen in wastewater by sequentially arranging a coarse / fine grid, a regulating tank, an anaerobic reaction tank, an anaerobic sedimentation tank, a Fenton reaction tank, an iron ammonia oxidation regulating tank, an iron ammonia oxidation reaction tank, an iron ammonia oxidation sedimentation tank, a liquid alkali sedimentation tank, a sulfur autotrophic regulating tank and a sulfur autotrophic tank, thereby meeting production and environmental protection requirements and improving the utilization rate of iron.

[0034] The iron-ammonia oxidation reaction tank and the sulfur autotrophic tank as core components of the utility model belong to the autotrophic process, with low sludge production, thus reducing the sludge treatment cost and carbon source addition cost to the greatest extent; the iron-ammonia oxidation has a strong tolerance to heavy metals, thus improving the operational stability of the treatment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The utility model discloses a schematic diagram of a wastewater denitrification treatment system containing high ammonia nitrogen and difficult-to-degrade organic matter.

[0036] In the figure:

[0037] 1. Coarse / fine screen; 2. Regulating tank; 3. Anaerobic reaction tank; 4. Anaerobic sedimentation tank; 5. Fenton reaction tank; 6. Iron ammonia oxidation regulating tank; 7. Iron ammonia oxidation reaction tank; 8. Iron ammonia oxidation sedimentation tank; 9. Liquid alkali sedimentation tank; 10. Sulfur autotrophic regulating tank; 11. Sulfur autotrophic tank; 12. Sludge thickening tank; 13. Sludge dewatering equipment. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0039] The utility model is further described in detail below in conjunction with the accompanying drawings:

[0040] like Figure 1 As shown, the utility model provides a denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter, comprising: a coarse / fine grid 1, a regulating tank 2, an anaerobic reaction tank 3, an anaerobic sedimentation tank 4, a Fenton reaction tank 5, an iron ammonia oxidation regulating tank 6, an iron ammonia oxidation reaction tank 7, an iron ammonia oxidation sedimentation tank 8, a liquid alkali sedimentation tank 9, a sulfur autotrophic regulating tank 10 and a sulfur autotrophic tank 11, the effluent of the sulfur autotrophic tank 11 enters a subsequent treatment system or is discharged in compliance with standards; at least part of the sludge in the anaerobic sedimentation tank 4 is sequentially connected along the treatment direction of the wastewater. It flows back to the anaerobic reaction tank 3, at least part of the sludge in the iron-ammonia oxidation sedimentation tank 8 flows back to the iron-ammonia oxidation sedimentation tank 7, at least part of the sludge in the liquid alkali sedimentation tank 9 flows back to the Fenton reaction tank 5, and the remaining sludge in the anaerobic sedimentation tank 4, the iron-ammonia oxidation sedimentation tank 8, the liquid alkali sedimentation tank 9 and the sulfur autotrophic tank 11 enter the sludge concentration tank 12 and the sludge dewatering equipment 13 in turn for sludge concentration and sludge dewatering, and the dewatered sludge is disposed of, and the dehydrated filtrate can be returned to the above-mentioned reaction tank (such as Fenton reaction tank) or enter the subsequent treatment system. Figure 1Only one situation is shown, namely: part of the sludge in the anaerobic sedimentation tank 4 is returned to the anaerobic reaction tank 3, and the remaining sludge enters the sludge thickening tank 12; all the sludge in the iron-ammonia oxidation sedimentation tank 8 is returned to the iron-ammonia oxidation reaction tank 7, part of the sludge in the liquid alkali sedimentation tank 9 is returned to the Fenton reaction tank 5, and the remaining sludge enters the sludge thickening tank 12; the sludge in the sulfur autotrophic tank 11 enters the sludge thickening tank 12.

[0041] It should be noted that the connection between the above-mentioned tank bodies or equipment can be achieved by conventional conveying pipes, overflows, etc., and the conveying power can be achieved by self-flowing with a pump or gravity difference; at the same time, corresponding valves, instruments, etc. can be optionally arranged on the pipelines; the utility model is an innovative combination of existing conventional tank bodies, which enables efficient treatment of wastewater, and each tank body or equipment can adopt existing conventional wastewater treatment equipment.

[0042] Specific:

[0043] The coarse / fine grid 1 of the utility model comprises a coarse grid and a fine grid sequentially arranged along the treatment direction of the wastewater, and is used to remove large suspended solids in the wastewater; wherein the specific grid apertures of the coarse grid and the fine grid are selected according to actual needs.

[0044] The regulating tank 2 of the utility model is used to regulate the water quality, water quantity and pH of wastewater; the regulating tank 2 is equipped with a pH meter, a sulfuric acid dosing system and / or a liquid alkali dosing system, and the pH is adjusted by adding acid or alkali, and the pH of the wastewater in the regulating tank is maintained at 7-8 based on the monitoring of the pH meter; the sulfuric acid dosing system and the liquid alkali dosing system are both connected by a dissolving tank, an agitator, a dosing metering pump and a drug delivery pipe, the agitator is placed in the dissolving tank, one end of the drug delivery pipe is connected to the dissolving tank, and the other end is connected to the dosing port of the regulating tank, and the dosing metering pump is installed on the drug delivery pipe.

[0045] The anaerobic reaction tank 3 of the utility model is used to remove most of the biodegradable organic matter in the wastewater. It is a conventional wastewater treatment equipment, so its structure is not described in detail here. The anaerobic reaction tank 3 is equipped with an anaerobic sedimentation tank sludge return pipe, which is composed of a return pipe, a sludge return pump and a flow meter. One end of the return pipe is connected to the anaerobic sedimentation tank and the other end is connected to the anaerobic reaction tank. The sludge return pump and the flow meter are installed on the return pipe.

[0046] The anaerobic sedimentation tank 4 of the utility model is used for separating mud and water after anaerobic reaction, and is a conventional wastewater treatment equipment.

[0047] The Fenton reaction tank 5 of the utility model is used to remove most of the organic pollutants in the wastewater after anaerobic treatment; wherein the Fenton reaction tank is equipped with a pH meter, a stirring device, a ferrous sulfate dosing system, a sulfuric acid dosing system, a hydrogen peroxide dosing system and a sludge return pipe of the liquid alkali precipitation tank; the pH is adjusted by adding acid, and the pH of the wastewater in the Fenton reaction tank is maintained at 3-4 based on the pH meter monitoring, preferably 3.5; the stirring device is placed in the Fenton reaction tank, and is used to stir and mix the added reagents; The ferrous sulfate dosing system, the sulfuric acid dosing system and the hydrogen peroxide dosing system are all connected by a dissolving tank, a stirrer, a dosing metering pump and a drug delivery pipe. The stirrer is placed in the dissolving tank. One end of the drug delivery pipe is connected to the dissolving tank and the other end is connected to the dosing port of the Fenton reaction tank. The dosing metering pump is installed on the drug delivery pipe. The sludge return pipe of the liquid alkali sedimentation tank is composed of a return pipe, a sludge return pump and a flow meter. One end of the return pipe is connected to the liquid alkali sedimentation tank and the other end is connected to the Fenton reaction tank. The sludge return pump and the flow meter are installed on the return pipe.

[0048] The iron ammonia oxidation regulating tank 6 of the utility model is equipped with a pH meter, a liquid alkali dosing system and a stirring device. Based on the pH meter, the pH of the iron ammonia oxidation regulating tank is monitored and maintained at 6.5-7.5, preferably 7.0; the stirring device is placed in the iron ammonia oxidation regulating tank for stirring and mixing, and the iron mud (mainly Fe(III)) and water directly enter the iron ammonia oxidation reaction zone; the liquid alkali dosing system is composed of a dissolving drug tank, a stirrer, and a dosing metering pump. The stirrer is placed in the dissolving drug tank, one end of the drug delivery tube is connected to the dissolving drug tank, and the other end is connected to the dosing port of the iron ammonia oxidation regulating tank, and the dosing metering pump is installed on the drug delivery tube.

[0049] The iron-ammonia oxidation reaction pool 7 of the utility model is the core of ammonia nitrogen removal. The iron-ammonia oxidation reaction pool is an existing conventional reaction pool. There are mainly a large number of iron-ammonia oxidizing bacteria, a small amount of dissimilatory iron-reducing bacteria and a small amount of iron-autotrophic bacteria in the iron-ammonia oxidation reaction pool; the iron-ammonia oxidizing bacteria use ammonia nitrogen to reduce iron sludge (Fe(III)) to Fe(II) and generate nitrogen, nitrous acid and nitric nitrogen; the dissimilatory iron-reducing bacteria use a small amount of degradable organic pollutants remaining in the water after Fenton to convert Fe(III) into Fe(II); the iron-autotrophic bacteria use Fe(II) to convert nitrous acid and nitric nitrogen into nitrogen and generate Fe(III), and its effluent mainly contains Fe(II); the iron-ammonia oxidation reaction pool 7 is equipped with a sludge return pipe of the iron-ammonia oxidation sedimentation tank, and the sludge return pipe of the iron-ammonia oxidation sedimentation tank is composed of a return pipe, a sludge return pump and a flow meter, one end of the return pipe is connected to the iron-ammonia oxidation sedimentation tank 8, and the other end is connected to the iron-ammonia oxidation reaction pool 7, and the sludge return pump and the flow meter are installed on the return pipe.

[0050] The iron-ammonia oxidation sedimentation tank 8 of the utility model is used for separating mud and water after the iron-ammonia oxidation, and is a conventional wastewater treatment equipment.

[0051] The liquid alkali precipitation tank 9 of the utility model is provided with a reaction zone and a precipitation zone, the reaction zone is provided with a pH meter and a liquid alkali dosing system, at least part of the chemical sludge in the precipitation zone is returned to the Fenton reaction tank through the sludge return pipe of the liquid alkali precipitation tank; the pH is adjusted by adding alkali, and the pH of the reaction zone is maintained at 9-10 based on the pH meter monitoring to ensure that a large amount of Fe(II) can be precipitated; the liquid alkali dosing system is composed of a dissolving tank, an agitator, and a dosing metering pump, the agitator is placed in the dissolving tank, one end of the drug delivery tube is connected to the dissolving tank, and the other end is connected to the dosing port of the reaction zone, and the dosing metering pump is installed on the drug delivery tube.

[0052] The sulfur autotrophic regulating tank 10 of the utility model is equipped with a pH meter, a sulfuric acid dosing system and a stirring device; the pH is adjusted by adding acid, and the pH of the sulfur autotrophic regulating tank is maintained at 7-8 based on the pH meter monitoring, and the stirring device is placed in the sulfur autotrophic regulating tank for stirring and mixing; the sulfuric acid dosing system consists of a dissolving tank, a stirrer, and a dosing metering pump, the stirrer is placed in the dissolving tank, one end of the drug delivery pipe is connected to the dissolving tank, and the other end is connected to the dosing port of the sulfur autotrophic regulating tank, and the dosing metering pump is installed on the drug delivery pipe.

[0053] The sulfur autotrophic tank 11 of the utility model is provided with a sulfur autotrophic filler layer for removing nitrous acid and nitric nitrogen generated in the iron ammonia oxidation reaction tank; further, the sulfur autotrophic filler layer contains a slow-release carbon source (such as sawdust, etc.) and an alkaline substance (such as shells, etc.) capable of buffering pH, which is used to reduce sulfate in the effluent of the sulfur autotrophic tank and maintain the stability of the reaction pH.

[0054] At least one of the anaerobic sedimentation tank 4, the iron ammonia oxidation sedimentation tank 8, the liquid alkali sedimentation tank 9 and the sulfur autotrophic tank 11 of the utility model is also provided with a sludge conveying pipe, one end of the sludge conveying pipe is connected to the anaerobic sedimentation tank 4, the iron ammonia oxidation sedimentation tank 8, the liquid alkali sedimentation tank 9 or the sulfur autotrophic tank 11, and the other end is connected to the sludge concentration tank 12, and a sludge pump is installed on the sludge conveying pipe; the sludge outlet of the sludge concentration tank 12 is connected to the feed port of the sludge dewatering equipment 13, the sludge dewatered by the sludge dewatering equipment 13 is disposed, and the dehydrated filtrate can be returned to the Fenton reaction tank or enter the subsequent treatment system.

[0055] Based on the above treatment system, the utility model provides a method for treating wastewater containing high ammonia nitrogen and difficult-to-degrade organic pollutants, comprising:

[0056] S1, the wastewater to be treated first enters the coarse / fine screen 1 to remove large suspended solids;

[0057] S2, after removing large suspended solids, enters regulating tank 2 to adjust the water quality, quantity and pH, and adjusts the pH to 7-8;

[0058] S3, the effluent from the regulating tank 2 enters the anaerobic reaction tank 3 to perform preliminary removal of organic pollutants in the water;

[0059] S4, the effluent from the anaerobic reaction tank 3 enters the anaerobic sedimentation tank 4 for mud-water separation, and the biomass of the anaerobic reaction tank 3 is ensured by returning the sludge;

[0060] S5, the effluent from the anaerobic sedimentation tank 4 enters the Fenton reaction tank 5, where the pH is adjusted to 3.5, and the wastewater is subjected to advanced oxidation to remove most of the difficult-to-degrade organic matter and the easily biodegradable organic matter remaining in the anaerobic effluent;

[0061] S6, the effluent from the Fenton reaction tank 5 enters the iron-ammonia oxidation regulating tank 6 to adjust the water quality and quantity pH, and the pH is adjusted to 7. After being stirred by a stirring device, the iron mud is mixed with water and enters the iron-ammonia oxidation reaction tank 7;

[0062] S7, iron-ammonia oxidation reaction pool 7 contains a large number of iron-ammonia oxidizing bacteria, a small number of iron-autotrophic bacteria, and a small number of dissimilatory iron-reducing bacteria. The iron-ammonia oxidizing bacteria use ammonia nitrogen to reduce iron sludge (Fe(Ⅲ)) to Fe(Ⅱ), and generate nitrogen, nitrous acid and nitrate nitrogen; dissimilatory iron-reducing bacteria use a small amount of degradable organic pollutants remaining in the water after Fenton to convert Fe(Ⅲ) into Fe(Ⅱ); iron-autotrophic bacteria use Fe(Ⅱ) to convert nitrous acid and nitrate nitrogen into nitrogen and generate Fe(Ⅲ). The effluent from the iron-ammonia oxidation reaction pool mainly contains Fe(Ⅱ);

[0063] S8, the effluent of the iron ammonia oxidation reaction tank 7 enters the iron ammonia oxidation precipitation tank 8, performs mud-water separation, and ensures the biomass of the iron ammonia oxidation reaction tank 7 by returning the sludge;

[0064] S9, the effluent from the iron-ammonia oxidation sedimentation tank 8 enters the liquid alkali sedimentation tank 9 to remove the residual iron Fe(II) in the wastewater;

[0065] S10, chemical sludge in the liquid alkali sedimentation tank 9, replenishes the Fe(Ⅱ) required by the front-end Fenton reaction tank 5 through sludge return;

[0066] S11, the effluent from the liquid alkali precipitation tank 9 enters the sulfur autotrophic regulating tank 10 to adjust the water quality, water quantity and pH;

[0067] S12, the effluent from the sulfur autotrophic regulating tank 10 enters the sulfur autotrophic tank 11 to remove the nitrous acid and nitric nitrogen generated in the iron ammonia oxidation reaction tank;

[0068] S13, the residual sludge in the anaerobic sedimentation tank 4, the iron-ammonia oxidation sedimentation tank 8, the liquid alkali sedimentation tank 9 and the sulfur autotrophic tank 11 is disposed after being concentrated in the sludge concentration tank 12 and dehydrated in the sludge dehydration equipment 13.

[0069] The advantages of the utility model are:

[0070] The utility model can effectively remove organic pollutants and total nitrogen in wastewater by sequentially arranging a coarse / fine grid, a regulating tank, an anaerobic reaction tank, an anaerobic sedimentation tank, a Fenton reaction tank, an iron ammonia oxidation regulating tank, an iron ammonia oxidation reaction tank, an iron ammonia oxidation sedimentation tank, a liquid alkali sedimentation tank, a sulfur autotrophic regulating tank and a sulfur autotrophic tank, thereby meeting production and environmental protection requirements and improving the utilization rate of iron.

[0071] The iron-ammonia oxidation reaction tank and the sulfur autotrophic tank as core components of the utility model belong to the autotrophic process, with low sludge production, thus reducing the sludge treatment cost and carbon source addition cost to the greatest extent; the iron-ammonia oxidation has a strong tolerance to heavy metals, thus improving the operational stability of the treatment system.

[0072] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter, characterized in that: include: A coarse / fine grid, a regulating tank, an anaerobic reaction tank, an anaerobic sedimentation tank, a Fenton reaction tank, an iron ammonia oxidation regulating tank, an iron ammonia oxidation reaction tank, an iron ammonia oxidation sedimentation tank, a liquid alkali sedimentation tank, a sulfur autotrophic regulating tank and a sulfur autotrophic tank are sequentially connected along the treatment direction of the wastewater, and the effluent of the sulfur autotrophic tank enters a subsequent treatment system or is discharged in compliance with the standards; At least part of the sludge in the anaerobic sedimentation tank is returned to the anaerobic reaction tank, at least part of the sludge in the iron ammonia oxidation sedimentation tank is returned to the iron ammonia oxidation reaction tank, at least part of the sludge in the liquid alkali sedimentation tank is returned to the Fenton reaction tank, and the remaining sludge in the anaerobic sedimentation tank, the iron ammonia oxidation sedimentation tank, the liquid alkali sedimentation tank and the sulfur autotrophic tank enters the sludge thickening tank and the sludge dewatering equipment in turn.

2. The denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter as claimed in claim 1, characterized in that: The coarse / fine grid comprises a coarse grid and a fine grid which are sequentially arranged along the treatment direction of the wastewater, and is used to remove large pieces of suspended matter in the wastewater.

3. The denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter as claimed in claim 1, characterized in that: The regulating tank is used to regulate the water quality, quantity and pH of the wastewater; the regulating tank is equipped with a pH meter, a sulfuric acid dosing system and / or a liquid alkali dosing system, and based on the pH meter, the pH of the wastewater in the regulating tank is monitored and maintained at 7-8; the sulfuric acid dosing system and the liquid alkali dosing system are both connected by a dissolving tank, an agitator, a dosing metering pump and a drug delivery pipe, the agitator is placed in the dissolving tank, one end of the drug delivery pipe is connected to the dissolving tank, and the other end is connected to the dosing port of the regulating tank, and the dosing metering pump is installed on the drug delivery pipe.

4. The denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter as claimed in claim 1, characterized in that: The anaerobic reaction tank is used to remove most of the biodegradable organic matter in the wastewater; the anaerobic reaction tank is equipped with an anaerobic sedimentation tank sludge return pipe, which is composed of a return pipe, a sludge return pump and a flow meter. One end of the return pipe is connected to the anaerobic sedimentation tank and the other end is connected to the anaerobic reaction tank. The sludge return pump and the flow meter are installed on the return pipe.

5. The denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter as claimed in claim 1, characterized in that: The Fenton reaction tank is used to remove most of the organic pollutants in the anaerobic wastewater; wherein the Fenton reaction tank is equipped with a pH meter, a stirring device, a ferrous sulfate dosing system, a sulfuric acid dosing system, a hydrogen peroxide dosing system and a sludge return pipe of the liquid alkali precipitation tank; Based on the pH meter, the pH of the wastewater in the Fenton reaction tank is monitored and maintained at 3-4; the stirring device is placed in the Fenton reaction tank for stirring and mixing; the ferrous sulfate dosing system, the sulfuric acid dosing system and the hydrogen peroxide dosing system are all connected by a dissolving tank, a stirrer, a dosing metering pump and a drug delivery tube, the stirrer is placed in the dissolving tank, one end of the drug delivery tube is connected to the dissolving tank, and the other end is connected to the dosing port of the Fenton reaction tank, and the dosing metering pump is installed on the drug delivery tube; the sludge return pipe of the liquid alkali sedimentation tank is composed of a return pipe, a sludge return pump and a flow meter, one end of the return pipe is connected to the liquid alkali sedimentation tank, and the other end is connected to the Fenton reaction tank, and the sludge return pump and the flow meter are installed on the return pipe.

6. The denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter as claimed in claim 1, characterized in that: The iron ammonia oxidation regulating tank is equipped with a pH meter, a liquid alkali dosing system and a stirring device. Based on the pH meter, the pH of the iron ammonia oxidation regulating tank is monitored and maintained at 6.5-7.5; the stirring device is placed in the iron ammonia oxidation regulating tank for stirring and mixing; the liquid alkali dosing system consists of a dissolving drug tank, a stirrer, and a dosing metering pump. The stirrer is placed in the dissolving drug tank, one end of the drug delivery tube is connected to the dissolving drug tank, and the other end is connected to the dosing port of the iron ammonia oxidation regulating tank, and the dosing metering pump is installed on the drug delivery tube.

7. The denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter as claimed in claim 1, characterized in that: The iron ammonia oxidation reaction tank is equipped with an iron ammonia oxidation sedimentation tank sludge return pipe, which is composed of a return pipe, a sludge return pump and a flow meter. One end of the return pipe is connected to the iron ammonia oxidation sedimentation tank and the other end is connected to the iron ammonia oxidation reaction tank. The sludge return pump and the flow meter are installed on the return pipe.

8. The denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter as claimed in claim 1, characterized in that: The liquid alkali precipitation tank is provided with a reaction zone and a precipitation zone, the reaction zone is provided with a pH meter and a liquid alkali dosing system, and at least part of the chemical sludge in the precipitation zone is returned to the Fenton reaction tank through a sludge return pipe of the liquid alkali precipitation tank; Based on the pH meter, the pH of the reaction zone is monitored and maintained at 9-10; the liquid alkali dosing system consists of a dissolving drug tank, an agitator, and a dosing metering pump, the agitator is placed in the dissolving drug tank, one end of the drug delivery tube is connected to the dissolving drug tank, and the other end is connected to the dosing port of the reaction zone, and the dosing metering pump is installed on the drug delivery tube.

9. The denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter as claimed in claim 1, characterized in that: The sulfur autotrophic regulating tank is equipped with a pH meter, a sulfuric acid dosing system and a stirring device; Based on a pH meter, the pH of the sulfur autotrophic regulating tank is monitored and maintained at 7-8. A stirring device is placed in the sulfur autotrophic regulating tank for stirring and mixing. The sulfuric acid dosing system consists of a dissolving tank, a stirrer, and a dosing metering pump. The stirrer is placed in the dissolving tank. One end of the drug delivery tube is connected to the dissolving tank and the other end is connected to the dosing port of the sulfur autotrophic regulating tank. The dosing metering pump is installed on the drug delivery tube.

10. The denitrification treatment system for wastewater containing high ammonia nitrogen and refractory organic matter according to claim 1, characterized in that: A sulfur autotrophic filler layer is provided in the sulfur autotrophic tank for removing nitrous acid and nitric nitrogen generated in the iron ammonia oxidation reaction tank; the sulfur autotrophic filler layer is filled with a slow-release carbon source and an alkaline substance capable of buffering pH, for reducing sulfate in the effluent of the sulfur autotrophic tank and maintaining the stability of the reaction pH.

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