A garbage leachate treatment system

Abstract

The invention discloses a landfill leachate treatment system, comprising: an anaerobic tank, a two-stage A / O tank, an external MBR unit, a catalytic flocculation reaction tank, a first sedimentation tank, and a built-in MBR unit; the landfill leachate to be treated is treated in the anaerobic tank, and the effluent enters the two-stage A / O tank, and the effluent of the two-stage A / O tank enters the external MBR unit, and the sludge outlet of the external MBR unit is respectively connected to the first anoxic tank and the second anoxic tank of the two-stage A / O tank through a first sludge return pump, and the effluent of the external MBR unit enters the catalytic flocculation reaction tank, and the effluent of the catalytic flocculation reaction tank is separated from the mud and water in the first sedimentation tank, and the supernatant enters the built-in MBR unit. The effluent of the system can meet the national Class A standard, and the system has stable operation, small dosage of reagents, low operating cost, and can achieve the effect of zero concentrated liquid.

Description

Technical Field

[0001] The invention belongs to the field of landfill leachate treatment, and in particular relates to a landfill leachate zero-concentrate liquid treatment system. Background Art

[0002] Garbage incineration is an important means of treating domestic waste in cities in my country, which can achieve the reduction, harmlessness and resource utilization of domestic waste in cities. However, garbage incineration plants will also produce secondary pollution problems such as leachate. Garbage leachate is the liquid carried by domestic waste and the liquid produced by the degradation of garbage in the storage pit. Depending on the climate conditions, living habits of residents, etc., its production can reach 5% to 20% of the total amount of garbage. Garbage leachate is a high-concentration organic wastewater with complex components, high pollutant concentration, high chroma and strong toxicity. Its COD (chemical oxygen demand) is often as high as 30,000 mg / L or even more than 80,000 mg / L, and the total nitrogen (TN) concentration is usually more than 1,500 mg / L. It is very difficult to treat. It is a recognized problem in the current water treatment industry. It not only contains a large amount of organic pollutants, but also contains various heavy metal pollutants. If it is not properly handled, it will not only affect the quality of surface water, but also endanger the safety of groundwater. At present, the domestic leachate treatment methods are generally divided into physical and chemical methods, biological methods and membrane methods. According to the process flow, they can be divided into pretreatment, biological treatment, deep treatment and post-treatment (sludge treatment and concentrated liquid treatment). The outflow quality of traditional treatment processes is difficult to meet the Class A standard (no more than 5%) of the "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB18918-2002). Secondary pollution (especially the treatment of concentrated liquid) is a difficult problem faced by landfill leachate treatment. Therefore, it is necessary to develop a new landfill leachate treatment process to solve the problem of concentrated liquid from the source, improve the biochemical treatment system, and improve the effluent quality. Summary of the invention

[0003] In view of the above problems in the prior art, the present invention provides a landfill leachate treatment system, the effluent of which can meet the national Class A standard, and the system has stable operation, small dosage of reagents, low operating cost, and can achieve the effect of zero concentrated liquid.

[0004] To solve the above problems, the technical solution of the present invention is:

[0005] A landfill leachate treatment system, comprising: an anaerobic tank, a two-stage A / O tank, an external MBR unit, a catalytic flocculation reaction tank, a first sedimentation tank, and a built-in MBR unit;

[0006] The effluent of the landfill leachate to be treated after being treated in the anaerobic tank enters the two-stage A / O tank, the effluent of the two-stage A / O tank enters the external MBR unit, the sludge outlet of the external MBR unit is respectively connected to the primary anoxic tank and the secondary anoxic tank of the two-stage A / O tank through the first sludge return pump, the effluent of the external MBR unit enters the catalytic flocculation reaction tank, the effluent of the catalytic flocculation reaction tank is separated from the mud and water in the first sedimentation tank, and the supernatant enters the built-in MBR unit.

[0007] In a preferred embodiment, it further comprises an anaerobic hydrolysis tank and a second sedimentation tank, wherein the anaerobic hydrolysis tank is connected to the second sedimentation tank;

[0008] The supernatant outlet of the first sedimentation tank is connected to the anoxic hydrolysis tank, the supernatant outlet of the second sedimentation tank is connected to the built-in MBR unit, and the sludge outlet of the second sedimentation tank is connected to the anoxic hydrolysis tank. Adding anoxic hydrolysis tank and a second sedimentation tank after the first sedimentation tank can further convert insoluble organic matter into soluble organic matter, and convert difficult-to-degrade macromolecular organic matter into small molecular easily degradable organic matter, thereby improving the biodegradability of the effluent.

[0009] The preferred embodiment further comprises a primary sedimentation tank, wherein the landfill leachate to be treated first enters the primary sedimentation tank, and the effluent of the primary sedimentation tank enters the anaerobic tank. The landfill leachate to be treated is first treated in the primary sedimentation tank, which can reduce the suspended solids (SS) content of the influent and ensure the stable operation of subsequent equipment.

[0010] A preferred embodiment further comprises a regulating tank, wherein the landfill leachate to be treated first enters the regulating tank, and the outlet of the regulating tank is connected to the primary sedimentation tank. The landfill leachate is first homogenized and weighed in the regulating tank, and then transported to the primary sedimentation tank or the anaerobic tank.

[0011] In a preferred embodiment, a peripheral anaerobic treatment three-phase separator is arranged along the wall of the anaerobic tank. At present, UASB (upflow anaerobic sludge blanket) and UBF (upflow sludge blanket) are commonly used in anaerobic tanks, which have problems such as easy blockage of the water distribution system and poor mud-water mixing effect. The preferred embodiment adopts an anaerobic tank with a peripheral three-phase separator and a stirring system independently developed by the invention, and the anaerobic effluent direction and the mixed liquid reaction direction form a cross flow to strengthen the mixing effect; there is no water distribution system, and the mud and water are fully mixed by stirring, and the treatment effect is stable; the mud and water separation effect is good, and there is no need to adopt the large height-to-diameter ratio and large flow reflux design of traditional UASB and UBF, which saves energy consumption and is particularly suitable for projects using old tanks for renovation.

[0012] In a preferred embodiment, a rotary shear mixed flow aeration device is provided in the primary / secondary anoxic tank and the primary / secondary aerobic tank of the two-stage A / O tank, and a magnetic levitation fan is connected to the air inlet of the rotary shear mixed flow aeration device, and the air inlet of the rotary shear mixed flow aeration device is connected to an air duct.

[0013] In a preferred embodiment, a rotary shearing mixed flow aeration device is installed in the anoxic hydrolysis tank, and the air inlet of the rotary shearing mixed flow aeration device is connected to an air duct. A self-developed rotary shearing mixed flow aeration device is installed in the anoxic hydrolysis tank, and an intermittent stirring function is designed to control the dissolved oxygen to be maintained below 0.5 mg / L, thereby ensuring the stability and efficiency of the hydrolysis acidification process.

[0014] In a preferred embodiment, an ultrafiltration membrane assembly and a rotary shear mixed flow aeration device are installed in the built-in MBR unit, and the air inlet of the rotary shear mixed flow aeration device is connected to an air duct. The unit can be conveniently transformed into an anoxic / aerobic process or a completely aerobic process by changing the aeration mode (intermittent or continuous) according to specific water quality conditions (total nitrogen concentration of the inlet water of the built-in MBR unit), so as to ensure that the final effluent TN and COD meet the standards, and the final effluent can meet the Class A standard of the Pollutant Discharge Standard for Municipal Wastewater Treatment Plants (GB18918-2002).

[0015] In a preferred embodiment, a rotary shear mixed flow aeration device is installed in the regulating tank, and the air inlet of the rotary shear mixed flow aeration device is connected to the air duct. The independently developed rotary shear mixed flow aeration device is installed in the regulating tank, and the regulating tank is stirred in the form of intermittent aeration to avoid silt accumulation in the regulating tank. Therefore, the regulating tank does not need to be cleaned; at the same time, no additional mechanical stirring facilities are used, and equipment maintenance work can be eliminated. At the same time, the amount of gas required for intermittent air stirring is small, and the fan can be shared with the subsequent biochemical tank to save energy.

[0016] In a preferred embodiment, the first sedimentation tank, the primary sedimentation tank, the anaerobic tank, the external MBR unit and the residual sludge of the internal MBR unit are connected to a sludge treatment system.

[0017] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0018] The present invention comprehensively adopts an anaerobic process, a two-stage aerobic / anoxic process, an external MBR process, a catalytic flocculation sedimentation process and a built-in MBR process, so that no concentrated liquid will appear in the entire treatment system. First, the landfill leachate to be treated is introduced into the anaerobic tank to remove the high molecular organic matter in the landfill leachate, improve the biodegradability of the sewage, and facilitate the subsequent aerobic treatment; the effluent after anaerobic treatment is introduced into the two-stage A / O tank for nitrification and denitrification; after the two-stage nitrification and denitrification treatment, the mud and water separation is achieved through the external MBR unit, and part of the sludge is returned to the anoxic tank of the two-stage A / O; the effluent of the external MBR unit enters the catalytic flocculation reaction tank to convert the difficult-to-degrade, toxic and harmful substances into easily degradable, small molecular, non-toxic or low-toxic substances, and the heavy metal ions are reduced and removed, the biodegradability of the wastewater is greatly improved, and the chromaticity is greatly reduced. The effluent of the catalytic flocculation reactor enters the first sedimentation tank for mud and water separation, and the supernatant enters the built-in MBR unit. After the supernatant is treated by the built-in MBR unit, the final effluent meets the Class A standard of the Pollutant Discharge Standard for Urban Sewage Treatment Plants (GB18918-2002).

[0019] The present invention adopts a self-developed catalytic reduction reactor adopted in the catalytic flocculation reactor, which is mainly composed of a metal frame, a metal active filler, a water distributor, and a jet circulation aeration device. Under the action of the catalyst, non-degradable high-molecular organic matter reacts with the active filler to generate a precipitate, which is degraded. The pH value in the reaction process is adjusted by acetic acid. Since the acetic acid is decomposed under the subsequent aeration conditions, there is no need to repeatedly adjust the pH, which saves the amount of reagents used and effectively reduces the salt content of the system, ensuring that the system can operate stably for a long time.

[0020] The present invention adopts a catalytic flocculation sedimentation process and a built-in MBR process to replace the traditional NF / RO process, achieving the same treatment effect but without producing concentrated liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flow chart of a landfill leachate treatment system according to a preferred embodiment of the present invention;

[0022] Figure 2 This is a process diagram for treating landfill leachate according to a preferred embodiment of the present invention.

[0023] Explanation of the reference numerals: 1-regulating tank; 2-primary sedimentation tank; 3-anaerobic tank; 4-two-stage A / O tank; 401-anoxic tank; 402-aerobic tank; 5-external MBR unit; 6-catalytic flocculation reaction tank; 7-first sedimentation tank; 8-anoxic hydrolysis tank; 9-second sedimentation tank; 10-built-in MBR unit; 11-rotary shear mixed flow aeration device. DETAILED DESCRIPTION

[0024] The following is a further detailed description of a landfill leachate treatment system proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims.

[0025] See also Figure 1 and Figure 2 , a landfill leachate treatment system, comprising: an anaerobic tank 3, a two-stage A / O tank 4, an external MBR unit 5, a catalytic flocculation reaction tank 6, a first sedimentation tank 7, and a built-in MBR unit 10;

[0026] The effluent of the landfill leachate to be treated after being treated in the anaerobic tank 3 enters the two-stage A / O tank 4, which includes two-stage anoxic tanks 401 and two-stage aerobic tanks 402. The mixed liquid at the end of the primary aerobic tank 402 is transported to the primary anoxic tank 401 through a reflux pump, and the mixed liquid at the end of the secondary aerobic tank 402 is transported to the secondary anoxic tank 401 through a reflux pump. The effluent of the two-stage A / O tank 4 enters the external MBR unit 5, and the sludge outlet of the external MBR unit 5 is respectively connected to the primary anoxic tank 401 and the secondary anoxic tank 401 of the two-stage A / O tank 4 through a first sludge reflux pump. The effluent of the external MBR unit 5 enters the catalytic flocculation reaction tank 6, and the effluent of the catalytic flocculation reaction tank 6 is separated from the mud and water in the first sedimentation tank 7, and the supernatant enters the built-in MBR unit 10.

[0027] It should be noted that the traditional treatment method (NF / RO) produces more than 30% of concentrated liquid, with extremely high concentration of pollutants, which is more harmful. The concentrated liquid is usually treated by recharging the landfill, but this will only lead to the continuous accumulation of pollutants in the leachate. If incineration technology is used, the treatment cost will be greatly increased.

[0028] The present embodiment adopts the anaerobic process, the two-stage aerobic / anoxic process, the external MBR process, the catalytic flocculation sedimentation process and the internal MBR process in a comprehensive manner, so that no concentrated liquid will appear in the entire treatment system. First, the landfill leachate to be treated is introduced into the anaerobic tank 3 to remove the high molecular organic matter of the landfill leachate, improve the biodegradability of the sewage, and facilitate the subsequent aerobic treatment; the effluent after the anaerobic treatment is introduced into the two-stage A / O tank 4 for nitrification and denitrification; after the two-stage nitrification and denitrification treatment, the mud and water separation is achieved through the external MBR unit 5, and part of the sludge is returned to the anoxic tank 401 of the two-stage aerobic tank 402 / anoxic tank 401; the effluent of the external MBR unit 5 enters the catalytic flocculation reaction tank 6, so that the difficult-to-degrade, toxic and harmful substances are converted into easily degradable, small molecules, non-toxic or low-toxic substances, heavy metal ions are reduced and removed, the biodegradability of the wastewater is greatly improved, and the chromaticity is greatly reduced. The effluent of the catalytic flocculation reactor enters the first sedimentation tank 7 for mud and water separation, and the supernatant enters the internal MBR unit 10. After the supernatant is treated by the internal MBR unit 10, the final effluent meets the Class A standard of the Pollutant Discharge Standard for Urban Sewage Treatment Plants (GB18918-2002).

[0029] This embodiment adopts a catalytic flocculation reactor using a self-developed catalytic reduction reactor (authorization announcement number: CN202705069U), which is mainly composed of a metal frame, metal active fillers, a water distributor, and a jet circulation aeration device. Under the action of the catalyst, non-degradable high-molecular organic matter reacts with the active filler to generate a precipitate that is degraded. The pH value during the reaction is adjusted by acetic acid. Since acetic acid is decomposed under subsequent aeration conditions, there is no need to repeatedly adjust the pH, which saves the amount of reagents used and effectively reduces the salt content of the system, ensuring that the system can operate stably for a long time.

[0030] This embodiment adopts a catalytic flocculation sedimentation process and a built-in MBR process to replace the traditional NF / RO process, achieving the same treatment effect but without producing concentrated liquid.

[0031] In a preferred embodiment, it further comprises an anoxic hydrolysis tank 8 and a second sedimentation tank 9, wherein the anoxic hydrolysis tank 8 is connected to the second sedimentation tank 9;

[0032] The supernatant outlet of the first sedimentation tank 7 is connected to the anoxic hydrolysis tank 8 , the supernatant outlet of the second sedimentation tank 9 is connected to the built-in MBR unit 10 , and the sludge outlet of the second sedimentation tank 9 is connected to the anoxic hydrolysis tank 8 . The facultative anoxic hydrolysis tank 8 is preferably equipped with a self-developed rotary shear mixed flow aeration device 11 (authorization announcement number: CN106145315A). The rotary shear mixed flow aeration device 11 is mainly composed of an outer cylinder, a central air inlet pipe, a forward swirl plate, a reverse swirl plate, and a diverter. The lower part of the outer cylinder is a water inlet, and the upper part is a water outlet. The central air inlet pipe is vertically built into the outer cylinder and has an air inlet at the upper part and an air outlet at the lower part. The forward swirl plate and the reverse swirl plate are fixed to the central air inlet pipe, and a buffer space is provided between the forward swirl plate and the reverse swirl plate; the diverter is fixed to the bottom of the central air inlet pipe and the gas discharged from the bottom of the central air inlet pipe is discharged to the surroundings; a diversion cutter is provided above the water outlet of the rotary shear mixed flow aeration device 11, the diversion cutter is provided outside the central air inlet pipe, and there is a buffer distance between the diversion cutter and the water outlet, and the diversion cutter is an inverted cone;

[0033] An anaerobic hydrolysis tank 8 and a second sedimentation tank 9 are added after the first sedimentation tank 7, and a rotary shear mixed flow aeration device 11 is preferably installed in the anaerobic hydrolysis tank 8. Intermittent aeration is designed to realize the stirring function, and the dissolved oxygen is controlled to be maintained below 0.5 mg / L to ensure the stability and efficiency of the hydrolysis and acidification process; at the same time, regular addition of acetic acid is beneficial to the domestication of the bacteria, and plays an inducing role in the degradation of pollutants by the bacteria, thereby ensuring the efficiency of hydrolysis and acidification. Acetic acid also serves as an electron donor for the denitrifying bacteria to convert nitrate nitrogen, which can enhance the denitrification effect of the reactor. Therefore, the anaerobic hydrolysis tank 8 combines the functions of the hydrolysis and acidification tank and the denitrification tank, and plays a role in increasing the effluent BOD5 / COD and reducing COD and nitrate nitrogen / total nitrogen.

[0034] In a preferred embodiment, a primary sedimentation tank 2 is further included, and the landfill leachate to be treated first enters the primary sedimentation tank 2, and the effluent of the primary sedimentation tank 2 enters the anaerobic tank 3. The landfill leachate to be treated is first treated in the primary sedimentation tank 2, which can reduce the content of suspended solids (SS) in the influent and ensure the stable operation of subsequent equipment.

[0035] In a preferred embodiment, a regulating tank 1 is further included, and the landfill leachate to be treated first enters the regulating tank 1, and the outlet of the regulating tank 1 is connected to the primary sedimentation tank 2. The landfill leachate is first homogenized and weighed in the regulating tank 1, and then transported to the primary sedimentation tank 2 or the anaerobic tank 3.

[0036] Preferably, a rotary shear mixed flow aeration device 11 is installed in the regulating tank 1. The rotary shear mixed flow aeration device 11 independently developed is installed in the regulating tank 1. The regulating tank 1 is stirred in the form of intermittent aeration, thereby avoiding sludge accumulation in the regulating tank 1. Therefore, the regulating tank 1 does not need to be cleaned. At the same time, no additional mechanical stirring facilities are used, and equipment maintenance work can be eliminated. At the same time, the amount of gas required for intermittent air stirring is small, and the fan can be shared with the subsequent biochemical tank to save energy.

[0037] In a preferred embodiment, a peripheral anaerobic treatment three-phase separator is arranged along the wall of the anaerobic tank 3. At present, UASB (upflow anaerobic sludge blanket) and UBF (upflow sludge blanket) are often used in the anaerobic tank 3, which have problems such as easy blockage of the water distribution system and poor mud-water mixing effect. In this preferred embodiment, a self-developed peripheral anaerobic treatment three-phase separator (authorization announcement number: CN202643431U) is arranged along the wall of the anaerobic tank 3. The three-phase separator is composed of a packing layer, a mud guide plate, a baffle plate, and a mixer. The mixer stirs the leachate and the anaerobic sludge to mix fully and the anaerobic reaction is complete. The mud guide plate and the baffle plate can allow large particles of sludge to settle at the bottom of the tank. The packing layer can further intercept the sludge to prevent the loss of anaerobic sludge. This unit can significantly reduce the concentration of organic pollutants, improve the biodegradability of wastewater, and is conducive to the subsequent two-stage nitrification and denitrification treatment.

[0038] The anaerobic effluent direction and the mixed liquid reaction direction form a cross flow, which strengthens the mixing effect. There is no water distribution system, and the mud and water are fully mixed through stirring, and the treatment effect is stable. The mud and water separation effect is good, and there is no need to adopt the large height-to-diameter ratio and large-flow reflux design of traditional UASB and UBF, which saves energy and is especially suitable for projects that utilize old pools for reconstruction.

[0039] In a preferred embodiment, a rotary shear mixed flow aeration device 11 is provided in both the primary / secondary anoxic tank 401 and the primary / secondary aerobic tank 402 of the two-stage A / O tank 4, and a magnetic levitation fan is connected to the air inlet of the rotary shear mixed flow aeration.

[0040] When treating landfill leachate, the sludge concentration in aerobic tank 402 is generally very high, so air jet aeration is used. However, jet aeration not only consumes a lot of energy, but also produces a lot of foam, which seriously affects the normal operation of the system.

[0041] The rotary shearing mixed flow device used in this embodiment is suitable for sludge concentrations of 2 to 30 g / L, and can reach 60 g / L in extreme cases (such as used in the SBR process). When used in conjunction with a magnetic levitation fan, the overall aeration energy consumption is saved by about 30% compared with the current blast jet aeration method, and there will be no problem of foam coverage on the water surface.

[0042] In addition, the first and second anoxic tanks 401 are equipped with patented aerators to stir the water body by utilizing the gas-liquid turbulence formed by aeration, which can replace mechanical stirring equipment; intermittent stirring is used to maintain DO≤0.5mg / L, and the anoxic environment of the denitrification reaction is ensured by controlling the air valve to achieve denitrification; acetic acid can be added as a supplementary carbon source according to the BOD / TN value; the first and second aerobic tanks 402 are equipped with rotary shear mixed flow aerators, and the magnetic levitation fan is used to provide the air source. Under aerobic conditions, ammonia nitrogen is oxidized to generate nitrite ions and nitrate ions, and the nitrified liquid is then returned to the front anoxic tank 401.

[0043] In a preferred embodiment, an ultrafiltration membrane assembly and a rotary shear mixed flow aeration device 11 are installed in the built-in MBR unit 10. The unit can be conveniently transformed into an anoxic / aerobic process or a completely aerobic process by changing the aeration mode (intermittent or continuous) according to the specific water quality conditions (total nitrogen concentration of the inlet water of the built-in MBR unit 10), so as to ensure that the final effluent TN and COD meet the standards. The final effluent can meet the Class A standard of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB18918-2002).

[0044] In a preferred embodiment, the first sedimentation tank 7, the primary sedimentation tank 2, the anaerobic tank 3, the external MBR unit 5 and the excess sludge of the internal MBR unit 10 are connected to the sludge treatment system.

[0045] The process of using the preferred implementation method in this embodiment is:

[0046] The landfill leachate to be treated is homogenized and weighed in the regulating tank 1, and then transported to the primary sedimentation tank 2. After the solid suspended matter is removed from the primary sedimentation tank 2, the effluent enters the anaerobic tank 3 for anaerobic reaction, and the precipitated sludge is treated by the sludge treatment system; a mixer and filler are installed in the anaerobic tank 3, and the sludge is intercepted after the reaction effluent passes through the filler. The effluent of the anaerobic tank 3 enters the two-stage A / O tank 4, and the remaining sludge is discharged to the sludge treatment system; the two-stage A / O tank 4 is mainly composed of an anoxic tank 401 and an aerobic tank 402. The first and second anoxic tanks 401 use intermittent stirring to keep DO ≤ 0.5 mg / L, and the sludge is discharged to the sludge treatment system. The air valve is controlled to ensure the anoxic environment of the denitrification reaction to achieve denitrification; acetic acid can be added as a supplementary carbon source according to the BOD / TN value; rotary shear mixed flow aeration devices 11 are installed in the primary aerobic tank 402 and the secondary aerobic tank 402, and a magnetic levitation fan is used to provide air; the mixed liquid at the end of the primary aerobic tank 402 is transported to the front end of the primary anoxic tank 401 through a reflux pump, and the mixed liquid at the end of the secondary aerobic tank 402 is transported to the front end of the secondary anoxic tank 401 through a reflux pump, and the effluent from the secondary A / O tank enters the external MBR unit 5; the mud and water are separated through the external MBR unit 5, and the effluent enters the catalytic flocculant The sludge is returned to the primary and secondary anoxic tanks 401 of the secondary A / O tank; the catalytic flocculation reaction tank 6 is equipped with a metal frame, metal active fillers, a water distributor, and a jet circulation aeration device. Under the action of the catalyst, non-degradable high-molecular organic pollutants react with the active fillers to generate precipitates that are degraded, and the pH value in the reactor is adjusted by acetic acid; the effluent of the catalytic flocculation reaction 6 enters the first sedimentation tank 7 for mud-water separation, the supernatant enters the anoxic hydrolysis tank 8, and the sludge enters the sludge treatment system; the anoxic hydrolysis tank 8 is equipped with a rotary shear mixed flow aeration device 11 and a biofilm filler , intermittent aeration is used to achieve the stirring function, the dissolved oxygen content is controlled to be kept below 0.5 mg / L, acetic acid is regularly added to the anoxic hydrolysis tank 8, the effluent of the anoxic hydrolysis tank 8 enters the second sedimentation tank 9, the sludge is returned to the anoxic hydrolysis tank 8 after mud and water separation, and the supernatant enters the built-in MBR unit 10; the built-in MBR unit 10 is installed with a rotary shear mixed flow aeration device 11 and an ultrafiltration membrane assembly, and the aeration mode (intermittent or continuous) can be changed according to the specific water quality conditions (influent TN concentration) to achieve the role of anoxic / aerobic process or a completely aerobic process, ensuring that the final effluent TN and COD meet the standards. The remaining sludge is discharged to the sludge treatment system, and the final effluent can meet the Class A standard of the "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB18918-2002) for external discharge.

[0047] In this embodiment, if not specifically stated, the air inlet of the rotary mixed flow aeration device is connected to the air duct.

[0048] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the protection scope of the present invention.

Claims

1. A landfill leachate treatment system, characterized in that: include: Anaerobic tank, two-stage A / O tank, external MBR unit, catalytic flocculation reaction tank, first sedimentation tank, internal MBR unit; The effluent of the landfill leachate to be treated after being treated in the anaerobic tank enters the two-stage A / O tank, and the effluent of the two-stage A / O tank enters the external MBR unit. The sludge outlet of the external MBR unit is respectively connected to the primary anoxic tank and the secondary anoxic tank of the two-stage A / O tank through the first sludge return pump. The primary anoxic tank and the secondary anoxic tank are both kept at DO≤0.5mg / L by intermittent stirring. The effluent of the external MBR unit enters the catalytic flocculation reaction tank, which is equipped with a metal frame, metal active fillers, a water distributor, and a jet circulation aeration device. Under the action of the catalyst, non-degradable high-molecular organic pollutants react with the active fillers to generate precipitates that are degraded. The pH value in the reactor is adjusted by acetic acid. The effluent of the catalytic flocculation reaction tank is separated from the mud and water in the first sedimentation tank, and the supernatant enters the built-in MBR unit. The landfill leachate treatment system further comprises an anaerobic hydrolysis tank, a second sedimentation tank, a primary sedimentation tank and a regulating tank. The landfill leachate to be treated first enters the regulating tank, the outlet of the regulating tank is connected to the primary sedimentation tank, the effluent of the primary sedimentation tank enters the anaerobic tank, and the anaerobic hydrolysis tank is connected to the second sedimentation tank. The supernatant outlet of the first sedimentation tank is connected to the anoxic hydrolysis tank, the supernatant outlet of the second sedimentation tank is connected to the built-in MBR unit, and the sludge outlet of the second sedimentation tank is connected to the anoxic hydrolysis tank; A peripheral anaerobic treatment three-phase separator is arranged along the wall of the anaerobic tank, and a first rotary shearing mixed flow aeration device is installed in both the facultative anoxic hydrolysis tank and the regulating tank, and an air inlet of the first rotary shearing mixed flow aeration device is connected to an air duct; A second rotary shear mixed flow aeration device is provided in the primary / secondary anoxic tank and the primary / secondary aerobic tank of the two-stage A / O tank, and a magnetic levitation fan is connected to the air inlet of the second rotary shear mixed flow aeration, and the magnetic levitation fan is connected to the air duct.

2. The landfill leachate treatment system according to claim 1, characterized in that: An ultrafiltration membrane assembly and a rotary shear mixed flow aeration device are installed in the built-in MBR unit, and an air inlet of the rotary shear mixed flow aeration device is connected to an air duct.

3. The landfill leachate treatment system according to claim 1, characterized in that: The surplus sludge of the first sedimentation tank, the primary sedimentation tank, the anaerobic tank, the external MBR unit and the internal MBR unit is connected to a sludge treatment system.

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