Full-amount treatment system for low-carbon landfill leachate

Abstract

The invention relates to a full-amount treatment system for low-carbon landfill leachate. The full-amount treatment system comprises a pretreatment unit, an anaerobic treatment unit, an external membrane bioreactor unit, a nanofiltration unit and a reverse osmosis unit which are connected in sequence, the external membrane bioreactor unit comprises a denitrification reactor, a nitration reactor and an ultrafiltration membrane; effluent of the anaerobic treatment unit enters a denitrification reactor, effluent of the denitrification reactor enters an ultrafiltration membrane to generate concentrated sludge, and part of the concentrated sludge flows back to the denitrification reactor; produced water of the ultrafiltration membrane assembly enters a nanofiltration unit; the nanofiltration unit generates nanofiltration produced water, the nanofiltration produced water enters the reverse osmosis unit to be treated to generate reverse osmosis produced water, and the reverse osmosis produced water is discharged or recycled; the nanofiltration concentrated solution enters a nanofiltration concentrated solution treatment unit to be subjected to flocculent precipitation and oxidative degradation treatment, and generated water returns to the external membrane bioreactor unit from the second water tank; the reverse osmosis concentrated solution enters the reverse osmosis concentrated solution treatment unit to be subjected to oxidative degradation, precipitation separation and evaporative crystallization treatment so as to generate recycled evaporative condensate water. The device has the characteristics of excellent effluent quality and low energy consumption.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a low-carbon garbage leachate full-volume treatment system. Background Art

[0002] A large amount of leachate will be generated during the collection, transportation, transfer, landfill and incineration of domestic garbage. If it is not treated, it will cause serious pollution to the environment. The pollution components of garbage leachate are very complex, mainly ammonia nitrogen and various dissolved cations, heavy metals, phenols, soluble fatty acids and other organic pollutants. The COD of leachate can reach up to 70,000 mg / L or more, and the lowest is nearly 40,000 mg / L, and it contains a large amount of humic acid. It is difficult to treat it to the secondary or even primary standard using traditional biochemical treatment processes. Generally speaking, when the COD in the leachate is nearly 500-1000 mg / L, it will not be able to be treated by biological treatment. The ammonia nitrogen concentration of garbage leachate is very high, generally around 1500-2500 mg / L. In addition, since the classification of domestic garbage is not detailed enough at present, it contains a lot of industrial waste, etc., so the heavy metal content and salt content are relatively high.

[0003] The main processes for treating landfill leachate are: pretreatment + anaerobic + external membrane bioreactor (MBR) + nanofiltration (NF) + reverse osmosis (RO). Among them, the nanofiltration unit and the reverse osmosis unit will produce a concentrate accounting for about 15% of their respective water intake; the nanofiltration concentrate contains a high concentration of difficult-to-biodegrade organic matter, and its CODcr can be as high as 5000mg / L, and contains a large amount of humic acid, which is very difficult to biodegrade. Although the organic matter content in the reverse osmosis concentrate is low, it contains a very high salt content, reaching more than 15g / L. In addition, the nanofiltration concentrate also contains a relatively high concentration of salt, among which the divalent salt ions are mainly calcium, magnesium, barium, sulfate ions, etc.

[0004] There are differences in the concentration of organic matter and the types and concentrations of salts contained in nanofiltration concentrate and reverse osmosis concentrate. At present, the treatment of these two types of concentrates is the focus and difficulty of the landfill leachate treatment process. The existing technology generally adopts the mode of merging the above two streams of concentrated liquids, and realizes full-scale treatment through technical means such as oxidation and evaporation. This mode has problems such as large amount of concentrated liquid, large evaporation volume of evaporator and final solid waste output, which brings high energy consumption; in addition, in order to match the large volume of concentrated liquid, large-scale intermediate tanks and evaporation equipment must be equipped, which also directly increases the purchase cost and maintenance cost. Therefore, it is very necessary to optimize the current leachate treatment process. It is of great practical significance to study how to reduce the total amount of concentrated liquid and achieve efficient disposal, and develop new landfill leachate disposal technology and processes. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a low-carbon landfill leachate full-scale treatment system, which treats the nanofiltration concentrate and reverse osmosis concentrate of the landfill leachate respectively, and greatly reduces the COD value of the concentrate through a high-efficiency oxidation reactor, greatly reduces the load of the evaporator, and improves the effluent water quality, so that the effluent can meet the relevant requirements of agricultural irrigation, industrial cooling water, urban greening and landscape water, etc.

[0007] (II) Technical solution

[0008] In a first aspect, the present invention provides a low-carbon landfill leachate full-volume treatment system, comprising:

[0009] A pretreatment unit, an anaerobic treatment unit, an external membrane bioreactor unit, a nanofiltration unit and a reverse osmosis unit connected in sequence; wherein the nanofiltration unit is also connected to a nanofiltration concentrate treatment unit, and the reverse osmosis unit is also connected to a reverse osmosis concentrate treatment unit; the nanofiltration concentrate treatment unit comprises a flocculation sedimentation reactor, a sand filtration device, a first water tank, a first advanced oxidation reactor and a second water tank connected in sequence; the second water tank is connected to the external membrane bioreactor unit; the reverse osmosis concentrate treatment unit comprises a third water tank, a second advanced oxidation reactor, a fourth water tank and an evaporation crystallizer connected in sequence;

[0010] The external membrane bioreactor unit includes a denitrification reactor, a nitrification reactor and an ultrafiltration membrane assembly; the effluent of the denitrification reactor enters the nitrification reactor, and part of the nitrified liquid of the nitrification reactor flows back to the denitrification reactor; the effluent of the anaerobic treatment unit enters the denitrification reactor of the external membrane bioreactor unit, and the effluent of the nitrification reactor enters the ultrafiltration membrane assembly for treatment to produce concentrated sludge, and part of the concentrated sludge flows back to the nitrification reactor; the produced water of the ultrafiltration membrane assembly enters the nanofiltration unit;

[0011] The nanofiltration unit produces nanofiltration concentrate and nanofiltration water, and the nanofiltration water enters the reverse osmosis unit for treatment to produce reverse osmosis concentrate and reverse osmosis water, and the reverse osmosis water is the system effluent; the nanofiltration concentrate enters the nanofiltration concentrate treatment unit for flocculation precipitation and oxidation degradation treatment, and the produced water returns to the external membrane bioreactor unit from the second water tank; the reverse osmosis concentrate enters the reverse osmosis concentrate treatment unit for oxidation degradation, precipitation separation and evaporation crystallization treatment to obtain evaporated condensed water (recyclable water) and crystallized salt. The evaporated condensed water meets the requirements of fountains, urban greening water and other indicators.

[0012] According to a preferred embodiment of the present invention, the first advanced oxidation reactor and the second advanced oxidation reactor respectively include a reaction tower shell, and the reaction tower shell is provided with an ozone reaction zone, an ultraviolet catalytic reaction zone, an atomization zone and a gas-liquid separation zone from the bottom to the top in sequence; the ozone reaction zone is connected to an ozone source, the ultraviolet catalytic reaction zone is provided with two or more layers of ultraviolet lamps arranged in an array, the atomization zone is provided with an atomization nozzle, and the gas-liquid separation zone is provided with a gas-liquid separator; a water outlet pipe is provided at the bottom of the reaction tower shell, and the water outlet pipe is connected to a circulation pipe and a drainage pipe by a three-way connection; the circulation pipe is connected to the atomization nozzle, and is used to circulate the sewage at the bottom of the reaction tower shell to the atomization nozzle above the ultraviolet lamp, and the sewage is sprayed out in the form of tiny droplets by the atomization nozzle; the circulation pipe is also connected to the water inlet pipe. Among them, the diameter of the water droplet particles sprayed by the atomization nozzle is between 50-2000μm, and the operating pressure is lower than 0.1mPa.

[0013] Wherein, in the first advanced oxidation reactor, the water inlet pipe is connected to the water outlet of the first water tank of the nanofiltration concentrated liquid processing unit; in the second advanced oxidation reactor, the water inlet pipe is connected to the water outlet of the third water tank of the reverse osmosis concentrated liquid processing unit.

[0014] According to a preferred embodiment of the present invention, the reaction tower shell is made of plastic, glass fiber reinforced plastic, carbon fiber reinforced plastic (FRP), these materials have good corrosion resistance; or the reaction tower shell is made of stainless steel and coated with anti-corrosion paint inside, or it is a reinforced concrete structure and coated with anti-corrosion paint inside.

[0015] According to a preferred embodiment of the present invention, the circulation pipe includes a circulation main pipe and a plurality of circulation branch pipes, the circulation main pipe is connected to the circulation branch pipes, the circulation main pipe is arranged outside the reaction tower shell, and the circulation branch pipes are arranged inside the reaction tower shell; at least one atomizing nozzle is arranged on each circulation branch pipe.

[0016] According to a preferred embodiment of the present invention, a gas circulation pipe is provided at the top of the reaction tower shell and above the gas-liquid separator, and a gas extraction device is provided on the gas circulation pipe. The gas collected at the top of the reaction tower shell is returned from the ozone reaction zone of the reaction tower shell to the inside of the reaction tower shell by means of the gas extraction device and the gas circulation pipe. Preferably, the gas circulation pipe is connected to the input pipeline of the ozone source, so that the recovered gas is mixed with the ozone source and input into the ozone reaction zone of the reaction tower shell together. The gas circulation pipe can greatly improve the utilization rate of ozone molecules and reduce the consumption of ozone. Preferably, the ozone source is an ozone generator. An exhaust valve is also provided at the top of the reaction tower shell to discharge excess gas in time to maintain the inside of the reaction tower shell in a constant pressurized environment, and the excess gas is discharged. Preferably, the pressure of the reaction tower shell is maintained at 0.10mPa-0.8mPa.

[0017] According to a preferred embodiment of the present invention, the ultraviolet lamp is connected to the ultraviolet generator; the ultraviolet generator is located outside the reaction tower shell, and the ultraviolet lamp is located inside the reaction tower shell; a bracket is provided inside the reaction tower shell along the inner wall of the reaction tower shell, and the ultraviolet lamp is arranged on the bracket; or a plurality of transversely penetrating mounting holes are provided on the reaction tower shell, and a transparent sleeve is provided in the hole, and the ultraviolet lamp is directly installed in the transparent sleeve, and the transparent sleeve has an open end facing the outside of the reaction shell. Thereby, the assembly and maintenance of the ultraviolet lamp become very convenient.

[0018] Preferably, when the UV lamp is installed inside the reaction tower shell through the bracket, the UV lamp is doped with TiO 2 / ZnO transparent matrix material, or coated with TiO on the surface of the UV lamp 2 / ZnO、TiO 2 / Ag、TiO 2 / graphene at least one transparent photocatalyst; when the ultraviolet lamp is installed through a sleeve located inside the reaction tower shell, the transparent sleeve is doped with TiO 2 / ZnO transparent matrix material, or the transparent sleeve is coated with TiO 2 / ZnO、TiO 2 / Ag、TiO 2 At least one transparent photocatalyst in graphene. The transparent photocatalyst does not affect the emission of ultraviolet light and can greatly enhance the degradation of organic molecules in sewage.

[0019] Preferably, the cross-section of the ultraviolet lamp tube is circular, elliptical, gourd-shaped or droplet-shaped, and the equivalent diameter of each ultraviolet lamp tube is 1-5 cm; the ultraviolet lamp tube with an elliptical cross-section has its major axis arranged along the vertical direction.

[0020] According to a preferred embodiment of the present invention, the ultraviolet lamp tubes are arranged in two or more layers and have an interlayer spacing; single layers of ultraviolet lamp tubes are arranged in parallel and a tube spacing is formed between two ultraviolet lamp tubes; two adjacent layers of ultraviolet lamp tubes are staggered so that one layer of ultraviolet lamp tubes is exactly located within the tube spacing of another layer of ultraviolet lamp tubes; or two adjacent layers of ultraviolet lamp tubes are cross-arranged so that one layer of ultraviolet lamp tubes is exactly crossed with another layer of ultraviolet lamp tubes in spatial position.

[0021] According to a preferred embodiment of the present invention, the gas-liquid separator is composed of a group of obliquely installed corrugated plates, the horizontal spacing between adjacent corrugated plates is 1-10 mm, and the corrugated plates are coated with TiO 2 / MnO 2The composite catalyst has a coating thickness of 0.1-0.5 mm. The composite catalyst has ozone catalysis and photocatalysis functions. The corrugated plate is made of a hydrophilic material or has a hydrophilic surface, which improves the gas-liquid separation efficiency.

[0022] According to a preferred embodiment of the present invention, the vertical distance between the topmost layer of ultraviolet lamp tubes in the ultraviolet reaction zone and the lower edge of the atomizing nozzle above it is 15cm-30cm; the single-layer ultraviolet lamp tubes are arranged in parallel and the spacing between two ultraviolet lamp tubes is 3-10 times the diameter of the ultraviolet lamp tube; the interlayer spacing between two layers of ultraviolet lamp tubes is 1-3 diameters of the ultraviolet lamp tubes.

[0023] According to a preferred embodiment of the present invention, in the ozone reaction zone, the position where the ozone source (ozone generator) is connected to the gas inlet of the ozone reaction zone is higher than the sewage liquid level, a conical groove is provided at the bottom of the reaction tower shell, and the outlet pipe is provided at the bottom of the conical groove; or the position where the ozone source (ozone generator) is connected to the gas inlet of the ozone reaction zone is below the liquid level, and a transparent suspended spherical filler is placed in the sewage, and the suspended spherical filler is a porous structure and amino or carboxyl functional groups are introduced on the surface. The suspended spherical filler is made of materials such as PMMA and PS (close to the specific gravity of sewage), for example, a large number of amino groups can be introduced on its surface by dipping polyethyleneimine film; most of the acidic organic molecules are anchored on the surface of the suspended spherical filler; the porous structure increases the specific surface area, and the pore structure has a certain proportion (preferably >30%) of mesopores (2-50nm), which can adsorb more organic molecules, and the mesopores, especially the pores of 2-20nm, are particularly suitable for the transmission and retention of ozone molecules, so that a place for cavitation and oxidation of organic matter can be provided for ozone molecules.

[0024] According to a preferred embodiment of the present invention, the water inlet pipes of the first advanced oxidation reactor and the second advanced oxidation reactor are also connected to a Fenton reagent adding device; a valve is provided between the Fenton reagent adding device and the water inlet pipe; and a decision is made whether to open the valve based on the COD value of the influent water in the water inlet pipe so as to decide whether to add Fenton reagent to the influent water.

[0025] According to a preferred embodiment of the present invention, the first water pool and the second water pool of the nanofiltration concentrated liquid treatment unit are respectively provided with a pH adjusting device for adjusting the pH of the water in the first water pool to 3.0-5.0 and the pH of the water in the second water pool to 7-8; the third water pool and the fourth water pool of the reverse osmosis concentrated liquid treatment unit are respectively provided with a pH adjusting device for adjusting the pH of the water in the third water pool to 3.0-5.0 and the pH of the water in the fourth water pool to 7-8.

[0026] Among them, the pH of the water in the first and third water tanks is adjusted to 3.0-5.0 to facilitate Fenton catalytic oxidation in the first and second advanced oxidation reactors; the water in the second water tank is adjusted to pH7-8 so that the effluent of the second water tank can enter the external membrane bioreactor unit for biochemical treatment. At the same time, the iron ions produced by Fenton catalysis produce iron hydroxide under pH7-8 conditions. The iron hydroxide has strong adsorption and flocculation effects, and precipitates sludge at the bottom of the second water tank, thereby reducing the content of iron ions in the water, which is convenient for subsequent biochemical treatment. The water in the fourth water tank is adjusted to pH7-8, which can also make the iron ions produced by Fenton catalysis produce iron hydroxide under pH7-8 conditions. The strong adsorption and flocculation effects of iron hydroxide can be used to reduce the concentration of metal salts in the water, reduce the operating load of the evaporation crystallizer in the reverse osmosis concentrate treatment unit, and prevent rapid and large-scale scaling.

[0027] According to a preferred embodiment of the present invention, a multivalent ion capture agent is added to the flocculation and precipitation reactor of the nanofiltration concentrated liquid treatment unit. Typical agents include: one or more of polyaluminium chloride, polyferric sulfate, polyacrylamide, lime, sodium carbonate, silicate, phosphate, organic sulfur TMT, amine precipitants, etc., to promote flocculation and precipitation, avoid clogging of the atomizing nozzle caused by the influent entering the first advanced oxidation reactor, improve the oxidation effect of organic matter, reduce the output of sludge in the reaction tower shell, and also avoid excessive metal ion concentration affecting the biodegradability of the effluent from the nanofiltration concentration treatment unit.

[0028] It should be noted that the ozone reaction zone does not only undergo ozone oxidation reaction, and similarly, the ultraviolet photocatalytic reaction zone does not only undergo photocatalytic reaction. At any position in the entire reaction tower shell, ozone catalysis, photocatalysis and even Fenton catalysis can occur simultaneously.

[0029] (III) Beneficial effects

[0030] (1) The present invention provides a low-carbon landfill leachate full-volume treatment system, which treats the nanofiltration concentrate and reverse osmosis concentrate of the landfill leachate separately, which can greatly reduce the evaporation of the evaporator (the evaporation is reduced by more than half), has the advantage of low energy consumption, and achieves the "low-carbon" goal. At the same time, the treatment system of the present invention realizes the full-volume treatment of the leachate, and the water produced by the entire system (permeate water of reverse osmosis and evaporation condensate) meets different levels of reuse standards. After the effluent of the nanofiltration concentrate treatment unit is treated, the COD is reduced and the biodegradability is greatly improved. It returns to the external membrane bioreactor unit for biochemical treatment again, which can dilute the landfill leachate, reduce the difficulty and operating pressure of the landfill leachate biochemical treatment, and enable the external membrane bioreactor unit to operate more sustainably and stably.

[0031] (2) The advanced oxidation reactor of the present invention integrates ultraviolet catalytic degradation and sterilization, ozone catalytic degradation, Fenton oxidation degradation, etc., and coordinates the three catalytic technologies to greatly enhance the oxidation intensity, reduce the COD value in the water, and improve the effluent quality. In the advanced oxidation reactor, an atomizing nozzle is used to disperse the wastewater into tiny droplets, which increases the contact area between the ozone molecules and the wastewater pollutants. The continuous phase ozone atmosphere is used to contact the dispersed phase sewage droplets, which shortens the contact path between the organic molecules and the ozone, accelerates the reaction rate, and strengthens the ozone oxidation effect. Compared with the oxidation mode in which the liquid phase is the continuous phase and the ozone is the dispersed phase, this mode greatly enhances the penetration length of the ultraviolet light, thereby further increasing the ultraviolet oxidation efficiency.

[0032] (3) The advanced oxidation reactor of the present invention can be fully or partially activated during use according to the water quality conditions entering the advanced oxidation reactor. For example, when only ozone catalytic degradation is activated, the ultraviolet lamp is not turned on. At this time, the ultraviolet lamp can serve as a place for film catalytic reaction. The water mist generated by the atomizing nozzle drips on the surface of the ultraviolet lamp to form a thin layer of liquid film, which contacts with ozone to achieve efficient catalytic decomposition of organic molecules in the liquid film. When the ozone catalysis is not turned on but the ultraviolet catalysis is turned on, the (composite catalyst) on the surface of the ultraviolet light and the surface of the gas-liquid separator can also be used to achieve catalytic degradation of organic molecules in the water.

[0033] Compared with other landfill leachate treatment processes, the present invention has significant energy saving and consumption reduction, and can achieve low-carbon, high-efficiency and fully quantitative treatment. The effluent of the system mainly comes from the permeate of reverse osmosis and the evaporated condensate of the evaporative crystallizer. The permeate of reverse osmosis can meet the requirements of agricultural irrigation and industrial cooling water, while the evaporated condensate meets the requirements of urban greening and landscape water. The present invention has the advantages of small concentrated liquid evaporation treatment volume, small final salt-containing solid waste generation, and low operating energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural block diagram of the full-scale treatment system of low-carbon garbage leachate of the present invention.

[0035] Figure 2 It is a schematic diagram of the structure of the advanced oxidation reactor in the full-scale treatment system of low-carbon landfill leachate of the present invention.

[0036] Figure 3 This is a side view of the advanced oxidation reactor in the low-carbon landfill leachate full-scale treatment system.

[0037] Figure 4 Schematic diagram of the layout of the wastewater inlet pipe and atomizing nozzle of the advanced oxidation reactor.

[0038] Reference numerals:

[0039] 1-pretreatment unit; 2-anaerobic treatment unit; 3-external membrane bioreactor unit; 4-nanofiltration unit; 5-reverse osmosis unit; 6-nanofiltration concentrate treatment unit; 7-reverse osmosis concentrate treatment unit; 31-denitrification reactor; 32-nitrification reactor; 33-ultrafiltration membrane assembly; 61-flocculation sedimentation reactor; 62-sand filter device; 63-first water tank; 64-advanced oxidation reactor; 65-second water tank; 71-third water tank; 72 - the second advanced oxidation reactor; 73 - the fourth water tank; 74 - the evaporation crystallizer; 640 - the reaction tower shell; 6401 - the water outlet pipe; 641 - the atomizing nozzle; 642 - the circulation pump; 643 - the three-way joint; 6431 - the drain pipe; 644 - the ozone generator; 645 - the gas-liquid separator; 6461 - the gas circulation pipe; 646 - the exhaust device; 647 - the exhaust valve; 648 - the ultraviolet generator; 649 - the bracket; 6410 - the ultraviolet lamp. DETAILED DESCRIPTION

[0040] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0041] The contents not described in detail in this specification belong to the prior art known to the professional and technical personnel in this field. In the description of the present invention, it is recommended to understand that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", clockwise", "counterclockwise", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0042] Example 1

[0043] like Figure 1As shown, a low-carbon garbage leachate full-volume treatment system in an embodiment of the present invention includes a pretreatment unit 1, an anaerobic treatment unit 2, an external membrane bioreactor unit 3, a nanofiltration unit 4 and a reverse osmosis unit 5 connected in sequence by pipelines. The permeate of the nanofiltration unit 4 is connected to the water inlet of the reverse osmosis unit 5. The concentrated liquid outlet of the nanofiltration unit 4 is connected to the nanofiltration concentrated liquid treatment unit 6 through a pipeline. The water outlet of the nanofiltration concentrated liquid treatment unit 6 is connected to the external membrane bioreactor unit 3 through a pipeline, so that the effluent of the nanofiltration concentrated liquid treatment unit 6 returns to the external membrane bioreactor unit 3 for circulation and biochemical treatment. The permeate of the reverse osmosis unit 5 is discharged or reused, and the concentrated liquid outlet of the reverse osmosis unit 5 is connected to the water inlet of the reverse osmosis concentrated liquid treatment unit 7 through a pipeline. The external membrane bioreactor unit 3 includes a denitrification reactor 31, a nitrification reactor 32 and an ultrafiltration membrane assembly 33, and the three are connected in sequence by pipelines. The effluent of the anaerobic treatment unit 2 enters the external membrane bioreactor unit 3 and then first enters the denitrification reactor 31. The effluent of the denitrification reactor 31 enters the nitrification reactor 32, and part of the nitrified liquid of the nitrification reactor 32 flows back to the denitrification reactor 31. The effluent of the nitrification reactor 32 enters the ultrafiltration membrane assembly 33 for treatment to produce concentrated sludge, part of which flows back to the nitrification reactor 32, and part of which is discharged; the produced water of the ultrafiltration membrane assembly 33 enters the nanofiltration unit 4.

[0044] The nanofiltration unit 4 produces nanofiltration concentrate and nanofiltration water, and the nanofiltration water enters the reverse osmosis unit 5 for treatment to produce reverse osmosis concentrate and reverse osmosis water, and the reverse osmosis water is the effluent of the entire treatment system. The nanofiltration concentrate enters the nanofiltration concentrate treatment unit 6. The nanofiltration concentrate treatment unit 6 includes a flocculation sedimentation reactor 61, a sand filter device 62, a first water tank 63, a first advanced oxidation reactor 64, and a second water tank 65 connected in sequence by pipelines. Among them, the water inlet of the flocculation sedimentation reactor 61 is connected to the concentrated liquid outlet of the nanofiltration unit 4. The second water tank 65 is connected to the denitrification reactor 31 of the external membrane bioreactor unit 3 to achieve the reflux of the nanofiltration concentrate after treatment. The reverse osmosis concentrate treatment unit 7 includes a third water tank 71, a second advanced oxidation reactor 72, a fourth water tank 73, and an evaporation crystallizer 74 connected in sequence by pipelines. The water inlet of the third water tank 71 is connected to the concentrated liquid outlet of the reverse osmosis unit 5 through a pipeline, and the evaporated condensed water produced by the evaporation crystallizer 74 is discharged or reused, and the crystallized salt is safely disposed of. The evaporated condensed water meets the requirements of fountains, urban greening water and other indicators.

[0045] The pretreatment unit 1 mainly removes larger particles in the landfill leachate, and then enters the anaerobic treatment unit to remove more than 80% of the organic matter. At the same time, the degraded organic matter is converted into biogas under the action of anaerobic bacteria (acidogenic and methanogenic bacteria). In the nitrification reactor 32 of the external membrane bioreactor unit 3, through the action of highly active aerobic microorganisms (a microbial supplement device can be set), most of the organic matter is degraded, and ammonia nitrogen and organic nitrogen are oxidized into nitrates and nitrites, which are refluxed to the denitrification reactor 31 in front of it, and are reduced to nitrogen gas in an anaerobic environment and discharged, achieving the purpose of denitrification, and the denitrification rate is greater than 99%. The effluent of the nitrification reactor 32 is separated and purified from the water and the bacteria through the ultrafiltration membrane assembly 33, while maintaining a high sludge concentration inside the external membrane bioreactor unit 3, so that the microorganisms are in high activity. The effluent of the ultrafiltration membrane assembly 33 enters the nanofiltration unit 4, and further separates the difficult-to-degrade macromolecular organic matter, heavy metal ions and multivalent non-metallic ions (such as phosphorus, etc.) through nanofiltration. The nanofiltration permeate effluent enters the reverse osmosis unit 5 at the rear end to further remove salt, and the effluent is discharged or reused. The filter pores of the nanofiltration unit 4 are about 1 nanometer to 10 nanometers, which can intercept relatively small molecular weight organic matter, multivalent ions (such as divalent salts such as calcium and magnesium) and some larger monovalent ions. The operating pressure of nanofiltration is 1-4MPa. The pore size of the reverse osmosis unit 5 is smaller, usually less than 0.001 microns (about 1 nanometer), which can almost block all dissolved inorganic matter and most organic compounds, and the operating pressure is usually above 4-8MPa. Reverse osmosis can remove almost all salts (including monovalent and multivalent ions), bacteria, viruses and other microorganisms, as well as almost all organic matter, so that water close to pure water is obtained to meet high reuse requirements.

[0046] The nanofiltration concentrate produced by the nanofiltration unit 4 enters the nanofiltration concentrate treatment unit 6. Specifically, it first passes through the flocculation sedimentation reactor 61, and a multivalent ion capture agent is added to the flocculation sedimentation reactor. Typical agents include: one or more of polyaluminum chloride, polyferric sulfate, polyacrylamide, lime, sodium carbonate, silicate, phosphate, organic sulfur TMT, amine precipitant, etc., to promote flocculation and remove most of the high-valent ions, and discharge them in the form of precipitated sludge. The clear liquid of the flocculation sedimentation reactor 61 is then filtered through a sand filter device, and the effluent enters the first water tank 62, and the pH value is adjusted to 3.0-5.0 to prepare for Fenton catalysis. The first water tank 62 can stabilize the water volume and balance the water quality to avoid impacting the first advanced oxidation reactor 63. Subsequently, the effluent from the first water tank 62 enters the first advanced oxidation reactor 63, and is synergistically oxidized by two or more oxidation methods to reduce the CODcr in the water, destroy the structure of macromolecular organic matter in the wastewater, and improve its biodegradability. The oxidized effluent enters the second water tank 64, and its pH value is adjusted to 7.0-8.0, and finally enters the denitrification reactor 31 of the external membrane bioreactor unit 3 through the reflux pipe. When the pH value of the water entering the second water tank 64 is adjusted to 7.0-8.0, the iron ions produced by the Fenton reagent form hydroxides, which have strong adsorption and flocculation effects, and can produce precipitated sludge at the bottom of the second water tank 64. This part of the precipitated sludge is discharged, and the water is close to neutral at this time, which is suitable for biochemical treatment. The reverse osmosis concentrate produced by the reverse osmosis unit 5 enters the reverse osmosis concentrate treatment unit 7. Specifically, it first enters the third water tank 71, adjusts its pH value to 3.0-5.0, and then enters the second advanced oxidation reactor 72. Through the synergistic effect of two or more oxidation means, the CODcr in the wastewater is degraded to below 50, and the oxidized water enters the fourth water tank 73, and then enters the evaporation crystallizer 74, the salt crystallization is discharged, and the evaporated water is condensed and reused. The pH of the water in the fourth water tank 73 is adjusted to 7-8, so that the effluent water quality is more environmentally friendly, reducing corrosion to the evaporator, while removing part of the trivalent iron ions (introduced by Fenton catalysis) and other metal ions and some organic molecules, and using the strong adsorption and flocculation of trivalent iron, sludge is generated at the bottom of the fourth water tank 73 and discharged, thereby greatly reducing the operating load of the evaporation crystallizer 74. The second advanced oxidation reactor 72 is set before the evaporation crystallizer 74 in the present invention, which can greatly reduce the COD value in the water and avoid the adverse effects of higher COD on the evaporation crystallizer, such as scaling and clogging and affecting heat transfer efficiency and equipment corrosion.

[0047] like Figure 2 As shown, it is an advanced oxidation reactor of a preferred embodiment of the present invention, as Figure 1 The first advanced oxidation reactor and the second advanced oxidation reactor in the treatment system shown. Figure 2As shown, the advanced oxidation reactor of the preferred embodiment of the present invention includes a reaction tower shell 640, and the reaction tower shell 640 is provided with an ozone reaction zone, an ultraviolet catalytic reaction zone, an atomization zone and a gas-liquid separation zone in sequence from the bottom to the top. Among them, the ozone reaction zone is connected to an ozone generator 644, and the ultraviolet catalytic reaction zone is provided with two or more layers of array-arranged ultraviolet lamp tubes 6410, and the ultraviolet lamp tubes 6410 are arranged on a bracket 649. The atomization zone is provided with a plurality of atomization nozzles 641, and the atomization nozzles 641 are arranged as follows. Figure 4 On the circulation branch pipe shown, the circulation branch pipe is located inside the reaction tower shell 640 and is suspended a distance above the ultraviolet lamp tube 6410. The circulation branch pipe is connected to the circulation main pipe outside the reaction tower shell 640. A gas-liquid separator 645 is provided in the gas-liquid separation area near the top of the reaction tower shell 640. An outlet pipe 6401 is provided at the bottom of the reaction tower shell 640. The outlet pipe 6401 is connected to the circulation main pipe and the drain pipe 6431 with a tee 643. The drain pipe 6431 is used to discharge the treated water to the outside of the advanced oxidation reactor. The outlet pipe 6401 is connected to the circulation pump 642. The circulation pump 642 provides water circulation power. The circulation main pipe is used to circulate the sewage at the bottom of the reaction tower shell 640 to the atomizing nozzle 641 above the ultraviolet catalytic reaction zone, and then the atomizing nozzle 641 is used to spray the sewage in the form of tiny droplets to form a number of dispersed phase water droplets. Preferably, the flow specification of the circulation pump 642 is 30m 3 / h. This circulation flow rate is related to the design specifications of the entire reaction tower shell 640. The vertical distance between the uppermost UV lamp tube 6410 in the UV reaction zone and the lower edge of the atomizing nozzle 641 above it is 15cm-30cm. This distance constitutes the area where the dispersed phase water droplets and the continuous phase ozone mix and react. Figure 2 As shown, the circulation main pipe is also connected to the water inlet pipe of the advanced oxidation reactor. The diameter of the water droplets sprayed by the atomizing nozzle 641 is between 50-2000 μm, and its operating pressure is lower than 0.1 mPa (preferably 0.7 bar), and the flow rate of a single atomizing nozzle 641 is 20 L / min. In the first advanced oxidation reactor 64, the water inlet pipe is connected to the outlet of the first water tank 63 of the nanofiltration concentrated liquid treatment unit 6; in the second advanced oxidation reactor 72, the water inlet pipe is connected to the outlet of the third water tank 71 of the reverse osmosis concentrated liquid treatment unit 7. Figure 4 As shown, three atomizing nozzles are respectively provided on the two circulation branches, with a total of six atomizing nozzles, so that the atomizing nozzles are evenly distributed on the cross section of the reaction tower shell 640 .

[0048] like Figure 2 and Figure 3As shown, 6 layers of 33 ultraviolet lamp tubes 6410 are installed in the reaction tower shell 640. The ultraviolet lamp tubes 6410 are installed on the bracket 649 and connected to the ultraviolet generator 648 outside the reaction tower shell 640. Among them, there is a spacing between each layer of the 6 layers of ultraviolet lamp tubes 6410, and there is also a spacing between the ultraviolet lamp tubes of a single layer; and the ultraviolet lamp tubes 6410 of two adjacent layers are staggered, so that the ultraviolet lamp tubes 6410 of one layer are just located within the tube spacing of the ultraviolet lamp tubes 6410 of another layer. In other embodiments, the ultraviolet lamp tubes 6410 of two adjacent layers can also be arranged crosswise, that is, the ultraviolet lamp tubes 6410 of one layer just cross with the ultraviolet lamp tubes 6410 of another layer in space. Among them, in the same layer, the spacing between two ultraviolet lamp tubes is 3-10 times the diameter of the ultraviolet lamp tube, and the layer spacing between the two adjacent layers of ultraviolet lamp tubes is 1-3 diameters of the ultraviolet lamp tube. These reasonable spacings can provide a path for rapid diffusion and mass transfer of ozone and atomized water droplets, and can also enable the sewage droplets produced by the atomizing nozzle to cover more of the surface of the ultraviolet lamp tube 6410 to form a liquid film, preventing the sewage droplets from quickly falling to the bottom of the reaction tower shell 640.

[0049] Preferably, the UV lamp can be doped with TiO 2 / ZnO transparent matrix material, or coated with TiO on the surface of the UV lamp 2 / ZnO、TiO 2 / Ag、TiO 2 / graphene, preferably the latter. The transparent photocatalyst does not affect the emission of ultraviolet light and can greatly enhance the degradation of organic molecules in sewage. These catalysts also have ozone catalysis function. Even in the mode where ultraviolet light is not turned on, these ultraviolet lamp tubes 6410 can form a film reactor, so that the atomized droplets produced by the atomizing nozzle 641 fall on the surface of these ultraviolet lamp tubes 6410 to form a very thin liquid film, and the continuously filled continuous phase ozone can quickly contact and react with the organic matter in the liquid film when it contacts the ultraviolet lamp tube 6410, and the transparent photocatalyst also plays the role of ozone catalysis. The cross section of the ultraviolet lamp tube 6410 can be circular, elliptical, gourd-shaped or droplet-shaped, among which elliptical is preferred. The equivalent diameter of each ultraviolet lamp tube is 1-5cm; the ultraviolet lamp tube with an elliptical cross section has its long axis direction arranged along the vertical direction. These shapes have a larger specific surface area, and the elliptical and droplet-shaped ultraviolet lamp tube 6410 can reduce its top surface area and increase the area of ​​contact between the liquid film and ozone.

[0050] like Figure 2As shown, the advanced oxidation reactor also includes a gas circulation system. Specifically, a gas circulation pipe 6461 is provided at the top of the reaction tower shell 640 and above the gas-liquid separator 645. The gas circulation pipe 6461 is provided with a gas extraction device 646. The gas collected at the top of the reaction tower shell 640 is returned to the ozone reaction zone of the reaction tower shell from the bottom of the reaction tower shell 640 by using the gas extraction device 646 and the gas circulation pipe 6461. Preferably, an ozone sensor is provided on the gas circulation pipe 6461. When the ozone concentration is high, it can be directly reused. Otherwise, the ozone generator 644 is used to generate new ozone for supplementation. The gas circulation pipe 6461 can be directly returned to the ozone reaction zone of the reaction tower shell 640, or it can be connected to the connecting pipeline between the ozone generator 644 and the reaction tower shell 640, so that the recycled gas and the newly generated ozone gas are evenly mixed and then input into the ozone reaction zone of the reaction tower shell 640 together. The present invention utilizes the gas circulation pipe 6461 to greatly improve the utilization rate of ozone molecules and reduce the consumption of ozone. An exhaust valve 647 is also provided on the top of the reaction tower shell 640, which can timely discharge excess gas to maintain the interior of the reaction tower shell 640 in a constant and safe pressurized environment and discharge excess gas in time. The pressure of the reaction tower shell 640 is maintained at 0.10mPa-0.8mPa, which can greatly enhance the movement speed of ozone molecules in sewage droplets or liquid films, accelerate the oxidation speed of organic matter, and reduce the effluent COD.

[0051] The gas-liquid separator 645 is composed of a group of corrugated plates installed obliquely, and the horizontal spacing between adjacent corrugated plates is 1-10 mm. The corrugated plates are made of hydrophilic materials or have hydrophilic surfaces, so that when the gas-liquid mixture passes through the gaps between adjacent corrugated plates, water droplets are adsorbed on the surface of the corrugated plates, thereby improving the gas-liquid separation efficiency. The corrugated plates are coated with TiO 2 / MnO 2 The composite catalyst has a coating thickness of 0.1-0.5 mm. The composite catalyst has ozone catalysis and photocatalysis functions, so it can catalyze the decomposition of organic matter when only the partial oxidation mode is turned on in the advanced oxidation reactor. 2 / MnO 2 The composite catalyst is a metal oxide and also has good hydrophilicity. The distance between the bottom of the gas-liquid separator 645 and the upper surface of the atomizing nozzle 641 is 10 cm, and the distance between the top of the gas-liquid separator 645 and the top of the reaction tower shell 640 is 25 cm, which can provide a long distance for the ozone to fully oxidize the sewage, and also specially reserve a gas gathering space to form a certain pressurized environment for the reaction tower shell 640, and can also increase the concentration of the gas in the gas circulation pipe 6461.

[0052] Among them, the connection pipeline between the ozone generator 644 and the reaction tower shell 640 is provided with a valve, a valve is provided between the circulation branch pipe and the circulation main pipe, a connecting valve is provided between the water inlet and the circulation main pipe, a valve is provided between the drain pipe 6431 and the tee 643, and a COD online sensor is provided at the bottom of the reaction tower shell 640 to detect the degradation of water quality COD. When the degradation is good, the guest gas drain pipe 6431 is opened for continuous drainage and continuous water inlet of the water inlet pipe, otherwise the drain pipe 6431 and the water inlet pipe are closed, so that the water circulation in the reaction tower shell 640 is subjected to enhanced oxidation degradation. Further, the water inlet pipe is also connected to a Fenton reagent adding device, and a valve is provided between the Fenton reagent adding device and the water inlet pipe, and the valve determines whether to open the valve according to the COD value of the water in the water inlet pipe, so as to determine whether to add Fenton reagent to the water inlet. It can be seen that the advanced oxidation reactor of the present invention is very flexible and can produce a variety of combined modes of synergistic oxidation according to the water quality.

[0053] In this embodiment, the position of the gas inlet of the ozone generator 644 connected to the ozone reaction zone is higher than the sewage liquid level (the sewage liquid level is lower than the gas inlet of the ozone generator 644), and a conical groove is provided at the bottom of the reaction tower shell, and a water outlet pipe 6401 is provided at the bottom of the conical groove. The conical groove constitutes a water collection tank, the upper part of the oxidation reaction tower shell 640 is a rectangular parallelepiped, and the lower part is a water collection tank. The total height of the reaction tower shell 640 is 3.5m, the length is 1.5m, the width is 1m, the height of the water collection tank is 0.5m, and the bottom angle of the water collection tank is 90 degrees. The reaction tower shell 640 can be made of plastic, glass fiber reinforced plastic, carbon fiber reinforced plastic (glass fiber reinforced plastic), and these materials have good corrosion resistance; or the reaction tower shell is made of stainless steel and coated with anti-corrosion paint inside, or a reinforced concrete structure and coated with anti-corrosion paint inside.

[0054] The above-mentioned low-carbon landfill leachate full-scale treatment system is used to carry out full-scale treatment of landfill leachate. The influent is landfill leachate. The system has a treatment capacity of 300-400 tons / day. The reverse osmosis effluent is discharged or reused (if used as irrigation water and industrial cooling water). The evaporated condensed water fully meets the reuse requirements, and the sludge and crystallized salt are safely disposed of.

[0055] Example 2

[0056] The difference between this embodiment and embodiment 1 is that the ultraviolet lamp tube 6410 in the advanced oxidation reactor in this embodiment is installed as follows: a plurality of installation holes are provided on the reaction tower shell 640, which penetrate the two sides of the reaction tower shell 640 horizontally, and a sleeve with high light transmittance (such as a sleeve made of PMMA material) is provided in the hole, and the ultraviolet lamp tube or light bar is directly installed in the transparent sleeve, and the transparent sleeve has an open end facing the outside of the reaction shell. The ultraviolet lamp tube or light bar is connected to the ultraviolet generator 648 outside the reaction tower shell 640. This structure has the advantages of convenient assembly and maintenance of the ultraviolet lamp tube, and the ultraviolet lamp tube does not need to use special waterproof materials. At this time, there is no need to set the bracket 649, and the transparent sleeve is made of TiO doped 2 / ZnO transparent matrix material, or the transparent sleeve is coated with TiO 2 / ZnO、TiO 2 / Ag、TiO 2 / graphene at least one transparent photocatalyst. Figure 3 As shown, 6 layers of 33 sleeves can be set to penetrate the two sides of the reaction tower shell 640, and then the ultraviolet light strips are placed inside, and the power cord is connected to the ultraviolet generator 648 outside the reaction tower shell 640.

[0057] Example 3

[0058] The difference between this embodiment and embodiment 1 is that in the advanced oxidation reactor of this embodiment, the sewage level of the ozone reaction tower shell 640 is only about 5-10 cm lower than the ultraviolet lamp 6410, and the position of the gas inlet of the ozone generator 644 connected to the ozone reaction zone is below the sewage level. At this time, the area below the ultraviolet lamp 6410 constitutes a bubbling ozone reaction zone. Compared with the method of embodiment 1, this embodiment can relatively increase the water intake of sewage, thereby increasing the processing speed of the advanced oxidation reactor. In order to enhance the degradation efficiency of wastewater COD, a transparent suspended spherical filler accounting for about 30-40% of the volume of the ozone reaction zone can be placed in the sewage. The suspended spherical filler is made of materials such as PMMA, PS (preferably corrosion-resistant and close to the specific gravity of sewage), has a porous structure, and amino or carboxyl functional groups are introduced on the surface. Amino groups have a good anchoring effect on organic molecules. A transparent organic polymer material can be used to make a suspended spherical filler with macropores and mesopores by a template method, and a large number of amino groups can be introduced on its surface by dip-coating a polyethyleneimine film. The porous structure increases the specific surface area, and the pore structure has a certain proportion (preferably >30%) of mesopores (2-50nm), which can adsorb more organic molecules. The mesopores, especially the pores of 2-20nm, are particularly suitable for the transmission and retention of ozone molecules. Therefore, it can provide a place for ozone molecules to cavitate (ozone bubbling can stir and produce cavitation on the surface of the porous filler) and oxidize organic matter, thereby improving the degradation effect of ozone on organic matter in water and the utilization rate of ozone, reducing the working frequency of the exhaust device 646, and improving the quality of the effluent water. In this embodiment, a screen can be set in front of the outlet pipe 6401 at the bottom of the conical groove to prevent the suspended spherical filler from being sucked into the circulation pump 642 to block the pipeline.

[0059] In the above embodiment, the suspended spherical filler is made of transparent material, which does not affect the ultraviolet light irradiation into the water by the ultraviolet lamp 6410, and can promote the synergistic effect of ultraviolet light and ozone molecules on organic matter in the water. The particle size of the suspended spherical filler is 0.5-1.5 cm.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. These modifications or replacements, or the technical features in the above embodiments may be combined in the manner described in the embodiments if they do not conflict with each other, and these modifications, replacements or combinations do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-carbon landfill leachate full-volume treatment system, characterized in that: include: A pretreatment unit, an anaerobic treatment unit, an external membrane bioreactor unit, a nanofiltration unit and a reverse osmosis unit connected in sequence; wherein the nanofiltration unit is also connected to a nanofiltration concentrate treatment unit, and the reverse osmosis unit is also connected to a reverse osmosis concentrate treatment unit; the nanofiltration concentrate treatment unit comprises a flocculation sedimentation reactor, a sand filtration device, a first water tank, a first advanced oxidation reactor and a second water tank connected in sequence; the second water tank is connected to the external membrane bioreactor unit; the reverse osmosis concentrate treatment unit comprises a third water tank, a second advanced oxidation reactor, a fourth water tank and an evaporation crystallizer connected in sequence; The external membrane bioreactor unit includes a denitrification reactor, a nitrification reactor and an ultrafiltration membrane assembly; the effluent of the denitrification reactor enters the nitrification reactor, and part of the nitrified liquid of the nitrification reactor flows back to the denitrification reactor; the effluent of the anaerobic treatment unit enters the denitrification reactor of the external membrane bioreactor unit, and the effluent of the nitrification reactor enters the ultrafiltration membrane assembly for treatment to produce concentrated sludge, and part of the concentrated sludge flows back to the nitrification reactor; the produced water of the ultrafiltration membrane assembly enters the nanofiltration unit; The nanofiltration unit produces nanofiltration concentrate and nanofiltration produced water, and the nanofiltration produced water enters the reverse osmosis unit for treatment to produce reverse osmosis concentrate and reverse osmosis produced water, and the reverse osmosis produced water is the system effluent; the nanofiltration concentrate enters the nanofiltration concentrate treatment unit for flocculation precipitation and oxidative degradation treatment, and the produced water returns to the external membrane bioreactor unit from the second water tank; the reverse osmosis concentrate enters the reverse osmosis concentrate treatment unit for oxidative degradation, precipitation separation and evaporative crystallization treatment to obtain evaporated condensed water and crystalline salt.

2. The low-carbon garbage leachate full-volume treatment system according to claim 1 is characterized in that: The first advanced oxidation reactor and the second advanced oxidation reactor respectively comprise a reaction tower shell, wherein the reaction tower shell is provided with an ozone reaction zone, an ultraviolet catalytic reaction zone, an atomization zone and a gas-liquid separation zone in sequence from the bottom to the top; the ozone reaction zone is connected to an ozone source, the ultraviolet catalytic reaction zone is provided with two or more layers of ultraviolet lamps arranged in an array, the atomization zone is provided with an atomization nozzle, and the gas-liquid separation zone is provided with a gas-liquid separator; a water outlet pipe is provided at the bottom of the reaction tower shell, and the water outlet pipe is connected to a circulation pipe and a drainage pipe by a tee; the circulation pipe is connected to the atomization nozzle, and is used to circulate and transport the sewage at the bottom of the reaction tower shell to the atomization nozzle above the ultraviolet lamp, and the sewage is sprayed out in the form of tiny droplets by the atomization nozzle; the circulation pipe is also connected to the water inlet pipe; The circulation pipe comprises a circulation main pipe and a plurality of circulation branches, the circulation main pipe is connected with the circulation branches, the circulation main pipe is arranged outside the reaction tower shell, and the circulation branches are arranged inside the reaction tower shell; at least one atomizing nozzle is arranged on each circulation branch pipe; the circulation main pipe is connected with the water inlet pipe.

3. The low-carbon garbage leachate full-volume treatment system according to claim 2 is characterized in that: A gas circulation pipe is provided at the top of the reaction tower shell and above the gas-liquid separator. A vacuum device is provided on the gas circulation pipe. The gas collected at the top of the reaction tower shell is returned from the ozone reaction zone of the reaction tower shell to the inside of the reaction tower shell by means of the vacuum device and the gas circulation pipe. An exhaust valve is also provided at the top of the reaction tower shell to discharge excess gas in a timely manner to maintain the inside of the reaction tower shell in a constant pressurized environment. The pressure of the pressurized environment is 0.10mPa-0.8mPa.

4. The low-carbon garbage leachate full-volume treatment system according to claim 2 is characterized in that: The ultraviolet lamp is connected to the ultraviolet generator; the ultraviolet generator is located outside the reaction tower shell, and the ultraviolet lamp is located inside the reaction tower shell; a bracket is provided inside the reaction tower shell along the inner wall of the reaction tower shell, and the ultraviolet lamp is arranged on the bracket; or a plurality of transversely penetrating mounting holes are provided on the reaction tower shell, and a transparent sleeve is provided in the hole, and the ultraviolet lamp is directly installed in the transparent sleeve, and the transparent sleeve has an open end facing the outside of the reaction shell.

5. The low-carbon garbage leachate full-volume treatment system according to claim 5 is characterized in that: When the ultraviolet lamp tube is installed inside the reaction tower shell through a bracket, the ultraviolet lamp tube is made of a transparent matrix material doped with TiO2 / ZnO, or a transparent photocatalyst is coated on the surface of the ultraviolet lamp tube; when the ultraviolet lamp tube is installed through a sleeve located inside the reaction tower shell, the transparent sleeve tube is made of a transparent matrix material doped with TiO2, or a transparent photocatalyst is coated on the surface of the transparent sleeve tube.

6. The low-carbon garbage leachate full-volume treatment system according to claim 2 is characterized in that: The cross-section of the ultraviolet lamp tube is circular, oval, gourd-shaped or drop-shaped, and the equivalent diameter of each ultraviolet lamp tube is 1-5 cm; the ultraviolet lamp tube with an oval cross-section has its long axis arranged in the vertical direction; The ultraviolet lamp tubes are arranged in two or more layers and have a layer spacing; The single-layer UV lamp tubes are arranged in parallel and a tube spacing is formed between two UV lamp tubes; Two adjacent layers of ultraviolet lamp tubes are arranged in a staggered manner so that one layer of ultraviolet lamp tubes is exactly located within the tube spacing of another layer of ultraviolet lamp tubes; or two adjacent layers of ultraviolet lamp tubes are arranged in a cross manner so that one layer of ultraviolet lamp tubes is exactly crossed with another layer of ultraviolet lamp tubes in space.

7. The low-carbon garbage leachate full-volume treatment system according to claim 2 is characterized in that: The gas-liquid separator is composed of a group of obliquely installed corrugated plates, the horizontal spacing between adjacent corrugated plates is 1-10 mm, and the corrugated plates are coated with TiO2 / MnO2 composite catalyst.

8. The low-carbon garbage leachate full-volume treatment system according to claim 2 is characterized in that: In the ozone reaction zone, the position where the ozone source is connected to the gas inlet of the ozone reaction zone is higher than the sewage liquid level, a conical groove is provided at the bottom of the reaction tower shell, and the water outlet pipe is provided at the bottom of the conical groove; or the position where the ozone source is connected to the gas inlet of the ozone reaction zone is below the liquid level, and a transparent suspended spherical filler is placed in the sewage, the suspended spherical filler has a porous structure and amino or carboxyl functional groups are introduced on the surface; the pore structure contains mesopores.

9. The low-carbon garbage leachate full-volume treatment system according to claim 2 is characterized in that: The water inlet pipes of the first advanced oxidation reactor and the second advanced oxidation reactor are also connected to a Fenton reagent adding device; a valve is provided between the Fenton reagent adding device and the water inlet pipe; whether to open the valve is determined according to the COD value of the influent water in the water inlet pipe, so as to determine whether to add Fenton reagent to the influent water.

10. The low-carbon garbage leachate full-volume treatment system according to claim 2 is characterized in that: The first water pool and the second water pool of the nanofiltration concentrated liquid treatment unit are respectively provided with pH adjusting devices for adjusting the pH of the water in the first water pool to 3.0-5.0 and the pH of the water in the second water pool to 7-8; the third water pool and the fourth water pool of the reverse osmosis concentrated liquid treatment unit are respectively provided with pH adjusting devices for adjusting the pH of the water in the third water pool to 3.0-5.0 and the pH of the water in the fourth water pool to 7-8.

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