CN111362520A

CN111362520A - Landfill leachate treatment system and method

Info

Publication number: CN111362520A
Application number: CN202010279239.2A
Authority: CN
Inventors: 朱斌; 刘伟
Original assignee: Guangdong Zihua Technology Co ltd
Current assignee: Guangdong Zihua Technology Co ltd
Priority date: 2020-04-10
Filing date: 2020-04-10
Publication date: 2020-07-03

Abstract

The invention discloses a landfill leachate treatment system and a method. The system comprises an ozone oxidation tank, an MBR biochemical tank and a humic acid separation system, wherein the humic acid separation system, the ozone oxidation tank and the MBR biochemical tank are sequentially communicated along the flow direction of the landfill leachate. The method comprises the steps of removing humic acid in the landfill leachate through a precipitation separation step, and then decomposing residual humic acid in the landfill leachate through the strong oxidation of ozone to improve the biodegradability of sewage; and then the leachate is subjected to biological denitrification and COD degradation. The garbage leachate treatment system and the method provided by the invention have the advantages of simple process, low construction investment and operation cost, extremely low concentration of pollutants such as humic acid, salts and the like, capability of properly treating the garbage leachate, and good environmental benefit and economic benefit.

Description

Landfill leachate treatment system and method

Technical Field

The invention relates to the field of sewage treatment, in particular to a garbage leachate treatment system and method.

Background

The components of the landfill leachate are very complex, the pollution of organic matters is various, and the water quality characteristics are influenced by various factors such as garbage components, landfill time, climate conditions and the like. The landfill leachate is mainly characterized by various organic pollutants, including low molecular fatty acids, medium molecular fulvic acids, high molecular humic substances, ammonia nitrogen, heavy metals and the like. The landfill leachate has high pollutant concentration, wide variation range, COD value from thousands to tens of thousands mg/L, ammonia nitrogen concentration from hundreds to thousands of mg/L, and great treatment difficulty.

The garbage leachate treatment process is mainly as follows: biological treatment technology, physical and chemical treatment technology, membrane treatment technology, advanced oxidation treatment technology, evaporation treatment technology, various combinations of the technologies and the like. Common combined processes include UASB + SBR + CMF + RO, MBR + NF, UASB + MBR + RO, etc., and non-membrane processes UASB + A/O + advanced oxidation + BAF and evaporation processes.

The first three processes are collectively called as a 'double-membrane process', namely, an anaerobic reactor (landfill leachate treatment can be not used) and a membrane bioreactor are firstly used for treating biochemically degradable organic matters, ammonia nitrogen, total nitrogen and the like in sewage to the discharge standard, and NF or RO is used for filtering, so that humic acid and other substances which are difficult to biochemically degrade are trapped in membrane concentrated solution. The membrane concentrated solution accounts for about 15-30% of the raw solution of the landfill leachate. Because the membrane filtration is a physical filtration process and cannot eliminate pollution factors, the concentration of pollutants such as humic acid, salts and the like is higher, and the pollutants are more difficult to treat, which is the biggest defect of the double-membrane process. In order to solve the problem of the membrane concentrated solution, domestic and foreign experts have conducted extensive research, and the current typical membrane concentrated solution treatment method comprises the following steps: recharging process, furnace spraying process, advanced oxidation technology and the like. The recharging process method is simple, but long-term recharging can cause unstable garbage piles, humic acid and other difficultly-degraded pollutants in the percolate are continuously accumulated, the concentration is increased, and the treatment effect of a biochemical system is influenced. The furnace spraying process is mainly used for treating percolate in a garbage incineration plant, the water spraying amount needs to be strictly controlled, and the working condition of the incinerator is influenced by large water amount. Meanwhile, the salt content in the concentrated solution is high, and the back spraying to the hearth also has influence on the service life of the fire grate. The concentrated solution can be oxidized by Fenton method, ozone oxidation method, electrochemical method, etc. The advanced oxidation method is difficult to directly treat the sewage to reach the standard, and usually combines a plurality of oxidation technologies to be used together with a biochemical system. The advanced oxidation reaction conditions are harsh, the treatment cost is high, the treatment effect is unstable, and at present, few cases of success exist.

The non-membrane process UASB + A/O + advanced oxidation + BAF takes a UASB + A/O biochemical treatment system as a main body to reduce biochemical pollutant components in water, takes the advanced oxidation + BAF as an advanced treatment system to change the molecular structure of humic acid substances which are difficult to degrade in percolate through the advanced oxidation action, improves the biodegradability of the substances, and then biochemically degrades through a BAF (aeration biological filter) to reach the standard for discharge. The process has no concentrated water discharge, but the advanced oxidation reaction conditions are harsh, the treatment cost is high, and the treatment effect is unstable.

The evaporation process is a leachate treatment process taking an MVC evaporator as a core. The landfill leachate has complex components and high hardness, and the structure is very easy to realize by adopting an evaporation process, so that an evaporator needs to be descaled and cleaned every day. Such frequent cleaning results in a large amount of reagent consumption and labor costs, and the process has been phased out.

The difficulty of landfill leachate treatment is high, and the existing treatment process can not solve the problem completely. Therefore, research and development of a method capable of properly treating the landfill leachate are important in the research of the landfill leachate treatment industry.

Disclosure of Invention

The invention aims to provide a system and a method for treating landfill leachate, which have the advantages of difficult treatment of a membrane-free concentrated solution, no need of a complex process for removing humic acid by advanced oxidation, low construction investment and operation cost, simple flow, capability of properly treating the landfill leachate and good environmental benefit and economic benefit.

In order to achieve the purpose, the invention provides a landfill leachate treatment system which comprises an ozone oxidation tank, an MBR biochemical tank and a humic acid separation system, wherein the humic acid separation system, the ozone oxidation tank and the MBR biochemical tank are sequentially communicated along the flow direction of the landfill leachate.

As a further improvement of the invention, the humic acid separation system comprises a PH regulating tank, a precipitation tank, a first coagulation tank, a first sedimentation tank, a reaction tank, a second coagulation tank and a second sedimentation tank which are connected in sequence; the precipitation pool is provided with a barium salt feeding device.

As a further improvement of the invention, a first intermediate tank is connected between the humic acid separation system and the ozone oxidation tank; the pond is kept in for sewage in first middle pond, be equipped with agitating unit in the pond is kept in to sewage, the pond is kept in to sewage passes through the sewage elevator pump and is connected with the ozone oxidation pond.

As a further improvement of the invention, a second intermediate tank is connected between the ozone oxidation tank and the MBR biochemical tank; the second middle tank is an ozone removal tank, and a stirring device is arranged in the ozone removal tank.

As a further improvement of the invention, the device also comprises a UASB reaction tank, and the UASB reaction tank is communicated with the humic acid separation system in sequence along the flow direction of the landfill leachate.

As a further improvement of the invention, the upper part of the UASB reaction tank is provided with a water outlet, a reflux device and a three-phase separator, and the lower part of the UASB reaction tank is provided with a water distribution device; the backflow device comprises a first backflow pump, a water inlet of the first backflow pump is connected with a backflow port of the UASB reaction tank, and a water outlet of the first backflow pump is connected with a water inlet of the water distribution device.

As a further improvement of the invention, the device also comprises a sludge treatment system, wherein the sludge treatment system comprises a sludge tank, a sludge lifting pump, a sludge dewatering machine and a dosing device, and the sludge tank is connected with the bottoms of the UASB reaction tank, the humic acid separation system and the MBR biochemical tank.

As a further improvement of the invention, the ozone oxidation tank is a closed reaction tank, and a diversion folded plate is arranged in the ozone oxidation tank; the bottom of the ozone oxidation tank is provided with a titanium alloy aeration head; the ozone oxidation pond is connected with an ozone generator and a tail gas treatment device.

As a further improvement of the invention, the MBR biochemical tank comprises a fan, and a primary denitrification tank, a primary nitrification tank, a secondary denitrification tank, a secondary nitrification tank and a membrane tank which are sequentially connected along the water flow direction; an ultrafiltration device is arranged in the membrane tank; the fan is connected with the primary nitrification tank and the secondary nitrification tank through pipelines; the second-stage nitrification tank is connected with the first-stage denitrification tank through a second reflux pump, and the membrane tank is connected with the first-stage denitrification tank through a sludge reflux pump; the ultrafiltration device is connected with a water producing pump.

In order to achieve the above object, the present invention further provides a landfill leachate treatment method, comprising the following steps: removing humic acid in the landfill leachate through a precipitation separation step, and then decomposing residual humic acid in the landfill leachate through strong oxidation of ozone to improve the biodegradability of sewage; and then the leachate is subjected to biological denitrification and COD degradation.

As a further improvement of the invention, before the precipitation separation step, the landfill leachate is firstly introduced into a UASB reaction tank for anaerobic digestion reaction.

Advantageous effects

Compared with the prior art, the garbage leachate treatment system and the method have the advantages that:

1. compared with the existing landfill leachate process, the technical scheme does not adopt a membrane advanced treatment system, so that the problem of treatment of membrane concentrated solution does not exist, and the concentration of pollutants such as humic acid, salts and the like is extremely low. In addition, the complex process of advanced oxidation treatment of humic acid is saved, and the operation is simple. The investment of equipment at the early stage is low, the treatment cost is low, and the treatment cost is about 80-90% of that of the existing treatment process. Compared with the existing humic acid treatment process of the landfill leachate, the method adopting humic acid precipitation separation has the advantages of small investment, low operation cost and no secondary pollution.

2. Humic acid organic matters which are difficult to be biochemically degraded are effectively removed, so that the tank capacity of biochemical treatment structures of an MBR system can be reduced by 15-20%, and the construction cost is reduced.

3. When the humic acid in the landfill leachate is separated, about 10 to 20 percent of ammonia nitrogen is removed in the form of humic acid barium ammonium complex salt, so that the carbon source and the oxygen demand required by biological denitrification are reduced, and the operation cost is saved.

The invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, which illustrate embodiments of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a landfill leachate treatment system;

FIG. 2 is a schematic structural view of a UASB reaction tank;

fig. 3 is a schematic structural diagram of an ozone oxidation tank.

Detailed Description

Embodiments of the present invention will now be described with reference to the accompanying drawings.

Examples

Referring to fig. 1 to 3, a landfill leachate treatment system includes a regulating tank 1, a UASB reaction tank 2, a humic acid separation system 3, a first intermediate tank 4, an ozone oxidation tank 5, a second intermediate tank 6, and an MBR biochemical tank 7, which are connected in sequence.

A stirring device and a sewage lifting pump are arranged in the adjusting tank 1. The hydraulic retention time of the adjusting tank 1 is more than or equal to 2 days.

The upper part of the UASB reaction tank 2 is provided with a water outlet 21, a reflux device 22 and a three-phase separator 23, and the lower part of the UASB reaction tank 2 is provided with a water distribution device 24. The backflow device 22 comprises a first backflow pump, a water inlet of the first backflow pump is connected with a backflow port of the UASB reaction tank 2, and a water outlet of the first backflow pump is connected with a water inlet of the water distribution device 24. The UASB reaction tank 2 is an option of the system according to the water quality condition of the inlet water, and can be selectively arranged or not arranged. The ascending flow velocity of the water flow of the UASB reaction tank 2 is 0.5-1.0 m/h. The volume load of the UASB reaction tank 2 is controlled at 8kgCOD/m³D is less than 1:1 to 2:1 in aspect ratio.

The humic acid separation system 3 comprises a PH adjusting tank 37, a precipitation tank 31, a first coagulation tank 32, a first sedimentation tank 33, a reaction tank 34, a second coagulation tank 35 and a second sedimentation tank 36 which are connected in sequence. The pH adjusting tank 37 is provided with an acid/alkali feeding device 371. The precipitation tank 31 is provided with a barium salt feeding device 311. The first coagulation tank 32 is provided with a first coagulant adding device 321 and a first flocculant adding device 322. The reaction tank 34 is provided with a sulfate feeding device 341. The second coagulation tank 35 is provided with a second coagulant feeding device 351 and a second flocculant feeding device 352.

A first intermediate tank 4 is connected between the humic acid separation system 3 and the ozone oxidation tank 5. The first intermediate tank 4 is a temporary sewage storage tank, and the hydraulic retention time is more than or equal to 1 h. The sewage temporary storage tank is internally provided with a stirring device and is connected with the ozone oxidation tank 5 through a sewage lifting pump.

A second intermediate tank 6 is connected between the ozone oxidation tank 5 and the MBR biochemical tank 7. The second intermediate tank 6 is an ozone removal tank, the hydraulic retention time is more than or equal to 1h, and a stirring device is arranged in the ozone removal tank.

The ozone oxidation tank 5 is a closed reaction tank, and the effective water depth in the tank is 5 m. A deflector 51 is provided inside the tank. The bottom of the ozone oxidation tank 5 is provided with a titanium alloy aeration head. The ozone oxidation tank 5 is connected with an ozone generator 52 and a tail gas treatment device 53. The ozone generator 52 is connected to the titanium alloy aeration head. The adding amount of the ozone is 10mg/L-100mg/L, and the sewage retention time is 0.5h-1.5 h.

The MBR biochemical tank 7 comprises a fan 76, and a primary denitrification tank 71, a primary nitrification tank 72, a secondary denitrification tank 73, a secondary nitrification tank 74 and a membrane tank which are sequentially connected along the water flow direction. An ultrafiltration device 75 is provided in the membrane tank. The blower 76 is connected with the primary nitrification tank 72 and the secondary nitrification tank 74 through pipelines. The second-stage nitrification tank 74 is connected with the first-stage denitrification tank 71 through a second reflux pump, and the membrane tank is connected with the first-stage denitrification tank 71 through a sludge reflux pump. The ultrafiltration device 75 is connected with a water producing pump. The blower 76 blows air into the primary nitrification tank 72 and the secondary nitrification tank 74. And stirring devices are arranged in the two-stage denitrification tank 71. Wherein the DO concentration is controlled below 0.5mg/L in the two-stage denitrification reaction, and the DO concentration is controlled between 2 and 6mg/L in the two-stage nitrification reaction. The sludge concentration of the biochemical pool is 15-35g/L, the organic sludge load is 0.05-0.11 kgCOD/kgMLSS.d, and the total nitrogen sludge load is 0.02-0.06kgTN/kgMLSS d, the membrane flux of the ultrafiltration membrane is controlled to be 70L/m²∙ h or less.

This landfill leachate processing system still includes sludge treatment system 8, and sludge treatment system 8 includes sludge impoundment, mud elevator pump, sludge dewaterer and charge device, and the sludge impoundment is connected with UASB retort 2, humic acid piece-rate system 3's sedimentation tank and MBR biochemical pond 7's membrane cisterna bottom. The hydraulic retention time of the sludge tank is more than or equal to 1d, and the sludge dewatering machine is a centrifugal dewatering machine.

The landfill leachate treatment method comprises the following steps: firstly, the landfill leachate is introduced into the UASB reaction tank 2 to carry out anaerobic digestion reaction, then humic acid in the landfill leachate is removed through a precipitation separation step, and then residual humic acid in the landfill leachate is decomposed through strong oxidation of ozone, so that the biodegradability of sewage is improved. And then the leachate is subjected to biological denitrification and COD degradation.

When the precipitation separation is carried out, firstly, the PH of the landfill leachate is regulated in a PH regulating tank 37: the PH value of the landfill leachate is adjusted by adding acid and alkali, wherein the acid is inorganic acid or organic acid, the alkali is sodium hydroxide, potassium hydroxide or calcium hydroxide and the like, and the PH value is 6-9. And then reacting barium salt serving as a precipitating agent with humic acid in a precipitation tank 31 to generate a humic acid barium suspension, wherein the barium salt is a barium salt solution or a water-soluble barium salt solid, and the adding concentration of the barium salt is 500mg/L-5000 mg/L. The precipitation reaction time is 0.5h-2.0 h. And then, a coagulant and a flocculant are sequentially added into the first coagulation tank 32, so that the humic acid barium suspension forms flocculent alumen ustum for facilitating precipitation and separation, and the reaction time is 10-20 min. And settling the barium humate sludge in the first sedimentation tank 33 by adopting a standing mode to separate the barium humate sludge from the landfill leachate, wherein the settling separation time is 1-2.5 h. Sulfate is added into the reaction tank 34, and barium ions and sulfate ions react to generate barium sulfate. And (3) the garbage filtrate enters a second coagulation tank 35, coagulant and flocculant are added again to enable the humic acid barium suspension to further form flocculent alum floc, the generated barium sulfate is precipitated in a second precipitation tank 36, and the standing and separating time is 1-2.5 hours. The second coagulation aims at increasing the precipitation speed of barium sulfate and improving the treatment effect.

The coagulant is polyaluminium chloride, and the flocculating agent is polyacrylamide. The adding mass concentration of the polyaluminium chloride is 100mg/L-1000mg/L, and the adding mass concentration of the polyacrylamide is 1mg/L-5 mg/L. The sulfate is sulfate solution or water-soluble sulfate solid, the adding mass concentration is 100mg/L-500mg/L, and the reaction time is 10min-30 min.

In this embodiment, the raw water quality of the landfill leachate is: COD 25000mg/L, NH₃-N1430 mg/L, TN 1700 mg/L. The treatment method of the system is used for treating the landfill leachate, and the treatment process and the treatment result are as follows:

the landfill leachate firstly enters an adjusting tank 1, the hydraulic retention time of the adjusting tank is 7 days, and the water quality and the water quantity of the leachate are balanced. The landfill leachate of the regulating reservoir 1 is input into a UASB reaction tank 2 through a lift pump for further treatment.

After the garbage percolate enters the UASB reaction tank 2, the volume load of the UASB reaction tank 2 is controlled at 6kgCOD/m³D, the upward flow velocity of the reaction tank is 0.8m/h, the height-diameter ratio of the tank body is 2:1, and the COD removal efficiency is 75%. The effluent quality of the UASB reaction tank 2 is COD 6250mg/L and NH₃-N＝1360mg/L，TN＝1550mg/L。

The effluent of the UASB reaction tank 2 enters a humic acid separation system 3, and most humic acid substances in the sewage are removed by a chemical precipitation mode. The sewage quality after the reaction is as follows: COD 4060mg/L, TN 1330mg/L, NH₃-N＝1156mg/L。

And then the sewage is transferred into a first intermediate tank 4, the hydraulic retention time of the first intermediate tank 4 is 4 hours, a stirring device and a sewage lifting pump are arranged in the first intermediate tank 4, and the sewage lifting pump of the first intermediate tank 4 is connected with an ozone oxidation tank 5.

The sewage in the first intermediate pool 4 is sent into the ozone oxidation pool 5 through a sewage lifting pump, and the residual humic acid in the percolate is decomposed through the strong oxidation effect of the ozone, so that the biodegradability of the sewage is improved. The adding concentration of the ozone is 100mg/L, and the reaction time is 1.0 h.

The effluent after the ozone reaction is then transferred into a second intermediate tank 6, and the incompletely reacted ozone remained in the water in the second intermediate tank 6 can be attenuated and removed by itself so as to avoid damaging the activated sludge in the MBR biochemical tank 7 at the later stage. The hydraulic retention time of the second intermediate pool 6 is 2h, and a stirrer is arranged in the second intermediate pool.

The effluent of the second intermediate tank 6 flows into an MBR biochemical tank 7 for decarburization, denitrification and nitration treatment, and COD, TN and NH in the leachate are degraded₃-N and the like contamination factors. Then enters a membrane pool to be filtered by an ultrafiltration device 75, and the effluent of the produced water pump reaches the standard and is discharged. In the step, the leachate enters a primary denitrification tank 71, a primary nitrification tank 72, a secondary denitrification tank 73 and a secondary nitrification tank 74 in sequence to perform decarburization, denitrification and nitrification reactions. Wherein the DO concentration is controlled to be below 0.5mg/L in the two-stage denitrification reaction, and the DO concentration is controlled to be 2-4mg/L in the two-stage nitrification reaction; meanwhile, the sludge concentration of the MBR biochemical tank 7 is controlled to be 15-20g/L, the organic sludge load is 0.06 kgCOD/kgMLSS.d, the total nitrogen sludge load is 0.04 kgTN/kgMLSS.d, the ammonia nitrogen sludge load is 0.03 kgTN/kgMLSS.d, and the membrane flux of the ultrafiltration membrane is controlled to be 60L/m²∙ h or less. The leachate is subjected to biological denitrification and COD degradation in an MBR biochemical tank 7, the removal rate of COD is more than 98%, TN and NH are performed₃the-N removal rate reaches more than 99 percent. The water quality of the effluent of the MBR biochemical tank 7 is COD which is 85mg/L and NH₃-N-9 mg/L, TN-15 mg/L. The effluent quality meets the standard requirements of Table 2 of the national Standard of pollutant control Standard of municipal solid waste landfill (GB16889-2008), COD is less than or equal to 100mg/L, TN is less than or equal to 40mg/L, and NH₃-N≤25mg/L。

Sludge discharged from the UASB reaction tank 2, the humic acid separation system 3 and the MBR biochemical tank 7 enters a sludge tank of a sludge treatment system 8, is conveyed to a sludge dewatering machine by a sludge lifting pump for dewatering, and is conveyed to a garbage incinerator for treatment.

The present invention has been described in connection with the preferred embodiments, but the present invention is not limited to the embodiments disclosed above, and is intended to cover various modifications, equivalent combinations, which are made in accordance with the spirit of the present invention.

Claims

1. The utility model provides a landfill leachate processing system, includes ozone oxidation pond (5) and MBR biochemical pond (7), its characterized in that still includes humic acid piece-rate system (3), ozone oxidation pond (5) and MBR biochemical pond (7) communicate along landfill leachate flow direction in proper order.

2. The landfill leachate treatment system according to claim 1, wherein the humic acid separation system (3) comprises a PH adjusting tank (37), a precipitation tank (31), a first coagulation tank (32), a first sedimentation tank (33), a reaction tank (34), a second coagulation tank (35) and a second sedimentation tank (36) which are connected in sequence; the precipitation tank (31) is provided with a barium salt feeding device (311).

3. A landfill leachate treatment system according to claim 1, wherein a first intermediate tank (4) is connected between the humic acid separation system (3) and the ozone oxidation tank (5); pond (4) are the pond of keeping in sewage in the middle of first, be equipped with agitating unit in the pond of keeping in sewage, the pond of keeping in sewage passes through the sewage elevator pump and is connected with ozone oxidation pond (5).

4. The landfill leachate treatment system of claim 1, wherein a second intermediate tank (6) is connected between the ozone oxidation tank (5) and the MBR biochemical tank (7); the second intermediate tank (6) is an ozone removal tank, and a stirring device is arranged in the ozone removal tank.

5. The landfill leachate treatment system according to claim 1, further comprising a UASB reactor tank (2), wherein the UASB reactor tank (2) is in communication with the humic acid separation system (3) in sequence along the landfill leachate flow direction.

6. The landfill leachate treatment system according to claim 5, wherein the UASB reaction tank (2) is provided with a water outlet (21), a reflux device (22) and a three-phase separator (23) at the upper part thereof, and the UASB reaction tank (2) is provided with a water distribution device (24) at the lower part thereof; the backflow device (22) comprises a first backflow pump, a water inlet of the first backflow pump is connected with a backflow port of the UASB reaction tank (2), and a water outlet of the first backflow pump is connected with a water inlet of the water distribution device (24).

7. The landfill leachate treatment system according to claim 1, wherein the ozone oxidation tank (5) is a closed reaction tank, and a diversion flap (51) is arranged in the ozone oxidation tank; the bottom of the ozone oxidation tank (5) is provided with an aeration head; the ozone oxidation pond (5) is connected with an ozone generator (52) and a tail gas treatment device (53).

8. The landfill leachate treatment system according to claim 1, wherein the MBR biochemical tank (7) comprises a fan (76) and a primary denitrification tank (71), a primary nitrification tank (72), a secondary denitrification tank (73), a secondary nitrification tank (74) and a membrane tank which are connected in sequence along the water flow direction; an ultrafiltration device (75) is arranged in the membrane tank; the fan (76) is connected with the primary nitrification tank (72) and the secondary nitrification tank (74) through pipelines; the secondary nitrification tank (74) is connected with the primary denitrification tank (71) through a second reflux pump, and the membrane tank is connected with the primary denitrification tank (71) through a sludge reflux pump; the ultrafiltration device (75) is connected with a water producing pump.

9. A landfill leachate treatment method is characterized by comprising the following steps: removing humic acid in the landfill leachate through a precipitation separation step, and then decomposing residual humic acid in the landfill leachate through strong oxidation of ozone to improve the biodegradability of sewage; and then the leachate is subjected to biological denitrification and COD degradation.

10. The landfill leachate treatment method according to claim 9, wherein the landfill leachate is introduced into the UASB reaction tank (2) for anaerobic digestion reaction before the precipitation separation step.