CN105060607A - Landfill leachate treatment method - Google Patents

Abstract

The invention relates to a treatment method of landfill leachate, which comprises the following steps in sequence: pretreatment consisting of flocculation precipitation, ammonia stripping, ammonia absorption, pH adjustment and filtrate temperature adjustment not lower than 15°C, primary anoxic - Aerobic biological treatment, primary precipitation treatment, chemical oxidation treatment, secondary precipitation treatment, secondary anoxic-aerobic biological treatment, tertiary precipitation treatment and disinfection treatment. Aiming at the characteristics of the leachate of urban domestic waste landfills, the present invention adopts a combined physicochemical-biochemical treatment system to ensure the stable and efficient operation of the whole system, and finally make the landfill leachate reach the "Pollution Control Standards for Domestic Waste Landfills (GB16889-2008 )"Emission Standards.

Description

A kind of landfill leachate treatment method

technical field

The invention relates to a treatment method for leachate of sanitary landfills of urban domestic garbage, and belongs to the technical field of environmental engineering sewage treatment.

Background technique

Landfill leachate refers to the moisture contained in the garbage itself in the landfill, the rain and snow water and other moisture entering the landfill, deducting the saturated water holding capacity of the garbage and the covering soil, and passing through the garbage layer and the covering soil. A high concentration wastewater. High concentration of ammonia nitrogen is one of the water quality characteristics of leachate, and the concentration of ammonia nitrogen in leachate generally ranges from tens to thousands of milligrams per liter. According to the law of water quality change of leachate produced in domestic solid waste landfills, with the prolongation of landfill time, the concentration of ammonia nitrogen in leachate tends to increase, and its biochemical properties decrease.

The character height should be between 3.5 mm and 4.5 mm. The main processes of the first category are as follows:

① Membrane bioreactor (MBR) + nanofiltration (NF) + reverse osmosis (RO) process, the utility model patent number for this process is: ZL200810056984.X;

② Membrane bioreactor (MBR) + nanofiltration (NF) process, the patent authorization announcement number for this process is: CN101244880B;

③Ammonia stripping + membrane bioreactor (MBR) + nanofiltration (NF) process, the invention patent number of this process is: ZL200610034517.8;

The main processes of the second category are as follows:

Disc type reverse osmosis membrane (DTRO) process, the invention patent number of this process is: ZL200510102945.5;

The main processes of the third category are as follows:

Evaporation + ion exchange process, the invention patent number of this process is: ZL200710031584.9;

The main processes of the fourth category are as follows:

Biological nitrification/denitrification + Fenton oxidation (Fenton) + biological aerated filter (BAF) process, the invention patent number for this process is: ZL200510035132.9.

The first type of treatment process is currently the most widely used process. Nanofiltration (NF) and reverse osmosis (RO) used in this type of process are a physical separation process. The pore size of the reverse osmosis membrane is as small as nanometers. Under pressure, H ₂ O molecules can pass through the RO membrane, while impurities such as inorganic salts, heavy metal ions, organic matter, colloids, bacteria, and viruses in the leachate cannot pass through the RO membrane. The nanofiltration membrane allows substances with a relative molecular weight less than 200 to pass through. Ultrafiltration membranes allow substances with relatively larger molecular weights to pass through. In the first category of treatment processes, nanofiltration membranes and ultrafiltration membranes have extremely low interception efficiency for NO ₃ ^- , NO ₂ ^- , NH ₃ , and NH ₄ ⁺ in water; only reverse osmosis membranes can intercept the above four ions. Therefore, in the current membrane process that does not use reverse osmosis, the removal of total nitrogen is entrusted to the nitrification/denitrification treatment in the MBR. If the carbon source in the wastewater is insufficient or the biological nitrification/denitrification is abnormal, then There will be situations where the total nitrogen exceeds the standard. Therefore, reverse osmosis membrane modules are added to the current membrane treatment process to ensure that the total nitrogen in the effluent reaches the standard. Membrane systems all produce concentrates, nanofiltration systems produce about 15% concentrates, and reverse osmosis systems produce about 15% concentrates.

The second major treatment process is the application of butterfly tube reverse osmosis membrane (DTRO) components to trap organic matter, ammonia nitrogen and other pollutants in wastewater on one side of the membrane, and _H2O molecules pass through the reverse osmosis membrane to reach the other side of the membrane , so as to obtain clean water. This process is a purely physical separation process, and the concentrate produced by this type of process is usually greater than 25% of the treatment capacity.

The third type of process: Evaporation + ion exchange process, this process heats landfill leachate to evaporate, produces about 90% distilled water and 10% evaporated concentrated liquid, organic matter, heavy metals and other pollutants in the leachate are concentrated in 10 % of the concentrate. The collected distilled water can reach the discharge standard after being passed through a strong acidic cation exchange resin to remove ammonia nitrogen.

The biggest feature of the fourth category of treatment process is that it does not use ultrafiltration membrane (UF), nanofiltration membrane (NF), reverse osmosis membrane (RO) and other membrane components, so there is no concentrated liquid. This type of process uses traditional biological nitrification and denitrification to remove the total nitrogen in the leachate, and uses (Fenton) oxidation to remove the refractory organic pollutants in the leachate with subsequent biochemical processes.

The technical and economic comparison of the four common types of processes is shown in Table 1:

Table 1 Technical and economic comparison of four major treatment processes

There are two difficulties in leachate treatment: one is to remove total nitrogen, and the other is to reduce the operating cost of per ton of water treatment.

It can be seen from the above table that although the treatment effects of the first, second and third categories of treatment processes are stable and the effluent quality is excellent, the total investment of the project and the cost of per ton of water treatment are high, and the high investment and operation costs will affect the landfill. The operation has brought a heavy economic burden. The fourth type of process has the advantages of low total project investment and low operation cost per ton of water, but the operation of treatment facilities is greatly affected by the environment and the operation and management are more complicated. When the external ambient temperature changes sharply, the fourth category of treatment processes will fluctuate greatly in total nitrogen removal efficiency.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a landfill leachate treatment system with low engineering investment, low operating cost, good treatment effect, wide application range, and easy automatic control and operation.

In order to solve the above-mentioned technical problems, the technical solution proposed by the present invention is a treatment method of landfill leachate, referring to Fig. 1, including pretreatment, primary anoxic-aerobic biological treatment, primary precipitation treatment, chemical oxidation treatment, secondary Precipitation treatment, secondary anoxic-aerobic biological treatment, tertiary precipitation treatment and disinfection treatment process, the detailed steps of each treatment process are as follows:

(1) Pretreatment

Preprocessing includes the following steps in sequence:

(1) Flocculation and precipitation:

Add iron salt flocculant to the landfill leachate for precipitation treatment, the precipitation time is 1-3 hours; during precipitation, appropriate amount of NaOH can be added as needed to adjust the pH of the leachate to 7-9.

(2) One pH adjustment:

The landfill leachate supernatant after precipitation treatment flows into the pH adjustment tank, and NaOH or lime is added to adjust its pH value to 10.5-11.5. While adjusting the pH value, adjust the leachate temperature to not be lower than 10°C; in the environment When the temperature is low, the leachate can be heated to meet the temperature requirement by passing an appropriate amount of high-temperature saturated water vapor into the leachate.

(3) Blow off ammonia nitrogen:

The landfill leachate after PH value adjustment is pumped to the ammonia stripping tower, the leachate flows from the top of the stripping tower to the bottom of the tower, and the air flows from the bottom of the tower to the top of the tower to strip off the ammonia nitrogen in the leachate. The gas-liquid ratio in the stripping tower is 2000-3500; the ammonia-containing nitrogen stripping tail gas flows out from the top of the ammonia stripping tower, and the leachate flows out from the bottom of the ammonia stripping tower.

(4) Absorb ammonia nitrogen:

The tail gas containing ammonia nitrogen blowing off enters from the bottom of the ammonia absorption tower, and the tail gas is discharged at high altitude after being absorbed by acid.

(5) Secondary pH adjustment:

The landfill leachate after blowing off treatment flows into the pH adjustment tank, adding sulfuric acid to adjust the pH value to 7-8.5, and adjust the leachate temperature to not be lower than 15°C; when the ambient temperature is low, an appropriate amount of high-temperature saturated water vapor can be introduced Heating the leachate to meet temperature requirements.

(2) Primary anoxic-aerobic biological treatment

The leachate after pretreatment enters the anoxic-aerobic pool, and the elastic packing is filled in the pool, and the microorganisms attach to the elastic packing to form a biofilm;

Control the dissolved oxygen content in the anoxic pool to not exceed 0.4mg/L, and the hydraulic retention time in the anoxic pool is 2.4 to 7 hours;

The dissolved oxygen content in the aerobic pool is 2-5 mg/L, and the hydraulic retention time is 70-140 hours; under aerobic conditions, nitrifying bacteria are used to convert nitrogen compounds into nitrates;

Set up a reflux pump to return the mixed solution containing nitrate nitrogen in the aerobic tank to the anoxic tank. The reflux ratio is controlled at 4 to 10. The reflux liquid is denitrified in the denitrification tank. Reduce nitrate to gaseous nitrogen and remove total nitrogen and BOD in wastewater.

(3) Primary precipitation treatment

The leachate after the anoxic-aerobic treatment is sedimented in the sedimentation tank, and the supernatant enters the chemical oxidation advanced treatment.

(4) Chemical oxidation advanced treatment

Sulfuric acid is added to adjust the supernatant after the primary precipitation treatment to make the pH = 3, and advanced chemical oxidation treatment is carried out.

The chemical oxidant used in the chemical oxidation treatment is Fenton's reagent, the mass ratio of Fe2 ⁺ and H2O2 in the Fenton's reagent is 0.75: ₁ ～1.2: ₁ , and the addition amount of the Fenton's reagent is Fenton's reagent The mass ratio of hydrogen peroxide to COD in the water to be treated is 0.5:1-2.4:1, and the reaction time is 0.5-1.5 hours.

(5) Secondary precipitation treatment

Add NaOH to the effluent treated with Fenton’s reagent to adjust its pH value to 6-8; add coagulant, the leachate will flocculate and precipitate in the sedimentation tank, and the hydraulic retention time is 1-2 hours; the water after precipitation enters the secondary anoxic- For aerobic treatment, the coagulant can be PAC (polyaluminum chloride).

(6) Secondary anoxic-aerobic biological treatment

The anoxic-aerobic biological treatment is carried out in a reinforced concrete sewage tank or in a steel container, and the sewage pool or steel container is filled with elastic fillers, and microorganisms attach to the elastic fillers to form biofilms.

Control the dissolved oxygen content in the anoxic process to not exceed 0.4mg/L, and the hydraulic retention time of the anoxic pool is 1.5 to 3 hours;

The dissolved oxygen content in the aerobic process is 2-5mg/L, and the hydraulic retention time is 30-60 hours;

The mixed liquid in the aerobic process is returned to the anoxic process, and the reflux ratio is controlled at 3 to 6. The reflux liquid is denitrified in the denitrification tank, and the nitrate is reduced to gaseous nitrogen by denitrifying bacteria under anoxic conditions. Remove total nitrogen and BOD in wastewater.

(7) Three precipitation treatments

After the secondary anoxic-aerobic biological treatment, the leachate settles in the sedimentation tank, and the supernatant enters the disinfection treatment.

(8) Disinfection treatment

The supernatant after three precipitations enters the disinfection tank and is disinfected with chlorine dioxide.

There can also be a sludge treatment process. The sludge is dehydrated by a filter press and then backfilled to the landfill, and the filtrate is returned to the raw water inlet of the leachate for treatment.

As a further improvement, part of the sludge in the sludge tank is returned to the two anoxic tanks respectively, and the sludge return ratio is determined according to the nitrogen kinetic formula, which can effectively control the concentration of activated sludge and reduce the amount of sludge treatment.

The leachate from the _Heimifeng landfill in Changsha was used as influent water for pilot test. The treatment capacity was 300L/d. ), NH ₃ -N (1500mg/L), TN (1800mg/L), pH (6.0-8.5) and chromaticity concentration (1100 times), adopt the technical scheme of the present invention to carry out by a definite date 12 months processing test, after processing The average value of effluent quality is BOD ₅ (25mg/L), CODCr (90mg/L), SS (25mg/L), NH ₃ -N (20mg/L), TN (35mg/L), pH (6.0-8.5 ) and chromaticity concentration (35 times), as shown in Table 2.

Table 2 Influent water quality of landfill leachate treatment station

serial number Pollutant name unit Influent water quality Water quality Removal rate (%) 1 BOD ₅ mg/L 3500 25 99.29 2 COD _Cr mg/L 10000 90 99.10 3 SS mg/L 500 25 95.00 4 NH ₃ -N mg/L 1500 20 98.67 5 TN mg/L 1800 35 98.06 6 pH - 6.0-8.5 6.0-8.5 7 Chroma Dilution factor 1100 35 96.8

It can be seen from Table 2 that the removal rate of the above typical pollution factors by adopting the technical solution of the present invention is high, wherein the removal rates of typical high-concentration BOD ₅ , COD, NH ₃ -N and TN in landfill leachate are as high as 99.29%, 99.10%, 98.67%, and 98.06. Therefore, the application of this process can reach the pollutant discharge mass concentration limit of "Pollution Control Standards for Domestic Waste Landfill Sites" (GB16889-2008). Compared with existing treatment methods, the present invention has the following beneficial effects:

1. Using iron salt for coagulation pretreatment can greatly reduce the cost of subsequent process treatment;

2. Due to the use of heating and temperature adjustment, the biological treatment is less affected by environmental factors and the operation is stable;

3. The total project investment, maintenance cost and per ton water treatment cost are lower than nanofiltration (NF) and reverse osmosis (RO) process, butterfly tube reverse osmosis membrane (DTRO) process and evaporation + ion exchange process;

4. The operation stability is better than the traditional biological nitrification and denitrification process, and the operation is simple and the management is convenient.

The invention has the advantages of low engineering cost, simple operation and maintenance, low follow-up cost, and low cost per ton of water treatment; the discharge of sewage after treatment meets national standards, and the treatment effect is good; the effluent treatment reaches the standard. The management of the whole sewage treatment system is simple and convenient, and the invention can be widely used in the treatment of landfill leachate and domestic sewage.

Description of drawings

Fig. 1 is a process flow diagram of the present invention

Fig. 2 is a schematic diagram of a specific embodiment of the present invention

In Figure 2:

A——sedimentation tank; 1-leachate raw water inlet pipe, 2-iron salt dosing pipe, 3-alkali dosing pipe; 4-sedimentation tank outlet pipe; 5-sedimentation tank mud discharge pipe;

B——pH adjustment pool; 6—steam heating pipeline, 7—alkali dosing pipeline;

C——Ammonia stripping tower; booster pump, 9-leachate delivery pipe, 10-ammonia tail gas delivery pipe, 11-leachate discharge pipe, 43-air inlet;

D——ammonia absorption tower; 12—purification tail gas discharge pipe;

E——pH adjustment tank; 13-H2SO4 dosing pipe; 14-steam heating pipe;

F—_anoxic pool; 15-leachate inlet pipe;

G——Aerobic pool; 16—Air pipe; 17—Mixed liquid return pipe;

H——sedimentation tank; 18—supernatant liquid outlet pipe, 19—sedimented sludge discharge pipe;

I——Fenton chemical oxidation reactor; 20-H2SO4 dosing pipe, 21-Fenton reagent dosing pipe, 22-reflux pump, 23-reflux pipeline, 24-Fenton oxidation reactor outlet pipe;

J——sedimentation tank; 25-NaOH dosing pipe, 26-PAC dosing pipe, 27-supernatant liquid outlet pipe, 28-settled sludge discharge pipe;

K—anoxic pool; 30—reflux pipe in the nitrification pool;

L——aerobic pool; 29—air pipeline;

M——Sedimentation tank; 31—Supernatant outlet pipe, 32—Sludge discharge pipe, 33—Sludge pump, 34—Sludge pipe;

N—disinfection pool; 35-chlorine dioxide dosing pipe, 36-discharging pipe;

O——sludge storage tank; 37-return sludge pipe, 38-return sludge pipe;

P——sludge filter press; 39—sludge pump inlet pipe; 40—sludge pump; 41—filter press inlet pipe, 42—press filtrate discharge pipe.

Detailed ways

Below in conjunction with Fig. 2 illustrate the specific embodiment of landfill leachate treatment method of the present invention:

The leachate enters the sedimentation tank A through the leachate raw water inlet pipe 1, and iron salt flocculant is added to the leachate in the leachate raw water inlet pipe 1 through the iron salt dosing pipe 2 through the pipeline mixer, and at the same time, it is added by alkali as needed. Pipeline 3 adds an appropriate amount of NaOH to leachate raw water inlet pipe 1 to adjust the pH of the leachate to 7-9. The sedimentation time of the leachate in the sedimentation tank A is 1 to 3 hours. The sludge in the sedimentation tank A is discharged into the mud storage tank O through the sedimentation tank sludge discharge pipe 5, and the effluent from the sedimentation tank A enters the pH adjustment tank B through the sedimentation tank outlet pipe 4, and NaOH is added to adjust the osmosis in the tank through the alkali dosing pipe 7. The pH of the filtrate is 10.5 to 11.5. While adjusting the pH, according to the measured temperature of the leachate, an appropriate amount of high-temperature saturated water steam is passed into the pH adjustment tank B through the steam heating pipeline 6 to heat the leachate, so that the leachate before entering the stripping tower The temperature of the leachate should not be lower than 10°C. The leachate in the pH adjustment tank B is transported to the ammonia stripping tower C through the booster pump 8 through the leachate delivery pipe 9, the leachate flows from the top of the ammonia stripping tower C to the bottom of the tower, and the air flows from the bottom of the tower to the top of the tower , blow off the ammonia nitrogen in the leachate, the gas-liquid ratio in the ammonia stripping tower C is 2000-3500, and the stripping tail gas containing ammonia enters the ammonia absorption tower from the top of the ammonia stripping tower C through the ammonia tail gas delivery pipe 10 At the bottom of D, the air enters the lower part of the bottom of the ammonia stripping tower C from the air inlet 43, and the leachate is discharged from the bottom of the ammonia stripping tower C through the leachate discharge pipe ₁₁ into the pH adjustment tank E, in which _H2SO4 Add H ₂ SO ₄ into the dosing pipe 13 to adjust the pH of the leachate between 7 and 8.5, and at the same time, according to the temperature of the leachate in the pool, pass an appropriate amount of high-temperature saturated water vapor through the steam heating pipe 14 to heat the leachate, so that the leachate entering the anoxic The temperature of the leachate in pond F is not lower than 15°C.

The leachate in the pH adjustment pool E enters the anoxic pool F through the leachate inlet pipe 15 . The anoxic pool F is filled with elastic packing, and microorganisms attach to the elastic packing to form a biofilm; the dissolved oxygen content in the anoxic pool is controlled not to exceed 0.4mg/L. An aeration device is installed in the aerobic pool G, and the gas enters through the air pipe 16, and the dissolved oxygen content in the aerobic pool G is controlled at 2-5 mg/L. The ammonia nitrogen in the leachate is oxidized to nitrate nitrogen under the action of nitrifying bacteria and nitrosifying bacteria in the aerobic tank G. The nitrate nitrogen in the aerobic tank G is returned to the anoxic tank F through the mixed liquid return pipe 17, and the denitrification process occurs under the action of the denitrifying bacteria in the anoxic tank F, and the total nitrogen and BOD in the leachate are removed.

After the leachate undergoes the first-stage anoxic-aerobic reaction, it enters the sedimentation tank H from the aerobic tank G for solid-liquid separation, and the supernatant of the sedimentation tank H enters the Fenton chemical oxidation reactor through the supernatant outlet pipe No. 18 I, the sludge in the sedimentation tank H is discharged into the sludge storage tank O through the sedimentation sludge discharge pipe 19.

The oxidant used in the Fenton chemical oxidation reactor I is Fenton’s reagent, which is an oxidation system composed of hydrogen peroxide and catalyst Fe ²⁺ , and the mass ratio of Fe ²⁺ to H ₂ O ₂ in the Fenton’s reagent is 0.75: 1～1.2:1, the mass ratio of hydrogen peroxide in the Fenton’s reagent to COD in the water to be treated is 0.5:1～2.4:1, and the Fenton’s reagent is added to the leachate to be treated by the Fenton’s reagent dosing pipe 21 through the pipeline mixer In this process, H ₂ SO ₄ is added to the leachate to be treated from the H ₂ SO ₄ feeding pipe 20 through a pipeline mixer, and the pH of the leachate is adjusted to be 3. In order to enhance the treatment effect, a reflux pump 22 is provided to guide the fluid from the upper part of the Fenton chemical oxidation reactor 1 back to the lower part.

The outlet water of the Fenton chemical oxidation reactor I enters the sedimentation tank J through the outlet pipe 24 of the Fenton oxidation reactor, and NaOH is added through the NaOH dosing pipe 25 to adjust the pH in the pond to 7-8.5, and PAC (polymerized chlorine) is added through the PAC dosing pipe 26 aluminum) coagulant, the leachate is flocculated and precipitated in the sedimentation tank J, after the precipitation, the supernatant enters the anoxic tank K through the supernatant outlet pipe 27, and the sludge of the sedimentation tank J enters the mud storage tank O through No. 28 pipelines .

The anoxic pool K is filled with elastic packing, and microorganisms attach to the elastic packing to form a biofilm; the dissolved oxygen content in the anoxic pool K is controlled not to exceed 0.4mg/L. An aeration device is installed in the aerobic tank L, and the gas enters through the air pipe 29, and the dissolved oxygen content in the aerobic tank is controlled at 2-5 mg/L. The ammonia nitrogen in the leachate is oxidized to nitrate nitrogen under the action of nitrifying bacteria and nitrosifying bacteria in the aerobic tank L. The nitrate nitrogen in the aerobic pool L is returned to the anoxic pool K through the No. 30 pipeline, and the denitrification process occurs under the action of denitrifying bacteria in the anoxic pool K, and the total nitrogen and BOD in the leachate are removed.

After the leachate undergoes the second-stage anoxic-aerobic reaction, the water from the upper part of the aerobic tank L enters the sedimentation tank M for solid-liquid separation, and the supernatant of the sedimentation tank M enters the disinfection tank N through the supernatant outlet pipe 31. The sludge in the sedimentation tank M is discharged into the sludge storage tank O through the sludge discharge pipe 32 through the sludge pump 33 and through the sludge pipe 34 .

Chlorine dioxide is added into the disinfection pool N through the chlorine dioxide dosing pipe 35 for disinfection, and the disinfected water is discharged up to the standard through the discharge pipe 36.

Part of the sludge in the sludge storage tank O flows back to the anoxic pool F and the anoxic pool K respectively through the return sludge pipe 37 and the return sludge pipe 38, and the remaining sludge enters the sludge pipe 39 and the sludge pump 40 through the sludge pump . Filter press mud inlet pipe 41, dewatered by filter press P, the dehydrated sludge is backfilled to the landfill, and the press filtrate produced by sludge dehydration flows back to the leachate raw water inlet pipe 1 through the press filtrate discharge pipe 42 for treatment .

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. a treatment process for percolate, is characterized in that: comprise pre-treatment, an Anoxybiotic-aerobic biologic process, primary sedimentation process, chemical oxidation treatment, secondary sedimentation process, the process of secondary Anoxybiotic-aerobic biologic, three precipitation process successively and disinfect technique.

2., by the treatment process of a kind of percolate according to claim 1, it is characterized in that:

Described pre-treatment comprises the following steps successively:

Molysite is added, flocculation, precipitation process in percolate;

In percolate supernatant liquor after treatment, add NaOH regulates pH to be 10.5 ~ 11.5, while adjustment pH, heat percolate by passing into appropriate high temperature saturated vapor in percolate, the temperature of the percolate before making to enter stripping tower is not less than 10 DEG C;

Percolate pump delivery is after treatment gone out ammonia to Ammonia blowing-out tower stripping;

Ammonia-containing exhaust enters ammonia absorber, and tail gas is high altitude discharge after acid absorbs;

In the percolate after stripping process, add sulfuric acid, regulate pH to be 7 ~ 8.5, pass into appropriate high temperature saturated vapor according to the temperature of percolate and it is heated, make percolate temperature be not less than 15 DEG C.

3., by the treatment process of a kind of percolate according to claim 1, it is characterized in that:

A described Anoxybiotic-aerobic biologic process is carried out in reinforced concrete sewage pond, and install elastic filler in sewage lagoon, microorganic adhesion forms microbial film in elastic filler;

Control dissolved oxygen content in anoxic pond and be not more than 0.4mg/L, anoxic pond hydraulic detention time 12 ~ 24 hours;

Controlling dissolved oxygen content in Aerobic Pond is 2 ~ 5mg/L, hydraulic detention time 70 ~ 140 hours;

By the mixed-liquor return in Aerobic Pond to anoxic pond, control of reflux ratio is 4 ~ 10.

4., by the treatment process of a kind of percolate according to claim 1, it is characterized in that:

Described chemical oxidation advanced treatment comprises:

Add sulfuric acid and regulate pH=3;

The chemical oxidizing agent that chemical oxidation treatment adopts is Fenton reagent, Fe in described Fenton reagent ²⁺with H ₂o ₂mass ratio be 0.75: 1 ~ 1.2: 1, the add-on of described Fenton reagent is that in Fenton reagent, in hydrogen peroxide and pending water, COD mass ratio is 0.5: 1 ~ 2.4: 1;

Reaction times is 0.5 ~ 1.5 hour;

Through water outlet adjust ph to 6 ~ 8 of Fenton reagent process.

5. by the treatment process of a kind of percolate according to claim 1, it is characterized in that: the hydraulic detention time of described secondary sedimentation process is 1 ~ 2 hour.

6., by the treatment process of a kind of percolate according to claim 1, it is characterized in that:

The process of described secondary Anoxybiotic-aerobic biologic is carried out in reinforced concrete sewage pond or in Steel Vessel, and load elastic filler in sewage lagoon or Steel Vessel, microorganic adhesion forms microbial film in elastic filler;

The dissolved oxygen content controlling anoxic operation is not more than 0.4mg/L, anoxic pond hydraulic detention time 1.5 ~ 3 hours;

Control aerobic in-process dissolved oxygen content at 2 ~ 5mg/L, hydraulic detention time 30 ~ 60 hours;

By the mixed-liquor return of aerobic in-process to anoxic operation, control of reflux ratio is 3 ~ 6.

7. by the treatment process of a kind of percolate according to claim 1, it is characterized in that: use dioxide peroxide disinfection.

8. by the treatment process of a kind of percolate according to claim 1, it is characterized in that: also comprise sludge treatment technique, mud is backfilled to landfill yard after being dewatered by pressure filter.

9. by the treatment process of the arbitrary described a kind of percolate of claim 1 ~ 8, it is characterized in that: biological treatment adopts activated sludge process, according to nitrogen dynamics formula determination return sludge ratio.