CN215559474U

CN215559474U - Landfill leachate membrane process pretreatment equipment

Info

Publication number: CN215559474U
Application number: CN202121241729.XU
Authority: CN
Inventors: 章思航; 陈坤; 黄春霞; 王康
Original assignee: Wuhan Jiubang Environment Technology Co ltd
Current assignee: Wuhan Jiubang Environment Technology Co ltd
Priority date: 2021-06-04
Filing date: 2021-06-04
Publication date: 2022-01-18
Anticipated expiration: 2031-06-04

Abstract

The utility model discloses a pretreatment device for a landfill leachate membrane process, which comprises the following components: the device comprises a water inlet, an acid adjusting pool, a stirrer a, an overflowing hole a, an oxidation reaction pool, a stirrer b and the like; the acid adjusting tank is of a water tank structure with an upper opening, an oxidation reaction tank of the water tank structure is arranged beside the acid adjusting tank, an alkali adjusting tank of the water tank structure is arranged beside the oxidation reaction tank, two coagulation reaction tanks of the water tank structures are arranged beside the alkali adjusting tank, a water outlet of the coagulation reaction tank is connected with a sedimentation tank of the water tank structure through a central guide pipe, a clean water tank of the water tank structure is arranged beside the sedimentation tank, the bottom of the sedimentation tank is of a conical hollow shell structure, and a sludge discharge pipe for discharging sludge is arranged at the bottom end of the conical hollow shell structure of the sedimentation tank; the utility model has the beneficial effects that: through the pretreatment of the water inlet at the front end of the membrane, the concentration of pollutants easy to block the membrane is reduced, the water yield of the membrane system is improved, the cleaning frequency of the membrane system is reduced, and the service life of the membrane is prolonged.

Description

Landfill leachate membrane process pretreatment equipment

Technical Field

The utility model relates to the field of leachate treatment, in particular to a pretreatment device for a landfill leachate membrane process.

Background

The landfill leachate is high-concentration organic and inorganic sewage formed by internal source water and external water generated in the process of garbage decomposition; the landfill leachate has complex water quality and contains various toxic and harmful inorganic matters and organic matters; besides, the leachate also contains non-chlorinated aromatic compounds such as naphthalene and phenanthrene, chlorinated aromatic compounds, phosphoric acid vinegar, phenolic compounds, aniline compounds and the like which are difficult to biodegrade, and is an internationally recognized technical problem for treating high-concentration wastewater.

The mainstream process of the landfill leachate treatment is a biochemical process and a membrane advanced treatment process, biodegradable pollutants in the leachate are removed in a biochemical process, and organic matters, salt and other impurities which are difficult to be biologically decomposed in the leachate are intercepted through the physical interception effect of a membrane, so that the purpose of removing the pollutants is achieved; the water yield and the service life of the membrane system are determined by the water quality condition of the inlet water at the front end of the membrane advanced treatment system; therefore, the prior art needs a pretreatment device for the membrane process of the garbage leachate, which can reduce the concentration of pollutants easy to block the membrane, improve the water yield of the membrane system, reduce the cleaning frequency of the membrane system and prolong the service life of the membrane by pretreating the water entering from the front end of the membrane.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a pretreatment device for a landfill leachate membrane process, which solves the problems mentioned in the background technology.

In order to achieve the purpose, the utility model provides the following technical scheme:

a landfill leachate membrane process pretreatment unit comprising: the system comprises a water inlet, an acid regulating pool, a stirrer a, an overflowing hole a, an oxidation reaction pool, a stirrer b, an overflowing hole b, an alkali regulating pool, a stirrer c, an overflowing hole c, a coagulation reaction pool, a stirrer d, a stirrer e, a sedimentation pool, a central flow guide pipe, an overflowing hole d, a clean water pool, a drain pipe, an acid dosing device, an oxidant dosing device, a catalyst dosing device, an alkali dosing device, a PAC dosing device, a PAM dosing device, a reflux pump, a sludge discharge pipe and an equipment support; the acid adjusting tank is of a water tank structure with an upper opening, an oxidation reaction tank of the water tank structure is arranged beside the acid adjusting tank, an alkali adjusting tank of the water tank structure is arranged beside the oxidation reaction tank, two coagulation reaction tanks of the water tank structures are arranged beside the alkali adjusting tank, a water outlet of the coagulation reaction tank is connected with a sedimentation tank of the water tank structure through a central guide pipe, a clean water tank of the water tank structure is arranged beside the sedimentation tank, the bottom of the sedimentation tank is of a conical hollow shell structure, and a sludge discharge pipe for discharging sludge is arranged at the bottom end of the conical hollow shell structure of the sedimentation tank; the acid adjusting tank is in spatial communication with the oxidation reaction tank through an overflowing hole a, the oxidation reaction tank is in spatial communication with the alkali adjusting tank through an overflowing hole b, the alkali adjusting tank is in spatial communication with the coagulation reaction tank through an overflowing hole c, and the sedimentation tank is in spatial communication with the clean water tank through an overflowing hole d; an acid dosing device is arranged above the acid adjusting pool, and a stirrer a for promoting the mixing of acid in the acid adjusting pool is arranged in the acid adjusting pool; an oxidant dosing device and a catalyst dosing device are arranged above the oxidation reaction tank, and a stirrer b for promoting the mixing of the oxidant and the catalyst in the oxidation reaction tank is arranged in the oxidation reaction tank; an alkali dosing device is arranged above the alkali adjusting tank, and a stirrer c for promoting alkali mixing in the alkali adjusting tank is arranged in the alkali adjusting tank; a PAC dosing device and a PAM dosing device are respectively arranged above the two groups of coagulation reaction tanks, and a stirrer d and a stirrer e for respectively mixing a PAC coagulation reagent and a PAM coagulation reagent are arranged in the coagulation reaction tanks; a reflux pump is arranged in the clean water tank, a water pumping port of the reflux pump is positioned in the clean water tank, and a water outlet of the reflux pump is positioned in the coagulation reaction tank; a transverse drainage pipe is arranged on the clean water tank; the upper opening of the acid adjusting pool is provided with a transverse pipe body structure to form a water inlet.

Preferably, the bottom between the two groups of coagulation reaction tanks is provided with an overflowing hole for communication.

Preferably, the acid adjusting pool, the oxidation reaction pool, the alkali adjusting pool, the coagulation reaction pool, the sedimentation pool and the clean water pool are integrally supported and fixed by at least six groups of equipment supports with rod-shaped structures.

Preferably, the stirrer a, the stirrer b, the stirrer c, the stirrer d and the stirrer e are all composed of a stirring motor, a stirring paddle and a stirring shaft, the stirring shaft concentrically connects the stirring paddle and an output shaft of the stirring motor, and the distance between the stirring paddle and the bottom of the reaction tank where the stirring paddle is located is not more than fifty centimeters.

Preferably, among the overflowing holes a, b, c and d, the overflowing holes a, b and c are located at the bottoms of two adjacent reaction tanks for facilitating water liquid exchange, and the overflowing holes d are located at or above the horizontal middle part of the clean water tank and the coagulation reaction tank for facilitating the discharge of clean liquid.

Preferably, the upper part of the central draft tube is a horizontal transverse tube, one end of the transverse tube is positioned on the upper part of the coagulation reaction tank, the other end of the transverse tube is connected with a vertical tube through a ninety-degree elbow, and the bottom of the vertical tube is positioned on the lower part of the sedimentation tank.

Preferably, the lower part of the central flow guide pipe is provided with a trumpet-shaped liquid outlet with a narrow upper part and a wide lower part.

Compared with the prior art, the utility model has the beneficial effects that:

through the establishment of an acid adjusting tank, a stirrer a, an overflowing hole a, an oxidation reaction tank, a stirrer b, an overflowing hole b, an alkali adjusting tank, a stirrer c, an overflowing hole c, a coagulation reaction tank, a stirrer d, a stirrer e, a sedimentation tank, a central flow guide pipe, an overflowing hole d, a clean water tank, a drain pipe, an acid dosing device, an oxidant dosing device, a catalyst dosing device, an alkali dosing device, a PAC dosing device and a PAM dosing device, sulfuric acid is added into the acid adjusting tank through the acid dosing device and is mixed through the stirrer a, and the PH of the percolate is adjusted to two to four, so that the PH condition of the subsequent oxidation reaction is ensured; the leachate after acid adjustment enters an oxidation reaction tank through an overflowing hole a; adding an oxidant and a catalyst into the oxidation reaction tank through an oxidant dosing device and a catalyst dosing device in the oxidation reaction tank, wherein the ratio of the catalyst to the oxidant is 0.5: 1-2: 1, fully mixing and reacting the catalyst and the oxidant in the oxidation reaction tank through a stirrer c to generate a strong-oxidizing-component hydroxyl radical, oxidizing and decomposing organic matters which are difficult to biodegrade in the percolate into water and carbon dioxide, and removing pollutants; the leachate after the oxidation reaction enters an alkali regulation pool through a overflowing hole b, sodium hydroxide alkali liquor is added through an alkali dosing device, and the PH value is regulated to a neutral value of seven to eight; leachate treated by the oxidation reaction tank contains a large amount of chemical sludge and solid suspended matters, and the leachate can enter a membrane advanced treatment system only after being removed; the leachate after the oxidation reaction enters a coagulation reaction tank through an overflowing hole c, PAC and PAM coagulation agents are added into the coagulation reaction tank through a PAC dosing device and a PAM dosing device, and large-particle floccules are generated through mixing reaction of a stirrer d and a stirrer e; the leachate after coagulation reaction enters a sedimentation tank through a central guide pipe, the sludge sedimentation effect can be enhanced by the central guide pipe, the mixed liquid of large-particle floccule and the leachate flows out from a horn-shaped water outlet below the central guide pipe, the large-particle floccule sinks due to gravity, clear liquid floats upwards, and chemical sludge and part of solid suspended matters in the leachate are further removed in the sedimentation tank in a physical sedimentation mode; through the pretreatment of the water inlet at the front end of the membrane, the concentration of pollutants easy to block the membrane is reduced, the water yield of the membrane system is improved, the cleaning frequency of the membrane system is reduced, and the service life of the membrane is prolonged.

Drawings

Fig. 1 is a schematic view of the structure of a pretreatment apparatus for a landfill leachate membrane process.

FIG. 2 is a schematic sectional view of A-A in FIG. 1.

FIG. 3 is a schematic sectional view of B-B in FIG. 1.

FIG. 4 is a schematic view of a connection structure of a central draft tube and a coagulation reaction tank of a landfill leachate membrane process pretreatment device.

In the figure: 1. a water inlet; 2. an acid adjusting pool; 3. a stirrer a; 4. an overflowing hole a; 5. an oxidation reaction tank; 6. A stirrer b; 7. an overflowing hole b; 8. an alkali adjusting tank; 9. a stirrer c; 10. an overflowing hole c; 11. a coagulation reaction tank; 12. a stirrer d; 13. a stirrer e; 14. a sedimentation tank; 15. a central draft tube; 16. an overflowing hole d; 17. a clean water tank; 18. a drain pipe; 19. an acid dosing device; 20. an oxidant dosing device; 21. a catalyst dosing device; 22. an alkali dosing device; 23. a PAC dosing device; 24. PAM dosing device; 25. a reflux pump; 26. a sludge discharge pipe; 27. an equipment support.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 4, in an embodiment of the present invention, a landfill leachate membrane process pretreatment apparatus includes: the system comprises a water inlet 1, an acid adjusting tank 2, a stirrer a3, an overflowing hole a4, an oxidation reaction tank 5, a stirrer b6, an overflowing hole b7, an alkali adjusting tank 8, a stirrer c9, an overflowing hole c10, a coagulation reaction tank 11, a stirrer d12, a stirrer e13, a sedimentation tank 14, a central guide pipe 15, an overflowing hole d16, a clean water tank 17, a drain pipe 18, an acid dosing device 19, an oxidant dosing device 20, a catalyst dosing device 21, an alkali dosing device 22, a PAC dosing device 23, a PAM dosing device 24, a reflux pump 25, a sludge discharge pipe 26 and an equipment bracket 27; the acid adjusting tank 2 is of a water tank structure with an upper opening, an oxidation reaction tank 5 of the water tank structure is arranged beside the acid adjusting tank 2, an alkali adjusting tank 8 of the water tank structure is arranged beside the oxidation reaction tank 5, two coagulation reaction tanks 11 of the water tank structure are arranged beside the alkali adjusting tank 8, a water outlet of the coagulation reaction tank 11 is connected with a sedimentation tank 14 of the water tank structure through a central guide pipe 15, a clear water tank 17 of the water tank structure is arranged beside the sedimentation tank 14, the bottom of the sedimentation tank 14 is of a conical hollow shell structure, and a sludge discharge pipe 26 for discharging sludge is arranged at the bottom end of the conical hollow shell structure of the sedimentation tank 14; the acid adjusting tank 2 is in spatial communication with the oxidation reaction tank 5 through an overflowing hole a4, the oxidation reaction tank 5 is in spatial communication with the alkali adjusting tank 8 through an overflowing hole b7, the alkali adjusting tank 8 is in spatial communication with the coagulation reaction tank 11 through an overflowing hole c10, and the sedimentation tank 14 is in spatial communication with the clean water tank 17 through an overflowing hole d 16; an acid dosing device 19 is arranged above the acid adjusting pool 2, and a stirrer a3 for promoting the mixing of acid in the acid adjusting pool 2 is arranged in the acid adjusting pool 2; an oxidant dosing device 20 and a catalyst dosing device 21 are arranged above the oxidation reaction tank 5, and a stirrer b6 for promoting the mixing of the oxidant and the catalyst in the oxidation reaction tank 5 is arranged in the oxidation reaction tank 5; an alkali dosing device 22 is arranged above the alkali adjusting tank 8, and a stirrer c9 for promoting alkali mixing in the alkali adjusting tank 8 is arranged in the alkali adjusting tank 8; a PAC dosing device 23 and a PAM dosing device 24 are respectively arranged above the two groups of coagulation reaction tanks 11, and a stirrer d12 and a stirrer e13 for respectively mixing a PAC coagulation reagent and a PAM coagulation reagent are arranged on the coagulation reaction tanks 11; a reflux pump 25 is arranged in the clean water tank 17, a water pumping port of the reflux pump 25 is positioned in the clean water tank, and a water outlet of the reflux pump 25 is positioned in the coagulation reaction tank 11; a transverse water drainage pipe 18 is arranged on the clean water tank 17; the upper opening of the acid adjusting pool 2 is provided with a transverse pipe body structure to form a water inlet 1.

And the bottoms of the two groups of coagulation reaction tanks 11 are communicated through overflowing holes.

The acid adjusting pool 2, the oxidation reaction pool 5, the alkali adjusting pool 8, the coagulation reaction pool 11, the sedimentation pool 14 and the clean water pool 17 are integrally supported and fixed by at least six groups of equipment supports 27 with rod-shaped structures.

The stirrer a3, the stirrer b6, the stirrer c9, the stirrer d12 and the stirrer e13 are all composed of a stirring motor, a stirring paddle and a stirring shaft, the stirring shaft concentrically connects the stirring paddle and an output shaft of the stirring motor, and the distance between the stirring paddle and the bottom of the reaction tank where the stirring paddle is located is not more than fifty centimeters.

Among the overflowing holes a4, b7, c10 and d16, the overflowing holes a4, b7 and c10 are located at the bottoms of two adjacent reaction cells for facilitating water liquid exchange, and the overflowing hole d16 is located at or above the horizontal middle part of the clean water tank 17 and the coagulation reaction cell 11 for facilitating clear liquid discharge.

The upper part of the central draft tube 15 is a horizontal transverse tube, one end of the transverse tube is positioned at the upper part of the coagulation reaction tank 11, the other end of the transverse tube is connected with a vertical tube through a ninety-degree elbow, and the bottom of the vertical tube is positioned at the lower part of the sedimentation tank 14.

The lower part of the central flow guide pipe 15 is provided with a horn-shaped liquid outlet with a narrow upper part and a wide lower part.

The working principle of the utility model is as follows:

the utility model relates to a pretreatment device designed for a nanofiltration and reverse osmosis membrane advanced treatment system in a landfill leachate treatment station; leachate subjected to front-end biochemical treatment enters a pretreatment device through a water inlet 1, sulfuric acid is added into an acid adjusting tank 2 through an acid dosing device 19 and is mixed through a stirrer a3, and the PH of the leachate is adjusted to two to four, so that the PH condition of a subsequent oxidation reaction is ensured; the leachate after acid adjustment enters an oxidation reaction tank 5 through an overflowing hole a 4; adding an oxidant and a catalyst into the oxidation reaction tank 5 through an oxidant dosing device 20 and a catalyst dosing device 21 in the oxidation reaction tank 5, wherein the ratio of the catalyst to the oxidant is 0.5: 1-2: 1, fully mixing the catalyst and the oxidant in the oxidation reaction tank 5 through a stirrer c9, and reacting to generate a strong-oxidative-component hydroxyl free radical to oxidize and decompose the organic matters which are difficult to biodegrade in the percolate into water and carbon dioxide, so that pollutants are removed; the leachate after the oxidation reaction enters an alkali adjusting tank 8 through an overflowing hole b7, sodium hydroxide alkali liquor is added through an alkali dosing device 22, and the PH value is adjusted to a neutral value of seven to eight; the percolate treated by the oxidation reaction tank 5 contains a large amount of chemical sludge and solid suspended matters, and can enter a membrane advanced treatment system only by being removed; the leachate after the oxidation reaction enters a coagulation reaction tank 11 through an overflowing hole c10, PAC and PAM coagulation agents are added into the coagulation reaction tank 11 through a PAC dosing device 23 and a PAM dosing device 24, and a stirrer d12 and a stirrer e13 are used for mixing and reacting to generate large-particle floccules; the leachate after coagulation reaction enters a sedimentation tank 14 through a central guide pipe 15, the sludge sedimentation effect 15 can be enhanced by the central guide pipe 15, the mixed liquid of large-particle floccules and the leachate flows out from a horn-shaped water outlet below the central guide pipe 15, the large-particle floccules sink due to gravity, clear liquid floats upwards, and chemical sludge and partial solid suspended matters in the leachate are further removed in the sedimentation tank 14 in a physical sedimentation mode; the clear percolate after precipitation enters a clear water tank 17 through a overflowing hole d16 to be stored and the treatment effect is judged, and the percolate reaching the pretreatment effect is pumped from a drain pipe 18 to a membrane system for advanced treatment through a water inlet pump of the membrane advanced treatment system; when the treatment effect is poor and the chemical sludge content is more and does not reach the standard, the percolate in the clean water tank 17 is sent to the front-end coagulation reaction tank 11 through the return pump 25 to be treated again and reaches the standard, and the sludge in the sedimentation tank 14 can be discharged and removed through the sludge discharge pipe 26.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention; furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated; thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature.

In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof; the present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein; any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A landfill leachate membrane process pretreatment unit comprising: the device comprises a water inlet (1), an acid adjusting tank (2), a stirrer a (3), an overflowing hole a (4), an oxidation reaction tank (5), a stirrer b (6), an overflowing hole b (7), an alkali adjusting tank (8), a stirrer c (9), an overflowing hole c (10), a coagulation reaction tank (11), a stirrer d (12), a stirrer e (13), a sedimentation tank (14), a central guide pipe (15), an overflowing hole d (16), a clean water tank (17), a drain pipe (18), an acid dosing device (19), an oxidant dosing device (20), a catalyst dosing device (21), an alkali dosing device (22), a PAC dosing device (23), a PAM dosing device (24), a reflux pump (25), a mud discharge pipe (26) and an equipment support (27); the method is characterized in that: the acid adjusting tank (2) is of a water tank structure with an upper opening, an oxidation reaction tank (5) of the water tank structure is arranged beside the acid adjusting tank (2), an alkali adjusting tank (8) of the water tank structure is arranged beside the oxidation reaction tank (5), two coagulation reaction tanks (11) of the water tank structure are arranged beside the alkali adjusting tank (8), a water outlet of each coagulation reaction tank (11) is connected with a sedimentation tank (14) of the water tank structure through a central guide pipe (15), a clear water tank (17) of the water tank structure is arranged beside the sedimentation tank (14), the bottom of the sedimentation tank (14) is of a conical empty shell structure, and a sludge discharge pipe (26) for discharging sludge is arranged at the bottom end of the conical empty shell structure of the sedimentation tank (14); the acid adjusting tank (2) is in spatial communication with the oxidation reaction tank (5) through an overflowing hole a (4), the oxidation reaction tank (5) is in spatial communication with the alkali adjusting tank (8) through an overflowing hole b (7), the alkali adjusting tank (8) is in spatial communication with the coagulation reaction tank (11) through an overflowing hole c (10), and the sedimentation tank (14) is in spatial communication with the clean water tank (17) through an overflowing hole d (16); an acid dosing device (19) is arranged above the acid adjusting pool (2), and a stirrer a (3) for promoting acid mixing in the acid adjusting pool (2) is arranged in the acid adjusting pool (2); an oxidant dosing device (20) and a catalyst dosing device (21) are arranged above the oxidation reaction tank (5), and a stirrer b (6) for promoting the mixing of the oxidant and the catalyst in the oxidation reaction tank (5) is arranged in the oxidation reaction tank (5); an alkali dosing device (22) is arranged above the alkali adjusting tank (8), and a stirrer c (9) for promoting alkali mixing in the alkali adjusting tank (8) is arranged in the alkali adjusting tank (8); a PAC dosing device (23) and a PAM dosing device (24) are respectively arranged above the two sets of coagulation reaction tanks (11), and a stirrer d (12) and a stirrer e (13) for respectively mixing a PAC coagulation reagent and a PAM coagulation reagent are arranged on the coagulation reaction tanks (11); a reflux pump (25) is arranged in the clean water tank (17), a water pumping port of the reflux pump (25) is positioned in the clean water tank, and a water outlet of the reflux pump (25) is positioned in the coagulation reaction tank (11); a transverse drainage pipe (18) is arranged on the clean water tank (17); the upper opening of the acid adjusting pool (2) is provided with a transverse pipe body structure to form a water inlet (1).

2. The apparatus for the pretreatment of landfill leachate membrane process of claim 1, wherein: and an overflowing hole is arranged at the bottom between the two groups of coagulation reaction tanks (11) for communication.

3. The apparatus for the pretreatment of landfill leachate membrane process of claim 1, wherein: the acid adjusting pool (2), the oxidation reaction pool (5), the alkali adjusting pool (8), the coagulation reaction pool (11), the sedimentation pool (14) and the clean water pool (17) are integrally supported and fixed by at least six groups of equipment supports (27) with rod-shaped structures.

4. The apparatus for the pretreatment of landfill leachate membrane process of claim 1, wherein: the stirrer a (3), the stirrer b (6), the stirrer c (9), the stirrer d (12) and the stirrer e (13) are composed of a stirring motor, a stirring paddle and a stirring shaft, the stirring shaft concentrically connects the stirring paddle and an output shaft of the stirring motor, and the distance between the stirring paddle and the bottom of the reaction tank where the stirring paddle is located is not more than fifty centimeters.

5. The apparatus for the pretreatment of landfill leachate membrane process of claim 1, wherein: in the overflowing holes a (4), b (7), c (10) and d (16), the overflowing holes a (4), b (7) and c (10) are located at the bottoms of two adjacent reaction tanks for facilitating water liquid exchange, and the overflowing holes d (16) are located in the horizontal middle part or above the horizontal middle part of a clean water tank (17) and a coagulation reaction tank (11) for facilitating clear liquid discharge.

6. The apparatus for the pretreatment of landfill leachate membrane process of claim 1, wherein: the upper part of the central flow guide pipe (15) is a horizontal transverse pipe, one end of the transverse pipe is positioned on the upper part of the coagulation reaction tank (11), the other end of the transverse pipe is connected with a vertical pipe through a ninety-degree elbow, and the bottom of the vertical pipe is positioned on the lower part of the sedimentation tank (14).

7. The apparatus for the pretreatment of landfill leachate membrane process of claim 1, wherein: the lower part of the central flow guide pipe (15) is provided with a trumpet-shaped liquid outlet with a narrow upper part and a wide lower part.