CN115321762B

CN115321762B - Filter equipment that can backwash

Info

Publication number: CN115321762B
Application number: CN202211117228.XA
Authority: CN
Inventors: 喻黎明; 张玉胜; 李娜; 赵鑫荣
Original assignee: Kunming University of Science and Technology
Current assignee: Kunming University of Science and Technology
Priority date: 2022-09-14
Filing date: 2022-09-14
Publication date: 2023-07-04
Anticipated expiration: 2042-09-14
Also published as: CN115321762A

Abstract

The application provides a filtering device capable of back flushing, which comprises a filtering tank body, a primary filtering mechanism, a transmission mechanism and a filter residue pipeline. The first-stage filtering mechanism comprises a filter screen, a first round hole is formed in the center of the filter screen, when the conical head covers the first round hole, the filtering device is in a filtering state, and sewage flowing into the sewage inlet is guided to the filter screen through the conical head to be filtered and discharged through the purified water outlet. The top of connecting rod and the bottom fixed connection of cone, first motor control connecting rod remove along the axis of filtering jar body. The top end of the filter residue pipeline is communicated with the first round hole. After the conical head moves up along the axis of the filtering tank body, the filtering device is in a back flushing state, the filter screen is flushed by the purified water flowing in through the sewage inlet, and filter residues on the filter screen are discharged into the sewage discharge pipeline together with the purified water through the filter residue pipeline. According to the self-cleaning device, after working for a preset time, the filter screen is self-cleaned on the premise that the filter layer device is not dismounted.

Description

Filter equipment that can backwash

Technical Field

The application relates to the technical field of filtering equipment, in particular to a filtering device capable of back flushing.

Background

The filtering equipment is also called a multi-medium filter, and is one of main equipment for water quality pretreatment. According to the condition of water quality, the corresponding design scheme is adopted to efficiently remove suspended matters, colloid, sediment, clay, humus, particulate matters and other impurities in the water body, reduce the turbidity of the water, achieve the aim of clarifying the water quality, and are commonly used in industrial production.

In the use process of the filtering equipment, a large amount of filter residues can be accumulated on the filter screen, so that the filtering effect is affected. Regular maintenance and cleaning of the screen is therefore required.

Because filtration equipment's structure is complicated, if clear up the filter screen needs to dismantle filtration equipment, then clear up the filter screen. The disassembly process is tedious, and the arrangement such as installation again is needed after cleaning, so that the operation is cumbersome, and the working efficiency is affected.

In view of the foregoing, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.

Disclosure of Invention

An object of the embodiment of the application is to provide a filtering device capable of back flushing, which is capable of facilitating self-cleaning of a filtering screen by a self-structure after working for a preset time.

The application specifically provides a filter equipment that can back flush, including filtering jar body, one-level filtering mechanism, drive mechanism and filter residue pipeline.

The filtering tank body comprises a sewage inlet arranged at the top and a purified water outlet arranged at the bottom.

The first-stage filtering mechanism is arranged in the filtering tank body and comprises a filtering net fixedly connected with the filtering tank body, a first round hole is formed in the center of the filtering net, a conical head is arranged on the first round hole, when the conical head covers the first round hole, the filtering device is in a filtering state, and sewage flowing in from the sewage inlet is guided to the filtering net through the conical head to be filtered and discharged through the purified water outlet.

The transmission mechanism comprises a connecting rod and a first motor in transmission connection with the bottom of the connecting rod, the top end of the connecting rod is fixedly connected with the bottom of the conical head, and the first motor controls the connecting rod to move along the axis of the filtering tank body.

The filter residue pipeline is arranged on the axis of the filter tank body, the top end of the filter residue pipeline is communicated with the first round hole, and the bottom of the filter residue pipeline extends downwards and is connected with the sewage pipeline; after the conical head moves upwards along the axis of the filtering tank body, the filtering device is in a back flushing state, the filter screen is flushed by the purified water flowing in through the sewage inlet, and filter residues on the filter screen are discharged into the sewage discharge pipeline along with the purified water through the filter residue pipeline.

In one embodiment, a supporting plate is arranged on the connecting rod, the supporting plate is arranged at the lower part of the filter screen and corresponds to the shape of the filter screen, a second round hole is arranged at the center of the supporting plate, and the supporting plate is sleeved outside the filter residue pipeline through the second round hole; after the supporting plate moves upwards through the connecting rod, when the filtering device is placed in a back flushing state, the supporting plate is attached to the filter screen and supports the filter screen.

In one embodiment, the sewage inlet is coaxially arranged with the conical head, the conical head moves upwards along the axis of the filtering tank body and is inserted into the sewage inlet, the water inlet area of the sewage inlet is reduced, and the water inlet pressure at the sewage inlet is increased.

In one embodiment, the filter screen comprises a plurality of folding surfaces, and the folding surfaces are uniformly distributed around the circumference of the filter screen.

In one embodiment, the included angle between two adjacent folding surfaces is 85-95 degrees; the outer edge of the filter screen is turned upwards, and the turning angle is 25-40 degrees.

In one embodiment, the purified water outlet comprises a straight discharge port and a backflow port, wherein the straight discharge port is used for being connected with a purified water pipe and discharging filtered purified water, the backflow port is communicated with the sewage inlet through a backflow pipeline, and the filtered purified water is used for backwashing the filter screen.

In one embodiment, a tee joint is arranged at the sewage inlet, and the tee joint comprises a first water inlet, a second water inlet and a water outlet; the first water inlet is communicated with the backflow pipeline, the second water inlet is communicated with an external water purifying pipe, and the water outlet is communicated with the filtering tank body.

In one embodiment, the sewage treatment device further comprises a secondary filtering mechanism arranged at the bottom of the filter screen, wherein the secondary filtering mechanism is a biological membrane filtering mechanism, and the biological membrane filtering mechanism is used for filtering out organic matters in the sewage and then discharging the organic matters downwards.

In one embodiment, the biological membrane filter further comprises a three-stage filter mechanism arranged at the bottom of the biological membrane filter mechanism, wherein the three-stage filter mechanism comprises a dosing stirring tank body and a dosing port arranged on the dosing stirring tank body, and the dosing port is used for adding chemical reagents and carrying out chemical filtration on sewage.

In one embodiment, the three-stage filtering mechanism comprises a stirring part arranged at the bottom of the dosing stirring tank body, and the stirring part is controlled to rotate by a second motor.

Compared with the prior art, the beneficial effects of this application are:

in the technical scheme of the application, the provided backflushing filter device has a filter state and a backflushing state. After the filter device works for a preset time, the connecting rod and the conical head are controlled to move upwards through the transmission mechanism, the filter residue pipeline is opened, purified water is introduced into the sewage water inlet to wash the filter screen, the filter residue is washed into the filter residue pipeline, and the filter screen is self-cleaned on the premise that the filter layer device is not dismounted. The distance between the filter screen and the supporting plate is controlled by adjusting the moving distance of the connecting rod, so that the hydraulic performance of high-pressure water can be changed, and the adjustment of the flushing amplitude is realized; and the washed dirt can be discharged into a filter residue pipeline, so that the blockage phenomenon caused by unclean long-term washing is avoided.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a front view of a backflushing filter apparatus provided in accordance with the present embodiment;

FIG. 2 is a side view of a backflushing filter apparatus provided in accordance with the present embodiment;

FIG. 3 is a schematic view showing the internal structure of a backflushing filter apparatus according to the present embodiment;

fig. 4 is a longitudinal sectional view in a filtering state of the back-washable filtering apparatus provided according to the present embodiment;

fig. 5 is a longitudinal sectional view in a flushing state of the backflushing filter apparatus provided according to the present embodiment;

FIG. 6 is a schematic structural view of a transmission mechanism in the backflushing filter device according to the present embodiment;

FIG. 7 is a schematic view of the structure of a conical head in the backflushing filter apparatus according to the present embodiment;

FIG. 8 is a schematic view of the structure of a back-flushable heating plate in the back-flushable filtering apparatus according to the present embodiment;

FIG. 9 is a schematic view of a biofilm filter mechanism in the backflushing filter device provided in accordance with the present embodiment;

FIG. 10 is a longitudinal cross-sectional view of a biofilm filtration mechanism in a backwashable filtering device provided in accordance with this embodiment;

FIG. 11 is a schematic view of the structure of a cylindrical dosing tank in the backflushing filter apparatus according to the present embodiment;

FIG. 12 is a perspective view of a three stage filtration mechanism in a backflushing filter apparatus according to this embodiment;

FIG. 13 is a schematic view showing the assembly of a support plate in the backflushing filter apparatus according to the present embodiment;

fig. 14 is a schematic perspective view of a support plate in the backflushing filter apparatus according to the present embodiment;

fig. 15 is a schematic structural view of a filter screen in the backflushing filter device according to the present embodiment.

Reference numerals:

1. a primary filtering mechanism; 11. a filtering tank body; 12. a filter screen; 13. a conical head; 14. fin-shaped baffles; 15. a support plate; 151. a sloping plate; 16. a filter residue pipeline; 161. a slag discharging hole; 17. a return line; 18. a digital display screen; 2. a sewage inlet; 21. a first water inlet; 22. a second water inlet; 3. a purified water outlet; 31. a straight exhaust port; 32. a return port; 4. a connecting rod; 41. a first motor; 42. a gear; 43. a rack; 5. a secondary filtering mechanism; 51. a flow-dredging heating plate; 52. a tubular membrane; 6. a three-stage filtering mechanism; 61. a cylindrical dosing tank; 62. a pull rod; 63. and a stirring part.

Detailed Description

The following describes the embodiments of the present invention in further detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and are not intended to be limiting.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

Referring to fig. 1 to 12, the present application specifically provides a backflushing filtering device, which comprises a filtering tank 11, a primary filtering mechanism 1, a transmission mechanism and a filter residue pipeline 16.

As shown in fig. 1, the filtering tank 11 includes a sewage inlet 2 provided at the top and a purified water outlet 3 provided at the bottom.

As shown in fig. 1 to 6, the first-stage filtering mechanism 1 is arranged in the filtering tank 11 and comprises a filter screen 12 fixedly connected with the filtering tank 11, a first round hole is formed in the center of the filter screen 12, a conical head 13 is arranged on the first round hole, as shown in fig. 4, when the conical head 13 covers the first round hole, the filtering device is in a filtering state, and sewage flowing in from the sewage inlet 2 is guided to the filter screen 12 through the conical head 13 to be filtered and discharged through the purified water outlet 3.

The transmission mechanism comprises a connecting rod 4 and a first motor 41 in transmission connection with the bottom of the connecting rod 4, the top end of the connecting rod 4 is fixedly connected with the bottom of the conical head 13, and the first motor 41 controls the connecting rod 4 to move along the axis of the filtering tank 11.

The output shaft of the first motor 41 is coaxially provided with a gear 42, the connecting rod 4 is provided with a rack 43, the first motor 41 is in transmission connection with the connecting rod 4 through a rack 43 transmission mechanism, and the first motor 41 controls the gear 42 to rotate forward or reversely so as to control the connecting rod 4 to move up or down through the rack 43.

The filter residue pipeline 16 is arranged on the axis of the filter tank 11, the top end of the filter residue pipeline 16 is communicated with the first round hole, and the bottom of the filter residue pipeline 16 extends downwards and is connected with the sewage pipeline; after the conical head 13 moves upwards along the axis of the filtering tank 11, the filtering device is in a back flushing state, the filter screen 12 is flushed by the purified water flowing in through the sewage inlet 2, and filter residues on the filter screen 12 are discharged into a sewage discharge pipeline along with the purified water through a filter residue pipeline 16.

As shown in fig. 7, fin-shaped guide vanes 14 are provided on the side surface of the conical head 13, and the filter screen 12 is rinsed in consideration of the fact that the purified water flowing in through the sewage inlet 2 is pressurized after passing through the fin-shaped guide vanes 14.

The back-flushable filter device provided by the application has a filtering state and a back-flushing state. After the filtering device works for a preset time, the connecting rod 4 and the conical head 13 are controlled by the transmission mechanism to move upwards, the filter residue pipeline 16 is opened, purified water is introduced into the sewage inlet 2 to wash the filter screen 12, filter residues are washed into the filter residue pipeline 16, and the filter screen 12 is self-cleaned on the premise of not disassembling the filtering layer device.

In one embodiment, the connecting rod 4 is provided with a supporting plate 15, the supporting plate 15 is arranged at the lower part of the filter screen 12 and corresponds to the shape of the filter screen 12, a second round hole is arranged at the center of the supporting plate 15, and the supporting plate 15 is sleeved outside the filter residue pipeline 16 through the second round hole; as shown in fig. 5, after the support plate 15 is moved up by the link 4, the support plate 15 is attached to the filter screen 12 and supports the filter screen 12 when the filter apparatus is placed in a backwashed state. Because the water pressure of the connected flushing water is large, the supporting plate 15 provides supporting force for the filter screen 12, and the filter screen 12 is ensured to be intact on the premise of ensuring the flushing effect.

In one embodiment, the sewage inlet 2 and the conical head 13 are coaxially arranged, as shown in fig. 5, the conical head 13 moves upwards along the axis of the filtering tank 11 and is inserted into the sewage inlet 2, the water inlet area of the sewage inlet 2 is reduced, the water inlet pressure at the sewage inlet 2 is increased, the back flushing acting force of the filter screen 12 is increased through the conical head 13, and the flushing effect of the filter screen 12 is ensured.

In one embodiment, the filter screen 12 includes a plurality of folds, the folds being uniformly distributed around the circumference of the filter screen 12, and the included angle between two adjacent folds being 85-95 degrees, preferably 90 degrees. Through the setting of the face of folding, can increase the filtration area of filter screen 12 in the limited space of filtering jar body 11, guarantee the filter effect.

In one embodiment, the outer edge of filter 12 is turned up at a angle of 25-40 degrees, preferably 30 degrees. By turning the outer edge of the filter screen 12 upwards, the filter residue is more easily slid into the filter residue pipeline 16 under the action of high-pressure water purification and self gravity.

As shown in fig. 14 and 15, the shape of the support plate 15 is the same as the shape of the filter screen 12, so that in the filter state, the multiple folded surfaces on the support plate 15 play a role in guiding flow, and at this time, the support plate 15 plays a role in reducing the impact force of water flow.

As shown in fig. 13 and 14, a plurality of slag holes 161 are provided at the top of the slag pipe 16, and the plurality of slag holes 161 are uniformly distributed on the periphery of the slag pipe 16. The center of the support plate 15 includes a plurality of inclined plates 151, one side of the inclined plates 151 is connected to the folded surface of the support plate 15, and the other side of the inclined plates 151 is downwardly inclined to be directed to the slag hole 161. When the water current washes the residue on the filter screen 12 to the upper surface of the support plate 15, the residue flows into the residue discharge hole 161 along the inclined plate 151 and is discharged through the residue pipe 16.

In one embodiment, as shown in fig. 4 and 5, the purified water outlet 3 includes a straight discharge port 31 and a return port 32, the straight discharge port 31 is used for being connected with a purified water pipe to discharge filtered purified water, and the return port 32 is communicated with the sewage inlet 2 through a return pipe 17 to backwash the filter screen 12 with the filtered purified water. By the arrangement of the return pipeline 17, the filter screen 12 is self-cleaned on the premise of not accessing external water purifying facilities.

In one embodiment, as shown in fig. 2, a tee joint is arranged at the sewage inlet 2, and the tee joint comprises a first water inlet 21, a second water inlet 22 and a water outlet; the first water inlet 21 is communicated with the return pipeline 17, the second water inlet 22 is communicated with an external water purifying pipe, and the water outlet is communicated with the filtering tank 11. Through the tee bend setting, under the condition that the water purification water yield that self filtration produced is insufficient for satisfying the washing requirement, inserts external water purification water source, washes filter screen 12, has strengthened the adaptability of equipment in different environment.

In one embodiment, the application further comprises a secondary filtering mechanism 5, wherein the secondary filtering mechanism 5 is a biological membrane filtering mechanism arranged at the bottom of the filter screen 12, and the biological membrane filtering mechanism is used for filtering out organic matters in sewage and then discharging the organic matters downwards.

Specifically, as shown in fig. 8 and 10, the biofilm filtering mechanism includes a membrane treatment tank, a flow-dispersing heating plate 51 is arranged at the top of the membrane treatment tank, and a tubular membrane 52 is arranged at the bottom of the flow-dispersing heating plate 51. The flow-dispersing heating plate 51 is made of a heat-conducting material and has a heating function and is used for heating and dispersing water flow flowing in from the primary filtering mechanism 1, a plurality of flow guide walls and flow guide holes are uniformly distributed on the flow-dispersing heating plate 51, and the water flow is uniformly conveyed into the tubular membrane 52 for filtering through the arrangement of the flow-dispersing heating plate 51.

In one embodiment, as shown in fig. 10, an insulation layer is disposed on the outer side of the tubular membrane 52, and the insulation layer is detachable, so that the tubular membrane 52 can maintain a specific water temperature, and the filtration efficiency of the tubular membrane 52 is maximized.

In one embodiment, the tubular membrane 52 within the membrane treatment tank may be replaced after a predetermined period of use.

In one embodiment, the application further comprises a three-stage filtering mechanism 6 arranged at the bottom of the biological membrane filtering mechanism, wherein the three-stage filtering mechanism 6 comprises a dosing stirring tank body and a dosing port arranged on the dosing stirring tank body, and the dosing port is used for adding chemical reagents and carrying out chemical filtering on sewage.

Specifically, as shown in fig. 11, the cylindrical dosing tank 61 is inserted into the dosing stirring tank body through the dosing port, the cylindrical dosing tank 61 includes a pull rod 62 provided on the outer surface, the cylindrical dosing tank 61 is pulled out from the dosing port through the pull rod 62, and the cylindrical dosing tank 61 is filled with a medicament. The operation of sterilizing and desulfurizing sewage is performed by controlling the type and concentration of the chemical in the cylindrical chemical feeding tank 61.

In one embodiment, as shown in fig. 12, the three-stage filtering mechanism 6 includes a stirring portion 63 provided at the bottom of the dosing stirring tank, and the stirring portion 63 is controlled to rotate by a second motor to stir the solution in the dosing stirring tank, so that the dissolution of the drug is accelerated. The second motor includes a proximity switch in communication with the second motor. The proximity switch comprises a metal detection body and an induction area, wherein the metal detection body is fixedly connected with the connecting rod 4, and the induction area is arranged on the dosing stirring tank body. When this application is in the state of washing, the metal detection body passes through connecting rod 4 and upwards moves, and the induction zone is kept away from to the metal detection body, and proximity switch outage, second motor control stirring portion 63 stop stirring. When the metal detector is in the filtering state and moves downwards through the connecting rod 4, the metal detector is close to the sensing area, the proximity switch is electrified, and the second motor controls the stirring part 63 to rotate. By this arrangement, energy waste can be reduced.

The tank bodies of the first filtering mechanism, the second filtering mechanism and the third filtering mechanism are connected by detachable flanges.

In one embodiment, the filtering tank 11 is provided with a digital display screen 18, and various parameters such as the inlet and outlet flow rate, pressure and the like of the current device can be reflected through the digital display screen.

Specifically, a water level sensor is arranged on the top surface in the filtering tank 11 and is in communication connection with the sewage inlet 2, and when the water level in the filtering tank 11 is higher than a limiting value in a filtering state, the water level sensor feeds back a signal to the sewage inlet 2, controls the sewage inlet 2 to be closed, and conveys the water level value to a digital display disc for display.

In summary, the backflushing filter device provided by the application has a filter state and a backflushing state. After the filtering device works for a preset time, the connecting rod 4 and the conical head 13 are controlled by the transmission mechanism to move upwards, the filter residue pipeline 16 is opened, purified water is introduced into the sewage inlet 2 to wash the filter screen 12, filter residues are washed into the filter residue pipeline 16, and the filter screen 12 is self-cleaned on the premise of not disassembling the filtering layer device. The distance between the filter screen 12 and the supporting plate 15 is controlled by adjusting the moving distance of the connecting rod 4, so that the hydraulic performance of high-pressure water can be changed, and the adjustment of the flushing amplitude is realized; and the washed dirt can be discharged into the filter residue pipeline 16, so that the blockage phenomenon caused by uncleanness in long-term washing is avoided.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present invention, and these modifications and substitutions should also be considered as being within the scope of the present invention.

Claims

1. A backflushing filter apparatus comprising:

the filtering tank body comprises a sewage water inlet arranged at the top and a purified water outlet arranged at the bottom;

the first-stage filtering mechanism is arranged in the filtering tank body and is fixedly connected with the inner wall of the filtering tank body, a first round hole is formed in the center of the filtering screen, a conical head is arranged on the first round hole, when the conical head covers the first round hole, the filtering device is in a filtering state, and sewage flowing in from the sewage inlet is guided to the filtering screen through the conical head for filtering and is discharged through the purified water outlet;

the transmission mechanism comprises a connecting rod and a first motor in transmission connection with the bottom of the connecting rod, the top end of the connecting rod is fixedly connected with the bottom of the conical head, and the first motor controls the connecting rod to move along the axis of the filtering tank body;

the filter residue pipeline is arranged on the axis of the filter tank body, the top end of the filter residue pipeline is communicated with the first round hole, and the bottom of the filter residue pipeline extends downwards and is connected with the sewage pipeline; after the conical head moves upwards along the axis of the filtering tank body, the filtering device is in a back flushing state, the filter screen is flushed by the purified water flowing in through the sewage inlet, and filter residues on the filter screen are discharged into the sewage discharge pipeline along with the purified water through the filter residue pipeline;

the connecting rod is provided with a supporting plate, the supporting plate is arranged at the lower part of the filter screen and corresponds to the shape of the filter screen, the center of the supporting plate is provided with a second round hole, and the supporting plate is sleeved outside the filter residue pipeline through the second round hole; after the supporting plate moves upwards through the connecting rod, when the filtering device is placed in a back flushing state, the supporting plate is attached to the filter screen and supports the filter screen;

the sewage water inlet and the conical head are coaxially arranged, the conical head moves upwards along the axis of the filtering tank body and is inserted into the sewage water inlet, the water inlet area of the sewage water inlet is reduced, and the water inlet pressure at the sewage water inlet is increased.

2. The backflushing filter of claim 1 wherein the filter screen includes a plurality of folds, the folds being evenly spaced about the circumference of the filter screen; the included angle between two adjacent folding surfaces is 85-95 degrees.

3. The backflushing filter according to claim 2, wherein the outer edge of the filter screen is turned upwards by an angle of 25-40 degrees.

4. The backwashable filtering apparatus of claim 1, wherein said clean water outlet includes a straight drain for connection to a clean water pipe for draining filtered clean water and a return for communicating with said sewage inlet through a return pipe for backwasha ng said filter screen with filtered clean water.

5. The backflushing, filter arrangement of claim 4, wherein a tee is provided at the sewage inlet, the tee including a first water inlet, a second water inlet, and a water outlet; the first water inlet is communicated with the backflow pipeline, the second water inlet is communicated with an external water purifying pipe, and the water outlet is communicated with the filtering tank body.

6. The backwashable filtering apparatus according to any one of claims 1 to 5, further comprising a secondary filter mechanism disposed at the bottom of the filter screen, wherein the secondary filter mechanism is a biofilm filter mechanism, and the biofilm filter mechanism is configured to filter out organic matters in the sewage and then drain the organic matters downwards.

7. The back-washable filter apparatus of claim 6, further comprising a tertiary filtration mechanism disposed at the bottom of the biofilm filtration mechanism, the tertiary filtration mechanism comprising a dosing agitation tank and a dosing port disposed on the dosing agitation tank, the dosing port being configured to add a chemical agent and chemically filter the wastewater.

8. The back-washable filter means of claim 7, wherein said tertiary filtration mechanism comprises a stirring portion disposed at the bottom of said dosing stirring tank, said stirring portion being rotated by a second motor.