CN103908832B - A kind of multi-stage sewage cycle for the treatment of reutilization system for inhaling dirty car - Google Patents

Abstract

The invention discloses a multi-stage sewage treatment recycling system for a sewage suction vehicle. The multi-stage sewage treatment recycling system of the present invention comprises a sewage collection tank and a clean water tank. When the water level of the sewage collection tank is greater than the first threshold, and when the water level of the clean water tank is less than the second threshold, the multi-stage sewage treatment and recycling system can automatically perform multi-stage filtration and sedimentation treatment on the sewage in the sewage collection tank, and The treated clean water is stored in the clean water tank. Therefore, compared with the prior art, the multi-stage sewage treatment recycling system of the present invention increases the operating time of the sewage suction truck and improves the sewage suction efficiency. In addition, due to the adoption of multi-stage filtration and multi-stage sedimentation devices, the multi-stage sewage treatment recycling system of the present invention improves the granularity of sewage treatment and reduces the use and maintenance costs of sewage suction trucks.

Description

A multi-stage sewage treatment recycling system for sewage suction trucks

technical field

The invention relates to the environmental sanitation engineering machinery industry, in particular to a multi-stage sewage treatment recycling system for a sewage suction truck.

Background technique

With the development of special construction machinery vehicles in China, the application of sewage suction vehicles in urban sewers is becoming more and more common. The main functions of the sewage suction truck include collecting, transporting and dredging to clean up sewage. Most of the existing sewage suction trucks only have the function of simple vacuum suction of sewage or high-pressure flushing with clear water. In the actual application process, due to the limited volume of the vehicle's own water tank, the amount of water that can be stored is small, resulting in a short operating time for the sewage suction truck. Moreover, frequent addition of clean water also reduces the operating radius and work efficiency of the sewage suction truck.

Other existing sewage suction trucks may be installed with a sewage treatment system to purify the sewage and recycle it. However, these sewage treatment systems cannot be used in the high-pressure dredging or vacuum suction stage of the sewage suction truck, so the sewage suction truck cannot perform long-lasting dredging and sewage suction operations. In addition, the sewage treatment particle size of these treatment systems is not high, for example: particles below 50μ cannot be treated, and the treated water still contains a large number of fine flocs. When the high-pressure water pump uses treated water for cleaning work, a large number of fine particles and flocs will wear the high-pressure water pump and the high-pressure flushing pipeline, thereby increasing the use and maintenance costs of the sewage suction truck.

Contents of the invention

The technical problem to be solved by the present invention is to provide a multi-stage sewage treatment and recycling system for sewage suction trucks, so as to realize the continuous and efficient purification and treatment of sewage by sewage suction vehicles in the high-pressure dredging or vacuum suction stage, and improve the granularity of sewage treatment , extend the operating radius of the sewage suction truck, and improve the working efficiency of the sewage suction truck.

The present invention solves its technical problem and adopts the following technical solutions:

The present invention provides a multi-stage sewage treatment and recycling system for sewage suction trucks, characterized in that the multi-stage sewage treatment and recycling system includes:

The sewage collection tank is used to collect the sewage sucked by the sewage suction truck; the sewage collection tank includes a sewage collection tank liquid level sensor, which is used to measure the water level of the sewage collection tank, and generates a signal indicating the water level of the sewage collection tank the first sensor signal;

The clean water tank is used to store clean water, and the clean water tank includes a clean water tank liquid level sensor for measuring the water level in the clean water tank and generating a second sensing signal representing the water level of the clean water tank;

A self-priming pump connected to the sewage collection tank;

A hydraulically driven self-cleaning filter connected to the self-priming pump for primary filtration of sewage;

A cyclone connected to the hydraulically driven self-cleaning filter for second-stage filtration of sewage;

A multi-stage sedimentation tank connected to the cyclone is used for multi-stage sedimentation and separation of sewage;

A sewage pump connected to the multi-stage sedimentation tank;

an electrically driven backwash filter connected to the sewage pump and the clean water tank, for fine filtering the sewage; and

A PLC controller connected with the sewage collection tank, the clean water tank and the self-priming pump is used to receive the first sensing signal and the second sensing signal;

Wherein, when the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is greater than the first preset water level threshold and the water level of the clean water tank is lower than the second preset water level threshold, the The PLC controller turns on the self-priming pump and the sewage pump; the self-priming pump sucks the sewage in the sewage collection tank into the hydraulically driven self-cleaning filter; the hydraulically driven self-cleaning filter Perform primary filtration on the sewage from the sewage collection tank, and discharge the primary filtered sewage into the cyclone; the cyclone performs secondary filtration on the sewage from the hydraulically driven self-cleaning filter , and discharge the second-stage filtered water into the multi-stage sedimentation water tank; the multi-stage sedimentation water tank carries out multi-stage sedimentation and separation of sewage from the hydraulically driven self-cleaning filter, and the sewage pump The water after multi-stage sedimentation and separation is sucked into the electric drive electric drive backwash filter; the electric drive electric drive backwash filter performs fine filtration on the water delivered by the sewage pump, and the filtered water The water stored in the clean water tank;

When the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is less than the first preset water level threshold, or the water level of the clean water tank is greater than the second preset water level threshold, the PLC controller generates a second control signal to the self-priming pump; the self-priming pump stops sucking the sewage in the sewage collection tank into the hydraulically driven self-priming pump according to the second control signal. Clean the filter.

In one embodiment, the sewage collection tank also includes:

The floating suction port includes a sewer water inlet, a sewage collection tank water outlet, a sewage collection tank water inlet, and a hose connected to the self-priming pump and the sewage collection tank water inlet;

A sewage suction control valve installed between the water outlet of the sewage collection tank and the water inlet of the sewer;

a reverse discharge control valve installed between the water inlet of the sewage collection tank and the water inlet of the sewer; and

A sewage circulation control valve installed at the connection between the hose and the water inlet of the sewage collection tank,

Wherein, the floating suction port selectively works in the sewage recycling mode and the high-pressure reverse discharge mode; when the floating suction port works in the sewage recycling mode, the PLC controller opens the sewage suction control valve And close the reverse discharge control valve to suck the sewage outside the sewage suction vehicle into the sewage collection tank through the sewer water inlet of the floating suction port and the sewage collection tank outlet;

When the floating suction port works in the sewage recycling mode, and when the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is greater than the first preset water level threshold and When the water level of the clean water tank is lower than the second preset water level threshold, the PLC controller opens the sewage circulation control valve so that the self-priming pump passes through the water inlet of the sewage collection tank and the hose The water in the sewage collection tank is sucked into the hydraulically driven self-cleaning filter;

When the floating suction port works in the sewage recycling mode, and when the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is less than the first preset water level threshold, Alternatively, when the water level of the clean water tank is greater than the second preset water level threshold, the PLC controller closes the sewage circulation control valve.

In one embodiment, when the floating suction port works in the high-pressure reverse discharge mode, the PLC controller closes the sewage suction control valve and the sewage circulation control valve, and opens the reverse discharge control valve , so that the water in the sewage collection tank is discharged from the sewage collection tank through the water inlet of the sewage collection tank and the water inlet of the sewer.

In one embodiment, the multi-stage treatment recycling system further includes:

a generator connected to the electrically driven cleaning filter for powering the electrically driven cleaning filter,

Wherein, when the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is greater than the first preset water level threshold and the water level of the clean water tank is lower than the second preset water level When the threshold is reached, the PLC controller turns on the generator and the sewage pump;

When the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is less than the first preset water level threshold, or the water level of the clean water tank is greater than the second preset water level threshold, the PLC controller turns off the generator and the sewage pump.

In one embodiment, the hydraulically driven self-cleaning filter filters particles with a particle size larger than a first threshold, the cyclone filters particles with a particle size larger than a second threshold, and the electrically driven backwash filter filters particles with a particle size larger than the second threshold. Three-threshold particles, wherein the first threshold is greater than the second threshold, and the second threshold is greater than the third threshold.

In one embodiment, the multi-stage sedimentation water tank includes a multi-stage sedimentation water tank control valve, a high-pressure water pump control valve, and a high-pressure water pump; when the multi-stage sedimentation water tank enters the self-cleaning mode, the multi-stage sedimentation water tank controls The valve and the high-pressure water pump control valve are opened, and the high-pressure water pump sprays high-pressure water to flush the sedimentation water tank, and the water after flushing is discharged to the outside of the sewage suction vehicle through the control valve of the multi-stage sinking water tank.

Compared with the prior art, the multi-stage sewage treatment recycling system of the present invention can monitor the water level of the sewage collection tank and the clean water tank during the high-pressure dredging or vacuum suction stage of the sewage suction truck, and carry out sewage treatment according to the monitored water level. That is to say, when the sewage in the sewage collection tank is about to be full and the water in the clean water tank is about to run out, the multi-stage sewage treatment recycling system of the present invention can timely purify the sewage in the sewage collection tank into clean water and store it in the clean water tank . Therefore, the operating time of the sewage suction truck is increased, and the sewage suction efficiency is improved. In addition, the multi-stage sewage treatment recycling system also adopts multi-stage filtration and multi-stage sedimentation devices, which improves the granularity of sewage treatment and reduces the use and maintenance costs of sewage suction vehicles.

Description of drawings

Fig. 1 shows a multi-stage sewage treatment recycling system according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a sewage collection tank according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a floating suction port according to an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a clean water tank and a multi-stage settling water tank according to an embodiment of the present invention.

Fig. 5 is a work flow diagram of the multi-stage sewage treatment recycling system according to an embodiment of the present invention.

Explanation of reference signs: 1-clean water tank liquid level sensor; 2-sewage collection tank; 3-floating suction port; 4-slag outlet control valve; 5-hydraulic drive self-cleaning filter; 6-cyclone; 7- Multi-stage sedimentation water tank; 8-clean water tank liquid level sensor; 9-sedimentation water tank liquid level sensor; 10-sewage pump; 11-electric drive backwash filter; 12-generator; 13-self-priming pump; 14-single Direction stop valve; 15- sewage suction control valve; 16- reverse discharge control valve; 17- sewage circulation control valve; 18- float support seat; 19- float guide rod; 20- hose; 21- water inlet; 22- inlet Nozzle support plate; 23-floating ring; 24-floating ring rotating seat; 25-high-pressure water pump; 26-high-pressure water pump control valve; 27-high-pressure flushing nozzle; 28-multi-stage sinking water tank control valve; -Water inlet of the sewer; 31-Water outlet of the sewage collection tank; 32-Water inlet of the sewage collection tank.

detailed description

A detailed description will be given below of embodiments of the present invention. Although the present invention will be described and illustrated in conjunction with some specific embodiments, it should be noted that the present invention is not limited to these embodiments. On the contrary, any modification or equivalent replacement made to the present invention shall be included in the scope of the claims of the present invention.

In addition, in order to better illustrate the present invention, numerous specific details are given in the specific embodiments below. It will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, processes, components and circuits are not described in detail so as to highlight the gist of the present invention.

FIG. 1 shows a multi-stage sewage treatment recycling system 100 according to an embodiment of the present invention. In one embodiment, the multi-stage sewage treatment and recycling system 100 is mounted on a sewage suction truck for absorbing sewage, and can spray clean water for use by a high-pressure water pump to dredge the sewer. The multi-stage sewage treatment recycling system 100 includes a programmable logic controller (hereinafter referred to as PLC controller) 102 and a sewage treatment device 104 . In one embodiment, the PLC controller 102 is a computer dedicated to industrial control, its hardware structure is basically the same as that of a microcomputer, it can scan and process input signals according to user-set programs, and then perform signal processing. output. Its working process is divided into three stages, namely input sampling, user program execution and output refreshing. The sewage treatment device 104 includes a sewage collection tank 2 , a clean water tank 29 , a self-priming pump 13 , a hydraulically driven self-cleaning filter 5 , a cyclone 6 , a multi-stage sedimentation tank 7 , a sewage pump and an electrically driven backwash filter 11 .

The sewage collecting tank 2 collects the sewage sucked by the sewage suction truck. The internal structure of the sewage collection tank 2 will be further described below in conjunction with FIG. 2 .

Fig. 2 is a schematic structural diagram of a sewage collection tank 2 according to an embodiment of the present invention. In one embodiment, the sewage collection tank 2 includes a sewage collection tank liquid level sensor 1 . The liquid level sensor 1 of the sewage collection tank is used to measure the water level of the sewage collection tank 2 , generate a first sensing signal representing the water level of the sewage collection tank 2 , and transmit the first sensing signal to the PLC controller 102 . The sewage collecting tank 2 also includes a floating suction port 3 , a sewage suction control valve 15 , a reverse discharge control valve 16 and a sewage circulation control valve 17 .

The structure of the floating suction port 3 will be described below with reference to FIG. 2 and FIG. 3 .

Fig. 3 is a schematic structural diagram of a floating suction port 3 according to an embodiment of the present invention. The floating suction port 3 includes a sewer water inlet 30, a sewage tank water outlet 31, a sewage tank water inlet 32, a hose 20, a floating ring 23, a float guide rod 19, a float support seat 18 and a floating ring rotating seat 24. The sewage suction control valve 15 is installed between the water outlet 31 of the sewage collection tank and the water inlet 30 of the sewer. The reverse discharge control valve 16 is installed between the water inlet 32 of the sewage collection tank and the water inlet 30 of the sewer. The sewage circulation control valve 17 is installed at the junction of the hose 20 and the water inlet 32 of the sewage collection tank. During work, the working mode of the floating suction port 3 can be controlled by adjusting the sewage suction control valve 15 and the reverse discharge control valve 16, and the sewage purification treatment function can be turned on or off by adjusting the sewage circulation control valve 17, which will be described later A detailed description.

Back to FIG. 1 , the self-priming pump 13 is connected to the sewage collection tank 2 . More specifically, the self-priming pump 13 is connected to the hose 20 of the floating suction port 3 through the sewage circulation control valve 17 . The hydraulically driven self-cleaning filter 5 is connected with the self-priming pump 13 for primary filtering of sewage. The cyclone 6 is connected with the hydraulically driven self-cleaning filter 5, and is used for second-stage filtration of sewage. The multi-stage sedimentation tank 7 is connected with the cyclone 6, and is used for multi-stage sedimentation and separation of sewage. The sewage pump 10 is connected with the multistage sedimentation water tank 7 . The electrically driven backwash filter 11 is connected with the sewage pump, and is used for finely filtering the sewage. The clear water tank 29 is connected with the electrically driven backwash filter 11, and is used for collecting clear water after multi-stage purification treatment. In one embodiment, the clean water tank 29 includes a clean water tank liquid level sensor 8 for measuring the water level in the clean water tank 29, generating a second sensor signal representing the water level of the clean water tank, and sending the second sensor signal to the PLC control device 102.

The PLC controller 102 generates multiple control signals to control the sewage suction control valve 15, reverse discharge control valve 16 and sewage circulation control valve 17 in the sewage collection tank 2, and can also generate control signals to control the generator 12, sewage pump 10 and self-priming pump13. When the sewage suction truck starts to suck the sewage, the PLC controller 102 opens the sewage suction control valve 15 and closes the reverse discharge control valve 16, so that the floating suction port 3 works in the sewage recycling mode. At this moment, the vacuum pump in the sewage collection tank 2 absorbs the air inside the sewage collection tank 2, and reduces the internal air pressure of the sewage collection tank 2. The sewage outside the sewage suction vehicle is sucked into the sewage collection tank 2 through the sewer water inlet 30 of the floating suction port 3 and the sewage collection tank water outlet 31. That is to say, the water level of the sewage collecting tank 2 increases gradually.

The PLC controller 102 obtains the water level conditions of the sewage collecting tank 2 and the clean water tank 29 through the first sensing signal and the second sensing signal. Wherein, when the first sensing signal and the second sensing signal indicate that the water level of the sewage collecting tank 2 is greater than the first preset water level threshold (that is, indicating that the sewage collecting tank 2 is about to be filled with sewage), and, when the water level of the clean water tank is less than the first 2. When the water level threshold is preset (that is, the water in the clean water tank is about to run out), the PLC controller 102 turns on the self-priming pump 13 and the sewage pump 10 . At the same time, the PLC controller 102 opens the sewage circulation control valve 17, so that the self-priming pump 13 sucks the water in the sewage collection tank 2 into the hydraulically driven self-cleaning filter 5 through the sewage collection tank water inlet 32 and the hose 22. More specifically, the surface water of the sewage collection tank 2 passes through the water inlet 21 of the floating suction port 3, and the hose 22 enters the self-priming pump 13 for recycling and regeneration treatment. Rotate around the buoy support seat 18 under the support of the buoy ring, under the effect of the buoy ring rotation base 24, the buoy ring 23 is always in a horizontal state. Then, the hydraulically driven self-cleaning filter 5 performs primary filtration on the sewage from the sewage collection tank 2 , and discharges the primary filtered sewage into the cyclone 6 . The cyclone 6 performs second-stage filtration on the sewage from the hydraulically driven self-cleaning filter 5 , and discharges the second-stage filtered water into the multi-stage sedimentation water tank 7 . The multi-stage settling water tank 7 performs multi-stage settling and separation of sewage from the hydraulically driven self-cleaning filter 5 , and the sewage pump 10 pumps the water after the multi-stage settling and separated into the electrically driven backwash filter 11 . The electrically driven backwash filter 11 finely filters the water delivered by the sewage pump 10 , and stores the filtered water into the clean water tank 29 .

The advantage is that the multi-stage sewage treatment recycling system of the present invention can monitor the water level of the sewage collection tank and the clean water tank during the high-pressure dredging or vacuum suction stage of the sewage suction truck, and carry out sewage treatment according to the monitored water level. That is to say, when the sewage in the sewage collection tank is about to be full and the water in the clean water tank is about to run out, the multi-stage sewage treatment recycling system of the present invention can timely purify the sewage in the sewage collection tank into clean water and store it in the clean water tank . Therefore, the operating time of the sewage suction truck is increased, and the sewage suction efficiency is improved.

In addition, the multi-stage sewage treatment recycling system 100 also adopts multi-stage filtration and multi-stage sedimentation devices. More specifically, the hydraulically driven self-cleaning filter 5 filters particles with a particle size larger than the first threshold, the cyclone 6 filters particles with a particle size larger than the second threshold, and the electrically driven backwash filter 11 filters particles with a particle size larger than the third threshold , wherein the first threshold is greater than the second threshold, and the second threshold is greater than the third threshold. For example, when the hydraulically driven self-cleaning filter 5 performs primary filtration, particles above 300 μ can be sent into the sewage collection tank 2 through the pneumatic control valve 4, and sewage with a particle size below 300 μ enters the cyclone 6 for treatment. The cyclone 6 can send the particles above 150μ into the sewage tank 2, and the particles below 150μ can enter the multi-stage sedimentation tank 7 for step-by-step sedimentation and separation. After the fine filtration operation of the electrically driven backwash filter 11 , the qualified water below 20 μ is sent back to the clear water tank 29 . It can be seen that the multi-stage sewage treatment recycling system 100 improves the granularity of sewage treatment and reduces the use and maintenance costs of sewage suction trucks.

When the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank 2 is lower than the first preset water level threshold (that is, it indicates that the sewage water level of the sewage collection tank 2 is relatively low), or when the water level of the clean water tank is higher than When the second preset water level threshold is reached (that is, the clean water tank is about to be full), the PLC controller 102 turns off the self-priming pump 13 and the sewage pump 10 . At the same time, the PLC controller 102 closes the sewage circulation control valve 17 . At this time, the sewage suction truck stops the sewage conversion work.

Returning to Fig. 3, the floating suction port 3 can also work in the high-pressure reverse discharge mode. In the high-pressure reverse discharge mode, the PLC controller 102 closes the sewage suction control valve 15 and the sewage circulation control valve 17 , and opens the reverse discharge control valve 16 . The vacuum pump in the sewage collection tank 2 pressurizes the air inside the sewage collection tank 2, so that the water in the sewage collection tank 2 is discharged from the sewage collection tank 2 through the sewage collection tank water inlet and the sewer water inlet.

Fig. 4 is a schematic structural diagram of a clean water tank and a multi-stage sedimentation water tank 7 according to an embodiment of the present invention. In one embodiment, the multi-stage sedimentation water tank 7 is equipped with a self-cleaning system, which can regularly clean the internal sediment. When the cleaning process is performed, the sewage recycling system is in a stopped working state, and the multi-stage sedimentation water tank control valve 28 and the high-pressure water pump control valve 26 are opened, and the high-pressure water pump 25 is in the working state. At this time, the high-pressure water flushes the sedimentation water tank through the high-pressure flushing nozzle 27, and the water after flushing is discharged to the sewer through the multi-stage sinking water tank control valve 28 and related pipelines. .

FIG. 5 shows a working flow chart 500 of the multi-stage sewage treatment recycling system 100 according to an embodiment of the present invention. In one embodiment, the multi-stage sewage treatment recycling system 100 can work in automatic gear or manual control. In step 502, the multi-stage sewage treatment recycling system 100 is started. In step 504, if the multi-stage sewage treatment and recycling system 100 is in automatic mode, go to step 508. Otherwise, the flowchart goes to step 506, and the system is controlled manually.

In step 508, it is detected whether the clean water tank 29 is in a water shortage state. If the water level of the clean water tank 29 is lower than the second threshold (indicating water shortage), go to step 510 . Otherwise, the flowchart stays at step 508 for continuous detection. In step 510, it is detected whether the water level of the sewage collecting tank 2 reaches the treatment water level. If the water level of the sewage collection tank 2 is higher than the first threshold (indicating that the treatment water level has been reached), go to steps 512-518. Otherwise, flowchart 500 returns to step 508 .

In steps 512-518, the reverse discharge control valve 16 is closed, the sewage circulation control valve 17 is opened, the self-priming pump 13 is opened, and the slag outlet control valve is opened. At this time, the multi-stage sewage treatment recycling system 100 performs multi-stage purification treatment on the sewage in the sewage collection tank 2, and puts the treated water into the multi-stage sedimentation water tank 7 for sedimentation purification treatment.

In step 520, if the sedimentation water tank of the last stage (for example: No. 4) reaches the set water level, then enter into steps 522 and 524, and start the centrifugal sewage suction pump 10 and the generator 12 . At this moment, the water in the multi-stage sedimentation tank 7 is sent into the electric-driven flushing filter 11 for fine filtration.

In step 526, if the sewage collection tank 2 reaches the minimum water level of operation or the clean water tank 29 is full of water (that is, the water level of the sewage collection tank 2 is less than the first threshold, or the water level of the clean water tank 29 is higher than the second threshold), enter Step 528, the multi-stage sewage treatment recycling system 100 stops working.

The above detailed description and drawings are only common embodiments of the present invention. Obviously, various additions, modifications and substitutions are possible without departing from the spirit and scope of the invention defined by the claims. Those skilled in the art should understand that the present invention may vary in form, structure, layout, proportion, material, elements, components and other aspects in actual application according to specific environment and work requirements without departing from the principle of the invention. Accordingly, the embodiments disclosed herein are for illustration only and not for limitation, and the scope of the invention is defined by the appended claims and their legal equivalents, not by the foregoing description.

Claims (6)

1. A multi-stage sewage treatment recycling system for sewage suction trucks, characterized in that, the multi-stage sewage treatment recycling system comprises: The sewage collection tank is used to collect the sewage sucked by the sewage suction truck; the sewage collection tank includes a sewage collection tank liquid level sensor, which is used to measure the water level of the sewage collection tank, and generates a signal indicating the water level of the sewage collection tank the first sensor signal; The clean water tank is used to store clean water, and the clean water tank includes a clean water tank liquid level sensor for measuring the water level in the clean water tank and generating a second sensing signal representing the water level of the clean water tank; A self-priming pump connected to the sewage collection tank; A hydraulically driven self-cleaning filter connected to the self-priming pump for primary filtration of sewage; A cyclone connected to the hydraulically driven self-cleaning filter for second-stage filtration of sewage; A multi-stage sedimentation tank connected to the cyclone is used for multi-stage sedimentation and separation of sewage; A sewage pump connected to the multi-stage sedimentation tank; An electrically driven backwash filter connected to the sewage pump and the clean water tank for fine filtering the sewage; and A PLC controller connected to the sewage collection tank, the clean water tank and the self-priming pump for receiving the first sensing signal and the second sensing signal; Wherein, when the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is greater than the first preset water level threshold and the water level of the clean water tank is lower than the second preset water level threshold, the The PLC controller turns on the self-priming pump and the sewage pump; the self-priming pump sucks the sewage in the sewage collection tank into the hydraulically driven self-cleaning filter; the hydraulically driven self-cleaning filter Perform primary filtration on the sewage from the sewage collection tank, and discharge the primary filtered sewage into the cyclone; the cyclone performs secondary filtration on the sewage from the hydraulically driven self-cleaning filter , and discharge the second-stage filtered water into the multi-stage sedimentation water tank; the multi-stage sedimentation water tank carries out multi-stage sedimentation and separation of sewage from the hydraulically driven self-cleaning filter, and the sewage pump The water after multi-stage sedimentation and separation is sucked into the electric drive backwash filter; the electric drive backwash filter performs fine filtration on the water delivered by the sewage pump, and stores the filtered water in the said clean water tank; When the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is less than the first preset water level threshold, or the water level of the clean water tank is greater than the second preset water level threshold, the PLC controller generates a second control signal to the self-priming pump; the self-priming pump stops sucking the sewage in the sewage collection tank into the hydraulically driven self-priming pump according to the second control signal. Clean the filter. 2. The multi-stage sewage treatment and recycling system for sewage suction trucks according to claim 1, wherein the sewage collection tank further comprises: The floating suction port includes a sewer water inlet, a sewage collection tank water outlet, a sewage collection tank water inlet, and a hose connected to the self-priming pump and the sewage collection tank water inlet; A sewage suction control valve installed between the water outlet of the sewage collection tank and the water inlet of the sewer; a reverse discharge control valve installed between the water inlet of the sewage collection tank and the water inlet of the sewer; and A sewage circulation control valve installed at the connection between the hose and the water inlet of the sewage collection tank, Wherein, the floating suction port selectively works in the sewage recycling mode and the high-pressure reverse discharge mode; when the floating suction port works in the sewage recycling mode, the PLC controller opens the sewage suction control valve And close the reverse discharge control valve to suck the sewage outside the sewage suction vehicle into the sewage collection tank through the sewer water inlet of the floating suction port and the sewage collection tank outlet; When the floating suction port works in the sewage recycling mode, and when the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is greater than the first preset water level threshold and When the water level of the clean water tank is lower than the second preset water level threshold, the PLC controller opens the sewage circulation control valve so that the self-priming pump passes through the water inlet of the sewage collection tank and the hose The water in the sewage collection tank is sucked into the hydraulically driven self-cleaning filter; When the floating suction port works in the sewage recycling mode, and when the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is less than the first preset water level threshold, Alternatively, when the water level of the clean water tank is greater than the second preset water level threshold, the PLC controller closes the sewage circulation control valve. 3. The multi-stage sewage treatment recycling system for sewage suction trucks according to claim 2, characterized in that, when the floating suction port works in the high-pressure reverse discharge mode, the PLC controller is closed The sewage suction control valve and the sewage circulation control valve, and the reverse discharge control valve are opened, so that the water in the sewage collection tank is discharged from the sewage collection tank through the water inlet of the sewage collection tank and the water inlet of the sewer. Dirty tank. 4. The multi-stage sewage treatment and recycling system for sewage suction trucks according to claim 1, 2 or 3, wherein the multi-stage treatment and recycling system further comprises: a generator connected to the electrically driven cleaning filter for powering the electrically driven backwash filter, Wherein, when the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is greater than the first preset water level threshold and the water level of the clean water tank is lower than the second preset water level When the threshold is reached, the PLC controller turns on the generator and the sewage pump; When the first sensing signal and the second sensing signal indicate that the water level of the sewage collection tank is less than the first preset water level threshold, or the water level of the clean water tank is greater than the second preset water level threshold, the PLC controller turns off the generator and the sewage pump. 5. The multi-stage sewage treatment and recycling system for sewage suction vehicles according to claim 1, 2 or 3, wherein the hydraulically driven self-cleaning filter filters particles with a particle size greater than the first threshold, so The cyclone filters particles with a particle size larger than a second threshold, and the electrically driven backwash filter filters particles with a particle size larger than a third threshold, wherein the first threshold is larger than the second threshold, and the first The second threshold is greater than the third threshold. 6. The multi-stage sewage treatment recycling system for sewage suction trucks according to claim 1, 2 or 3, wherein the multi-stage sedimentation water tank includes a multi-stage sedimentation water tank control valve, a high-pressure water pump control valve and a high-pressure water pump; when the multi-stage sedimentation water tank enters the self-cleaning mode, the control valve of the multi-stage sedimentation water tank and the high-pressure water pump control valve are opened, and the high-pressure water pump sprays high-pressure water to flush the multi-stage sedimentation water tank, and after flushing The water is discharged to the outside of the sewage suction vehicle through the control valve of the multi-stage sedimentation water tank.