CN215365170U

CN215365170U - Car washing sewage recycling system

Info

Publication number: CN215365170U
Application number: CN202121595533.0U
Authority: CN
Inventors: 王会才; 张耀
Original assignee: Shaoxing Zhongling Automobile Service Co ltd
Current assignee: Shaoxing Zhongling Automobile Service Co ltd
Priority date: 2021-07-14
Filing date: 2021-07-14
Publication date: 2021-12-31
Anticipated expiration: 2031-07-14

Abstract

The utility model relates to a car washing sewage recycling system, which comprises a sewage collecting pool, a sewage pump, an online desanding device, a solid-liquid mixing tank, a reclaimed water tank, a clean water tank, a booster pump, an electric control system and the like, wherein the solid-liquid mixing tank, the reclaimed water tank and the clean water tank are respectively provided with an outlet connected to a water inlet pipe, connected to the booster pump through the water inlet pipe and connected to a spray head through a water outlet pipe. The system is characterized in that the liquid outlets of the solid-liquid mixing tank, the intermediate water tank and the clean water tank are respectively provided with a valve which can be independently controlled to be opened and closed, when the system is used for cleaning automobiles, a mixture of solid-phase materials and water is used as a working medium and is sprayed to the surface of an automobile body from a spray head to strip dirt, and the mixing of the solid-phase materials and the water is completed in the solid-liquid mixing tank. The advantages are that: the method solves the problem of recycling light solid-phase materials, and the concentration of the solid-liquid mixture is stable and controllable, the equipment is simple in structure, can continuously and automatically operate, is simple to maintain, and has strong engineering practicability.

Description

Car washing sewage recycling system

Technical Field

The utility model relates to the technical field of sewage treatment in vehicle cleaning, in particular to a vehicle washing sewage recycling system related to a solid-liquid two-phase cleaning medium.

Background

With the rapid increase of automobile reserves in China, the water-saving problem in the automobile washing industry is more and more concerned. In reality, the water in the car washing is not recycled. If the sewage is treated and utilized on site according to the water quality standard of tap water, the cost is high, the maintenance is complex and the popularization is difficult. Particularly, under the process condition of descaling and cleaning by adopting solid-liquid two-phase flow, the process is more challenging to recycle the sewage and the solid-phase materials therein. The present inventor proposes a treatment scheme of car washing wastewater containing solid-phase materials, which is a Chinese utility model patent with patent number ZL201920856706.6, namely a car washing water supply device capable of recycling car washing wastewater. The technology is combined with an automobile cleaning process to treat and utilize sewage, the cost is lower, and the maintenance is simpler and more feasible. However, in reality, the technical scheme is also found to have serious defects: 1) if light solid-phase materials which are low in wet density and float or suspend in water are adopted, the materials cannot quickly sink to the bottom, so that the pushing of the solid-phase materials fails, and the concentration of a solid-liquid mixture cannot be controlled, so that the cleaning fails directly; 2) for high-density solid-phase materials, the materials are pushed by the screw rod extending into the discharge hole, so that the motor is very heavy in load and is easy to block or burn due to rotation blockage. Therefore, new sewage treatment and solid-liquid mixing technologies are urgently sought.

In order to solve the problems, the scheme is developed accordingly.

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved

Aiming at the defects of the prior art, the utility model provides a car washing sewage recycling system, which solves the problems of recycling, mixing and the like of sewage containing light solid-phase materials.

(II) technical scheme

In order to achieve the purpose, the utility model is realized by the following technical scheme: the utility model provides a carwash sewage cyclic utilization system, includes sewage catch basin, sewage pump, online desanding device, solid-liquid blending tank, well water pitcher, clear water pitcher, booster pump, electrical system, and wherein solid-liquid blending tank, well water pitcher, clear water pitcher all have the export to insert the inlet tube to insert the booster pump through the inlet tube, insert the shower nozzle by the outlet pipe again, the upper portion of solid-liquid blending tank is equipped with the charge door with the overflow mouth of online desanding device one intercommunication, with the overflow mouth two of well water pitcher intercommunication, the lower part is equipped with the discharge gate of intercommunication inlet tube, solid-liquid blending tank, well water pitcher, clear water pitcher liquid outlet department all are equipped with the valve that the independent control opened, closed, solid-liquid blending tank department still is equipped with the disturbance part that promotes the solid-liquid and mixes.

Preferably, the disturbance component comprises an electric stirrer arranged inside the solid-liquid mixing tank, and particularly adopts a propeller type stirrer with one layer or two layers of blades.

Preferably, the disturbing component comprises a booster pump, the booster pump is arranged on a branch pipeline arranged on the water outlet pipe and communicated with the solid-liquid mixing tank, and a water outlet of the branch pipeline is positioned at the lower part of the cavity of the solid-liquid mixing tank.

When the system is used for cleaning automobiles, a mixture of solid-phase materials and water is taken as a working medium and is sprayed to the surface of an automobile body from a spray head to strip dirt, the mixture of the solid-phase materials and the water is completed in a solid-liquid mixing tank,

preferably, the oil separating plate is installed inside the middle water tank, the water inlet and the water outlet of the middle water tank are arranged on two sides of the oil separating plate, two sides of the oil separating plate are communicated with each other through the lower portion of the oil separating plate, the upper portion of the middle water tank is provided with an overflow hole, and the overflow hole and the water inlet are located on the same side.

Preferably, an electric stirrer is arranged in the solid-liquid mixing tank, and the solid-phase material and the water are mixed in the solid-liquid mixing tank by means of the electric stirrer.

Preferably, a branch pipeline is arranged at the water outlet end of the booster pump and communicated with the solid-liquid mixing tank, and the water outlet of the pipeline is positioned at the lower part of the cavity of the solid-liquid mixing tank.

Preferably, a water level sensor is arranged in the sewage collecting tank, and when the liquid level exceeds a certain preset water level, the water level sensor triggers and starts a sewage pump to pump away sewage until the liquid level falls back to the specified low water level.

The vehicle cleaning method based on the system sequentially executes three independent steps:

firstly, high-pressure flushing: opening a valve at a discharge port of the solid-liquid mixing tank, taking the solid-liquid mixture as a working medium, and washing the outer surface of the vehicle through a spray head to destroy a dirt layer attached to the vehicle body;

secondly, rinsing with reclaimed water: closing the valve, opening a valve of a water outlet of the reclaimed water tank and a booster pump, flushing the outer surface of the vehicle by using reclaimed water as a working medium through a spray head, and removing vehicle body residues after high-pressure flushing;

thirdly, rinsing with clear water: and (3) opening a valve and a booster pump at the water outlet of the clean water tank, taking the clean water as a working medium, and further rinsing the outer surface of the vehicle body through a spray head so that the vehicle body only leaves clean water stains.

Preferably, the wet density of the solid-phase material selected by the vehicle cleaning process based on the system is between 0.8 and 1.2, and the wet density is less than 1.0.

(III) advantageous effects

After adopting the technical scheme, compared with the prior art, the utility model has the following advantages: the car washing sewage recycling system determines the key links of sewage recovery system configuration and process control by combining the cleaning process, provides a technical scheme for controlling the concentration stability of a solid-liquid mixture, solves the recycling problem of light solid-phase materials, and has the advantages of simple equipment composition, low cost, stable process and strong engineering practicability.

Drawings

FIG. 1 is a schematic diagram of the basic structure of the present invention;

FIG. 2 is a schematic view of a solid phase material mixing tank with an electric stirrer according to the present invention;

FIG. 3 is a schematic view of a solid phase material mixing tank of the present invention agitated with a high pressure water split stream;

fig. 4 is a schematic structural view of the reclaimed water tank with the oil removal plate according to the present invention.

Detailed Description

The utility model is described in further detail below with reference to the accompanying examples.

As shown in fig. 1 to 3, the system for recycling the car washing sewage comprises a sewage collecting tank 1, a sewage pump 2, an online desanding device 3, a solid-liquid mixing tank 4, a reclaimed water tank 5, a clean water tank 6, a booster pump 8, an electric control system and the like, wherein the solid-liquid mixing tank 4, the reclaimed water tank 5 and the clean water tank 6 are respectively provided with an outlet connected to a water inlet pipe 23, connected to the booster pump 8 through the water inlet pipe 23 and connected to a spray head 21 through a water outlet pipe 22. The upper part of the solid-liquid mixing tank 4 is provided with a feed inlet 41 communicated with the first overflow port 33 of the online desanding device 3 and a second overflow port 43 communicated with the reclaimed water tank 5, and the lower part is provided with a discharge port 42 communicated with the water inlet pipe 23. When the system is used for cleaning automobiles, a mixture of a solid-phase material and water is used as a working medium and is sprayed from the spray head 21 to the surface of an automobile body to peel off dirt. The mixing of the solid phase material and water is completed in the solid-liquid mixing tank 4.

An oil separation plate 54 is installed inside the reclaimed water tank 5, the water inlet 51 and the water outlet 52 of the reclaimed water tank 5 are respectively arranged on two sides of the oil separation plate 54, and two sides of the oil separation plate 54 pass through the lower part of the oil separation plate 54. The upper part of the intermediate water tank 5 is provided with an overflow hole 53, and the overflow hole 53 and the water inlet 51 are positioned on the same side.

An electric stirrer 44 is arranged inside the solid-liquid mixing tank 4, and the solid-phase material and the water are mixed inside the solid-liquid mixing tank 4 by means of the electric stirrer 44. Or, a branch pipeline is connected with the water outlet end of the booster pump 8 and communicated with the solid-liquid mixing tank 4, and the water outlet of the pipeline is positioned at the lower part of the cavity of the solid-liquid mixing tank 4.

Hereinafter, 2 examples will be provided focusing on the mixing manner in the solid-liquid mixing tank 4, and the disturbing member for promoting the solid-liquid mixing will be further described, and the process flow of the automobile cleaning will be described based on the above.

Example 1: mixing of solids and liquids by means of an electric stirrer 44

In this case, as shown in FIG. 2, an electric stirrer 44 (conventional equipment is used) is installed in the solid-liquid mixing tank 4, a blade 441 is provided at the middle-lower part of the shaft of the stirrer 44, and a driving motor 442 is installed at the upper end of the stirrer 44. The preferred propeller type agitator for the stirring process has stronger axial circulation ability, is suitable for the low viscosity solid-liquid two-phase medium in the small space of the tank body, and realizes the rapid uniform stirring with the high-speed small-diameter impeller. Specifically, one or two layers of blades can be adopted to meet the stirring requirement under the influence of liquid level height change in the automobile cleaning process

Example 2: solid-liquid mixing by high-pressure water flow back flushing

As shown in FIG. 3, in this example, the electric stirrer is not provided in the solid-liquid mixing tank 4, and a part of the effluent from the booster pump 8 is returned to the solid-liquid mixing tank 4. The first outlet 451 of the return line 45 is located at the lower part of the cavity of the solid-liquid mixing tank 4, and the outflow will generate strong disturbance to the solid-liquid mixture in the tank. As long as the flow speed and the flow rate of the water outlet are well matched with the volume of the tank body, the effect of uniform mixing can be achieved under different liquid levels of the tank body. The advantage of this scheme has saved one set of electric mixer, has improved the reliability. The disadvantage is that the solid-liquid mixing operation in the tank cannot be started in advance, possibly resulting in a low initial liquid stream concentration.

Of course, if the solid material is in suspension, for example, the wet density is close to 1 or a suspending agent is added to the water, the stirring design of both embodiments can be eliminated.

A water level sensor is arranged in the sewage collecting tank 1. When the liquid level exceeds a certain high water level set in advance, the water level sensor triggers and starts the sewage pump 2 to pump away sewage until the liquid level falls back to the specified low water level.

firstly, high-pressure flushing: opening a valve 421 of a discharge port 42 of the solid-liquid mixing tank 4, taking the solid-liquid mixture as a working medium, and washing the outer surface of the vehicle through the spray head 21 to destroy a dirt layer attached to the vehicle body;

secondly, rinsing with reclaimed water: closing the valve 421, opening the valve 521 at the water outlet II 52 of the reclaimed water tank 5 and the booster pump 8, flushing the outer surface of the vehicle through the spray head 21 by using reclaimed water as a working medium, and removing vehicle body residues after high-pressure flushing;

thirdly, rinsing with clear water: and opening a valve 621 of a water outlet III 62 of the clean water tank 6 and a booster pump 8, further rinsing the outer surface of the vehicle body by using clean water as a working medium through a spray head 21, and only leaving clean water stains on the vehicle body.

The wet density of the solid-phase material selected by the vehicle cleaning method based on the system is between 0.8 and 1.2, and the wet density is optimally less than 1.0.

The use of the examples of the present invention is further illustrated below:

the utility model aims to provide a device and a method for simply and effectively utilizing car washing wastewater, in particular to a technology for recycling and utilizing light solid-phase materials when a mixture of the solid-phase materials and water is used as a working medium for cleaning, so as to achieve the purposes of recycling the solid-phase materials and reducing the consumption of water resources.

The "solid phase material" referred to in the present invention refers to a fine solid phase medium artificially added for enhancing the car washing effect, such as: plant powder, various fibers, foam particles, rubber particles and the like are generally lower in hardness than paint on the surface of a vehicle and much lower in density than mud and sand attached to the vehicle body, and the particle size is set according to the cleaning requirement.

The term "wet density" as used herein refers to the specific gravity of a solid material after it has absorbed sufficient water. The physical meaning of wet density is: the solid-phase material with the wet density less than 1 can float on the water surface, and the solid-phase material with the wet density more than 1 finally sinks in the water.

The online desanding device 3 in this embodiment uses a hydrocyclone. The hydrocyclone is a common industrial grading device, sewage enters a cavity from a feeding hole 31 of the device at a certain initial speed along the tangential direction and flows in a rotary mode in an inner cavity of the device, gravel solid-phase materials with high specific gravity in a liquid flow are accelerated to settle to the bottom of the hydrocyclone under the action of centrifugal force and wall resistance, and the liquid flow containing small-particle-size and low-density solid-phase particles overflows from an overflow port 33 in the center of the upper part of the hydrocyclone.

When the sewage containing solid-phase materials in the sewage collecting tank 1 is extracted, the water discharged from the bottom sewage outlet 31 of the online desanding device 3 is completely abandoned and is not recycled. In the interval between two times of car washing, the water amount discharged from the drain outlet 31 is less than the fresh water which is added in the links of fresh water rinsing and the like in the previous car washing, so that the sufficient water amount is ensured to be available in each time of car washing. In actual design, the capacity of the solid-liquid mixing tank 4 is preferably larger than the consumption required for a single cleaning, and the capacities of the reclaimed water tank 5 and the clean water tank 6 are preferably larger than the single consumption. Otherwise, cleaning and replenishing are required, and a reliable operation state is difficult to guarantee.

In reality, the car washing operation of washing by using solid-phase materials according to the solid-liquid two-phase flow principle is completed in a closed car washing room, and sewage generated by car washing each time is effectively collected into a sewage collecting pool. Because the collection, the suction and the treatment of the sewage generated by the previous car washing are finished before a new car washing process is started each time, and the liquid level of the solid-liquid mixing tank 4 is output to the reclaimed water tank 5 only when reaching the overflow degree, the quality of the solid-phase material and the water at the liquid level of the solid-liquid mixing tank 4 is the same before the car washing each time, thereby ensuring that the solid-liquid mixture in the solid-liquid mixing tank 4 keeps the same concentration level before the car washing each time.

The water level sensor in the sewage collecting tank 1 can be a float switch. When the sewage water level reaches the preassigned high level, the water pump is started, and when the floating ball descends to the low water level along with the water level, the sewage pump 2 is automatically powered off. A stirring device can be arranged in the sewage collecting tank 1, or the sewage pump 2 is of a type with stirring blades.

The discharge port 42 of the solid-liquid mixing tank 4 is communicated with the water inlet pipe 23 at the position before the liquid flow in the water inlet pipe 23 enters the booster pump 8.

The working medium adopted by the corresponding cleaning process of the utility model is not single water, but is a solid-liquid mixture with a certain concentration formed by mixing solid-phase materials in water.

The vehicle cleaning and sewage circulating process of the system with the electric stirring function comprises the following steps:

firstly, the solid-liquid mixing tank 4, the intermediate water tank 5 and the clean water tank 6 are filled, and the car washing preparation is made.

Then, the electric stirrer 44 is started to fully and uniformly mix the materials in the tank, the outlet valve 421 of the solid-liquid mixing tank 4 is started, the booster pump 8 is started, and the mixture of the solid-phase materials and water is used as a working medium to perform high-pressure washing on the outside of the vehicle so as to destroy the dirt layer attached to the vehicle body. The water pressure is the largest in this stage, and the sewage generated by the previous car washing in the solid-liquid mixing tank 4 is used.

Then, the valve 421 is closed, the water outlet valve 521 of the reclaimed water tank 5 is opened, and the reclaimed water is used as a working medium to wash the outer surface of the vehicle body, so as to remove residual dirt and solid-phase materials.

After the intermediate water is washed, the water outlet valve 621 of the clean water tank 6 is opened, and the sewage on the outer surface of the vehicle body is thoroughly removed in a clean water rinsing mode. If the electric stirrer 44 is not used, the stirring is synchronously realized by using the return water of the booster pump 8 after the booster pump is started.

Sewage formed in the automobile cleaning process and solid-phase materials enter a sewage collecting tank 1, are extracted by a sewage pump 2 and are input into a hydrocyclone 3, and the upper overflow of the hydrocyclone 3 after sand removal enters a cavity of a solid-liquid mixing tank 4 through an overflow port 33 and a feeding port 41. After the water in the solid-liquid mixing tank 4 reaches the water level of the overflow port 43, the solid-phase material is intercepted in the tank because the filter screen separates the overflow port 43 from the inner cavity, and the filtered sewage flows to the reclaimed water tank 5 through the water inlet 51, large oil drops float on the liquid level of one side of the water inlet 51 in an air floatation mode and are discharged from the overflow hole 53 along with the overflow liquid level of the reclaimed water tank 5, so that the treatment effects of oil separation and oil removal are achieved, and the rest sewage can reach the water outlet two 52 through a water passage at the lower part of the oil separation plate 54.

The oil separating plate 54 may be suspended in the cavity of the reclaimed water tank 4 to allow sewage to flow between two sides below the oil separating plate, or integrally fixed at the bottom of the tank body but provided with a through hole at the lower part thereof to serve as a passage for sewage to flow between two sides.

Because clear water is continuously added in the car washing process, the amount of the waste water discharged from the bottom sewage outlet 31 of the online desanding device 3 is less than the amount of the clear water used for rinsing in the previous car washing, the sewage treatment process can be stably carried out, the collection and treatment of solid-phase materials and sewage are completed before the next car washing, the consumption of the solid-liquid mixing tank 4 and the middle water tank 5 is sufficiently supplemented, and the same initial state before the car washing is achieved every time.

The utility model is suitable for solid-phase materials with wet density more than 1. However, if the wet density of the solid phase material selected by the above cleaning method is too high, the solid phase material may be rapidly settled in water, the effect of mixing the solid phase and the liquid phase is seriously affected, and the method is not suitable for long-distance transmission, so that the wet density of 0.8-1.2 is selected from practical points of view. For light materials with wet density less than 1.0, the separation effect of the hydrocyclone 3 is more prominent, and the concentration of the solid-liquid mixture in the solid-liquid mixing tank 4 is less susceptible to the total amount of the solid phase materials in the tank body and is more stable.

Therefore, according to the three-step car washing method of 'solid-liquid mixture washing, medium water rinsing and clear water rinsing', most of the waste water formed after the last car is washed is recycled in the subsequent process, and a good water-saving effect can be achieved. In each car washing, only a small amount of water needs to be supplemented in the rinsing link of clear water, so that the water resource consumption is greatly reduced.

The above embodiments are provided to facilitate the description of the present invention. When in specific design, a sewage blocking grid can be arranged at the water inlet of the sewage collecting tank 1 to block large-size pollutants such as leaves, ground garbage and the like; the sewage pump 2 and the booster pump 8 can be selected reasonably according to working pressure, flow and medium; the solid-liquid two-phase flow is used for washing and the subsequent three procedures of reclaimed water rinsing and clear water rinsing, different booster pumps can be connected, different water pressures are adopted, or the booster pump 8 is shared in each time interval, and the flow rate is regulated and controlled by a frequency converter; it is further contemplated that different spray heads, different flow rates may be used without departing from the essence of the present invention, and so forth. These do not conflict with the essence of the present invention and the functionality of the device can be further optimized according to the actual situation. In the embodiment, the opening and closing of each electric valve/electromagnetic valve and each pump and the monitoring of the water level of the sewage collecting tank can be realized by a connected electric control system. The electrical control system may use well-established known techniques and will not be described in detail herein.

In order to further save water, a deep water treatment device (such as a membrane treatment device, a filtering device, an electric flocculation device, an air flotation device and the like) can be added behind the reclaimed water tank 5, the device carries out deep purification treatment on reclaimed water in the reclaimed water tank 5, pollutant components such as anionic detergent, ultrafine particles, floccules and the like are separated, pollution control indexes such as turbidity and SOD (superoxide dismutase) of the water are further improved, and the reclaimed water meets the high-standard sewage discharge requirement, and even is input into the clean water tank as a clean water source. The solid-liquid mixing tank 4, the reclaimed water tank 5 and the clean water tank 6 can also be provided with water level sensors, and when the storage amount reaches an early warning value, the sewage pump 2 is forcibly started or water is delivered from other water sources for supplement.

In addition, the technique of the present invention can also be used in other similar fields than the high-pressure water cleaning of automobiles, such as: the cleaning operation of the high-speed rail motor car/train carriage realizes the cleaning process target and the water-saving purpose. Compared with the prior art, the utility model has the advantages that: the problem of the recycle of the light solid phase material that suspends or floats in the aquatic is solved, and the concentration of solid phase material is stable controllable moreover, and equipment constitutes simply, and whole sewage treatment is combined with the car washing technology organically, can realize continuous, automatic operation, and the implementation, maintain also very simply, have very strong engineering practicality.

The foregoing description is provided for the purpose of teaching and understanding various modifications and changes, which will be apparent to those skilled in the art, without departing from the scope of the utility model. The technical scope of the present invention is not limited to the content of the specification, and the protection scope must be determined by the scope of the claims.

Claims

1. The utility model provides a carwash sewage cyclic utilization system, includes sewage catch basin (1), sewage pump (2), online desanding device (3), solid-liquid mixing tank (4), well water tank (5), clear water jar (6), booster pump (8), electrical system, wherein solid-liquid mixing tank (4), well water jar (5), clear water jar (6) all have export to insert inlet tube (23) that one side set up to insert booster pump (8) through inlet tube (23), the play water side of booster pump (8) has connect shower nozzle (21) through outlet pipe (22), the upper portion of solid-liquid mixing tank (4) is equipped with charge door (41) with the overflow mouth one (33) intercommunication of online desanding device (3), with overflow mouth two (43) of well water jar (5) intercommunication, the lower part is equipped with discharge gate (42) of intercommunication inlet tube (23), its characterized in that: the liquid outlets of the solid-liquid mixing tank (4), the reclaimed water tank (5) and the clean water tank (6) are respectively provided with a valve which can be independently controlled to be opened and closed, and the solid-liquid mixing tank (4) is also provided with a disturbance component for promoting solid-liquid mixing.

2. The carwash sewage recycling system of claim 1, characterized in that: the disturbance component comprises an electric stirrer (44) arranged in the solid-liquid mixing tank (4), and specifically adopts a propeller type stirrer with one layer or two layers of blades.

3. The carwash sewage recycling system of claim 1, characterized in that: the disturbance component comprises a booster pump (8), the booster pump (8) is arranged on a branch pipeline (45) arranged on the water outlet pipe (22) and communicated with the solid-liquid mixing tank (4), and a first water outlet (451) of the branch pipeline (45) is positioned at the lower part of the cavity of the solid-liquid mixing tank (4).

4. The carwash sewage recycling system of claim 1, characterized in that: wherein, the mixture of solid-phase materials and water is adopted as a working medium, and the capacity of the solid-liquid mixing tank (4) is larger than the volume of the solid-liquid mixture required by single car washing.

5. The carwash sewage recycling system of claim 1, characterized in that: the oil separation plate (54) is installed inside the reclaimed water tank (5), the water inlet (51) and the water outlet (52) of the reclaimed water tank (5) are respectively arranged on two sides of the oil separation plate (54), two sides of the oil separation plate (54) are communicated with each other through the lower part of the oil separation plate (54), the overflow hole (53) is formed in the upper part of the reclaimed water tank (5), and the overflow hole (53) and the water inlet (51) are located on the same side.

6. The carwash sewage recycling system of claim 1, characterized in that: a water level sensor is arranged in the sewage collecting tank (1), and when the liquid level exceeds a certain preset water level, the water level sensor triggers and starts a sewage pump (2) to pump away sewage until the liquid level falls back to the specified low water level.

7. The carwash sewage recycling system of claim 2, characterized in that: the selected solid phase material has a wet density of 0.8-1.2.