A system and process for recycling car wash wastewater and surfactant

Abstract

The present invention discloses a system and process for recycling car wash wastewater and surfactants. The system comprises, from left to right, a wastewater collection tank, a reaction tank, a sedimentation and separation tank, a quartz sand filter, a precision filter, an inert gas flotation tower, an ultraviolet disinfection tube, and a clean water tank, all connected by pipes. The reaction tank is connected to a polyaluminum chloride reagent tank, a polyacrylamide reagent tank, and a sodium hydroxide reagent tank, respectively, via pipes. The upper and middle portions of the inert gas flotation tower are connected to a foam collection tank via pipes. The present invention can achieve the recycling of car wash wastewater and surfactants used in car washes, thereby reducing pollutant emissions.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and more particularly to a system and process for recycling car wash wastewater and surfactant. Background Art

[0002] To achieve high-foaming cleaning, car washes use a lot of surfactants, which have excellent foaming properties. While using large amounts of these surfactants provides a better car wash experience, it also leads to significant surfactant waste and increases the environmental burden.

[0003] In the existing technology, patent CN206051750U, a car wash wastewater recycling device, discloses an ozone catalyst box, a deoxidation box, an activated carbon filter, an ultraviolet sterilizer, and a clean water tank. The ozone catalyst box is connected to the water inlet pipe and is also provided with an ozone generator. This patent uses ozone catalytic oxidation to pre-destroy the performance of the surfactant, making it inactive before reusing the wastewater, resulting in a waste of surfactant. At the same time, the use of ozone catalytic oxidation increases carbon emissions and is prone to secondary pollution.

[0004] Patent CN212833143U discloses a car wash wastewater purification device, which includes a wastewater collection tank, a filter tank, a diatom membrane filter device, an activated carbon filter, and a water purification tank. The wastewater generated by the car wash passes through the wastewater collection tank, the filter tank, the diatom membrane filter device, the activated carbon filter, and the water purification tank in sequence. The patent uses the diatom filter device and the activated carbon filter device to absorb and filter the surfactant, but does not achieve the recovery and utilization of the surfactant.

[0005] Patent CN205419950U, a car wash wastewater recycling system, discloses a lane diversion device, a collection and static system, a primary water purification and filtration system, a secondary water purification and filtration system, an ultimate pure water production system and a return water circulation system. The car wash wastewater treatment system achieves wastewater purification and reuse through sedimentation and three-stage filtration. However, the patent only treats car wash wastewater from the perspective of sedimentation and filtration, and does not involve the recycling of surfactants.

[0006] Therefore, providing a system and process for recycling car wash wastewater and surfactants is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a car wash wastewater and surfactant recycling system and process, which can simultaneously recycle car wash wastewater and car wash surfactants to reduce pollutant emissions.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A car wash wastewater and surfactant recycling system includes a wastewater collection tank, a reaction tank, a sedimentation separation tank, a quartz sand filter, a precision filter, an inert gas flotation tower, an ultraviolet disinfection tube and a clean water tank, which are connected from left to right through pipelines. The reaction tank is connected to a polyaluminum chloride agent barrel, a polyacrylamide agent barrel and a sodium hydroxide agent barrel respectively through pipelines; the upper and middle parts of the inert gas flotation tower are connected to a foam collection tank through a pipeline.

[0010] By adopting the above technical solution, the beneficial effects of the present invention are:

[0011] It can realize the recycling of car washing wastewater, and at the same time realize the recycling of car washing surfactants, thereby reducing pollutant emissions.

[0012] Furthermore, dosing pumps are installed on the pipes connecting the reaction tank and the polyaluminum chloride agent barrel, the pipes connecting the reaction tank and the polyacrylamide agent barrel, and the pipes connecting the reaction tank and the sodium hydroxide agent barrel.

[0013] Furthermore, a mud discharge pipe is installed at the bottom of the sedimentation separation tank.

[0014] Furthermore, an inert gas connecting pipe is installed at the bottom of the inert gas flotation tower.

[0015] A process for recycling car wash wastewater and surfactants comprises the following steps:

[0016] 1) After the car wash wastewater is collected, it is injected into the reaction tank, 10% concentration of polyaluminium chloride agent is added to the polyaluminium chloride agent barrel, 0.1% concentration of dissolved polyacrylamide agent is added to the polyacrylamide agent barrel, and 10% concentration of sodium hydroxide agent is added to the sodium hydroxide agent barrel;

[0017] 2) Add the volume ratio of the polyaluminum chloride agent barrel to the wastewater to the reaction tank at 1:800-1000, add the volume ratio of the polyacrylamide agent barrel to the wastewater to the reaction tank at 1:2400-2800, and add the volume ratio of the sodium hydroxide agent barrel to the wastewater to the reaction tank at 1:1550;

[0018] 3) Car wash wastewater reacts with mixed reagents in the reaction tank;

[0019] 4) The effluent from the reaction tank overflows into the sedimentation separation tank. The supernatant in the sedimentation separation tank enters the quartz sand filter and precision filter in sequence through a water pump, while the sediment at the bottom of the sedimentation separation tank is discharged;

[0020] 5) Car wash wastewater enters from the top of the inert gas flotation tower and flows from top to bottom, while the inert gas enters from the bottom of the inert gas flotation tower and flows from bottom to top;

[0021] 6) The foam separated by flotation in the inert gas flotation tower is transported to the foam collection box. The collected foam is connected to the foam gun for car washing for re-proportioning and use. The car washing wastewater after flotation separation is transported to the ultraviolet disinfection pipe for disinfection. After disinfection, it is transported to the clean water tank for car washing.

[0022] By adopting the above technical solution, the beneficial effects of the present invention are:

[0023] By adding polyaluminium chloride and polyacrylamide into the car wash wastewater, the colloid formed by the inactivated surfactant can be precipitated and separated in a sedimentation separation tank; at the same time, by adding sodium hydroxide, the hardness in the water can be removed and the decontamination ability of the wastewater can be increased; by contacting the wastewater with inert gas, part of the surfactant can be recovered and recycled; by adjusting the disinfection process to the back end, the surfactant can be avoided from being oxidized and inactivated, and losing its recycling value, thereby effectively improving the utilization efficiency of car wash water, improving the use efficiency of surfactants, and reducing pollutant emissions.

[0024] Furthermore, in step 4), the car wash wastewater stays in the sedimentation separation tank for 15 to 20 minutes.

[0025] Furthermore, in step 5), the volume ratio of the inert gas to the car wash wastewater is 1:7-10. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0027] Figure 1 The accompanying drawing is a structural schematic diagram of a car wash wastewater and surfactant recycling system provided by the present invention. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, an embodiment of the present invention discloses a car wash wastewater and surfactant recycling system, comprising, from left to right, a wastewater collection tank, a reaction tank 1, a sedimentation separation tank 2, a quartz sand filter 3, a precision filter 4, an inert gas flotation tower 5, an ultraviolet disinfection tube 6, and a clean water tank 7, which are connected by pipes. The reaction tank 1 is connected to a polyaluminum chloride reagent tank 8, a polyacrylamide reagent tank 9, and a sodium hydroxide reagent tank 10, respectively, via pipes. The upper and middle portion of the inert gas flotation tower 5 is connected to a foam collection tank 11 via pipes. The present invention can achieve the recycling of car wash wastewater and the recycling of car wash surfactants, thereby reducing pollutant emissions.

[0030] Specifically, dosing pumps are installed on the pipes connecting the reaction tank 1 and the polyaluminum chloride reagent barrel 8, the pipes connecting the reaction tank 1 and the polyacrylamide reagent barrel 9, and the pipes connecting the reaction tank 1 and the sodium hydroxide reagent barrel 10.

[0031] Specifically, a mud discharge pipe 12 is installed at the bottom of the sedimentation separation tank 2 .

[0032] Specifically, an inert gas connecting pipe 13 is installed at the bottom of the inert gas flotation tower 5 .

[0033] The embodiment of the present invention further discloses a process according to the above-mentioned car wash wastewater and surfactant recycling system, comprising the following steps:

[0034] 1) Car wash wastewater is collected and injected into the reaction tank 1, 10% concentration of polyaluminium chloride is added to the polyaluminium chloride reagent barrel 8, 0.1% concentration of dissolved polyacrylamide is added to the polyacrylamide reagent barrel 9, and 10% concentration of sodium hydroxide is added to the sodium hydroxide reagent barrel 10;

[0035] 2) sequentially adding the volume ratio of the polyaluminum chloride agent barrel 8 to the wastewater to the reaction tank according to 1:800-1000, adding the volume ratio of the polyacrylamide agent barrel 9 to the wastewater to the reaction tank according to 1:2400-2800, and adding the volume ratio of the sodium hydroxide agent barrel 10 to the wastewater to the reaction tank according to 1:1550;

[0036] 3) Car wash wastewater reacts with a mixed reagent (a reagent formed by mixing polyaluminum chloride reagent, neutral polyacrylamide reagent and sodium hydroxide reagent) in the reaction tank 1, thereby effectively agglomerating suspended matter such as colloids in the wastewater, while reducing the hardness of the car wash wastewater and improving the decontamination ability;

[0037] 4) The effluent from the reaction tank 1 overflows into the sedimentation separation tank 2, where efficient separation is achieved through sedimentation. The supernatant in the sedimentation separation tank 2 enters the quartz sand filter 3 and the precision filter 4 in sequence through a water pump to further remove fine particles such as colloids, thereby further improving the quality of the circulating water. The sediment at the bottom of the sedimentation separation tank 2 is discharged, that is, the bottom sediment is discharged through the mud discharge pipe 12. In this embodiment, the residence time of the car wash wastewater in the sedimentation separation tank 2 is 15 to 20 minutes.

[0038] 5) Car wash wastewater enters the top of the inert gas flotation tower 5 and flows downward, while the inert gas enters the bottom of the inert gas flotation tower 5 and flows upward. This allows the residual surfactant to be separated and reused in the form of foam. Furthermore, the contact between the inert gas and the car wash wastewater does not provide energy for the growth of microorganisms in the circulating liquid. In this embodiment, the volume ratio of the inert gas to the car wash wastewater is 1:7-10.

[0039] 6) The foam separated by flotation in the inert gas flotation tower 5 is transported to the foam collection box 11. The collected foam is connected to the foam gun for car washing and reused. The car wash wastewater after flotation separation is transported to the ultraviolet disinfection tube 6 for disinfection, which can further sterilize and disinfect, and improve the water quality of the car wash wastewater. After disinfection, it is transported to the clean water tank 7 for car washing.

[0040] The present invention adds polyaluminium chloride and polyacrylamide into car wash wastewater, and then precipitates and separates the colloid formed by the inactivated surfactant in a sedimentation and separation tank 2; at the same time, sodium hydroxide is added to remove the hardness of the water and increase the decontamination ability of the wastewater; inert gas is brought into contact with the wastewater to recover part of the surfactant for recycling; and by adjusting the disinfection process to the back end, the surfactant is avoided from being oxidized and inactivated, thereby losing its recycling value, thereby effectively improving the utilization efficiency of car wash water, enhancing the use efficiency of the surfactant, and reducing pollutant emissions.

[0041] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0042] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A car wash wastewater and surfactant recycling process, which is carried out using a car wash wastewater and surfactant recycling system, characterized in that: The following steps are involved: 1) After the car wash wastewater is collected, it is injected into the reaction tank. A 10% concentration of polyaluminium chloride agent is added to the polyaluminium chloride agent barrel, a 0.1% concentration of dissolved polyacrylamide agent is added to the polyacrylamide agent barrel, and a 10% concentration of sodium hydroxide agent is added to the sodium hydroxide agent barrel; 2) Add the volume ratio of the polyaluminum chloride reagent barrel to the wastewater into the reaction tank at 1:800~1000, add the volume ratio of the polyacrylamide reagent barrel to the wastewater into the reaction tank at 1:2400~2800, and add the volume ratio of the sodium hydroxide reagent barrel to the wastewater into the reaction tank at 1:1550; 3) Car wash wastewater reacts with mixed reagents in the reaction tank; 4) The effluent from the reaction tank overflows into the sedimentation separation tank. The supernatant in the sedimentation separation tank enters the quartz sand filter and precision filter in sequence through a water pump, while the sediment at the bottom of the sedimentation separation tank is discharged; 5) Car wash wastewater enters from the top of the inert gas flotation tower and flows from top to bottom, while the inert gas enters from the bottom of the inert gas flotation tower and flows from bottom to top. On the one hand, the residual surfactant can be separated and reused in the form of foam. On the other hand, the contact between the inert gas and the car wash wastewater will not provide energy for the reproduction of microorganisms in the circulating liquid; 6) The foam separated by flotation in the inert gas flotation tower is transported to the foam collection box. The collected foam is connected to the foam gun for car washing for re-proportioning and use. The car washing wastewater after flotation separation is transported to the ultraviolet disinfection pipe for disinfection. After disinfection, it is transported to the clean water tank for car washing.

2. The process according to claim 1, characterized in that In step 4), the car wash wastewater stays in the sedimentation separation tank for 15 to 20 minutes.

3. The process according to claim 1, characterized in that In step 5), the volume ratio of the inert gas to the car wash wastewater is 1:7-10.

4. The process according to claim 1, characterized in that The car wash wastewater and surfactant recycling system includes a wastewater collection tank, a reaction tank, a sedimentation separation tank, a quartz sand filter, a precision filter, an inert gas flotation tower, an ultraviolet disinfection tube and a clean water tank, which are connected from left to right through pipes. The reaction tank is connected to a polyaluminum chloride agent barrel, a polyacrylamide agent barrel and a sodium hydroxide agent barrel respectively through pipes; the middle and upper part of the inert gas flotation tower is connected to a foam collection box through a pipe.

5. The process according to claim 4, characterized in that Dosing pumps are installed on the connecting pipes between the reaction tank and the polyaluminum chloride reagent barrel, the connecting pipes between the reaction tank and the polyacrylamide reagent barrel, and the connecting pipes between the reaction tank and the sodium hydroxide reagent barrel.

6. The process according to claim 4, characterized in that A mud discharge pipe is installed at the bottom of the sedimentation separation tank.

7. The process according to claim 4, characterized in that An inert gas connecting pipe is installed at the bottom of the inert gas flotation tower.

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