Full dissolved air flotation stripping system for sewage treatment and treatment process

Abstract

This invention relates to the field of wastewater treatment technology, specifically to a fully dissolved air flotation (SAF) stripping system and treatment process for wastewater treatment. The SAF stripping system includes a flotation tank, a primary separation device, a first dissolved air device, a dissolved air water distribution tank, and an overflow collection unit. The flotation tank is cylindrical, with an inlet and an outlet at its axial ends. The inlet allows wastewater to enter the flotation tank, and the outlet allows treated water to be discharged from the flotation tank. The overflow collection unit is located inside the flotation tank and includes a collection cylinder and two overflow troughs. The axis of the collection cylinder extends vertically and is connected to the interior of both overflow troughs. The overflow troughs extend axially along the flotation tank, and the two overflow troughs are symmetrically fitted onto the inner wall of the flotation tank with their openings facing each other, thereby collecting floating foam on the liquid surface and improving the wastewater purification effect.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a fully dissolved air flotation stripping system and treatment process for wastewater treatment. Background Technology

[0002] The fully dissolved air flotation stripping system is the core process in the pressurized dissolved air flotation process. This process pressurizes and dissolves air in the entire water body to be treated, and then depressurizes and releases the air. It relies on the generated microbubbles to achieve efficient separation of suspended solids, oils and colloidal pollutants in the water body. It has advantages such as sufficient dissolved air, high contact efficiency and compact equipment tank structure, and is suitable for water treatment conditions with small water volume and high pollution concentration.

[0003] Currently, the scum and foam generated by dissolved air flotation (DAF) systems are mainly collected using two methods: mechanical scraping and hydraulic overflow. In practice, an adjustable-height overflow weir is typically installed at the end of the flotation tank, or a dedicated scum removal mechanism is used for scum cleaning. For example, patent application CN108002571A discloses a DAF machine, which mainly includes a mixing tank, a pressurized suction pump, a pressure dissolved air tank, a flotation tank, a scum removal belt, and a cleaning tank. The scum removal belt is equipped with scum removal plates, which are covered with bristles to improve solid-liquid separation efficiency and ensure effective separation. However, in actual operation, this traditional scum removal structure has poor effects on the encapsulation, transport, and collection of scum, resulting in low overall scum collection efficiency and problems such as scum residue and scum accumulation, which affect the wastewater purification effect. Summary of the Invention

[0004] Therefore, it is necessary to provide a fully dissolved air flotation stripping system and treatment process for wastewater treatment, addressing the technical problems of low foam collection efficiency and poor wastewater purification effect of current air flotation machines.

[0005] The above objectives are achieved through the following technical solutions:

[0006] A fully dissolved air flotation stripping system for wastewater treatment includes a flotation tank, a primary separation device, a first dissolved air device, a dissolved air water distribution tank, and an overflow collection unit. The flotation tank is cylindrical with its axis extending horizontally. The axial ends of the flotation tank are the inlet and outlet, respectively. The inlet allows wastewater to enter the flotation tank, and the outlet allows treated water to be discharged from the tank. The primary separation device is located inside the flotation tank and near the inlet, and is used for primary separation of the wastewater entering the flotation tank. The first dissolved air device is located outside the flotation tank and is used to distribute dissolved air water to the wastewater. Wastewater after primary separation is injected with gas to form dissolved air water; the dissolved air water distribution tank is located outside the flotation tank and is used to uniformly release the dissolved air water formed by the first dissolved air device into the interior of the flotation tank; the overflow collection unit is located inside the flotation tank and includes a collection cylinder and two overflow troughs. The axis of the collection cylinder extends in the vertical direction and is connected to the interior of the two overflow troughs. The overflow troughs extend along the axial direction of the flotation tank. The two overflow troughs are symmetrically fitted on the inner side wall of the flotation tank, and their openings are opposite each other to collect the foam floating on the liquid surface.

[0007] Furthermore, the overflow trough is made of foam material, which allows it to float on the surface of the flotation tank and fluctuate with the movement of the liquid.

[0008] Furthermore, the inner wall of the flotation tank is provided with a dovetail block, and the outer surface of the overflow trough is provided with a dovetail groove. The dovetail block and the dovetail groove correspond one-to-one and slide together, so that the overflow trough can rotate around the circumference of the flotation tank.

[0009] Furthermore, a limiting plate can be detachably installed at the opening of the dovetail groove, and the limiting plate can prevent the dovetail block from detaching from the dovetail groove.

[0010] Furthermore, the overflow channel has a V-shaped groove, the opening of which is the opening of the overflow channel, and a baffle is provided at the opening of the overflow channel, the baffle being disposed away from the bottom of the V-shaped groove.

[0011] Furthermore, each overflow tank is fixedly connected to an auxiliary spray pipe at its bottom. The auxiliary spray pipe extends along the axial direction of the flotation tank and is used to spray water into the bottom of the overflow tank, thereby causing the foam at the bottom of the overflow tank to gather towards the center of the flotation tank.

[0012] Furthermore, a radar ranging device is provided at the top of the air flotation tank. The radar ranging device can measure the height of the liquid level inside the air flotation tank, and the injection pressure of the auxiliary injection pipe is positively correlated with the height of the liquid level inside the air flotation tank.

[0013] Furthermore, the wastewater treatment dissolved air flotation stripping system also includes a second dissolved air device. The bottom of the auxiliary injection pipe is connected to a second flexible hose, which is fixedly installed on the flotation tank. One end of the second dissolved air device is connected to the outlet end through a second hydraulic pump, and the other end is connected to the second flexible hose. The injection pressure of the auxiliary injection pipe is adjusted by adjusting the suction power of the second hydraulic pump.

[0014] Furthermore, each end of the overflow trough is provided with a first flexible hose, which is connected to the interior of the collection cylinder.

[0015] The dissolved air flotation stripping process for wastewater treatment, using the aforementioned dissolved air flotation stripping system, includes the following steps:

[0016] S1. Sewage enters the flotation tank from the inlet end and undergoes primary separation through the primary separation device;

[0017] S2. The wastewater after primary separation enters the first dissolved air device and forms dissolved air water. The dissolved air water is then evenly injected into the flotation tank through the dissolved air water distribution tank for flotation separation.

[0018] S3. The water flowing out of the outlet of the flotation tank enters the second dissolved air device and forms dissolved air water. The dissolved air water is then sprayed into the bottom of the overflow tank through the auxiliary spray pipe, thereby promoting the foam to gather in the middle of the flotation tank. At the same time, the foam on the liquid surface is automatically collected through the symmetrically arranged overflow tank, and the foam is discharged outward through the collection cylinder.

[0019] S4. The liquid level is monitored in real time by a radar ranging device, and the suction power of the second hydraulic pump is dynamically adjusted to adjust the injection pressure of the auxiliary injection pipe.

[0020] The beneficial effects of this invention are:

[0021] The fully dissolved air flotation stripping system and treatment process for wastewater treatment provided by this invention, firstly, because the flotation tank is cylindrical, when the liquid level is higher than half the height of the flotation tank, the foam on the liquid surface will gather towards the center, resulting in a state where the center is thin and the sides are thick. By setting two symmetrical overflow troughs and positioning the openings of the two overflow troughs opposite each other, the foam on the sides of the flotation tank can be collected more effectively, thereby improving the wastewater purification effect.

[0022] Secondly, by making the overflow tank fluctuate with the liquid surface, it is easier to collect the foam on the liquid surface, thereby further improving the foam collection efficiency.

[0023] Third, when the overflow trough floats upward with the liquid surface and rotates along the inner wall of the flotation tank, the surface where the baffle is located has a certain angle with the vertical direction, and this angle gradually increases with the increase of the liquid level height, thereby gradually reducing the size of the baffle in the vertical direction. That is, the degree of baffle blocking the foam gradually decreases. Since the thickness of the foam layer on the side further increases at this time, the overflow trough can collect foam more easily, and the overflow trough is less likely to overflow the liquid, thus improving the overflow effect of the overflow trough overall.

[0024] Fourth, the radar ranging device can measure the height of the liquid level in the flotation tank, so that the injection pressure of the auxiliary injection pipe is positively correlated with the height of the liquid level in the flotation tank, which can always prevent foam from accumulating at the bottom of the overflow tank. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of a fully dissolved air flotation stripping system for wastewater treatment provided in an embodiment of the present invention;

[0026] Figure 2 This is a top view schematic diagram of a fully dissolved air flotation stripping system for wastewater treatment provided in an embodiment of the present invention;

[0027] Figure 3 for Figure 2 Schematic diagram of the AA section;

[0028] Figure 4 for Figure 2 Schematic diagram of the BB section;

[0029] Figure 5 This is a schematic diagram of the structure of a single overflow tank in a fully dissolved air flotation stripping system for wastewater treatment provided in an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of the flotation tank in a fully dissolved air flotation stripping system for wastewater treatment provided in an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of the first dissolved air device in a fully dissolved air flotation stripping system for wastewater treatment provided in an embodiment of the present invention.

[0032] in:

[0033] 100. Flotation tank; 101. Radar ranging device; 102. Inlet; 103. Outlet; 104. Gas distribution assembly; 105. Primary waste pipe; 106. Primary wastewater outlet; 107. Collection cylinder; 108. Dovetail block; 1081. Foam; 200. Ground; 300. First dissolved air device; 301. First nitrogen inlet pipe; 302. First water inlet; 303. First hydraulic pump; 304. First dissolved air water outlet; 305. Gas release device; 306. 400. Spiral plate; 401. Second dissolved gas device; 402. Second nitrogen inlet pipe; 403. Second dissolved gas water outlet; 404. Riser; 405. Second water inlet; 406. Second hydraulic pump; 407. Discharge pipeline; 500. Dissolved gas water distribution tank; 501. Nozzle; 600. Overflow trough; 6001. Dovetail trough; 6002. Limiting plate; 601. First hose; 602. Tank bottom; 603. Baffle; 604. Auxiliary injection pipe; 6041. Second hose. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0035] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage" used in this invention, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0036] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] like Figures 1 to 7 As shown, an embodiment of the present invention provides a fully dissolved air flotation stripping system for wastewater treatment, comprising a flotation tank 100, a primary separation device, a first dissolved air device 300, a dissolved air water distribution tank 500, and an overflow collection unit. The flotation tank 100 is cylindrical, with its axis extending horizontally. The two axial ends of the flotation tank 100 are an inlet end 102 and an outlet end 103, respectively. The inlet end 102 allows wastewater to enter the flotation tank 100, and the outlet end 103 allows treated water to be discharged from the flotation tank 100. The primary separation device is located inside the flotation tank 100 and near the inlet end 102, and is used for primary separation of the wastewater entering the flotation tank 100. The first dissolved air device 300 is located within the flotation tank 100. Externally, it is used to inject gas into the wastewater after primary separation to form dissolved air water; the dissolved air water distribution tank 500 is located outside the flotation tank 100, and is used to uniformly release the dissolved air water formed by the first dissolved air device 300 into the interior of the flotation tank 100; the overflow collection unit is located inside the flotation tank 100, and includes a collection cylinder 107 and two overflow troughs 600. The axis of the collection cylinder 107 extends in the vertical direction, and the collection cylinder 107 is simultaneously connected to the interior of the two overflow troughs 600. The overflow troughs 600 extend along the axial direction of the flotation tank 100. The two overflow troughs 600 are symmetrically fitted on the inner sidewall of the flotation tank 100, and their openings are opposite to each other, for collecting the foam 1081 floating on the liquid surface.

[0038] Because the flotation tank 100 is cylindrical, when the liquid level is higher than half the height of the flotation tank 100, the foam 1081 on the liquid surface will gather towards the center, resulting in a state where the foam is thinner in the middle and thicker on both sides (e.g., ...). Figure 4 (As shown by the dashed line). By setting two symmetrical overflow troughs 600 and positioning the openings of the two overflow troughs 600 opposite each other, the present invention can better collect the foam 1081 on the side of the flotation tank 100, thereby improving the purification effect of wastewater.

[0039] Furthermore, the overflow trough 600 is made of foam material, allowing it to float on the liquid surface of the flotation tank 100 and move with the fluctuations of the liquid surface. The foam material is a closed-cell organic foam material, such as polyurethane foam, polystyrene foam, or polyethylene foam. By making the overflow trough 600 move with the fluctuations of the liquid surface, it is easier to collect the foam 1081 on the liquid surface, thereby further improving the collection efficiency of the foam 1081.

[0040] Furthermore, the inner wall of the flotation tank 100 is provided with dovetail blocks 108, and the outer surface of the overflow trough 600 is provided with dovetail grooves 6001. The dovetail blocks 108 and dovetail grooves 6001 correspond one-to-one and slide together, thereby allowing the overflow trough 600 to rotate circumferentially along the flotation tank 100. When the overflow trough 600 fluctuates with the fluctuation of the liquid surface in the flotation tank 100, the overflow trough 600 can rotate around the axis of the flotation tank 100 by a certain angle. Each overflow trough 600 has at least two dovetail grooves 6001 distributed along the axial direction of the flotation tank 100 on its outer surface. The dovetail grooves 6001 and the dovetail blocks 108 are all trapezoidal, and the trapezoidal bases of the dovetail grooves 6001 and the dovetail blocks 108 face the axis of the flotation tank 100.

[0041] Furthermore, a limiting plate 6002 can be detachably installed at the opening of the dovetail groove 6001. The limiting plate 6002 prevents the dovetail block 108 from detaching from the dovetail groove 6001. The limiting plate 6002 is fixedly mounted on the overflow groove 600 with bolts, thereby facilitating the assembly and disassembly of the dovetail groove 6001 and the dovetail block 108 on the overflow groove 600. This also limits the movement range of the overflow groove 600, preventing it from moving arbitrarily and thus failing to collect the foam 1081.

[0042] Furthermore, the overflow trough 600 has a V-shaped groove, the opening of which is the opening of the overflow trough 600. A baffle 603 is provided at the opening of the overflow trough 600, and the baffle 603 is disposed away from the bottom 602 of the V-shaped groove.

[0043] The outer surface of the overflow trough 600 is arc-shaped, and the overflow trough 600 fits against the inner wall of the flotation tank 100 through the arc-shaped surface. Figure 4 As shown, the surface of the baffle 603 is parallel to the vertical direction. When the overflow trough 600 floats upward with the liquid surface and rotates along the inner wall of the flotation tank 100, the surface of the baffle 603 has a certain angle with the vertical direction, and this angle gradually increases with the increase of the liquid level height, thereby gradually reducing the size of the baffle 603 in the vertical direction. That is, the degree of obstruction of the foam 1081 by the baffle 603 gradually decreases. Since the thickness of the foam 1081 on the side further increases at this time, the overflow trough 600 can collect the foam 1081 more easily, and the overflow trough 600 is less likely to overflow the liquid, thus improving the overflow effect of the overflow trough 600 overall.

[0044] Furthermore, each overflow tank 600 is fixedly connected to an auxiliary spray pipe 604 at its bottom. The auxiliary spray pipe 604 extends axially along the flotation tank 100 and is used to spray water into the bottom of the overflow tank 600, thereby causing the foam 1081 at the bottom of the overflow tank 600 to gather towards the center of the flotation tank 100. By setting the auxiliary spray pipe 604, the foam 1081 is less likely to accumulate at the bottom of the overflow tank 600, and the foam 1081 can be gathered together for easy collection.

[0045] Furthermore, a radar ranging device 101 is provided at the inner top of the air flotation tank 100. The radar ranging device 101 can measure the height of the liquid level inside the air flotation tank 100. The injection pressure of the auxiliary injection pipe 604 is positively correlated with the height of the liquid level inside the air flotation tank 100.

[0046] As the liquid level rises, the overflow tank 600 moves closer to the center of the flotation tank 100, making it easier for scum 1081 to accumulate at the bottom of the overflow tank 600. The radar ranging device 101 measures the liquid level in the flotation tank 100, ensuring that the injection pressure of the auxiliary injection pipe 604 is positively correlated with the liquid level, thus preventing scum 1081 from accumulating at the bottom of the overflow tank 600.

[0047] Furthermore, the wastewater treatment dissolved air flotation stripping system also includes a second dissolved air device 400. A second flexible hose 6041 is connected to the bottom of the auxiliary injection pipe 604. The second flexible hose 6041 is fixedly installed on the flotation tank 100. One end of the second dissolved air device 400 is connected to the outlet end 103 via a second hydraulic pump 404, and the other end is connected to the second flexible hose 6041. The injection pressure of the auxiliary injection pipe 604 is adjusted by regulating the suction power of the second hydraulic pump 404. The second dissolved air device 400 is provided with a second dissolved air water outlet 402, which is connected to a riser pipe 4021, which is connected to the second flexible hose 6041.

[0048] When the auxiliary injection pipe 604 moves with the overflow tank 600, the second flexible hose 6041 can extend or retract. The water outlet 103 is connected to a discharge pipe 405, which is connected to the second inlet 403 of the second dissolved air device 400 via a second hydraulic pump 404. The second dissolved air device 400 is equipped with a second nitrogen inlet pipe 401, through which nitrogen enters the second dissolved air device 400, mixing with water to form dissolved air water. The dissolved air water flows sequentially from the second dissolved air water outlet 402 to the riser 4021, the second flexible hose 6041, and the auxiliary injection pipe 604.

[0049] Furthermore, each end of the overflow tank 600 is provided with a first flexible hose 601, which communicates with the interior of the collection cylinder 107. When the overflow tank 600 moves with the liquid level, the first flexible hose 601 can extend or retract.

[0050] The flotation tank 100 is placed horizontally on the ground 200. The interior of the flotation tank 100 is divided into a stripping chamber and a flotation chamber by a partition, with the upper part of the stripping chamber connected to the upper part of the flotation chamber. A primary separation device is installed corresponding to the stripping chamber, and the primary separation device includes an air distribution assembly 104 and a primary sludge pipe 105. The air distribution assembly 104 injects an upward high-velocity airflow into the stripping chamber, and the primary sludge pipe 105 is used to collect solid pollutants separated from the wastewater through the primary separation.

[0051] The first dissolved air device 300, the dissolved air water distribution tank 500, the second dissolved air device 400, and the overflow tank 600 all correspond to the flotation chamber. The first dissolved air device 300 is equipped with a first nitrogen inlet pipe 301, a first water inlet 302, and a first dissolved air water outlet 304. The first nitrogen inlet pipe 301 supplies nitrogen to the interior of the first dissolved air device 300. The first water inlet 302 is connected to the interior of the stripping chamber, and a first hydraulic pump 303 is provided between the first water inlet 302 and the stripping chamber. The suction of the first hydraulic pump 303 allows the wastewater after primary separation to enter the interior of the first dissolved air device 300. The dissolved air water distribution tank 500 is provided with a dissolved air water inlet and a nozzle 501. The first dissolved air water outlet 304 is connected to the dissolved air water inlet, so that dissolved air water can enter the dissolved air water distribution tank 500. The nozzle 501 faces the interior of the flotation tank 100, so that the dissolved air water in the dissolved air water distribution tank 500 enters the interior of the flotation tank 100 through the nozzle 501.

[0052] like Figure 7 As shown, the first dissolved air device 300 is a swirling dissolved air device, which contains a spiral plate 306 and a gas release device 305. The gas release device 305 is coaxially located inside the spiral plate 306 and is connected to the first nitrogen inlet pipe 301. Thus, the wastewater after primary separation and the nitrogen gas generate a swirling flow, and the inner surface of the fluid tangentially interacts with the gas release device 305, causing the gas released by the gas release device 305 to be continuously sheared and mixed by the liquid flow, forming a dissolved gas liquid flow. By adjusting the orifice diameter of the gas release device 305, the shear rate of the water flow, and the gas supply pressure, the size of the bubbles can be changed, thus obtaining the optimal dissolved air water and improving the dissolved air flotation efficiency. For example, by preparing bubbles with a larger specific surface area, the adsorption efficiency can be improved, and the removal rate of emulsified oil and fine suspended solids can reach 90%.

[0053] Both the first dissolved air device 300 and the second dissolved air device 400 use nitrogen gas because nitrogen can reduce the oxygen content in the dissolved water, thereby helping to reduce oxidation and having a better effect on oxygen-sensitive solid particles. Furthermore, nitrogen has a slightly lower density and molecular weight than air, allowing for the generation of more bubbles per volume. Increased pressure allows for finer release pore sizes, resulting in smaller and more abundant bubbles, thus ensuring effective flotation.

[0054] Based on the above embodiments, the usage principle and working process of the embodiments of the present invention are as follows:

[0055] like Figure 3 As shown, wastewater enters the stripping chamber of the flotation tank 100 from the inlet 102. The wastewater flows downwards and then upwards (in the directions indicated by arrows a and b in the diagram), then opposes the high-speed upward airflow generated by the gas distribution component 104 (in the direction indicated by arrow c). This causes dissolved gases, volatile substances, and free oil droplets in the wastewater to be carried out of the continuous liquid phase, completing the primary separation. At this time, solid pollutants in the wastewater enter the primary sludge pipe 105 and settle, finally being discharged from the bottom outwards (in the direction indicated by arrow f). The wastewater flows out of the primary sludge pipe 105 (in the direction indicated by arrow d) and continues to flow towards the outlet 103. A portion of the wastewater that has undergone primary separation enters the first dissolved air device 300 through the primary wastewater outlet 106 (in the direction indicated by arrow e), where it is sheared and mixed with nitrogen to form dissolved air water. The dissolved air water then re-enters the flotation tank 100 through the nozzle 501 of the dissolved air water distribution tank 500 (in the direction indicated by arrow g). During this stage, suspended solids, fine oil droplets, heavy metals, organic matter, and other adhering substances in the wastewater are rapidly released to the surface after being depressurized by the gas release device 305 in the first dissolved air device 300, forming foam 1081, thus completing the air flotation.

[0056] Since the flotation tank 100 is cylindrical, when the liquid level is higher than half the height of the flotation tank 100, the foam 1081 on the surface of the liquid will gather towards the center, resulting in a state where the center is thinner and the sides are thicker. The symmetrically arranged overflow tanks 600 can collect the foam located on both sides. The collected foam enters the collection cylinder 107 through the first hose 601 and is finally discharged outward (in the direction indicated by arrow i). The treated wastewater continues to flow towards the outlet end 103 (in the direction indicated by arrow j) and is finally discharged through the outlet end 103 (in the direction indicated by arrow k).

[0057] During this process, the water discharged from the outlet 103 is brought into the second dissolved air device 400 by controlling the second hydraulic pump 404, and dissolved air water is formed in the second dissolved air device 400. The dissolved air water enters the auxiliary spray pipe 604 through the second hose 6041, which can prevent the accumulation of foam 1081 at the bottom of the overflow tank 600 and improve the overflow effect of the overflow tank 600.

[0058] When the liquid level fluctuates, the overflow tank 600 fluctuates with the liquid level, making it easier to collect the foam 1081 on the liquid surface. Furthermore, the radar ranging device 101 can measure the height of the liquid level in the flotation tank 100 in real time and control the suction power of the second hydraulic pump 404, ensuring that the injection pressure of the auxiliary injection pipe 604 is positively correlated with the height of the liquid level in the flotation tank 100. This effectively prevents the foam 1081 from accumulating at the bottom of the overflow tank 600.

[0059] An embodiment of the dissolved air flotation stripping process for wastewater treatment, employing the aforementioned dissolved air flotation stripping system, includes the following steps:

[0060] S1. Sewage enters the flotation tank 100 from the inlet 102 and undergoes primary separation through the primary separation device;

[0061] S2. The wastewater after primary separation enters the first dissolved air device 300 and forms dissolved air water. The dissolved air water is then evenly injected into the flotation tank 100 through the dissolved air water distribution tank 500 for flotation separation.

[0062] S3. Water flowing out of the outlet 103 of the flotation tank 100 enters the second dissolved air device 400 and forms dissolved air water. The dissolved air water is sprayed into the bottom of the overflow tank 600 through the auxiliary spray pipe 604, thereby promoting the foam 1081 to gather in the middle of the flotation tank 100. At the same time, the foam 1081 on the liquid surface is automatically collected by the symmetrically arranged overflow tank 600, and the foam 1081 is discharged outward through the collection cylinder 107.

[0063] S4. The liquid level is monitored in real time by the radar ranging device 101, and the suction power of the second hydraulic pump 404 is dynamically adjusted to adjust the injection pressure of the auxiliary injection pipe 604.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A full dissolved air flotation stripping system for sewage treatment, characterized by, include: The air flotation tank is cylindrical with its axis extending horizontally. The two ends of the air flotation tank are the inlet and the outlet, respectively. The inlet is for sewage to enter the air flotation tank, and the outlet is for the treated water to be discharged from the air flotation tank. The interior of the air flotation tank is divided into a stripping chamber and an air flotation chamber by a partition. The upper part of the stripping chamber is connected to the upper part of the air flotation chamber. A primary separation device is located inside the flotation tank and near the inlet end. It is used to perform primary separation of the wastewater entering the flotation tank. The primary separation device is set in relation to the stripping chamber and includes an air distribution assembly and a primary sludge pipe. The first dissolved air device, located outside the flotation tank, is used to inject gas into a portion of the wastewater that has undergone primary separation to form dissolved air water. A dissolved air water distribution tank is located outside the flotation tank and is used to uniformly release the dissolved air water formed by the first dissolved air device into the interior of the flotation tank. An overflow collection unit is located inside the flotation tank. It includes a collection cylinder and two overflow troughs. The axis of the collection cylinder extends vertically and communicates with the interior of both overflow troughs. The overflow troughs extend axially along the flotation tank. The two overflow troughs are symmetrically fitted onto the inner wall of the flotation tank, with their openings facing each other, for collecting floating foam on the liquid surface. The overflow troughs are made of foam material, allowing them to float on the liquid surface and fluctuate with the liquid level. Each overflow trough has a V-shaped groove, the opening of which is the opening of the overflow trough. A baffle is provided at the opening of the overflow trough, facing away from the bottom of the V-shaped groove. An auxiliary spray pipe is fixedly connected to the bottom of each overflow trough, extending axially along the flotation tank. This auxiliary spray pipe sprays water into the bottom of the overflow trough, causing the foam at the bottom of the overflow trough to gather towards the center of the flotation tank. The air flotation tank is equipped with a radar ranging device at its inner top. The radar ranging device can measure the height of the liquid level inside the air flotation tank. The injection pressure of the auxiliary injection pipe is positively correlated with the height of the liquid level inside the air flotation tank.

2. The full dissolved air flotation stripping system for sewage treatment according to claim 1, characterized in that, The inner wall of the flotation tank is provided with a dovetail block, and the outer surface of the overflow trough is provided with a dovetail groove. The dovetail block and the dovetail groove correspond one-to-one and slide together, so that the overflow trough can rotate around the circumference of the flotation tank.

3. The fully dissolved air flotation stripping system for wastewater treatment according to claim 2, characterized in that, A limiting plate can be detachably installed at the opening of the dovetail groove, and the limiting plate can prevent the dovetail block from detaching from the dovetail groove.

4. The fully dissolved air flotation stripping system for wastewater treatment according to claim 1, characterized in that, It also includes a second dissolved air device. The bottom of the auxiliary injection pipe is connected to a second flexible hose. The second flexible hose is fixedly installed on the flotation tank. One end of the second dissolved air device is connected to the water outlet through a second hydraulic pump, and the other end is connected to the second flexible hose. The injection pressure of the auxiliary injection pipe is adjusted by adjusting the suction power of the second hydraulic pump.

5. The fully dissolved air flotation stripping system for wastewater treatment according to claim 1, characterized in that, Each overflow trough is provided with a first flexible hose at the same end, and the first flexible hose is connected to the inside of the collection cylinder.

6. A fully dissolved air flotation stripping treatment process for wastewater treatment, employing the fully dissolved air flotation stripping system for wastewater treatment as described in claim 4, characterized in that, Includes the following steps: S1. Sewage enters the flotation tank from the inlet end and undergoes primary separation through the primary separation device; S2. A portion of the wastewater after primary separation enters the first dissolved air device and forms dissolved air water. The dissolved air water is then evenly injected into the flotation tank via the dissolved air water distribution tank for flotation separation. S3. The water flowing out of the outlet of the flotation tank enters the second dissolved air device and forms dissolved air water. The dissolved air water is then sprayed into the bottom of the overflow tank through the auxiliary spray pipe, thereby promoting the foam to gather in the middle of the flotation tank. At the same time, the foam on the liquid surface is automatically collected through the symmetrically arranged overflow tank, and the foam is discharged outward through the collection cylinder. S4. The liquid level is monitored in real time by a radar ranging device, and the suction power of the second hydraulic pump is dynamically adjusted to adjust the injection pressure of the auxiliary injection pipe.

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