A fly ash-based deep wastewater treatment system capable of removing heavy metals and COD

Abstract

This invention belongs to the field of wastewater treatment technology and discloses a fly ash-based wastewater deep treatment system capable of removing heavy metals and COD. The system includes a pretreatment module, a heavy metal removal module, a COD degradation module, and a deep treatment and reuse module. The pretreatment module is an air flotation tank composed of a tank body, dissolved air equipment, stirring equipment, isolation mechanism, scraper mechanism, and baffle assembly. In this system, wastewater in the pretreatment module flocculates in the flocculation zone and then enters the dissolved air zone through a bend to undergo air flotation and form scum. Guided by the baffle assembly, the scum enters above the separating floating plate. Subsequently, the scraper mechanism scrapes the scum to the discharge zone for discharge. Pipeline two also discharges dissolved air water from the dissolved air equipment through a cover, filter cloth, and grid plate to the upper part of the separating floating plate, causing some of the flocculated material deposited on the separating floating plate to float again, forming scum and preventing scum from entering below the separating floating plate and affecting subsequent wastewater treatment.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically a fly ash-based deep wastewater treatment system capable of removing heavy metals and COD. Background Technology

[0002] Fly ash-based wastewater refers to industrial wastewater containing fly ash components, or secondary wastewater generated after fly ash is used as a treatment material.

[0003] For coal ash-based wastewater, the treatment typically involves preliminary sedimentation, neutralization aeration, and sterilization. Preliminary sedimentation is a crucial step in removing oil and COD from the wastewater. Operators usually introduce the wastewater into a flotation tank (flocculation zone). After adding flocculants and agitating the wastewater, large suspended particles (such as oil and coal dust) and some insoluble COD are removed. The wastewater then enters a dissolved air zone, where a large amount of clean water and microbubbles are pumped in. The microbubbles adhere to the flocs and float to the clear water zone (the upper layer is the scum zone, and the lower layer is the clear water zone). Finally, a scum scraper removes the floating scum from the upper layer to the discharge zone, while the wastewater in the clear water zone is discharged to the next stage through a drain pipe. However, when the scum removal equipment removes the upper layer of scum, it causes fluctuations in the water source in the clear water zone, which leads to the destruction of microbubbles on some of the flocs carrying microbubbles (or the accumulation of flocs over a long period of time leads to floc deposition). This causes the scum to detach from the scum zone and remain suspended in the clear water zone. Long-term accumulation will affect the quality of the wastewater in the clear water zone.

[0004] Therefore, to solve the above problems, a fly ash-based deep wastewater treatment system capable of removing heavy metals and COD is proposed. Summary of the Invention

[0005] To address the problems mentioned in the background section, this invention provides a fly ash-based wastewater deep treatment system capable of removing heavy metals and COD, thus solving the problem that scum from the clear water zone of the flotation tank enters the clear water zone and affects subsequent wastewater treatment.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a fly ash-based wastewater deep treatment system capable of removing heavy metals and COD, comprising a pretreatment module, a heavy metal removal module, a COD degradation module, and a deep treatment and reuse module. The pretreatment module is an air flotation tank composed of a tank body, dissolved air equipment, stirring equipment, isolation mechanism, scraper mechanism, and baffle assembly. The tank body is provided with a flocculation zone, a dissolved air zone, a clear water zone, and a sludge discharge zone.

[0007] The pool body is also equipped with a bent pipe for connecting the flocculation zone and the dissolved air zone, and a drain pipe for connecting the clear water zone and the heavy metal removal module. The dissolved air zone and the clear water zone are separated by a baffle assembly.

[0008] The tank is equipped with a gas-dissolving device, the output of which extends into the gas-dissolving zone.

[0009] The isolation mechanism is located above the clear water area, and the scraper mechanism is installed on the pool body and located above the isolation mechanism;

[0010] After floating in the dissolved air zone, the scum can float to the top of the isolation mechanism. The operating scraper mechanism can guide the scum through the isolation mechanism to the upper part of the scum discharge zone.

[0011] Preferably, the pool body is further provided with a reflux zone and a connecting pipe, and the clear water zone and the reflux zone are connected by the connecting pipe; the stirring device is installed on the pool body and its output end is located in the flocculation zone; the input end of the dissolved air device is a reflux pipe and is connected to the reflux zone.

[0012] Preferably, the isolation mechanism includes a separation float, a support assembly, and an air flotation assembly, wherein the support assembly is installed at the bottom of the clear water zone to support the separation float located at the top of the clear water zone;

[0013] The scum located in the dissolved air zone is guided to float above the separating float plate by the baffle assembly. The air flotation assembly is installed at the bottom of the separating float plate and is used to perform secondary air flotation on the scum on the separating float plate.

[0014] Preferably, the air flotation assembly includes a cover fixedly installed at the bottom of the partition float plate, a filter cloth and a grid plate fixedly connected to the top of the cover, and a second pipe fixedly connected to the bottom of the cover, the other end of the second pipe being connected to the output end of the dissolved air device.

[0015] Preferably, the separating float is movably installed in the clear water zone, and sealing components are provided on both sides of the separating float near the slag discharge zone.

[0016] The support assembly is a telescopic cylinder, the inner rod part of which has buoyancy, and the sleeve part of the support assembly is provided with a constant pressure hole;

[0017] The support assembly allows the partition float to rise and fall with the liquid level in the clear water zone, and the height of the partition float near the baffle assembly is always lower than that of the baffle assembly.

[0018] Preferably, the sealing assembly includes a slider mounted on a partition float and capable of sliding on the inner wall of the pool. A rotating shaft and a roller are vertically and equidistantly connected inside the slider. A sealing ring is movably disposed inside the slider. The rotating shaft is located inside the sealing ring, and the roller abuts against the pool body.

[0019] A sealing strip is fixedly connected to the inside of the pool, and the sealing strip contacts and seals with the sealing ring;

[0020] The downward movement of the slider causes the rotating shaft to rotate and move along the sealing strip.

[0021] Preferably, the baffle assembly includes a U-shaped baffle fixed to the bottom of the pool, and a bent plate with a height higher than one end of the separating float is movably connected inside the U-shaped baffle. The U-shaped baffle has vertically spaced grid holes.

[0022] A connecting column is fixedly connected to the partition float, and the middle part of the connecting column is fixedly connected to the bending plate.

[0023] Preferably, a water baffle is fixed to the bottom of the separating float plate, and the water baffle can gradually block the drain pipe during the downward movement of the float plate.

[0024] Preferably, the scraper mechanism includes a chain drive assembly, a scraper assembly, and a reduction gearbox. The chain drive assembly is installed on the top of the pool body, and both the scraper assembly and the reduction gearbox are installed on the chain drive assembly and connected to it in a transmission manner.

[0025] A cam is fixedly connected to the output end of the reduction gearbox, and a push valve is installed on the second pipe. During the rotation of the cam, the push valve can be squeezed to close it.

[0026] Preferably, the scraper assembly includes a scraper one that is driven to the chain drive assembly, a limit rod fixedly connected to the scraper one, a scraper two that is sleeved on the limit rod, and the scraper two having buoyancy.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] The above solution involves flocculating the wastewater in the flocculation zone of the pretreatment module, then allowing it to enter the dissolved air zone through a bend for flotation and the formation of scum. After being guided by the baffle assembly, the scum enters the area above the partition float plate. Subsequently, the scraper mechanism scrapes the scum to the discharge area for discharge. At the same time, the second pipe also discharges the dissolved air water from the dissolved air equipment through the cover, filter cloth, and grid plate to the upper part of the partition float plate, causing some of the flocs deposited on the partition float plate to float up again and form scum. This prevents the scum from entering below the partition float plate and affecting the subsequent treatment of the wastewater.

[0029] The above solution changes the length of the support components as the water level in the pool changes, thereby changing the height of the partition float. This prevents the scum from becoming too thick when the water level drops, causing some scum to enter below the partition float through the gap between the baffle components and the partition float. At the same time, it prevents the scum from becoming too shallow when the water level is too high, causing a large amount of sewage to enter the scum discharge area and be discharged.

[0030] The above solution ensures that the height of the grid holes changes simultaneously with the change in the height of the separating float, thus preventing scum from entering below the separating float. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 This is a front view of the present invention;

[0033] Figure 3 This is a frontal perspective view of the present invention;

[0034] Figure 4 This is a front cross-sectional view of the present invention;

[0035] Figure 5 This is a partial cross-sectional view of the pool body of the present invention;

[0036] Figure 6 for Figure 5 Enlarged view of point A in the middle;

[0037] Figure 7 This is a schematic diagram of the isolation mechanism of the present invention;

[0038] Figure 8 This is an exploded view of the air flotation component of the present invention;

[0039] Figure 9 This is a schematic diagram of the scraper mechanism of the present invention.

[0040] In the diagram: 1. Tank body; 11. Flocculation zone; 12. Dissolved air zone; 13. Bend; 14. Clear water zone; 15. Drainage pipe; 16. Return zone; 17. Connecting pipe; 18. Slag discharge zone; 19. Sealing strip; 2. Dissolved air equipment; 21. Return pipe; 3. Agitator; 4. Isolation mechanism; 41. Separating float; 411. Baffle plate; 412. Connecting column; 42. Support assembly; 421. Constant pressure orifice; 43. Air flotation assembly; 431. Cover; 4 32. Filter cloth; 433. Grating plate; 434. Pipeline 2; 435. Press valve; 5. Scraper mechanism; 51. Chain drive assembly; 52. Scraper assembly; 521. Scraper 1; 522. Limiting rod; 523. Scraper 2; 53. Reduction gearbox; 531. Cam; 6. Sealing assembly; 61. Slider; 62. Rotating shaft; 63. Sealing ring; 64. Roller; 7. Baffle assembly; 71. U-shaped baffle; 72. Bending plate; 73. Grating hole. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] like Figures 1 to 9 As shown, the present invention provides a fly ash-based wastewater deep treatment system capable of removing heavy metals and COD, including a pretreatment module, a heavy metal removal module, a COD degradation module, and a deep treatment and reuse module;

[0043] The pretreatment module is an air flotation tank consisting of tank body 1, dissolved air equipment 2, stirring equipment 3, isolation mechanism 4, scraper mechanism 5 and baffle assembly 7. Tank body 1 is equipped with flocculation zone 11, dissolved air zone 12, clear water zone 14 and slag discharge zone 18.

[0044] The tank body 1 is also equipped with a bend 13 for connecting the flocculation zone 11 and the dissolved air zone 12, and a drain pipe 15 for connecting the clear water zone 14 and the heavy metal removal module. The dissolved air zone 12 and the clear water zone 14 are separated by a baffle assembly 7. A dissolved air device 2 is installed on the tank body 1, and its output end extends into the dissolved air zone 12.

[0045] The isolation mechanism 4 is located above the clear water zone 14, and the scraper mechanism 5 is installed on the pool body 1 and located above the isolation mechanism 4;

[0046] After floating in the dissolved air zone 12, the scum can float to the top of the isolation mechanism 4. The scraper mechanism 5 can guide the scum through the isolation mechanism 4 to the upper part of the scum discharge zone 18.

[0047] The pool body 1 is also equipped with a return zone 16 and a connecting pipe 17, and the clear water zone 14 and the return zone 16 are connected through the connecting pipe 17;

[0048] The stirring device 3 is installed on the tank body 1 and its output end is located in the flocculation zone 11; the input end of the dissolved air device 2 is the return pipe 21 and is connected to the return zone 16.

[0049] The isolation mechanism 4 includes a separation float 41, a support assembly 42, and an air flotation assembly 43. The support assembly 42 is installed at the bottom of the clear water zone 14 to support the separation float 41 located at the top of the clear water zone 14. The scum in the dissolved air zone 12 floats to the top of the separation float 41 through the guiding energy of the baffle assembly 7. The air flotation assembly 43 is installed at the bottom of the separation float 41 to perform secondary air flotation on the scum on the separation float 41.

[0050] The air flotation assembly 43 includes a cover 431 fixedly installed at the bottom of the partition float 41. A filter cloth 432 and a grid plate 433 are fixedly connected to the top of the cover 431. A second pipe 434 is fixedly connected to the bottom of the cover 431. The other end of the second pipe 434 is connected to the output end of the dissolved air device 2.

[0051] Using the above scheme, after the wastewater is flocculated in the flocculation zone 11, it enters the dissolved air zone 12 through the bend pipe 13 for air flotation and forms scum. After being guided by the baffle assembly 7, it enters the area above the partition float plate 41. Then, the scraper mechanism 5 operates to scrape the scum to the scum discharge zone 18 for discharge. At the same time, the pipe 2 434 also discharges the dissolved air water from the dissolved air equipment 2 through the cover 431, filter cloth 432 and grid plate 433 to the upper part of the partition float plate 41, so that some of the flocs deposited on the partition float plate 41 float up again to form scum, avoiding the problem of scum entering below the partition float plate 41 and affecting the subsequent treatment of wastewater.

[0052] like Figure 1 and Figures 3-7 As shown, the separating float 41 is movably installed in the clear water zone 14, and sealing components 6 are provided on both sides of the separating float 41 near the slag discharge zone 18.

[0053] The support component 42 is a telescopic cylinder, and its inner rod part has buoyancy. A constant pressure hole 421 is opened on the sleeve part of the support component 42.

[0054] The support assembly 42 supports the partition float 41, which can float up and down with the liquid level in the clear water zone 14, and the height of the partition float 41 near the baffle assembly 7 is always lower than the baffle assembly 7; the baffle assembly 7 includes a U-shaped baffle 71 fixed to the bottom of the pool body 1, and a bent plate 72 with a height higher than one end of the partition float 41 is movably connected inside the U-shaped baffle 71. The U-shaped baffle 71 has vertically equidistant grid holes 73.

[0055] A connecting column 412 is fixedly connected to the partition floating plate 41, and the middle part of the connecting column 412 is fixedly connected to the bending plate 72.

[0056] By adopting the above scheme, the length of the support component 42 will also change when the water level in the pool 1 changes, thereby changing the height of the partition float 41. This avoids the scum from being too thick when the water level drops, causing some scum to enter below the partition float 41 through the gap between the baffle component 7 and the partition float 41. At the same time, it avoids the scum from being too shallow when the water level is too high, causing a large amount of sewage to enter the scum discharge area 18 and be discharged.

[0057] like Figure 1 and Figures 3-7As shown, the sealing assembly 6 includes a slider 61 mounted on the partition float 41 and capable of sliding on the inner wall of the pool body 1. A rotating shaft 62 and a roller 64 are vertically and equidistantly connected inside the slider 61. A sealing ring 63 is movably disposed inside the slider 61. The rotating shaft 62 is located inside the sealing ring 63, and the roller 64 abuts against the pool body 1. A sealing strip 19 is fixedly connected inside the pool body 1, and the sealing strip 19 contacts and seals the sealing ring 63.

[0058] By adopting the above solution, the downward movement of the slider 61 can cause the rotating shaft 62 to rotate and move along the sealing strip 19, which reduces the friction between the sealing ring 63 and the sealing strip 19. At the same time, it also prevents the sewage in the clear water zone 14 from entering the slag discharge zone 18 through the gap between the two sides of the separating float plate 41 and the inner wall of the pool body 1.

[0059] like Figures 1-3 and Figure 7 As shown, a baffle plate 411 is fixed to the bottom of the separating floating plate 41, and the baffle plate 411 can gradually block the drain pipe 15 during the downward movement.

[0060] By adopting the above scheme, the area of ​​the water baffle 411 blocking the drain pipe 15 changes with the height of the partition float 41, thereby reducing the amplitude of water level changes in the pool 1 and ensuring that the sewage in the pool 1 is at a relatively stable height.

[0061] like Figures 1-4 , Figure 8 and Figure 9 As shown, the scraper mechanism 5 includes a chain drive assembly 51, a scraper assembly 52, and a reduction gearbox 53. The chain drive assembly 51 is installed on the top of the pool body 1, and the scraper assembly 52 and the reduction gearbox 53 are both installed on the chain drive assembly 51 and connected to it for transmission.

[0062] A cam 531 is fixedly connected to the output end of the reduction gearbox 53, and a push valve 435 is installed on the second pipe 434. During the rotation of the cam 531, it can squeeze the push valve 435 to close it.

[0063] Scraper assembly 52 includes a scraper 521 that is connected to the chain drive assembly 51. A limit rod 522 is fixedly connected to the scraper 521. A scraper 523 is sleeved on the limit rod 522. The scraper 523 itself has buoyancy.

[0064] Using the above scheme, the scraper assembly 52 is moved by the chain drive assembly 51 to scrape the scum above the partition float 41 into the scum discharge area 18 for discharge; when the liquid level in the pool 1 changes, the scraper 523 will be inserted into the scum and extend into the liquid surface due to its own weight and the limiting rod 522; when the liquid level changes, the scraper 523 will also be subject to its own buoyancy to ensure that it follows the liquid level in the pool 1.

[0065] When the chain drive assembly 51 is running, it will also drive the cam 531 to rotate through the reduction gearbox 53 and intermittently squeeze the press valve 435, thereby enabling the flotation assembly 43 to work intermittently, avoiding the situation where the flotation assembly 43 works continuously and causes the flocs above the separation float 41 to mix with the sewage.

[0066] Working principle and usage process of this invention:

[0067] After removing suspended solids and colloidal COD from the wastewater through the pretreatment module, the wastewater is passed into the heavy metal treatment module where magnetic materials and coagulants are added and the heavy metals are allowed to precipitate. Then, the wastewater is passed into the COD degradation module for oxidation, Fenton oxidation or catalytic ozone oxidation to remove 95% of the COD from the wastewater. The resulting water is then pumped to the deep treatment and reuse module for membrane separation treatment, so that the heavy metal rejection rate in the water is greater than 95%, reaching the Class IV water standard.

[0068] During the pretreatment process, the wastewater flocculates in the flocculation zone 11 and then enters the dissolved air zone 12 through the bend pipe 13 for flotation and scum formation. After being guided by the baffle assembly 7, the scum enters above the partition float plate 41. Subsequently, the scraper mechanism 5 operates to scrape the scum to the scum discharge zone 18 for discharge. At the same time, the pipe 2 434 also discharges the dissolved air water from the dissolved air equipment 2 through the cover 431, filter cloth 432 and grid plate 433 to the upper part of the partition float plate 41, so that some of the flocs deposited on the partition float plate 41 float up again to form scum, thus preventing the scum from entering below the partition float plate 41 and affecting the subsequent treatment of wastewater.

[0069] When the water level in pool 1 changes, the length of the support component 42 will also change accordingly, thereby changing the height of the partition float 41. This prevents the scum from becoming too thick when the water level drops, causing some scum to enter below the partition float 41 through the gap between the baffle component 7 and the partition float 41. At the same time, it prevents the scum from becoming too shallow when the water level is too high, causing a large amount of sewage to enter the scum discharge area 18 and be discharged.

[0070] Meanwhile, as the height of the separating float 41 changes, the height of the grid holes 73 also changes, thereby ensuring that the height of the grid holes 73 is always higher than that of the separating float 41, and preventing scum from entering below the separating float 41.

[0071] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0072] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fly ash-based wastewater deep treatment system capable of removing heavy metals and COD, comprising a pretreatment module, a heavy metal removal module, a COD degradation module, and a deep treatment and reuse module, characterized in that: The pretreatment module is an air flotation tank consisting of a tank body (1), a dissolved air device (2), a stirring device (3), an isolation mechanism (4), a scraper mechanism (5), and a baffle assembly (7). The tank body (1) is provided with a flocculation zone (11), a dissolved air zone (12), a clear water zone (14), and a slag discharge zone (18). The pool body (1) is also provided with a bend (13) for connecting the flocculation zone (11) and the dissolved air zone (12), and a drain pipe (15) for connecting the clear water zone (14) and the heavy metal removal module. The dissolved air zone (12) and the clear water zone (14) are separated by a baffle assembly (7). The tank (1) is equipped with a dissolved air device (2), the output end of which extends into the dissolved air zone (12); The isolation mechanism (4) is located above the clear water area (14), and the scraper mechanism (5) is installed on the pool body (1) and located above the isolation mechanism (4); After the scum floats up in the dissolved air zone (12), it can float above the isolation mechanism (4). The scraper mechanism (5) can guide the scum through the isolation mechanism (4) to the upper part of the scum discharge zone (18). The isolation mechanism (4) includes a separation float (41), a support assembly (42) and an air flotation assembly (43). The support assembly (42) is installed at the bottom of the clear water zone (14) to support the separation float (41) located at the top of the clear water zone (14). The partition float (41) is movably installed in the clear water zone (14), and sealing components (6) are provided on both sides of the partition float (41) near the slag discharge zone (18). The sealing assembly (6) includes a slider (61) mounted on a partition float (41) and capable of sliding on the inner wall of the pool body (1). A rotating shaft (62) and a roller (64) are vertically and equidistantly connected inside the slider (61). A sealing ring (63) is movably disposed inside the slider (61). The rotating shaft (62) is located inside the sealing ring (63), and the roller (64) abuts against the pool body (1). A sealing strip (19) is fixedly connected inside the pool body (1), and the sealing strip (19) contacts and seals with the sealing ring (63); The downward movement of the slider (61) enables the rotating shaft (62) to rotate and move along the sealing strip (19).

2. The fly ash-based wastewater deep treatment system capable of removing heavy metals and COD according to claim 1, characterized in that: The pool body (1) is also provided with a reflux zone (16) and a connecting pipe (17), and the clear water zone (14) and the reflux zone (16) are connected by the connecting pipe (17); The stirring device (3) is installed on the tank body (1) and its output end is located in the flocculation zone (11); The input end of the dissolved gas device (2) is a reflux pipe (21) and is connected to the reflux zone (16).

3. The fly ash-based wastewater deep treatment system capable of removing heavy metals and COD according to claim 1, characterized in that: The scum located in the dissolved air zone (12) floats up to the top of the partition float plate (41) by the guiding energy of the baffle assembly (7). The air flotation assembly (43) is installed at the bottom of the partition float plate (41) to perform secondary air flotation on the scum on the partition float plate (41).

4. The fly ash-based wastewater deep treatment system capable of removing heavy metals and COD according to claim 1, characterized in that: The air flotation assembly (43) includes a cover (431) fixedly installed at the bottom of the partition float (41). A filter cloth (432) and a grid plate (433) are fixedly connected to the top of the cover (431). A second pipe (434) is fixedly connected to the bottom of the cover (431). The other end of the second pipe (434) is connected to the output end of the dissolved air device (2).

5. The fly ash-based wastewater deep treatment system capable of removing heavy metals and COD according to claim 4, characterized in that: The support assembly (42) is a telescopic cylinder with buoyancy in its inner rod portion, and a constant pressure hole (421) is provided on the sleeve portion of the support assembly (42). The support component (42) supports the partition float (41) which can float up and down with the liquid level in the clear water zone (14), and the height of the partition float (41) near the baffle component (7) is always lower than that of the baffle component (7).

6. The fly ash-based wastewater deep treatment system capable of removing heavy metals and COD according to claim 5, characterized in that: The baffle assembly (7) includes a U-shaped baffle (71) fixed to the bottom of the pool body (1), and a bent plate (72) with a height higher than one end of the dividing float (41) is movably connected inside the U-shaped baffle (71). The U-shaped baffle (71) has vertically equidistant grid holes (73). A connecting column (412) is fixedly connected to the partition float (41), and the middle part of the connecting column (412) is fixedly connected to the bending plate (72).

7. The fly ash-based wastewater deep treatment system capable of removing heavy metals and COD according to claim 5, characterized in that: The bottom of the separating float (41) is fixed with a baffle plate (411), and the baffle plate (411) can gradually block the drain pipe (15) during the downward movement.

8. The fly ash-based wastewater deep treatment system capable of removing heavy metals and COD according to claim 5, characterized in that: The scraper mechanism (5) includes a chain drive assembly (51), a scraper assembly (52), and a reduction gearbox (53). The chain drive assembly (51) is installed on the top of the pool body (1). The scraper assembly (52) and the reduction gearbox (53) are both installed on the chain drive assembly (51) and connected to it in a transmission manner. The output end of the reduction gearbox (53) is fixedly connected to a cam (531), and a push valve (435) is installed on the second pipe (434). During the rotation of the cam (531), it can squeeze the push valve (435) to close it.

9. The fly ash-based wastewater deep treatment system capable of removing heavy metals and COD according to claim 8, characterized in that: The scraper assembly (52) includes a scraper one (521) that is connected to the chain drive assembly (51). A limit rod (522) is fixedly connected to the scraper one (521). A scraper two (523) is sleeved on the limit rod (522). The scraper two (523) has its own buoyancy.

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