High-fluorine-content wastewater treatment system and method

Abstract

The invention discloses a high-fluorine-content wastewater treatment system and method, and relates to the technical field of fluorine-containing wastewater treatment.The high-fluorine-content wastewater treatment system comprises a raw water tank, a first reaction tank, a second reaction tank, a coagulation tank, a sedimentation tank, a treatment water tank, a sludge reaction tank, a sludge storage tank and a filtrate tank; according to the method, the high-fluorine-content wastewater is subjected to fluorine removal treatment, Ca (OH) 2 is added to react with fluorine ions in water to generate calcium fluoride, hydrochloric acid or Ca (OH) 2 is added to adjust the PH value of the wastewater after the calcium fluoride is generated, then PAC and a flocculating agent are added for flocculation of a coagulation machine, so that the calcium fluoride is coagulated in sludge, and then the sludge is dewatered and transferred to a professional treatment factory to be treated. Meanwhile, the sewage subjected to fluorine removal can reach the standard to be discharged.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorine-containing wastewater treatment, and specifically to a high-fluorine wastewater treatment system and method. Background Art

[0002] There are various methods for treating fluorine-containing wastewater. The commonly used methods are precipitation method and adsorption method. In addition, there are also freezing method, ion exchange method, reverse osmosis method, electrodialysis method, etc. However, the more effective, economical and applicable method for industrial wastewater treatment is the calcium salt precipitation method (also known as lime chemical precipitation method). That is, for high-concentration fluorine-containing industrial wastewater, by directly adding lime milk to the wastewater, the fluoride ions react with calcium ions to generate insoluble solid CaF 2 , and then precipitation and solid-liquid separation are carried out to remove it. Its process principle is: Ca 2+ +2F - =CaF 2 ↓; However, in actual industrial applications, the fluorine removal effect by only chemical precipitation reaction is often not good. Supplementary use of appropriate coagulants and flocculants can significantly improve the fluorine removal efficiency.

[0003] The application number: CN201910487349.5 also provides a method for treating fluorine-containing wastewater. Its treatment method includes: adjusting the pH of the to-be-treated fluorine-containing wastewater to 10-12, adding an appropriate amount of mixture, stirring for 5-10 min and then precipitating for 1-2 h; adding excessive calcium chloride to the fluorine-containing wastewater, fully stirring and standing for precipitation; adjusting the pH of the fluorine-containing wastewater to neutral, adding an appropriate amount of polyaluminum chloride, stirring for 5-10 min, and performing solid-liquid separation to obtain a clear liquid and a precipitate; introducing the clear liquid into an SBR reactor for treatment, and draining after the treatment is completed. It mainly uses calcium chloride to react with fluoride ions in water to generate insoluble calcium fluoride for fluorine removal treatment. However, the fluorine removal effect by only chemical reaction is not good and it is difficult to meet the discharge requirements.

[0004] An application number: CN201320332808.0 of a fluorine-containing wastewater treatment system is also used for fluorine removal treatment of fluorine-containing wastewater. This system includes a fluorine-containing wastewater collection tank, a pH adjustment tank, an electrocoagulation machine, a reaction tank, an intermediate tank, a solid-liquid separation device and a water tank connected in sequence through pipelines. It mainly performs fluorine removal treatment through an electrocoagulation machine. To achieve high fluorine removal efficiency, it requires a large amount of energy, thus increasing the fluorine removal cost.

[0005] An application number: CN202010440533.7 of a method for treating fluorine-containing wastewater performs fluorine removal treatment by adding lime. It mainly removes fluorine through the reaction of calcium ions and fluoride ions. However, the fluorine removal effect by only chemical reaction is not good. Although polyacrylamide is added, it is also difficult to meet the discharge requirements.

[0006] A fluorine-containing wastewater zero-discharge treatment system with the application number CN202222226081.X includes: a physical and chemical unit, which mainly makes the fluorine-containing wastewater fully contact and react with the reagent, so that fluorine or fluoride in the fluorine-containing wastewater forms a precipitate, obtaining a supernatant of the fluorine-containing wastewater and precipitated sludge; a biochemical unit, in which the fluorine-containing wastewater removes organic substances in the wastewater by means of microbial degradation; a filtration unit, in which the biochemical effluent intercepts suspended particles and other particulate matters after passing through two-stage filters and an ultrafiltration membrane; a desalination unit, which is used for desalination treatment of the filtered effluent to obtain fresh water and concentrated water respectively; the treatment process of the fluorine-containing wastewater in this patent document is long, the treatment process is relatively cumbersome, and it takes a long time to treat the same amount of wastewater, making it difficult to achieve rapid and efficient treatment of fluorine-containing wastewater. Summary of the Invention

[0007] The purpose of the present invention is to provide a high-fluorine wastewater treatment system and method to solve the problem that the calcium salt precipitation method used in the prior art only performs chemical precipitation reaction and has poor defluorination effect as proposed in the above background technology.

[0008] To achieve the above purpose, the present invention provides the following technical solution: A high-fluorine wastewater treatment system includes a raw water tank, a first reaction tank, a second reaction tank, a coagulation tank, a sedimentation tank, and a treatment tank that are all open at the top and arranged in sequence. The sedimentation tank is also connected to a sludge reaction tank and a sludge storage tank. The sludge reaction tank is connected to the first reaction tank through a pipeline. A filtrate tank is arranged at the rear of the sludge storage tank; a raw water pump is arranged in the raw water tank and its outlet end is connected to the first reaction tank through a pipeline. The first reaction tank is directly connected to the second reaction tank. The second reaction tank is directly connected to the coagulation tank. A coagulation tank discharge groove is arranged near the top of the side wall of the coagulation tank far from the inlet. The coagulation tank discharge groove is connected to the sedimentation tank through a discharge pipe. An upper clear liquid discharge groove is arranged on the upper part of the side wall of the sedimentation tank far from the inlet and is connected to a sedimentation tank outlet water pump through a pipeline and then connected to the treatment tank. The bottom of the sedimentation tank is convex downward in a conical shape, and a sludge pump is connected through a sludge discharge pipe at the lowest point. The outlet end of the sludge pump is connected to the sludge reaction tank and the sludge storage tank respectively through a branch pipeline. The bottom of the sludge reaction tank is connected to a mixed sludge discharge pump through a pipeline. The outlet end of the mixed sludge discharge pump is connected to the first reaction tank through a pipeline. The sludge storage tank is connected to a sludge dewatering treatment device. The sludge dewatering treatment device is connected to the filtrate tank through a pipeline. The filtrate tank is connected to the raw water tank.

[0009] Further, the first reaction tank is provided with a first electric stirrer and a first pH on-line detector.

[0010] Further, the second reaction tank is provided with a second electric stirrer and a second pH on-line detector. At the same time, an HCl dosing device and Ca(OH)2 Chemical dosing device, PAC chemical dosing device.

[0011] Furthermore, the coagulation tank is provided with a third electric stirrer and a flocculant dosing device.

[0012] Furthermore, the sedimentation tank is provided with an electric sludge scraper.

[0013] Furthermore, the sludge reaction tank is provided with a fourth electric stirrer and Ca(OH) 2 dosing device.

[0014] Furthermore, the sludge storage tank is provided with a fourth electric stirrer.

[0015] Furthermore, the HCl dosing device includes an HCl storage tank, the HCl storage tank is connected with an HCl metering pump through a pipeline, and the outlet end of the HCl metering pump is connected to the second reaction tank through a pipeline; the Ca(OH) 2 dosing device includes a Ca(OH) 2 chemical preparation storage tank, the Ca(OH) 2 chemical preparation storage tank is connected with two Ca(OH) 2 metering pumps through pipelines, and the two Ca(OH) 2 metering pumps are respectively connected to the second reaction tank and the sludge reaction tank through pipelines; the PAC dosing device includes a PAC storage tank, the PAC storage tank is connected with a PAC metering pump through a pipeline, and the outlet end of the PAC metering pump is connected to the second reaction tank through a pipeline; the flocculant dosing device includes a flocculant chemical preparation storage tank, the flocculant chemical preparation storage tank is connected with a flocculant metering pump through a pipeline, and the outlet end of the flocculant metering pump is connected to the coagulation tank through a pipeline.

[0016] A method for treating high-fluoride wastewater by using the above high-fluoride wastewater treatment system comprises the following steps:

[0017] Step 1: The high-fluoride wastewater is collected in the raw water tank through a pipeline and is pumped to the first reaction tank by a raw water pump. In the first reaction tank, the first electric stirrer mixes evenly with the sludge output from the sludge reaction tank, and then directly flows into the second reaction tank. At the same time, the pH value is detected by a first pH on-line detector in the first reaction tank;

[0018] Step 2: The first pH on-line detector is linked with the HCl dosing device and the Ca(OH) 2 dosing device. According to the difference between the pH value detected by the first pH on-line detector and the neutral value, the HCl dosing device adds HCl or the Ca(OH) 2 dosing device adds Ca(OH) 2, adjust the pH value of the high-fluoride wastewater in the second reaction tank to, and detect it in real time through the second on-line pH detector. After the detected value reaches, the PAC dosing device starts to add PAC, and stir and mix evenly through the second electric stirrer. Then, the high-fluoride wastewater flows through to the coagulation tank;

[0019] Step 3: Add a flocculant in the coagulation tank through the flocculant dosing device, and stir and mix evenly through the third electric stirrer. After stirring evenly, it directly flows to the sedimentation tank;

[0020] Step 4: The high-fluoride wastewater is statically precipitated in the sedimentation tank. After static precipitation, the clear water in the upper part is collected through the supernatant water outlet tank, and the clear water is transported to the treatment pool by the sedimentation tank water pump. The sludge at the bottom is collected at the lowest point through the electric sludge scraper, and then a small part of the sludge is sent to the sludge reaction tank and most of the sludge is sent to the sludge storage tank through pipelines and sludge pumps;

[0021] Step 5: Add Ca(OH) 2 to the sludge in the sludge reaction tank and stir evenly through the fourth electric stirrer, and then transport it to the first reaction tank through the mixed sludge discharge pump to be mixed with the high-fluoride wastewater transported from the original water tank;

[0022] Step 6: Stir the sludge in the sludge storage tank evenly through the fourth electric stirrer, and then the sludge dewatering treatment equipment sucks the sludge and performs dewatering treatment. The dewatered sludge is sent to a professional sludge treatment plant for treatment; the dewatered filtrate is transported to the filtrate tank through pipelines and then sent back to the original water tank to re-enter the treatment process;

[0023] Step 7: Repeat Steps 1 to 6 to continuously complete the treatment of the high-fluoride wastewater, so as to efficiently remove the sludge and fluorine in the high-fluoride wastewater.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The present invention performs defluorination treatment on high-fluoride wastewater. By adding Ca(OH)2 to react with fluoride ions in the water to generate calcium fluoride, after generating calcium fluoride, the pH value of the wastewater is adjusted by adding hydrochloric acid or Ca(OH)2, and then PAC and a flocculant are added for coagulation and flocculation, so that calcium fluoride is condensed in the sludge. Then, the sludge is dehydrated and transferred to a professional treatment plant for treatment. At the same time, the defluorinated sewage can meet the discharge standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic flow chart of the present invention;

[0027] In the figure: original water tank - 1, original water pump - 11, first reaction tank - 2, first electric stirrer - 21, first on-line pH detector - 22, second reaction tank - 3, second electric stirrer - 31, second on-line pH detector - 32, HCl dosing device - 33, Ca(OH) 2 dosing device - 34, PAC dosing device - 35, coagulation tank - 4, third electric stirrer - 41, flocculant dosing device - 42, coagulation tank discharge chute - 43, sedimentation tank - 5, supernatant water discharge chute - 51, sedimentation tank water pump - 52, sludge pump - 53, electric sludge scraper - 54, treatment water tank - 6, sludge reaction tank - 7, fourth electric stirrer - 71, mixed sludge discharge pump - 72, sludge storage tank - 8, fourth electric stirrer - 81, sludge dewatering treatment equipment - 82, filtrate tank - 9. Detailed implementation mode

[0028] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments.

[0029] The present invention provides a high-fluoride wastewater treatment system for efficiently removing fluoride from high-fluoride wastewater, including an original water tank 1, a first reaction tank 2, a second reaction tank 3, a coagulation tank 4, a sedimentation tank 5, and a treatment water tank 6 arranged in sequence. The sedimentation tank 5 is also connected to a sludge reaction tank 7 and a sludge storage tank 8. The sludge reaction tank 7 is connected to the first reaction tank 2 through a pipeline. A filtrate tank 9 is arranged at the rear side of the sludge storage tank 8, and all the tanks are open-top tanks.

[0030] The original water tank 1 is used for collecting and temporarily storing high-fluoride wastewater, and an original water pump 11 is arranged in the original water tank 1. The outlet end of the original water pump 11 is connected to the first reaction tank 2 through a pipeline. The high-fluoride wastewater in the original water tank 1 is transported to the first reaction tank 2 through the original water pump 11 for preliminary treatment.

[0031] The first reaction tank 2 is provided with a first electric stirrer 21 and a first on-line pH detector 22. The first electric stirrer 21 is used for stirring and mixing the high-fluoride wastewater in the first reaction tank 2 and the sludge output from the sludge reaction tank 7 evenly. The first on-line pH detector 22 is used for real-time detection of the pH value of the mixed high-fluoride wastewater in the first reaction tank 2. After actual application detection, the pH of the raw water is 9.6; the mixed high-fluoride wastewater automatically flows into the second reaction tank 3 through a pipeline.

[0032] The second reaction tank 3 is provided with a second electric stirrer 31 and a second on-line pH detector 32. At the same time, an HCl dosing device 33, Ca(OH)2 The chemical dosing device 34 and the PAC dosing device 35 add HCl and Ca(OH) 2 to the second reaction tank 3 through the HCl dosing device 33 and the Ca(OH) 2 chemical dosing device 34 respectively, which is used to adjust the pH value of the high-fluoride wastewater in the second reaction tank 3, and the pH value is detected in real time by the second on-line pH detector 32. After the pH value is adjusted to 6-8, PAC is added to the second reaction tank 3 through the PAC dosing device 35. The sludge in the high-fluoride wastewater is flocculated by the PAC, and the high-fluoride wastewater containing flocculation directly flows into the coagulation tank 4.

[0033] The coagulation tank 4 is provided with a third electric stirrer 41 and a flocculant dosing device 42. The flocculant agent is added to the coagulation tank 4 through the flocculant dosing device 42, and at the same time, the agent is mixed evenly by the third electric stirrer 41; a coagulation tank discharge chute 43 is arranged at the top of the side wall of the coagulation tank 4 far from the inlet, and the coagulation tank discharge chute 43 is connected with a discharge pipe and connected to the sedimentation tank 5.

[0034] The high-fluoride wastewater after adding PAC and flocculant and mixing evenly is statically precipitated after entering the sedimentation tank 5. The supernatant after precipitation passes through the supernatant water outlet chute 51 arranged on the side of the sedimentation tank 5 far from the inlet. The supernatant water outlet chute 51 is connected with a sedimentation tank water pump 52 through a pipeline, and then the supernatant of the sedimentation tank is transported to the treatment water tank 6 through a pipeline; the bottom of the sedimentation tank 5 is convex in a conical shape, and a sludge pump 53 is connected at the lowest point through a sludge discharge pipe. The outlet end of the sludge pump 53 is connected to the sludge reaction tank 7 and the sludge storage tank 8 through a branch pipeline, which is used to transport the sludge at the bottom of the sedimentation tank 5 to the sludge reaction tank 7 and the sludge storage tank 8 respectively; the sedimentation tank 5 is also provided with an electric sludge scraper 54, and the sludge at the bottom of the sedimentation tank 5 is scraped to the lowest point through the electric sludge scraper 54.

[0035] The treatment water tank 6 is used for temporarily storing the treated clear water. The temporarily stored clear water can be discharged into the natural water body through the treatment water tank 6 or can be reused.

[0036] The sludge reaction tank 7 is provided with a fourth electric stirrer 71 and Ca(OH) 2 chemical dosing device 34, which is used to add Ca(OH) 2 to the sludge stored in the sludge reaction tank 7, and the sludge and Ca(OH) 2Mix evenly. The bottom of the sludge reaction tank 7 is connected with a mixed sludge discharge pump 72 through a pipeline. The outlet end of the mixed sludge discharge pump 72 is connected to the first reaction tank 2 through a pipeline, and is used to transport the mixed sludge into the first reaction tank 2.

[0037] The sludge storage tank 8 is provided with a fourth electric stirrer 81 for stirring the sludge in the sludge storage tank 8 to prevent sludge deposition and condensation. The sludge storage tank 8 is also connected with a sludge dewatering treatment device 82. The sludge dewatering treatment device 82 sucks the sludge in the sludge storage tank 8 and dehydrates it. The dehydrated sludge is sent to a professional sludge treatment plant for treatment; while the filtrate after sludge dewatering is transported into the filtrate tank 9 through a pipeline.

[0038] The filtrate tank 9 is used for temporarily storing the filtrate after sludge dewatering. And the filtrate tank 9 is also connected to the raw water tank 1 through a pipeline, so as to transport the filtrate into the raw water tank 1 and re-enter the treatment process for treatment.

[0039] The HCl dosing device 33 includes an HCl storage tank. The HCl storage tank is connected with an HCl metering pump through a pipeline. The outlet end of the HCl metering pump is connected to the second reaction tank 3 through a pipeline.

[0040] The Ca(OH) 2 dosing device 34 includes a Ca(OH) 2 drug preparation storage tank. The Ca(OH) 2 drug preparation storage tank is connected with two Ca(OH) 2 metering pumps through pipelines. The two Ca(OH) 2 metering pumps are respectively connected to the second reaction tank 3 and the sludge reaction tank 7 through pipelines.

[0041] The PAC dosing device 35 includes a PAC storage tank. The PAC storage tank is connected with a PAC metering pump through a pipeline. The outlet end of the PAC metering pump is connected to the second reaction tank 3 through a pipeline.

[0042] The flocculant dosing device 42 includes a flocculant drug preparation storage tank. The flocculant drug preparation storage tank is connected with a flocculant metering pump through a pipeline. The outlet end of the flocculant metering pump is connected to the coagulation tank 4 through a pipeline.

[0043] When using the above high-fluoride wastewater treatment system to treat high-fluoride wastewater, it includes the following steps:

[0044] Step 1: The high-fluoride wastewater is collected in the raw water tank 1 through pipelines. In the raw water tank 1, the high-fluoride wastewater is transported to the first reaction tank 2 by the raw water pump 11, where it is mixed with the sludge output from the sludge reaction tank 7 and stirred evenly by the first electric stirrer 21. Then it directly flows into the second reaction tank 3. Meanwhile, the pH value is detected by the first on-line pH detector 22 in the first reaction tank 2;

[0045] Step 2: The first on-line pH detector 22 is linked with the HCl dosing device 33 and the Ca(OH)2 dosing device 34. According to the difference between the pH value detected by the first on-line pH detector 22 and the neutral value of 7, the HCl dosing device 33 adds HCl or the Ca(OH)2 dosing device 34 adds Ca(OH)2 to adjust the pH value of the high-fluoride wastewater in the second reaction tank 3 to 6 - 8, and it is detected in real time by the second on-line pH detector 32. After the detected value is 6 - 8, the PAC dosing device 35 starts to add PAC and stirs and mixes evenly by the second electric stirrer 31. Then the high-fluoride wastewater directly flows into the coagulation tank 4;

[0046] Step 3: In the coagulation tank 4, flocculant is added by the flocculant dosing device 42 and stirred and mixed evenly by the third electric stirrer 41. After being stirred evenly, it directly flows into the sedimentation tank 5;

[0047] Step 4: The high-fluoride wastewater is statically precipitated in the sedimentation tank 5. After static precipitation, the clear water in the upper part is collected through the supernatant water outlet tank 51 and the clear water is transported to the treatment tank 6 by the sedimentation tank water pump 52. The sludge at the bottom is collected at the lowest point by the electric sludge scraper 54, and then a small part of the sludge is sent to the sludge reaction tank 7 and most of the sludge is sent to the sludge storage tank 8 through pipelines and the sludge pump 53;

[0048] Step 5: Ca(OH)2 is added to the sludge in the sludge reaction tank 7 and stirred evenly by the fourth electric stirrer 71, and then it is transported to the first reaction tank 2 by the mixed sludge discharge pump 72 to be mixed with the high-fluoride wastewater transported from the raw water tank 1;

[0049] Step 6: The sludge in the sludge storage tank 8 is stirred evenly by the fourth electric stirrer 81, and then the sludge dewatering treatment equipment 82 sucks the sludge and performs dewatering treatment. The dewatered sludge is sent to a professional sludge treatment plant for treatment; the dewatered filtrate is transported to the filtrate tank 9 through pipelines and then sent back to the raw water tank 1 to re-enter the treatment process;

[0050] Step 7: Repeat Step 1 - Step 6 to continuously complete the treatment of the high-fluoride wastewater, thereby efficiently removing the sludge and fluorine in the high-fluoride wastewater.

[0051] The present invention performs defluorination treatment on high-fluoride wastewater. By adding Ca(OH)2 to react with fluoride ions in water to form calcium fluoride, after the formation of calcium fluoride, the pH value of the wastewater is adjusted by adding hydrochloric acid or Ca(OH)2, and then PAC and a flocculant are added for coagulation and flocculation, so that calcium fluoride is aggregated in the sludge. Then, the sludge is dehydrated and transferred to a professional treatment plant for treatment. At the same time, the defluorinated sewage can meet the discharge standards.

[0052] Although the embodiments of the present invention have been shown and described, it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, for those of ordinary skill in the art, it can be understood that without departing from the principles and spirit of the present invention, all other embodiments obtained by making various changes, modifications, substitutions, and variations to these embodiments without creative efforts belong to the scope of protection of the present invention.

Claims

1. A high-fluorine wastewater treatment system, characterized in that: The invention comprises a raw water tank (1), a first reaction tank (2), a second reaction tank (3), a coagulation tank (4), a sedimentation tank (5), and a treated water tank (6), all of which are open at the top and are arranged in sequence. The sedimentation tank (5) is also connected to a sludge reaction tank (7) and a sludge storage tank (8). The sludge reaction tank (7) is connected to the first reaction tank (2) through a pipeline. A filtrate tank (9) is arranged at the rear side of the sludge storage tank (8). A raw water pump (11) is arranged in the raw water tank (1) and its outlet end is connected to the first reaction tank (2) through a pipeline. The first reaction tank (2) is directly connected to the second reaction tank (3), and the second reaction tank (3) is directly connected to the coagulation tank (4). The coagulation tank (4) is provided with a coagulation tank discharge trough (43) near the top on the side wall away from the inlet. The coagulation tank discharge trough (43) is connected to the sedimentation tank through a discharge pipe. (5), a supernatant outlet trough (51) is arranged on the upper part of the side wall away from the inlet of the sedimentation tank (5), and is connected to a sedimentation tank outlet pump (52) through a pipeline and then connected to a treatment water tank (6), the bottom of the sedimentation tank (5) is conically convex, and is connected to a sludge pump (53) at the lowest point through a sludge discharge pipe, the outlet end of the sludge pump (53) is respectively connected to a sludge reaction tank (7) and a sludge storage tank (8) through branch pipes, the bottom of the sludge reaction tank (7) is connected to a mixed sludge discharge pump (72) through a pipeline, the outlet end of the mixed sludge discharge pump (72) is connected to the first reaction tank (2) through a pipeline, the sludge storage tank (8) is connected to a sludge dewatering treatment device (82), the sludge dewatering treatment device (82) is connected to the filtrate tank (9) through a pipeline, and the filtrate tank (9) is connected to the raw water tank (1).

2. The high-fluorine wastewater treatment system according to claim 1, characterized in that: The first reaction tank (2) is provided with a first electric stirrer (21) and a first pH online detector (22).

3. The high-fluorine wastewater treatment system according to claim 2, characterized in that: The second reaction tank (3) is provided with a second electric stirrer (31) and a second pH online detector (32). The second reaction tank (3) is also provided with an HCl dosing device (33), a Ca(OH)2 dosing device (34), and a PAC dosing device (35).

4. The high-fluorine wastewater treatment system according to claim 3, characterized in that: The coagulation tank (4) is provided with a third electric stirrer (41) and a flocculant dosing device (42).

5. The high-fluorine wastewater treatment system according to claim 4, characterized in that: The sedimentation tank (5) is provided with an electric sludge scraper (54).

6. The high-fluorine wastewater treatment system according to claim 5, characterized in that: The sludge reaction tank (7) is provided with a fourth electric stirrer (71) and a Ca(OH)2 dosing device (34).

7. The high-fluorine wastewater treatment system according to claim 6, characterized in that: The sludge storage tank (8) is provided with a fourth electric stirrer (81).

8. The high-fluorine wastewater treatment system according to claim 7, characterized in that: The HCl dosing device (33) comprises an HCl storage tank, the HCl storage tank is connected to an HCl metering pump via a pipeline, and the outlet end of the HCl metering pump is connected to the second reaction tank (3) via a pipeline; the Ca(OH)2 dosing device (34) comprises a Ca(OH)2 dispensing storage tank, the Ca(OH)2 dispensing storage tank is connected to two Ca(OH)2 metering pumps via a pipeline, and the two Ca(OH)2 metering pumps are respectively connected to the second reaction tank (3) and the sludge reaction tank (7) via pipelines; the PAC dosing device (35) comprises a PAC storage tank, the PAC storage tank is connected to a PAC metering pump via a pipeline, and the outlet end of the PAC metering pump is connected to the second reaction tank (3) via a pipeline; the flocculant dosing device (42) comprises a flocculant dispensing storage tank, the flocculant dispensing storage tank is connected to a flocculant metering pump via a pipeline, and the outlet end of the flocculant metering pump is connected to the coagulation tank (4) via a pipeline.

9. A method for treating high-fluorine-containing wastewater using the high-fluorine-containing wastewater treatment system according to claim 8, characterized in that: The following steps are involved: Step 1: High-fluorine-containing wastewater is collected in a raw water tank (1) through a pipeline and transported to a first reaction tank (2) through a raw water pump (11). In the first reaction tank (2), a first electric stirrer (21) is used to evenly mix the sludge output from the sludge reaction tank (7). The sludge is then directly circulated into a second reaction tank (3). At the same time, a pH test is performed in the first reaction tank (2) through a first pH online detector (22); Step 2: The first PH online detector (22) is linked with the HCl dosing device (33) and the Ca(OH)2 dosing device (34). According to the difference between the PH value detected by the first PH online detector (22) and the neutral value 7, the HCl dosing device (33) adds HCl or the Ca(OH)2 dosing device (34) adds Ca(OH)2, and the PH value of the high-fluorine-containing wastewater in the second reaction tank (3) is adjusted to 6-8, and the PH value is detected in real time by the second PH online detector (32). After the detected value is 6-8, the PAC dosing device (35) starts to add PAC, and the mixture is stirred and mixed evenly by the second electric stirrer (31), and then the high-fluorine-containing wastewater is directly passed to the coagulation tank (4); Step 3: Adding flocculants into the coagulation tank (4) through the flocculant dosing device (42), stirring and mixing evenly through the third electric stirrer (41), and then directly flowing to the sedimentation tank (5) after stirring evenly; Step 4: The high-fluorine-containing wastewater is allowed to settle in a sedimentation tank (5). After settling, the clean water on the top is collected through a supernatant outlet tank (51) and then transported to a treatment water tank (6) through a sedimentation tank outlet pump (52). The sludge at the bottom is collected at the lowest point through an electric sludge scraper (54). A small portion of the sludge is then sent to a sludge reaction tank (7) through a pipeline and a sludge pump (53), and most of the sludge is sent to a sludge storage tank (8). Step 5: Ca(OH)2 is added to the sludge in the sludge reaction tank (7) and stirred evenly by the fourth electric stirrer (71), and then transported to the first reaction tank (2) by the mixed sludge discharge pump (72) to mix with the high-fluorine wastewater transported from the raw water tank (1); Step 6: The sludge in the sludge storage tank (8) is stirred evenly by the fourth electric stirrer (81), and then the sludge dehydration treatment equipment (82) absorbs the sludge and performs dehydration treatment, and the dehydrated sludge is sent to a professional sludge treatment plant for treatment; The dehydrated filtrate is transported to the filtrate tank (9) through a pipeline and then sent to the raw water tank (1) to re-enter the treatment process; Step 7: Repeat steps 1 to 6 to continuously complete the treatment of high-fluoride wastewater, thereby efficiently removing sludge and fluorine in the high-fluoride wastewater.

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