Deep treatment device for fluorine-containing wastewater

Abstract

The utility model discloses a fluorine-containing wastewater advanced treatment device which comprises a high-density sedimentation tank, and a sludge internal reflux and sludge discharge system, an acid-base adding system, a fluorine removal agent adding system and a flocculating agent adding system which are matched with the high-density sedimentation tank, the high-density sedimentation tank is formed by sequentially communicating four groups of tank bodies, namely a first coagulation region, a second coagulation region, a flocculation region and a sedimentation region; the sludge internal reflux and sludge discharge system acts on the settling zone and the first coagulation zone, the fluorine removal agent adding system acts on the second coagulation zone and the outlet end of the settling zone, and the acid-base adding system acts on the first coagulation zone, the second coagulation zone and the flocculation zone. According to the utility model, the structure of the high-density sedimentation tank is improved, sludge flows back to the first coagulation area, and the intelligent dosing monitoring equipment is arranged at the rear, so that the device has the advantages that the concentration of fluorine ions in fluorine-containing wastewater which needs to be subjected to multi-section deep treatment originally can be reduced to a strict emission standard by only adopting a first-stage deep fluorine removal section; the chemical adding amount is accurately controlled, and the operation effect is improved.

Description

Technical Field

[0001] This utility model relates to a wastewater treatment device, and more particularly to a deep treatment device for fluoride-containing wastewater. Background Technology

[0002] With the rapid development of industries such as photovoltaics, new energy, and semiconductors, the negative environmental impact of fluoride in wastewater has become increasingly significant, and emission standards for the advanced treatment of fluoride-containing wastewater in various regions are becoming increasingly stringent. Currently, fluoride-containing wastewater is often pretreated using chemical precipitation, followed by further defluorination through other methods before discharge. Advanced treatment of pretreated fluoride-containing wastewater typically employs a two-stage chemical precipitation process or a combination of chemical precipitation and other defluorination methods, resulting in a lengthy and complex process flow. Using only a single-stage chemical precipitation method for advanced defluorination often fails to achieve the required defluorination efficiency, and it is impossible to accurately determine whether the actual fluoride ion removal in the treated wastewater meets the requirements. Furthermore, it suffers from the problem of high dosage and low utilization rate of defluorinating agents. Utility Model Content

[0003] Purpose of the utility model: The purpose of this utility model is to provide a deep treatment device for fluoride-containing wastewater that can meet the discharge standards for fluoride-containing wastewater by using only a single-stage deep defluorination process, can accurately determine whether the actual fluoride ion removal of the treated wastewater meets the requirements, and can also increase the utilization rate of the defluorinating agent.

[0004] Technical Solution: This utility model discloses a deep treatment device for fluoride-containing wastewater, comprising a high-density sedimentation tank and, in conjunction with the high-density sedimentation tank, a sludge internal recirculation and sludge discharge system, an acid-base dosing system, a defluorinating agent dosing system, and a flocculant dosing system. The high-density sedimentation tank consists of four interconnected tanks: a first coagulation zone, a second coagulation zone, a flocculation zone, and a sedimentation zone, with a volume ratio of 1-3:1-2:1-2:12-20. The sludge internal recirculation and sludge discharge system connects the sedimentation zone to the first coagulation zone, introducing a portion of the sludge from the sedimentation zone into the first coagulation zone to supplement the active adsorption sites and floc nuclei. The sludge contains a large number of flocs, which, after being recirculated to the first coagulation zone, can provide more coagulation nuclei for newly entering wastewater. These flocs, acting as crystal nuclei, can accelerate the reaction between the coagulant and impurities in the water, promoting the formation of micro-flocs and thus improving the coagulation effect. The returned sludge may contain unreacted coagulants. Reintroducing it into the coagulation zone allows for the reuse of these agents, reducing the amount of new coagulant needed and thus lowering operating costs. Especially for substances that are difficult to coagulate, such as fine colloidal particles and dissolved organic matter, the returned sludge can act as an auxiliary coagulation agent. The defluoridator dosing system is connected to the outlet of the second coagulation zone and the sedimentation zone, used to add defluoridator to the second coagulation zone and to monitor the fluoride ion concentration at the sedimentation zone outlet in real time. The acid-base dosing system is connected to the first coagulation zone, the second coagulation zone, and the flocculation zone, used to add acid-base balancers to the first and second coagulation zones and to monitor the pH value of the flocculation zone in real time.

[0005] Preferably, the first coagulation zone and the second coagulation zone are respectively equipped with a first coagulation zone mixer and a second coagulation zone mixer.

[0006] Preferably, the first coagulation zone has a first coagulation zone inlet on its upper side wall, and a second coagulation zone inlet on its lower side wall, sharing the same wall with the second coagulation zone. The second coagulation zone has a partition separating it into an independent, elongated area. An outlet for the middle section of the second coagulation zone is located at the upper part of the partition, and an outlet for the second coagulation zone is located at the bottom of the independent area, connected to the flocculation zone via a pipe. The flocculation zone contains a flocculation zone mixer and a guide tube, with a flocculation zone inlet on its side wall and a drain outlet at the bottom of the side wall. The sedimentation zone... The sedimentation zone is connected to the flocculation zone via the sedimentation zone inlet. The sedimentation zone is equipped with a sludge scraper, a sedimentation tank sludge hopper at the bottom, and inclined plate packing at the top. A water collection trough and an outlet weir are installed above the inclined plate packing. The water collection trough and the outlet weir are equipped with water collection trough outlets. The water collection trough and the outlet weir are connected to an outlet channel. The outlet channel has an outlet for the sedimentation zone at its end. The side wall of the sedimentation tank sludge hopper has openings, from top to bottom, namely a return sludge discharge port and a residual sludge discharge port. The return sludge discharge port is connected to the first coagulation zone.

[0007] Preferably, the spacing between the inclined tubes of the inclined plate packing is set to 80-120mm to prevent precipitated particles from clogging the inclined plates or tubes and to ensure the smooth progress of the sedimentation process.

[0008] Preferably, the slope of the sedimentation tank sludge hopper is in the range of 0.01-0.05, which can reduce the footprint and construction cost of the sedimentation tank sludge hopper.

[0009] Preferably, the surface of the high-density sedimentation tank is provided with a corrosion-resistant coating, and the number of high-density sedimentation tanks includes one or more, which are connected in series through the outlet of the sedimentation zone and the inlet of the next first coagulation zone.

[0010] Preferably, the sludge internal return and discharge system consists of a sludge pump, an external discharge pipeline system for discharging the fully reacted sludge from the sedimentation zone, an internal return pipeline system connected to the sludge return discharge port, a sludge interlock control system, and a sludge flow meter.

[0011] Preferably, the acid-base dosing system consists of an acid-base dosing device for adding acid-base modifiers to the first coagulation zone and the second coagulation zone, an acid-base pipeline system, an acid-base flow meter, an online pH meter for real-time detection of the pH value of the flocculation zone, and an acid-base interlocking control system for overall regulation of the acid-base dosing system.

[0012] Preferably, the defluorinating agent dosing system consists of a defluorinating agent dosing device for adding defluorinating agent to the second coagulation zone, a defluorinating pipeline system, a defluorinating flow meter, an online fluoride concentration detector for real-time monitoring of fluoride ion concentration at the outlet of the sedimentation zone, and a defluorinating interlock control system for overall regulation of the defluorinating agent dosing system.

[0013] Preferably, the flocculant dosing system consists of a flocculant dosing device for adding flocculant to the flocculation zone, a flocculant pipeline system for transporting flocculant, and a flocculant flow meter.

[0014] Beneficial effects: Compared with the prior art, the present invention has the following advantages: The present invention improves the structure of the high-efficiency sedimentation tank and places the intelligent dosing monitoring equipment at the end, thereby achieving precise control of the dosing of the reagent and improving the defluorination efficiency. Furthermore, by returning the sludge to the first coagulation tank at the front end, the improved high-efficiency sedimentation tank alone can reduce the concentration of fluoride ions in the fluoride-containing wastewater that originally required multiple stages of deep treatment to the level of strict emission standards. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the wastewater flow direction of this utility model.

[0016] Figure 2 This is a schematic diagram of the specific structure of this utility model.

[0017] Figure 3This is a plan view of the present invention.

[0018] Figure 4 This is a cross-sectional view of the present invention.

[0019] Figure 5 This is a BB cross-sectional view of the present invention.

[0020] Figure 6 This is a 1-1 cross-sectional view of the present invention. Detailed Implementation

[0021] The technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0022] Example 1:

[0023] like Figure 1-6 As shown, a deep treatment device for fluoride-containing wastewater includes a high-density sedimentation tank 1, a sludge internal return and sludge discharge system 500, an acid and alkali dosing system 600, a defluorinating agent dosing system 700, and a flocculant dosing system 800. The high-density sedimentation tank 1 includes a first coagulation zone 100, a second coagulation zone 200, a flocculation zone 300, and a sedimentation zone 400.

[0024] The first coagulation zone 100, the second coagulation zone 100, and the flocculation zone 300 are located on one side of the sedimentation zone 400. The first coagulation zone 100 and the second coagulation zone 200 are located on one side of the flocculation zone 300. The first coagulation zone 100, the second coagulation zone 100, the flocculation zone 300, and the sedimentation zone 400 are sequentially connected. The sludge internal return and sludge discharge system 500 is located below the first coagulation zone 100 and the second coagulation zone 200.

[0025] Fluoride-containing wastewater enters the system through inlet 102 on the upper side wall of the first coagulation zone 100. An online pH meter 602 interlocks with the acid / alkali dosing system 600. The first coagulation zone mixer 101 uniformly mixes the fluoride-containing wastewater with acid / alkali reagents, adjusting the pH to the optimal range for the defluorinating agent. Wastewater then flows by gravity into the second coagulation zone 200 through inlet 202. The defluorinating agent dosing system 700 and the acid / alkali dosing system 600 respectively control the addition of defluorinating agent and acid / alkali reagents. The addition of acid and alkali adjusts the pH change caused by the defluorinating agent. The second coagulation zone mixer 201 agitates the water, rapidly mixing the reagents with the raw water to achieve coagulation. Wastewater flows by gravity from the outlet 203 in the middle of the second coagulation zone into the narrow space between the second coagulation zone and the flocculation zone. The bottom of this part has an opening, and the wastewater is sloped to lead the wastewater from the outlet 203 of the second coagulation zone to the outlet 204 at the bottom of the narrow space. It is then connected by a pipeline and enters the flocculation zone guide tube 302 through the inlet 303 of the flocculation zone to achieve uniform water intake. The flocculant dosing system 800 in the flocculation zone controls the dosing of flocculant through the flocculant dosing device, the flocculant pipeline system for transporting flocculant, and the flocculant flow meter. The flocculant is mixed and formed into flocs by the mixer 301 in the flocculation zone and enters the sedimentation zone 400 through the inlet 402 of the sedimentation zone. In the sedimentation zone 400, the wastewater flows from bottom to top. The flocs that are easy to settle settle quickly, and the remaining flocs enter the upper inclined tube packing 403 of the sedimentation tank with the water flow. The wastewater rises and flows along the inclined plate packing, while the flocs slide down the inclined plate to the bottom of the tank under the action of gravity and are collected by the sedimentation tank scraper 401 into the lower sedimentation tank sludge hopper 407. The wastewater enters the upper water collection trough and the outlet weir 404 through the inclined tube packing, and is collected through the water outlet of the water collection trough to the outlet channel 405. The outlet channel 405 is connected to the sedimentation tank outlet 406 to discharge the wastewater. The sludge hopper 407 of the sedimentation tank has openings on its side wall, namely a return sludge discharge port 408 and a residual sludge discharge port 409. The upper return sludge discharge port 408 is pumped to the first coagulation zone 100 for recycling via a sludge pump 501 and an internal return pipeline system 503. The lower residual sludge discharge port 409 is discharged via a sludge pump 501 and an external discharge pipeline system 502. The equipment vent 304 is located within the flocculation zone 300. The sludge internal return and discharge system 500 can adjust the sludge return flow rate and the external sludge discharge rate as needed through the sludge interlock control system 504 and the sludge flow meter.

[0026] The inclined plate packing 403 in sedimentation zone 400 has an inclined tube spacing of 100mm to prevent sedimentation particles from clogging the inclined plates or tubes and ensure smooth sedimentation. The sludge hopper 407 in the sedimentation tank has a slope of 0.01, reducing the footprint and construction cost of the sludge hopper. The surface of the high-density sedimentation tank is coated with a corrosion-resistant coating to enhance its corrosion resistance, wear resistance, and service life.

[0027] An online fluoride concentration detector 702 and an online pH meter 602 are installed at the outlet end, specifically at the outlet of the sedimentation zone 400. The defluorinating agent is transported through the defluorination pipeline system and then added to the second coagulation zone 200 via the defluorinating agent dosing device 701. This process is controlled by a defluorination flow meter and a fluoride interlock control system 703. The online pH meter 602 is installed in the flocculation zone 300. Acid and alkali reagents are transported through an acid and alkali pipeline system and then added to the first coagulation zone 100 and the second coagulation zone 200 via the acid and alkali dosing device 601. This process is also controlled by an acid and alkali flow meter and an acid and alkali interlock control system 603. This allows for direct acquisition of the final fluoride ion concentration and pH value after all treatment steps. This accurately reflects the actual treatment effect of the entire fluoride-containing wastewater deep treatment device. The fluoride ion detection data at the outlet of the sedimentation zone 400 clearly indicates whether the expected defluorination standard has been met and determines whether the pH of the wastewater is within the appropriate range for the defluorinating agent. Interlocked control with the corresponding defluorinating agent dosing system 700 allows for dynamic adjustments based on actual treatment results. Taking the online fluoride concentration detector 702 as an example, when the fluoride ion concentration detected at the outlet of the sedimentation zone 400 exceeds the emission standard, the interlocked defluorinating agent dosing device 701 can immediately increase the amount of defluorinating agent added; when the fluoride ion concentration meets the standard and is low, the amount of defluorinating agent added can be appropriately reduced, thereby achieving precise control of agent dosing and saving agent costs. Similarly, the online pH meter 602 can monitor the pH of the treated wastewater in real time at the outlet. Based on the detection results, the acid or alkali dosage can be adjusted in a timely manner through the interlocked acid-base adjustment system to ensure that the pH value of the wastewater remains stable within a suitable range, guaranteeing the stable operation of the entire treatment system. Furthermore, the interlocking control of the dosing system and monitoring equipment is based on preliminary experimental data, specifically the variation curves of residual fluoride ion concentration and defluorinator dosage. This correlation is input into the intelligent dosing system, enabling it to adjust the dosage accurately in real time. The outlet-end detection device comprehensively considers all factors in the treatment process. It reflects the actual reaction degree between the defluorinator and fluoride ions, the removal effect of the precipitation process on fluoride ions, and the final pH adjustment result of the acid-base regulator throughout the process. Thus, through outlet-end detection and interlocking control, it can better adapt to various complex changes during the treatment process, making the entire treatment system more intelligent and efficient, ensuring that the treated wastewater achieves ideal fluoride ion concentration and pH levels.

[0028] Fluoride-containing wastewater with concentrations of 3, 8, 12, 16, and 20 mg / L is introduced into this device. It passes through a first coagulation zone 100, a second coagulation zone 200, a flocculation zone 300, and a sedimentation zone 400, respectively. An acid-base dosing system 600 controls the addition of acid and alkali to the first coagulation zone 100 and the second coagulation zone 200, maintaining the pH range of 6.0-8.0 in the first coagulation zone 100 and 6.0-6.5 in the second coagulation zone 200. A defluoridant dosing system 700 controls the addition of defluoridant to the second coagulation zone 200. In the second coagulation zone, the agitator 201 mixes and adsorbs fluoride ions from the wastewater. The flocculant dosing system 800 controls the addition of flocculant to the flocculation zone 300. The flocculant is then stirred and mixed evenly in the agitator 301, producing flocs. These flocs then enter the sedimentation zone 400 to separate the fluoride-containing sludge from the wastewater, thus removing fluoride ions. A portion of the sludge from the sedimentation zone 400 is returned to the first coagulation zone 100. For substances that are difficult to coagulate, such as fine colloidal particles and dissolved organic matter, the returned sludge can assist in coagulation. The first coagulation zone 100 has a residence time of 15 minutes and a sludge concentration of 600 mg / L. The second coagulation zone 200 has a residence time of 10 minutes and a sludge concentration of 2000-4000 mg / L. The longer coagulation time allows the coagulant to have more sufficient contact and reaction opportunities with impurities in the water, helping to form more micro-flocs and more thoroughly removing colloidal substances, fine particles, and some dissolved organic matter, thus improving the coagulation effect. A 5-minute residence time in the flocculation zone (300°C) shortens the flocculation time, ensuring further growth and stability of the flocs. Appropriate stirring intensity allows the small flocs to collide and combine, forming larger, easily settled flocs. The final effluent fluoride concentrations for several types of fluoride-containing wastewater were all below 1.5 mg / L.

[0029] Table 1 Treatment effect of fluoride-containing wastewater with different concentrations

[0030] Influent fluoride ion concentration 3mg / L 8mg / L 12mg / L 16mg / L 20mg / L effluent fluoride concentration 0.5mg / l 0.8 mg / L 1.0 mg / L 1.2 mg / L 1.5 mg / L

[0031] Example 2:

[0032] Fluoride-containing wastewater at concentrations of 8, 12, 16, and 20 mg / L was introduced into the apparatus of this invention. The wastewater passed through a first coagulation zone, a second coagulation zone, a flocculation zone, and a sedimentation zone, respectively. An acid-base dosing device controlled the addition of acid and alkali to the first and second coagulation zones, maintaining the pH range of 6.0–8.0 in the first coagulation zone and 6.0–6.5 in the second coagulation zone. A defluoridator dosing system controlled the addition of defluoridator to the second coagulation zone, and a flocculant dosing system controlled the addition of flocculant to the flocculation zone. Part of the sludge from the sedimentation zone was returned to the first coagulation zone, and a portion was returned to the flocculation zone for comparative testing. The retention times in the first, second, and flocculation zones were all 10 minutes. The effluent fluoride concentration in the wastewater returned to the first coagulation zone was significantly better than that returned to the flocculation zone; when the influent fluoride concentration was 8–20 mg / L, the effluent fluoride concentration was consistently below 1.5 mg / L.

[0033] Table 2 Treatment effect of fluoride-containing wastewater with different concentrations

[0034] Influent fluoride ion concentration 8mg / L 12mg / L 16mg / L 20mg / L Fluoride ion concentration in the effluent returned to the flocculation zone 1.2 mg / L 1.6 mg / L 1.9 mg / L 2.5 mg / L Fluoride ion concentration in the effluent returned to the coagulation zone 0.6 mg / L 0.8 mg / L 1.1 mg / L 1.3 mg / L

[0035] Example 3:

[0036] A 20 mg / L fluoride-containing wastewater is introduced into the device of this invention, passing through a first coagulation zone, a second coagulation zone, a flocculation zone, and a sedimentation zone. An acid-base dosing device controls the addition of acid and alkali to the first and second coagulation zones, maintaining the pH range of 6.0–8.0 in the first coagulation zone and 6.0–6.5 in the second coagulation zone. A defluoridator dosing system controls the addition of defluoridator to the second coagulation zone, and a flocculant dosing system controls the addition of flocculant to the flocculation zone. Part of the sludge from the sedimentation zone is returned to the first coagulation zone. The residence time in the first, second, flocculation, and sedimentation zones is varied. The fluoride ion concentration in the effluent can be controlled below 1.5 mg / L.

[0037] Table 3 Treatment effect of fluoride-containing wastewater at different retention times

[0038] Influent fluoride ion concentration 20mg / L 20mg / L 20mg / L 20mg / L Time spent in the first concrete zone 10min 10min 15min 15min Second concrete zone residence time 10min 5min 10min 10min Flocculation zone residence time 10min 10min 10min 5min Residence time in the sedimentation zone 45min 45min 45min 45min effluent fluoride concentration 1.3 mg / L 1.4 mg / L 1.1 mg / L 1.2 mg / L

[0039] Example 4:

[0040] The raw materials used in this embodiment are commercially available defluorinating agent products A, B, and C.

[0041] The primary defluoridation precipitation process uses a conventional high-efficiency sedimentation tank; the two-stage defluoridation precipitation process uses two conventional high-efficiency sedimentation tanks connected in series; and the tertiary defluoridation precipitation process uses three conventional high-efficiency sedimentation tanks connected in series. To compare the treatment effects with this device, 10L of fluoride-containing wastewater with a fluoride ion concentration of 10mg / L was prepared, and 3g of defluorinating agent was added. The effects of the four defluoridation processes were compared.

[0042] Table 4 Comparison of treatment effects of this device and coagulation sedimentation treatment

[0043] Dosage Primary fluoride precipitation Secondary defluorination precipitation Three-stage fluoride removal and precipitation The device of the present invention Defluorinating agent A 3g 2.3 mg / L 2.0 mg / L 1.6 mg / L 1.5 mg / L Defluorinating agent B 3g 1.9 mg / L 1.4 mg / L 0.9 mg / L 0.9 mg / L Defluorinating agent C 3g 2.0 mg / L 1.5 mg / L 1.2 mg / L 1.3 mg / L Area <![CDATA[2m 2 ]]> <![CDATA[4m 2 ]]> <![CDATA[6m 2 ]]> <![CDATA[3m 2 ]]>

[0044] This invention, along with its two-stage and three-stage defluoridation precipitation processes, can reduce the fluoride ion content in fluoride-containing wastewater from 10 mg / L to below 1.5 mg / L. The defluoridation effect of this invention is far superior to that of the one-stage and two-stage defluoridation precipitation processes, and comparable to that of the three-stage process. It can save 50% of floor space, and in practical engineering applications, it can save 40% to 60%. This device achieves the defluoridation effect of three-stage coagulation and sedimentation, significantly reducing equipment footprint and investment costs.

[0045] Example 5:

[0046] The raw materials used in this embodiment are commercially available defluorinating agent products A, B, and C.

[0047] The primary defluoridation precipitation process uses a conventional high-efficiency sedimentation tank; the two-stage defluoridation precipitation process uses two conventional high-efficiency sedimentation tanks connected in series; and the tertiary defluoridation precipitation process uses three conventional high-efficiency sedimentation tanks connected in series. To compare the treatment effect with this device, 10L of fluoride-containing wastewater was prepared with an initial fluoride ion concentration of 10mg / L. Defluoridating agent was added until the effluent fluoride ion concentration reached 1.5mg / L, and the dosage of defluoridating agent for the four defluoridation processes was compared.

[0048] Table 5 Comparison of different defluorination devices

[0049] Defluoridator dosage The device of the present invention Primary fluoride precipitation Secondary defluorination precipitation Three-stage fluoride removal and precipitation Defluorinating agent A 2.8g 5.0g 6.0g 6.3g Defluorinating agent B 3.1g 4.2g 6.0g 6.5g Defluorinating agent C 2.9g 4.8g 7.1g 8.1g effluent water quality 1.5 mg / L 1.8 mg / L 1.6 mg / L 1.5 mg / L

[0050] Under the same defluorination agent conditions, achieving the same treatment effect, the defluorination agent dosage of the device of this invention is lower than that of primary, secondary, and tertiary defluorination devices. Compared with primary defluorination devices, this device can save 35.7% of defluorination agent; compared with secondary defluorination devices, it can save 52.9%; and compared with tertiary defluorination devices, it can save 57.5%. Compared with ordinary defluorination processes, this device can save 30% to 50% of defluorination agent, effectively reducing operating costs.

[0051] Example 6

[0052] The fluoride-containing wastewater was prepared at concentrations of 3, 8, 12, 16, and 20 mg / L. This device was connected in series and entered a two-stage system. An acid-base dosing system controlled the addition of acid and alkali to both the first and second coagulation zones, maintaining the pH range of 6.0–8.0 in the first coagulation zone and 6.0–6.5 in the second. A defluoridant dosing system controlled the addition of defluoridant to the second coagulation zone, and a flocculant dosing system controlled the addition of flocculant to the flocculation zone. Part of the sludge from the sedimentation zone was returned to the first coagulation zone. The retention times in the first, second, and flocculation zones were all 10 minutes. The effluent quality was superior to that of a single-stage defluoridation unit, with the final effluent fluoride concentration all below 1.3 mg / L.

[0053] Table 6 Treatment effects of fluoride-containing wastewater with different concentrations

[0054] Influent fluoride ion concentration 3mg / L 8mg / L 12mg / L 16mg / L 20mg / L Fluoride ion concentration in primary effluent 0.5mg / l 0.8 mg / L 1.0 mg / L 1.2 mg / L 1.5 mg / L Fluoride ion concentration in primary effluent 0.4 mg / L 0.6 mg / L 0.9 mg / L 1.0 mg / L 1.3 mg / L

Claims

1. A deep treatment device for fluoride-containing wastewater, comprising a high-density sedimentation tank (1) and a sludge internal recirculation and sludge discharge system (500), an acid-base dosing system (600), a defluorinating agent dosing system (700), and a flocculant dosing system (800) cooperating with the high-density sedimentation tank (1), characterized in that: The high-density sedimentation tank (1) consists of four interconnected tanks: a first coagulation zone (100), a second coagulation zone (200), a flocculation zone (300), and a sedimentation zone (400). The volume ratio of the first coagulation zone (100), the second coagulation zone (200), the flocculation zone (300), and the sedimentation zone (400) is 1-3:1-2:1-2:12-20. The sludge internal return and sludge discharge system (500) connects the sedimentation zone (400) to the first coagulation zone (100) and is used to introduce part of the sludge from the sedimentation zone (400) into the first coagulation zone (100) as a supplement to the first coagulation zone. The active adsorption sites and floc cores of zone (100); the defluorinating agent dosing system (700) is connected to the outlet end of the second coagulation zone (200) and the sedimentation zone (400), and is used to add defluorinating agent to the second coagulation zone (200) and to detect the fluoride ion concentration at the outlet end of the sedimentation zone (400) in real time; the acid-base dosing system (600) is connected to the first coagulation zone (100), the second coagulation zone (200) and the flocculation zone (300), and is used to add acid-base conditioning agent to the first coagulation zone (100) and the second coagulation zone (200) and to detect the pH value of the flocculation zone (300) in real time.

2. The advanced treatment device for fluoride-containing wastewater according to claim 1, characterized in that: The first coagulation zone (100) and the second coagulation zone (200) are respectively equipped with a first coagulation zone mixer (101) and a second coagulation zone mixer (201).

3. The advanced treatment device for fluoride-containing wastewater according to claim 1 or 2, characterized in that: The first coagulation zone (100) has a first coagulation zone inlet (102) on the upper part of its side wall, and the other side shares a wall with the second coagulation zone (200) and has a second coagulation zone inlet (202) at the lower part; the second coagulation zone (200) is separated into an independent elongated area by a partition, and the middle outlet (203) of the second coagulation zone is set at the upper part of the partition, and the bottom of the independent area is set with a second coagulation zone outlet (204) connected to the flocculation zone (300) through a pipe; the flocculation zone (300) is equipped with a flocculation zone mixer (301) and a guide tube (302) inside, the side wall is set with a flocculation zone inlet (303), and the bottom of the side wall is set with an equipment drain outlet (304) for water discharge; the sedimentation zone (400) and the flocculation zone (300) are connected by a pipe. The sedimentation zone is connected to the inlet (402). A sludge scraper (401) is provided in the sedimentation zone (400). A sedimentation tank sludge hopper (407) is provided at the bottom and an inclined plate packing (403) is provided at the top. A water collection trough and an outlet weir plate (404) are provided at the top of the inclined plate packing (403). A water collection trough outlet is provided on the water collection trough and the outlet weir plate (404). The water collection trough and the outlet weir plate (404) are connected to the outlet channel (405). The outlet channel (405) has an opening at the end of the outlet channel (405) to provide a sedimentation zone outlet (406). The sedimentation tank sludge hopper (407) has openings on its side wall, which are a return sludge discharge port (408) and a residual sludge discharge port (409) from top to bottom. The return sludge discharge port (408) is connected to the first coagulation zone (100).

4. The advanced treatment device for fluoride-containing wastewater according to claim 3, characterized in that: The inclined tube spacing of the inclined plate packing (403) is set to 80-120mm.

5. The advanced treatment device for fluoride-containing wastewater according to claim 3, characterized in that: The slope of the sedimentation tank sludge hopper (407) ranges from 0.01 to 0.

05.

6. The advanced treatment device for fluoride-containing wastewater according to claim 3, characterized in that: The surface of the high-density sedimentation tank (1) is provided with a corrosion-resistant coating. The number of high-density sedimentation tanks (1) includes one or more, which are connected in series through the sedimentation zone outlet (406) and the next first coagulation zone inlet (102).

7. The advanced treatment device for fluoride-containing wastewater according to claim 3, characterized in that: The sludge internal return and discharge system (500) consists of a sludge pump (501), an external discharge pipeline system (502) for discharging the fully reacted sludge from the sedimentation zone (400), an internal return pipeline system (503) connected to the sludge return discharge port (408), a sludge interlock control system (504), and a sludge flow meter.

8. The advanced treatment device for fluoride-containing wastewater according to claim 1, characterized in that: The acid-base dosing system (600) consists of an acid-base dosing device (601) for adding acid-base modifiers to the first coagulation zone (100) and the second coagulation zone (200), an acid-base pipeline system, an acid-base flow meter, an online pH meter (602) for real-time detection of the pH value of the flocculation zone (300), and an acid-base interlocking control system (603) for overall regulation of the acid-base dosing system (600).

9. The advanced treatment device for fluoride-containing wastewater according to claim 1, characterized in that: The defluorinating agent dosing system (700) consists of a defluorinating agent dosing device (701) for adding defluorinating agent to the second coagulation zone (200), a defluorinating pipeline system, a defluorinating flow meter, an online fluoride concentration detector (702) for real-time detection of fluoride ion concentration at the outlet of the sedimentation zone (400), and a defluorinating interlock control system (703) for overall regulation of the defluorinating agent dosing system (700).

10. The advanced treatment device for fluoride-containing wastewater according to claim 1, characterized in that: The flocculant dosing system (800) consists of a flocculant dosing device for adding flocculant to the flocculation zone (300), a flocculant pipeline system, and a flocculant flow meter.

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