Deep defluorination water treatment device

Abstract

The utility model relates to the technical field of defluorination, in particular to a deep defluorination water treatment device which comprises an adjusting tank, the water outlet end of the adjusting tank is connected with the water inlet end of a neutralization reaction tank through a pipeline A, and the water outlet end of the neutralization reaction tank is connected with the water inlet end of a reaction sedimentation tank through a pipeline B; the water outlet end of the reaction sedimentation tank is connected with the water inlet end of the defluorination reaction tank through a pipeline C, the water outlet end of the defluorination reaction tank is connected with the water inlet end of the filtration adsorber through a pipeline D, and the water outlet end of the filtration adsorber is connected with the water inlet end of the clean water tank through a pipeline E; wherein water pumps are arranged on the pipeline A, the pipeline B, the pipeline C, the pipeline D and the pipeline E. According to the utility model, the modularized design is adopted, the system integration degree is high, the efficient removal of fluorine ions is realized through the synergistic effect of chemical reaction precipitation and filtration adsorption, and the system is suitable for a deep fluorine removal scene in which the fluorine ion concentration needs to be reduced to below 1mg / L.

Description

A deep defluoridation water treatment device Technical Field

[0001] This utility model relates to the field of defluoridation technology, specifically to a deep defluoridation water treatment device. Background Technology

[0002] With industrial development, industries such as photovoltaics, semiconductors, aluminum, and mining play important roles, but they are also major sources of fluoride-containing wastewater. Taking the photovoltaic industry as an example, the etching and cleaning processes of silicon wafers in the production of solar cells use large amounts of fluoride-containing chemicals such as hydrofluoric acid, generating significant amounts of fluoride-containing wastewater. In the semiconductor industry, processes such as photolithography and etching in chip manufacturing also use fluoride-containing gases and liquids, resulting in wastewater with extremely high fluoride content. In aluminum production, the electrolytic aluminum process generates fluoride-containing waste gas and wastewater, with fluorides existing in the form of hydrogen fluoride and silicon tetrafluoride. Mining, especially the mining and processing of fluoride-containing ores such as fluorite, generates large amounts of fluoride-containing waste residue and wastewater. If this wastewater is discharged directly without effective treatment, it will cause serious pollution to the surrounding environment.

[0003] Besides industrial wastewater containing fluoride, naturally occurring high-fluoride groundwater in some areas is also a significant source of fluoride pollution. Due to geological structure and hydrological conditions, groundwater generally has high fluoride levels. Residents in these areas who have been drinking high-fluoride groundwater for a long time face a significant threat to their health.

[0004] The harm of fluoride pollution to human health and the ecological environment should not be underestimated. Long-term excessive fluoride intake can lead to diseases such as dental fluorosis and skeletal fluorosis, while high-fluoride wastewater discharged from industries can disrupt the ecological balance of aquatic bodies. Currently, industry standards for fluoride emissions are becoming increasingly stringent. For example, some regions have lowered the fluoride emission limit to 2 mg / L, and some industry standards require it to be below 1 mg / L.

[0005] Currently, traditional defluorination technologies mainly include calcium salt precipitation, membrane separation, ion exchange, and electrochemical methods. These technologies have played a role in different periods and scenarios, but as fluoride emission standards continue to tighten, their limitations are gradually becoming apparent.

[0006] Among these methods, calcium salt precipitation is simple to operate and inexpensive, but it can only reduce the fluoride ion concentration to around 20 mg / L, which is insufficient to meet increasingly stringent emission standards. Adsorption methods, while showing good treatment results, suffer from difficulties in separating adsorbent materials and complex regeneration processes. Membrane separation and ion exchange methods, on the other hand, face challenges such as high cost and susceptibility to pollution. Summary of the Invention

[0007] In response to the limitations of traditional defluoridation technologies and the increasingly stringent fluoride emission standards, this invention provides a deep defluoridation water treatment device. It adopts a modular design and has a high degree of system integration. It achieves efficient removal of fluoride ions through the synergistic effect of chemical reaction precipitation and filtration adsorption. It is suitable for deep defluoridation scenarios that require reducing the fluoride ion concentration to below 1 mg / L.

[0008] The present invention adopts the following technical solution:

[0009] A deep defluoridation water treatment device includes an equalization tank. The outlet of the equalization tank is connected to the inlet of a neutralization reaction tank via pipe A. The outlet of the neutralization reaction tank is connected to the inlet of a reaction sedimentation tank via pipe B. The outlet of the reaction sedimentation tank is connected to the inlet of the defluoridation reaction tank via pipe C. The outlet of the defluoridation reaction tank is connected to the inlet of a filter adsorber via pipe D. The outlet of the filter adsorber is connected to the inlet of a clear water tank via pipe E. Each of pipes A, B, C, D, and E is equipped with a water pump. The neutralization reaction tank is equipped with a pH adjuster and calcium salt dosing port, and the reaction sedimentation tank is equipped with a flocculant dosing port.

[0010] It should be further noted that this utility model also includes a sludge treatment unit, which comprises a sludge tank and a plate and frame filter press. The inlet of the sludge tank is connected to the outlet of a sludge suction pump A located at the bottom of the reaction sedimentation tank via pipe F. A sludge suction pump B is located at the bottom of the sludge tank, and the outlet of pump B is connected to the inlet of the plate and frame filter press via pipe. There is no secondary pollution; the entire process operates in a closed loop; the sludge is stabilized and discharged in compliance with standards, and no toxic byproducts are generated.

[0011] It should be further noted that the outlet of the plate and frame filter press is connected to the inlet of the defluorination reaction tank via pipe G.

[0012] It should be further noted that the filter adsorber is equipped with a backwashing system, which includes a backwash water inlet and a backwash water outlet. The backwash water outlet is connected to the inlet of the neutralization reaction tank through pipe H.

[0013] It should be further noted that a defluorinating agent dosing port is provided on pipeline B.

[0014] It should be further noted that the filter adsorber is filled with two layers of adsorbent.

[0015] It should be further noted that the two adsorbent layers include a quartz sand layer and an activated carbon layer arranged from top to bottom.

[0016] It should be further noted that the particle size of the quartz sand in the quartz sand layer is 2~4mm, and the particle size of the activated carbon in the activated carbon layer is 1~2mm.

[0017] It should be further noted that the regulating tank, neutralization reaction tank, reaction sedimentation tank, defluorination reaction tank, and filter adsorber of this utility model are stacked one on top of the other and integrated into the same frame, reducing the need for planar extension, with high integration and modular design, reducing the floor space by 30% to 40% compared with traditional processes, making it particularly suitable for factories and mines with limited space.

[0018] The functions of each component in this utility model are as follows:

[0019] Equalization tank: Used to store water to be treated, balance water quality and quantity fluctuations, and provide stable influent for subsequent treatment.

[0020] Neutralization reaction tank: Receives effluent from the equalization tank through pipe A, adds reagents (such as acid / alkali) to adjust the pH value, and then adds defluoridating agents such as calcium salts to initially generate precipitate.

[0021] Reaction sedimentation tank: It receives the reaction mixture from the neutralization reaction tank and removes suspended solids and some fluorides through coagulation and sedimentation. The sludge at the bottom is discharged into the sludge treatment unit by sludge suction pump A.

[0022] Defluoridation reaction tank: The core defluoridation unit, which receives precipitated water through pipe C, and adds defluoridating agents (such as aluminum salts or iron salts) to react with fluoride ions to form precipitates. This invention has a defluoridating agent dosing port on pipe B.

[0023] Filter adsorber: It contains two layers of adsorption material (upper layer of quartz sand and lower layer of activated carbon) to further adsorb residual fluoride ions and organic matter.

[0024] Quartz sand layer: with a particle size of 2~4mm, used to trap large particles of impurities and provide physical filtration.

[0025] Activated carbon layer: Particle size 1~2mm, utilizing porous structure to adsorb fluoride ions and trace pollutants.

[0026] Backwashing system: The filter media is cleaned periodically through the backwash water inlet / outlet (pipe H connects to the neutralization reaction tank) to restore filtration capacity. The backwash wastewater is returned to the neutralization reaction tank for further treatment.

[0027] Clear water tank: Stores treated water that meets standards, which can be reused or discharged.

[0028] Function of the water pumps: The water pumps on pipelines A to E are used to provide water flow power, ensure continuous operation between units, and maintain processing efficiency.

[0029] Sludge tank: collects sludge discharged from the sedimentation reactor and transports it to the plate and frame filter press via sludge suction pump B.

[0030] Plate and frame filter press: Dewaters sludge to form sludge cake (which can be transported off-site for disposal), while the filter effluent is returned to the defluorination reaction tank through pipeline G to avoid waste of fluoride ions and reagents and to achieve recycling.

[0031] The beneficial effects of this utility model are as follows:

[0032] (1) Through the synergistic effect of precipitation and adsorption, this utility model can reduce the concentration of fluoride ions from the initial 20 mg / L to below 1 mg / L, with a removal rate of over 95%, which is better than the effect of single technology treatment. At the same time, this utility model first removes fluoride through precipitation pretreatment and fluoride removal reaction tank, which reduces the adsorption intensity of subsequent adsorption treatment, extends the service life of adsorption materials, and avoids or alleviates technical problems such as difficulty in regeneration treatment of adsorption materials due to long-term use.

[0033] (2) This utility model combines a neutralization reaction tank, a reaction sedimentation tank and a defluorination reaction tank. First, it uses the initial sedimentation in the neutralization reaction tank, the flocculation sedimentation in the reaction sedimentation tank and the defluorination in the defluorination reaction tank to remove most of the fluoride ions, thereby reducing the fluoride concentration of the wastewater. Then, it uses a filter adsorber for deep treatment to further reduce the fluoride ion concentration to below the discharge standard. It can treat various fluoride-containing water bodies with fluoride ion concentrations of 5-200 mg / L and has a strong buffering capacity against water quality fluctuations. Attached Figure Description

[0034] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 is a schematic diagram of the structure of a specific embodiment of this utility model.

[0036] In the diagram, 1-Equalization tank, 2-Neutralization reaction tank, 3-Reaction sedimentation tank, 4-Defluorination reaction tank, 5-Filter adsorber, 6-Clear water tank, 7-Sludge tank, 8-Plate and frame filter press. Detailed Implementation

[0037] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0038] Example 1

[0039] Referring to Figure 1, this utility model provides a deep defluoridation water treatment device, including an equalization tank 1. The outlet of the equalization tank 1 is connected to the inlet of the neutralization reaction tank 2 via pipe A. The outlet of the neutralization reaction tank 2 is connected to the inlet of the reaction sedimentation tank 3 via pipe B. The outlet of the reaction sedimentation tank 3 is connected to the inlet of the defluoridation reaction tank 4 via pipe C. The outlet of the defluoridation reaction tank 4 is connected to the inlet of the filter adsorber 5 via pipe D. The outlet of the filter adsorber 5 is connected to the inlet of the clear water tank 6 via pipe E. Water pumps are installed on pipes A, B, C, D, and E. The neutralization reaction tank 2 is equipped with pH adjuster and calcium salt dosing ports, and the reaction sedimentation tank 3 is equipped with flocculant dosing ports.

[0040] This utility model also includes a sludge treatment unit, which includes a sludge tank 7 and a plate and frame filter press 8. The input end of the sludge tank 7 is connected to the output end of a sludge suction pump A installed at the bottom of the reaction sedimentation tank 3 through a pipe F. A sludge suction pump B is installed at the bottom of the sludge tank 7, and the output end of the sludge suction pump B is connected to the input end of the plate and frame filter press 8 through a pipe.

[0041] In conjunction with Example 1, the usage method and defluorination principle of this utility model are as follows:

[0042] (1) Raw water conditioning: The fluoride ion concentration of a certain quartz sand pickling wastewater is 158 mg / L and the pH value is 2.5. It first enters the conditioning tank for buffering.

[0043] (2) Chemical precipitation: Pump the water from the conditioning tank into the neutralization reaction tank, adjust the pH, and add calcium hydroxide (300 mg / L) and calcium chloride (100 mg / L) at the same time. Stir the reaction for 30 min to form a mixed solution containing calcium fluoride precipitate.

[0044] (3) Flocculation and sedimentation: The mixed liquid produced by the reaction in the neutralization reaction tank is pumped into the reaction sedimentation tank, and 5 mg / L of polyaluminum chloride (PAC) is added. The liquid is continuously fed in and efficiently precipitated. The precipitated sludge is concentrated in the sludge tank and then enters the plate and frame filter press to dewater to a moisture content of less than 75%. The filtrate is returned to the equalization tank, and the sludge cake is disposed of in accordance with the hazardous waste regulations. The fluoride ion concentration in the supernatant in the reaction sedimentation tank is reduced to 9.8 mg / L.

[0045] (4) Deep defluorination: Add defluorinating agent (such as aluminum salt or iron salt) at the outlet pipe of the reaction precipitator to improve the reaction efficiency and carry out deep defluorination in the defluorination reaction tank.

[0046] (5) Filtration and Adsorption: The supernatant from the defluorination reaction tank is passed through a multi-stage filter at a filtration rate of 10 m / h. The filter passes through two layers of adsorbent: the first layer is quartz sand with a particle size of 2-4 mm, and the second layer is activated carbon with a particle size of 1-2 mm. The fluoride ion concentration in the effluent from the filter is 0.8 mg / L, meeting the requirements of the "Standards for Drinking Water Quality" (GB5749-2022). The filter needs to be backwashed after 1-2 days of operation.

[0047] Table 1 shows the technical indicators of the effluent after fluoride removal in Embodiment 1 of this utility model compared with the traditional calcium salt precipitation method and adsorption method.

[0048] Table 1. Technical indicators of effluent from Embodiment 1 of this utility model and traditional defluoridation devices.

[0049]

[0050] In some specific embodiments, the outlet of the plate and frame filter press 8 is connected to the inlet of the defluorination reaction tank 4 via a pipe G. The filter press effluent is returned to the defluorination reaction tank via pipe G, avoiding waste of reagents, achieving recycling, and preventing secondary pollution.

[0051] In some specific embodiments, the filter adsorber 5 is equipped with a backwashing system, which includes a backwash water inlet and a backwash water outlet. The backwash water outlet is connected to the inlet of the neutralization reaction tank 2 via a pipe H. The filter media in the filter adsorber 5 is periodically cleaned with backwash water to restore its filtration capacity. The backwash wastewater is returned to the neutralization reaction tank for further treatment.

[0052] In some specific embodiments, this invention includes a defluorinating agent inlet on pipe B. This allows for the pre-addition of the defluorinating agent, enabling efficient defluorination.

[0053] In some specific embodiments, the filter adsorber 5 is filled with two layers of adsorbent, comprising a quartz sand layer and an activated carbon layer arranged from top to bottom. The quartz sand in the quartz sand layer has a particle size of 2-4 mm, and the activated carbon in the activated carbon layer has a particle size of 1-2 mm. This quartz sand + activated carbon dual-layer structure combines physical filtration and chemical adsorption, with the activated carbon showing significant adsorption effect on low concentrations of fluoride ions. Simultaneously, the particle size design (2-4 mm for quartz sand and 1-2 mm for activated carbon) optimizes water flow distribution, prevents clogging, and improves adsorption efficiency.

[0054] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A deep defluoridation water treatment device, comprising an equalization tank, characterized in that, The outlet of the equalization tank is connected to the inlet of the neutralization reaction tank via pipe A. The outlet of the neutralization reaction tank is connected to the inlet of the reaction sedimentation tank via pipe B. The outlet of the reaction sedimentation tank is connected to the inlet of the defluorination reaction tank via pipe C. The outlet of the defluorination reaction tank is connected to the inlet of the filter adsorber via pipe D. The outlet of the filter adsorber is connected to the inlet of the clear water tank via pipe E. Water pumps are installed on pipes A, B, C, D, and E. The neutralization reaction tank is equipped with pH adjuster and calcium salt dosing ports, and the reaction sedimentation tank is equipped with flocculant dosing ports.

2. The deep defluoridation water treatment device as described in claim 1, characterized in that, It also includes a sludge treatment unit, which includes a sludge tank and a plate and frame filter press. The input end of the sludge tank is connected to the output end of the sludge suction pump A installed at the bottom of the reaction sedimentation tank through a pipe F. A sludge suction pump B is installed at the bottom of the sludge tank, and the output end of the sludge suction pump B is connected to the input end of the plate and frame filter press through a pipe.

3. The deep fluoride removal water treatment device of claim 1, wherein, The outlet of the plate and frame filter press is connected to the inlet of the defluorination reaction tank via pipe G.

4. The deep fluoride removal water treatment device of claim 1, wherein, The filter adsorber is equipped with a backwashing system, which includes a backwash water inlet and a backwash water outlet. The backwash water outlet is connected to the inlet of the neutralization reaction tank through pipe H.

5. The deep defluoridation water treatment device as described in claim 1, characterized in that, A defluorinating agent inlet is provided on pipeline B.

6. The deep defluoridation water treatment device as described in claim 1, characterized in that, The filter adsorber is filled with two layers of adsorbent.

7. The deep fluoride removal water treatment device of claim 6, wherein, The two adsorbent layers consist of a quartz sand layer and an activated carbon layer arranged from top to bottom.

8. The deep defluoridation water treatment device as described in claim 1, characterized in that, The quartz sand in the quartz sand layer has a particle size of 2-4 mm, and the activated carbon in the activated carbon layer has a particle size of 1-2 mm.

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