Multistage defluorination device for industrial wastewater

Abstract

The utility model discloses a kind of industrial wastewater multistage defluorination device, it is related to fluorine-containing wastewater treatment technical field, water inlet regulating pool, pre-deposition reaction zone, main adsorption reaction zone, fine reaction zone, sedimentation clarification zone and water outlet collection zone are sequentially communicated, pre-deposition reaction zone is also connected first dosing tank, fine reaction zone is also connected second dosing tank, main adsorption reaction zone is filled with adsorbent;First dosing tank is filled with quicklime, second dosing tank is filled with aluminium salt and / or iron salt.The utility model alleviates the technical problem that present technology exists single-stage processing is difficult to take into account removal rate and operation economy, energy consumption and high drug consumption, water stability is insufficient.

Description

Technical Field

[0001] This utility model relates to the field of fluoride-containing wastewater treatment technology, specifically to a multi-stage defluorination device for industrial wastewater. Background Technology

[0002] With the acceleration of industrialization, products such as aluminum fluoride, fluorosilicates, fluororesins, and inorganic fluoride salts are widely used in the electronics, metallurgy, refrigeration, pharmaceutical, and new energy industries, making fluoride-containing wastewater a significant component of industrial wastewater. However, fluoride ions (F...) - Fluoride ions are stable in water bodies, and excessive discharge can harm ecosystems and human health: for humans, long-term consumption of high-fluoride water can lead to skeletal fluorosis and dental fluorosis; for the environment, fluoride ions are difficult to degrade in water bodies and can easily cause persistent pollution.

[0003] Currently, commonly used defluoridation methods mainly include: lime precipitation, aluminum / iron salt co-precipitation, adsorption, and membrane separation technology. Lime precipitation requires a high pH (>10), large reagent dosages, and easily generates fine CaF2 particles, resulting in poor settling performance and large sludge volume. Aluminum / iron salt co-precipitation requires large reagent dosages and must be used in conjunction with flocculants, and the effluent may contain aluminum or iron residues. Adsorption methods (activated alumina, modified zeolite, modified bentonite, etc.) have high adsorption efficiency, but the adsorbents are expensive, difficult to regenerate, and lack long-term stability after single-stage treatment. Membrane separation technologies (nanofiltration, reverse osmosis), while having high removal rates, suffer from severe membrane fouling, high operating energy consumption, and high investment and maintenance costs, making them unsuitable for large-scale long-term operation.

[0004] In summary, existing technologies suffer from problems such as difficulty in achieving both removal rate and operational economy in single-stage treatment, high energy and chemical consumption, and insufficient effluent stability. A new type of device is needed that combines multi-stage reactions, considers both sedimentation and adsorption, and has low operating costs and stable operation. Utility Model Content

[0005] The purpose of this invention is to provide a multi-stage defluoridation device for industrial wastewater in order to solve at least one of the above-mentioned technical problems.

[0006] This utility model provides a multi-stage defluoridation device for industrial wastewater, comprising an influent regulating tank, a pre-precipitation reaction zone, a main adsorption reaction zone, a fine reaction zone, a sedimentation and clarification zone, and an effluent collection zone connected in sequence. The pre-precipitation reaction zone is also connected to a first dosing tank, and the fine reaction zone is also connected to a second dosing tank. The main adsorption reaction zone is filled with adsorbent. The first dosing tank contains quicklime, and the second dosing tank contains aluminum salts and / or iron salts.

[0007] Optionally, a level gauge and a stirrer are installed in the inlet regulating tank to balance the water quality and quantity of the industrial wastewater to be treated.

[0008] Optionally, the adsorbent includes at least one of the following: aluminum-modified zeolite, iron-modified bentonite, and activated alumina.

[0009] Optionally, a backwashing pipeline is provided at the bottom of the main adsorption reaction zone for backwashing the bottom of the main adsorption reaction zone.

[0010] Optionally, the settling and clarification zone is an inclined tube sedimentation tank structure, and the inclined tube sedimentation tank structure is equipped with inclined plates or inclined tube packing.

[0011] Optionally, an adsorbent regeneration system is also provided in the main adsorption reaction zone. The adsorbent regeneration system includes a regeneration liquid storage tank, a circulation pump, and a regeneration liquid rinsing device. The regeneration liquid storage tank contains sodium hydroxide solution or hydrochloric acid solution.

[0012] This invention provides a multi-stage defluoridation device for industrial wastewater, employing a three-stage defluoridation mode. In the pre-precipitation zone, quicklime is added to generate CaF2 precipitate. In the main adsorption reaction zone, a modified adsorbent removes fluoride ions. In the fine reaction zone, a small dose of aluminum or iron salt is added to further remove any remaining trace amounts of fluoride ions. Finally, solid-liquid separation is achieved in the sedimentation and clarification zone, yielding compliant effluent. This device features a reasonable structure, stable operation, low energy consumption, and low cost. The effluent fluoride concentration is consistently below 1.0 mg / L, achieving highly efficient defluoridation in industrial wastewater treatment and demonstrating significant engineering application value. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of a multi-stage defluoridation device for industrial wastewater provided in an embodiment of the present invention.

[0015] In the diagram: 1. Inlet regulating tank; 2. Pre-sedimentation reaction zone; 3. Main adsorption reaction zone; 4. Fine reaction zone; 5. Sedimentation and clarification zone; 6. Effluent collection zone; 7. First dosing tank; 8. Second dosing tank; 9. Adsorbent. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Figure 1 This is a schematic diagram of a multi-stage defluoridation device for industrial wastewater according to an embodiment of this utility model. Figure 1 As shown, it includes an inlet regulating tank 1, a pre-sedimentation reaction zone 2, a main adsorption reaction zone 3, a fine reaction zone 4, a sedimentation and clarification zone 5, and an effluent collection zone 6 connected in sequence. The pre-sedimentation reaction zone 2 is also connected to a first dosing tank 7, and the fine reaction zone 4 is also connected to a second dosing tank 8. The main adsorption reaction zone 3 is filled with adsorbent 9.

[0018] Preferably, the first dosing tank 7 contains quicklime, and the second dosing tank 8 contains aluminum salts and / or iron salts.

[0019] Specifically, a level gauge and a stirrer are installed in the influent equalization tank 1 to balance the water quality and quantity of the industrial wastewater to be treated.

[0020] Preferably, the influent regulating tank 1 is also equipped with a bar screen or sieve to intercept and remove large particulate suspended solids in the industrial wastewater to be treated, so as to avoid subsequent clogging.

[0021] Pre-precipitation reaction zone 2 is equipped with a stirring and dosing port. Quicklime or alkaline reagents from the first dosing tank 7 are added to the zone, allowing fluoride ions and calcium in the industrial wastewater to react with each other. 2+ The reaction produces CaF2 precipitate.

[0022] Preferably, the pre-precipitation reaction zone 2 is a rectangular or circular tank, in which the industrial wastewater to be treated is retained for 20-30 minutes, the stirring speed is 60-80 rpm, an automatic dosing and pH control device is installed, and a baffle is installed at the outlet to intercept large particles.

[0023] Preferably, the main adsorption reaction zone 3 is a columnar filter bed or a rectangular filter bed, and the adsorbent 9 inside is at least one of the following: aluminum-modified zeolite, iron-modified bentonite, and activated alumina.

[0024] Preferably, a backwashing pipeline is provided at the bottom of the main adsorption reaction zone 3 to backwash the bottom of the main adsorption reaction zone and to avoid blockage.

[0025] Preferably, an adsorbent regeneration system is also provided in the main adsorption reaction zone 3. The adsorbent regeneration system includes a regeneration liquid storage tank, a circulation pump and a regeneration liquid rinsing device. The regeneration liquid storage tank contains sodium hydroxide solution or hydrochloric acid solution, wherein the sodium hydroxide solution or hydrochloric acid solution is used to regenerate the adsorbent 9.

[0026] Specifically, the main adsorption reaction zone 3 flows from bottom to top through the adsorption layer, and the adsorbent 9 is filled to a height of 70-80% of the tank. Backwashing pipelines and valve groups are provided, and backwashing is performed periodically to restore the flux. After adsorption saturation, the adsorbent is desorbed through the regeneration system and reused.

[0027] Preferably, the main adsorption reaction zone 3 is held for 30-40 minutes.

[0028] Preferably, a small amount of aluminum salt and / or iron salt (reduced to 30-40% compared to the traditional method) is added to the fine reaction zone 4, and the mixture is left to stand for 15-20 minutes with slow stirring to facilitate the formation of flocs to capture the remaining small amount of fluoride ions and improve the fluoride ion removal efficiency.

[0029] Preferably, the settling and clarification zone 5 is an inclined tube sedimentation tank structure, with inclined plates or inclined tube packing inside the structure, and a surface loading of 1-1.5 m. 3 / m 2 •h, improves the effective settling area and efficiency, automatically discharges sludge, and avoids sludge floating and secondary pollution.

[0030] Specifically, sampling ports and online monitoring are set up in the effluent collection area 6. After the clarified supernatant is collected, it will be discharged in compliance with standards and reused.

[0031] Example 1: Treatment of fluoride wastewater Wastewater F from a fluoride salt production enterprise - =50-80 mg / L, pH≈6.5. Add lime to the pre-precipitation zone, F - The concentration was reduced to approximately 20 mg / L; further reduced to approximately 5 mg / L in the main adsorption zone; and further reduced to 0.8 mg / L by a small dose of polyaluminum chloride in the fine reaction zone; finally, solid-liquid separation was completed in the sedimentation and clarification zone, and the effluent consistently met the standards.

[0032] Example 2: Treatment of aluminum fluoride wastewater Wastewater F from an aluminum fluoride production enterprise - ≈300 mg / L, pH≈3. First, neutralize to pH≈6.5-7.0 by adding alkali in the equalization tank; add lime in the pre-precipitation zone, F - The concentration was reduced to approximately 80 mg / L; further reduced to approximately 10 mg / L in the main adsorption zone; and reduced to 0.9 mg / L in the fine reaction zone with small-dose aluminum / iron salt treatment. The overall reagent consumption was reduced by approximately 35% compared to the traditional method, and the system operated stably.

[0033] The multi-stage defluoridation device for industrial wastewater provided in this embodiment of the invention has the following technical advantages compared with the prior art: (1) High efficiency in defluorination: multi-stage series reaction, precipitation-adsorption-precipitation synergistic reaction, high defluorination efficiency; (2) Low operating cost: The adsorbent is regenerable and recyclable, and multi-stage decentralized dosing reduces drug consumption; (3) Stable system: each area has a clear division of labor, strong resistance to shock loads, and small fluctuations in effluent; (4) Easy maintenance: compact structure, small footprint, and simple operation and maintenance; (5) Wide adaptability: It is applicable to fluorine-containing chemical wastewater such as aluminum fluoride and has strong engineering adaptability.

[0034] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0035] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A multi-stage defluoridation device for industrial wastewater, characterized in that, It includes an inlet regulating tank, a pre-sedimentation reaction zone, a main adsorption reaction zone, a fine reaction zone, a sedimentation and clarification zone, and an effluent collection zone connected in sequence. The pre-sedimentation reaction zone is also connected to a first dosing tank, and the fine reaction zone is also connected to a second dosing tank. The main adsorption reaction zone is filled with adsorbent. The first dosing tank contains quicklime, and the second dosing tank contains aluminum salts and / or iron salts.

2. The multi-stage defluoridation device for industrial wastewater according to claim 1, characterized in that: The inlet regulating tank is equipped with a level gauge and a stirrer to balance the water quality and quantity of the industrial wastewater to be treated.

3. The multi-stage defluoridation device for industrial wastewater according to claim 1, characterized in that: The adsorbent includes at least one of the following: aluminum-modified zeolite, iron-modified bentonite, and activated alumina.

4. The multi-stage defluoridation device for industrial wastewater according to claim 1, characterized in that: A backwashing pipeline is provided at the bottom of the main adsorption reaction zone for backwashing the bottom of the main adsorption reaction zone.

5. The multi-stage defluoridation device for industrial wastewater according to claim 1, characterized in that: The sedimentation and clarification zone is an inclined tube sedimentation tank structure, and the inclined tube sedimentation tank structure is equipped with inclined plates or inclined tube packing.

6. The multi-stage defluoridation device for industrial wastewater according to claim 1, characterized in that: An adsorbent regeneration system is also provided in the main adsorption reaction zone. The adsorbent regeneration system includes a regenerated liquid storage tank, a circulation pump, and a regenerated liquid rinsing device. The regenerated liquid storage tank contains sodium hydroxide solution or hydrochloric acid solution.

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