Method for removing fluoride, phosphorus and chemical oxygen demand in wastewater and application thereof

Abstract

The invention discloses a method for removing fluoride, phosphorus and chemical oxygen demand in wastewater and application thereof, belongs to the technical field of wastewater treatment, and solves the problems of high operation cost and complex operation in the prior art. The invention discloses a method for removing fluorides, phosphorus and chemical oxygen demand in wastewater. The method comprises the following steps: S1, adjusting the water quality and the water quantity of the wastewater in an adjusting tank; s2, conveying the adjusted wastewater to a defluorination system for reaction, monitoring the reacted wastewater, and conveying the wastewater to an ozone reaction system for ozone oxidation reaction after fluoride of the wastewater reaches the standard; s3, conveying the wastewater in the step S2 to a biochemical system for biochemical reaction and precipitation; and S4, conveying the wastewater treated in the step S3 to an advanced treatment system for precipitation and filtration, and discharging the effluent after phosphorus and chemical oxygen demand reach the standard. The whole process flow is short, the power consumption is low, the requirements of energy conservation and emission reduction are met, the operation cost is saved, and the operation management is convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for removing fluoride, phosphorus and chemical oxygen demand in wastewater and an application thereof. Background Art

[0002] The treatment of fluoride-containing wastewater is an important environmental issue, because fluoride is widely used in industrial production processes, resulting in the generation of a large amount of fluoride-containing wastewater. These wastewaters not only pollute the environment, but may also pose a threat to human health. And due to increasingly stringent environmental requirements, more and more fluoride-containing wastewater effluents need to reach less than 1.0 mg / L. Therefore, it is of great significance to study effective methods for treating fluoride-containing wastewater. At present, the methods for treating fluoride-containing wastewater mainly include chemical precipitation, reverse osmosis, coagulation and sedimentation, adsorption, electrodialysis and biological treatment. Chemical precipitation is the most commonly used method, which removes fluoride ions by forming precipitates by adding substances such as calcium salts. Reverse osmosis uses high pressure to remove fluoride ions by reverse osmosis. Adsorption and electrodialysis are also commonly used to treat fluoride-containing wastewater; however, the above treatment methods have high operating costs and are more complicated to operate. Summary of the invention

[0003] The purpose of the present invention is to provide a method for removing fluoride, phosphorus and chemical oxygen demand in wastewater and its application, which solves the problems of high running cost and complicated operation in the prior art.

[0004] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A method for removing fluoride, phosphorus and chemical oxygen demand in wastewater, comprising:

[0006] Step S1, regulating the water quality and quantity of wastewater in a regulating tank;

[0007] Step S2, conveying the regulated wastewater to a defluorination system for reaction, monitoring the wastewater after the reaction, and conveying the wastewater to an ozone reaction system for ozone oxidation reaction after the fluoride content of the wastewater meets the standard;

[0008] Step S3, transporting the wastewater that has undergone ozone oxidation reaction to a biochemical system for biochemical reaction and precipitation;

[0009] Step S4: transport the wastewater treated in step S3 to a deep treatment system for sedimentation and filtration, and discharge the wastewater after the phosphorus and chemical oxygen demand meet the standards.

[0010] In some embodiments, the fluoride concentration of the wastewater in step S1 is less than 20 mg / L; the wastewater in step S2 meets the standard specifically when the fluoride concentration of the wastewater is less than 1.0 mg / L, and the pH of the wastewater is neutral;

[0011] The wastewater meets the standards in step S4 when the fluoride concentration of the wastewater is less than 1.0 mg / L, the chemical oxygen demand is less than 20 mg / L, and the total phosphorus is less than 0.2 mg / L.

[0012] In some embodiments, the defluorination system includes three or more high-efficiency sedimentation tanks, each of which includes a pH adjustment tank, a coagulation reaction tank, a flocculation reaction tank and an inclined tube sedimentation tank. A defluorination agent is added to each coagulation reaction tank, and a flocculant is added to each flocculation reaction tank.

[0013] In some embodiments, the mass ratio of the added amount of the defluorinating agent in the primary coagulation reaction tank is 2.5-2.8‰, and the mass ratio of the added amount of the defluorinating agent in the secondary or higher coagulation reaction tank is 0.7-1.1‰.

[0014] In some embodiments, the defluoridation agent is any combination of bone char, zeolite, calcium chloride, calcium hydroxide, sodium aluminum phosphate, disodium hydrogen phosphate, polyaluminum iron silicate, lanthanide rare earth elements, and iron-aluminum-manganese complexes;

[0015] The flocculant is any combination of polyacrylamide, polymerized aluminum oxide, aluminum sulfate, and polymerized ferric sulfate.

[0016] In some embodiments, the amount of flocculant added to the primary flocculation reaction tank is 3-5 mg / L, and the amount of flocculant added to the secondary or higher flocculation reaction tank is 1-3 mg / L.

[0017] In some embodiments, the pH value of the pH adjustment tank in the primary high-efficiency sedimentation tank is 7.5-10, the pH value of the pH adjustment tank in the secondary high-efficiency sedimentation tank is 6.5-9.0, and the pH value of the pH adjustment tank in the secondary and higher high-efficiency sedimentation tanks is 5.5-8.

[0018] In some embodiments, the ozone reaction system in step S2 includes an ozone reaction tank and a deoxygenation tank. The ozone reaction tank is used to decompose the refractory organic matter in the wastewater into small molecular organic matter that is easy to biodegrade, and the deoxygenation tank is used to remove the ozone remaining in the water after oxidation.

[0019] In some embodiments, the biochemical system in step S3 includes a three-dimensional ecological reaction tank and a secondary sedimentation tank, wherein the three-dimensional ecological reaction tank is used to remove organic matter in water, and the secondary sedimentation tank is used for solid-liquid separation.

[0020] Another technical solution of the present invention is achieved as follows: an application of the above-mentioned method for removing fluoride, phosphorus and chemical oxygen demand in wastewater in defluoridation of production wastewater.

[0021] Compared with the prior art, the method of the present invention has a short overall process flow, fewer lifting times, and low lifting power consumption, which fully meets the requirements of energy conservation, emission reduction and green pollution control, saves operating costs, and is convenient for operation and management. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A flow chart of the method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to the present invention;

[0023] Figure 2 The present invention is a flow chart of a defluorination system for a method of removing fluoride, phosphorus and chemical oxygen demand in wastewater. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] Unless otherwise specified, all drugs / reagents used were commercially available.

[0027] Experimental materials: raw water from the fluoride wastewater regulating tank of a wastewater deep treatment project in Shenzhen (treated fluoride wastewater from an integrated circuit enterprise in Shenzhen, fluoride ion concentration below 20 mg / L), defluoridation agent (liquid agent with an active ingredient of metal oxide content >10%, acidic), 30% industrial-grade sodium hydroxide solution dilution, anionic polyacrylamide (PAM) solution (configuration concentration 2‰), etc.

[0028] Experimental equipment: electronic balance, magnetic stirrer, 1L beaker, Lei-Magnetic PXBJ-286F portable ion meter, Lei-Magnetic DZS-706 multi-parameter analyzer, 1L measuring cylinder, etc.

[0029] According to the "Water and Wastewater Monitoring and Analysis Methods", the following indicators are selected for testing:

[0030] (1) Fluoride ion detection: The Leix PXBJ-286F portable ion meter uses the fluoride ion selective electrode method and uses a total ionic strength buffer solution to eliminate the influence of interfering ions in water;

[0031] (2) pH meter: DZS-706 multi-parameter analyzer.

[0032] Example 1

[0033] like Figure 1 and Figure 2 As shown, the wastewater is regulated in the regulating tank for water quality and quantity; then it enters the three-stage defluoridation system, which consists of three high-efficiency sedimentation tanks, and NaOH, defluoridation agent, and PAM are added to remove fluoride in the water.

[0034] The primary high-efficiency sedimentation tank includes a primary pH rough adjustment tank and a primary pH fine adjustment tank. The pH value of the primary pH rough adjustment tank is 7.5, the pH value of the primary pH fine adjustment tank is 9, the fluoride removal dosage in the coagulation reaction tank is 2.5‰, the PAM dosage in the flocculation reaction tank is 3mg / L, and the fluoride concentration of the effluent is 4mg / L.

[0035] The secondary high-efficiency sedimentation tank includes a secondary pH rough adjustment tank and a secondary pH fine adjustment tank. The pH value of the secondary pH rough adjustment tank is 6.5, the pH value of the secondary pH fine adjustment tank is 8, the fluoride removal dosage in the coagulation reaction tank is 0.7‰, the PAM dosage in the flocculation reaction tank is 1mg / L, and the fluoride concentration of the effluent is less than 1.0mg / L;

[0036] The three-stage high-efficiency sedimentation tank is used as a bottom-up treatment unit. When the system is started in an emergency, it includes a three-stage pH rough adjustment tank and a three-stage pH fine adjustment tank. The pH value of the three-stage pH rough adjustment tank is 5.5, the pH value of the three-stage pH fine adjustment tank is 7, the defluorination dosage in the coagulation reaction tank is 0.7‰, and the PAM dosage in the flocculation reaction tank is 1mg / L; when the maintenance or bottom-up treatment unit is not started, the pH adjustment tank, coagulation reaction tank and flocculation reaction tank are not added; when the three-stage high-efficiency sedimentation tank is only a water-passing unit, the pH value in the pH adjustment tank is 6.5;

[0037] The sludge in the inclined tube sedimentation tank in each stage of high-efficiency sedimentation tank is returned on demand. The first-stage inclined tube sedimentation tank is returned to the first-stage flocculation reaction tank, and the sludge return ratio is 2-3%; the second-stage inclined tube sedimentation tank is returned to the second-stage flocculation reaction tank, and the sludge return ratio is 3-4%; the third-stage inclined tube sedimentation tank is returned to the third-stage flocculation reaction tank, and the sludge return ratio is 4-5%.

[0038] An online fluoride monitoring instrument is installed at the outlet of each high-efficiency sedimentation tank to monitor the fluoride in the effluent in real time; the pH of the effluent is neutral after passing through the three-stage high-efficiency sedimentation tank and directly enters the ozone reaction system.

[0039] The ozone reaction system consists of an ozone reaction tank and a deoxygenation tank; the ozone reaction tank is used to introduce ozone to decompose the difficult-to-degrade organic matter in the wastewater into small molecular organic matter that is easy to biodegrade, generate substances that are easy to biodegrade, eliminate or reduce toxicity, and improve the biodegradability of the wastewater; the deoxygenation tank is used to remove the ozone remaining in the water after oxidation without affecting subsequent biochemical treatment.

[0040] The biochemical system consists of a three-dimensional ecological reaction tank and a secondary sedimentation tank. The effluent from the ozone reaction system enters the three-dimensional ecological reaction tank, where the organic matter in the water is removed through anoxic and aerobic biochemical reactions. The effluent then enters the secondary sedimentation tank for solid-liquid separation.

[0041] The deep treatment system consists of a high-efficiency sedimentation tank and a sand filter tank. The effluent from the high-efficiency sedimentation tank enters the sand filter tank to ensure that the total phosphorus and suspended solids meet the standards. The fluoride in the discharged wastewater is less than 1.0 mg / L, the chemical oxygen demand (CODcr) is less than 20 mg / L, and the total phosphorus (TP) is less than 0.2 mg / L.

[0042] Example 2

[0043] like Figure 1 and Figure 2 As shown, the wastewater is regulated in the regulating tank for water quality and quantity; then it enters the three-stage defluoridation system, which consists of three high-efficiency sedimentation tanks, and NaOH, defluoridation agent, and PAM are added to remove fluoride in the water.

[0044] The primary high-efficiency sedimentation tank includes a primary pH rough adjustment tank and a primary pH fine adjustment tank. The pH value of the primary pH rough adjustment tank is 8, the pH value of the primary pH fine adjustment tank is 9.5, the fluoride removal dosage in the coagulation reaction tank is 2.8‰, the PAM dosage in the flocculation reaction tank is 5mg / L, and the fluoride concentration of the effluent is 6mg / L;

[0045] The secondary high-efficiency sedimentation tank includes a secondary pH rough adjustment tank and a secondary pH fine adjustment tank. The pH value of the secondary pH rough adjustment tank is 7, the pH value of the secondary pH fine adjustment tank is 8.5, the fluoride removal dosage in the coagulation reaction tank is 1.1‰, the PAM dosage in the flocculation reaction tank is 3mg / L, and the fluoride concentration of the effluent is less than 1.0mg / L;

[0046] The three-stage high-efficiency sedimentation tank is used as a bottom-up treatment unit. When the system is started in an emergency, it includes a three-stage pH rough adjustment tank and a three-stage pH fine adjustment tank. The pH value of the three-stage pH rough adjustment tank is 6, the pH value of the three-stage pH fine adjustment tank is 7.5, the defluorination dosage in the coagulation reaction tank is 1.1‰, and the PAM dosage in the flocculation reaction tank is 3mg / L; when the maintenance or bottom-up treatment unit is not started, the pH adjustment tank, coagulation reaction tank and flocculation reaction tank are not added; when the three-stage high-efficiency sedimentation tank is only a water-passing unit, the pH value in the pH adjustment tank is 7.5;

[0047] The sludge in the inclined tube sedimentation tank in each stage of high-efficiency sedimentation tank is returned on demand. The first-stage inclined tube sedimentation tank is returned to the first-stage flocculation reaction tank, and the sludge return ratio is 2-3%; the second-stage inclined tube sedimentation tank is returned to the second-stage flocculation reaction tank, and the sludge return ratio is 3-4%; the third-stage inclined tube sedimentation tank is returned to the third-stage flocculation reaction tank, and the sludge return ratio is 4-5%.

[0048] An online fluoride monitoring instrument is installed at the outlet of each high-efficiency sedimentation tank to monitor the fluoride in the effluent in real time; the pH of the effluent is neutral after passing through the three-stage high-efficiency sedimentation tank and directly enters the ozone reaction system.

[0049] The ozone reaction system consists of an ozone reaction tank and a deoxygenation tank; the ozone reaction tank is used to introduce ozone to decompose the difficult-to-degrade organic matter in the wastewater into small molecular organic matter that is easy to biodegrade, generate substances that are easy to biodegrade, eliminate or reduce toxicity, and improve the biodegradability of the wastewater; the deoxygenation tank is used to remove the ozone remaining in the water after oxidation without affecting subsequent biochemical treatment.

[0050] The biochemical system consists of a three-dimensional ecological reaction tank and a secondary sedimentation tank. The effluent from the ozone reaction system enters the three-dimensional ecological reaction tank, where the organic matter in the water is removed through anoxic and aerobic biochemical reactions. The effluent then enters the secondary sedimentation tank for solid-liquid separation.

[0051] The deep treatment system consists of a high-efficiency sedimentation tank and a sand filter tank. The effluent from the high-efficiency sedimentation tank enters the sand filter tank to ensure that the total phosphorus and suspended solids meet the standards. The fluoride in the discharged wastewater is less than 1.0 mg / L, the chemical oxygen demand (CODcr) is less than 20 mg / L, and the total phosphorus (TP) is less than 0.2 mg / L.

[0052] Example 3

[0053] like Figure 1 and Figure 2 As shown, the wastewater is regulated in the regulating tank for water quality and quantity; then it enters the three-stage defluoridation system, which consists of three high-efficiency sedimentation tanks, and NaOH, defluoridation agent, and PAM are added to remove fluoride in the water.

[0054] The primary high-efficiency sedimentation tank includes a primary pH rough adjustment tank and a primary pH fine adjustment tank. The pH value of the primary pH rough adjustment tank is 9.5, the pH value of the primary pH fine adjustment tank is 10, the fluoride removal dosage in the coagulation reaction tank is 2.6‰, the PAM dosage in the flocculation reaction tank is 4mg / L, and the fluoride concentration of the effluent is 3.5mg / L.

[0055] The secondary high-efficiency sedimentation tank includes a secondary pH rough adjustment tank and a secondary pH fine adjustment tank. The pH value of the secondary pH rough adjustment tank is 8.5, the pH value of the secondary pH fine adjustment tank is 9, the fluoride removal dosage in the coagulation reaction tank is 1‰, the PAM dosage in the flocculation reaction tank is 1.5mg / L, and the fluoride concentration of the effluent is less than 1.0mg / L;

[0056] The three-stage high-efficiency sedimentation tank is used as a bottom-up treatment unit. When the system is started in an emergency, it includes a three-stage pH rough adjustment tank and a three-stage pH fine adjustment tank. The pH value of the three-stage pH rough adjustment tank is 7.5, the pH value of the three-stage pH fine adjustment tank is 8, the fluorine removal dosage in the coagulation reaction tank is 0.7‰, and the PAM dosage in the flocculation reaction tank is 1mg / L; when the maintenance or bottom-up treatment unit is not started, the pH adjustment tank, coagulation reaction tank and flocculation reaction tank are not added; when the three-stage high-efficiency sedimentation tank is only a water-passing unit, the pH value in the pH adjustment tank is 6.5;

[0057] The sludge in the inclined tube sedimentation tank in each stage of high-efficiency sedimentation tank is returned on demand. The first-stage inclined tube sedimentation tank is returned to the first-stage flocculation reaction tank, and the sludge return ratio is 2-3%; the second-stage inclined tube sedimentation tank is returned to the second-stage flocculation reaction tank, and the sludge return ratio is 3-4%; the third-stage inclined tube sedimentation tank is returned to the third-stage flocculation reaction tank, and the sludge return ratio is 4-5%.

[0058] An online fluoride monitoring instrument is installed at the outlet of each high-efficiency sedimentation tank to monitor the fluoride in the effluent in real time; the pH of the effluent is neutral after passing through the three-stage high-efficiency sedimentation tank and directly enters the ozone reaction system.

[0059] The ozone reaction system consists of an ozone reaction tank and a deoxygenation tank; the ozone reaction tank is used to introduce ozone to decompose the difficult-to-degrade organic matter in the wastewater into small molecular organic matter that is easy to biodegrade, generate substances that are easy to biodegrade, eliminate or reduce toxicity, and improve the biodegradability of the wastewater; the deoxygenation tank is used to remove the ozone remaining in the water after oxidation without affecting subsequent biochemical treatment.

[0060] The biochemical system consists of a three-dimensional ecological reaction tank and a secondary sedimentation tank. The effluent from the ozone reaction system enters the three-dimensional ecological reaction tank, where the organic matter in the water is removed through anoxic and aerobic biochemical reactions. The effluent then enters the secondary sedimentation tank for solid-liquid separation.

[0061] The deep treatment system consists of a high-efficiency sedimentation tank and a sand filter tank. The effluent from the high-efficiency sedimentation tank enters the sand filter tank to ensure that the total phosphorus and suspended solids meet the standards. The fluoride in the discharged wastewater is less than 1.0 mg / L, the chemical oxygen demand (CODcr) is less than 20 mg / L, and the total phosphorus (TP) is less than 0.2 mg / L.

[0062] The method of the present invention has a short overall process flow, a small number of lifting times, and a low lifting power consumption, which fully meets the requirements of energy conservation and emission reduction and green pollution control, and saves operating costs; the fluoride removal efficiency is high: three-stage sedimentation gradient control, high stability, no regeneration requirement, and saving investment costs; convenient operation and management: the effluent is neutral, no pH adjustment tank is required, and no sulfuric acid, a precursor chemical required by other processes, is required; the high-efficiency sedimentation tank includes an independent sludge return system: each stage of flocculation reaction tank is equipped with sludge return, and the return volume is flexibly controlled, thereby improving the flocculation effect and saving the dosage of the reagent; the defluorination system of the present invention is conventionally operated in two stages, and the third stage is reserved; any two stages are operated in series to realize online maintenance without stopping production; intelligent control: an AI algorithm is introduced to optimize the dosage of the reagent in real time (dynamically adjusting the dosage ratio of the defluorination agent based on the online monitoring data of fluoride), thereby ensuring the effluent water quality while saving the dosage of the reagent.

[0063] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for removing fluoride, phosphorus and chemical oxygen demand in wastewater, characterized in that: include: Step S1, regulating the water quality and quantity of wastewater in a regulating tank; Step S2, conveying the regulated wastewater to a defluorination system for reaction, monitoring the wastewater after the reaction, and conveying the wastewater to an ozone reaction system for ozone oxidation reaction after the fluoride content of the wastewater meets the standard; Step S3, transporting the wastewater that has undergone ozone oxidation reaction to a biochemical system for biochemical reaction and precipitation; Step S4: transport the wastewater treated in step S3 to a deep treatment system for sedimentation and filtration, and discharge the wastewater after the phosphorus and chemical oxygen demand meet the standards.

2. The method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to claim 1, characterized in that: The fluoride concentration of the wastewater in step S1 is less than 20 mg / L; the wastewater in step S2 meets the standard specifically when the fluoride concentration of the wastewater is less than 1.0 mg / L, and the pH of the wastewater is neutral; The wastewater meets the standards in step S4 when the fluoride concentration of the wastewater is less than 1.0 mg / L, the chemical oxygen demand is less than 20 mg / L, and the total phosphorus is less than 0.2 mg / L.

3. The method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to claim 1, characterized in that: The defluorination system comprises three or more high-efficiency sedimentation tanks, each of which comprises a pH adjustment tank, a coagulation reaction tank, a flocculation reaction tank and an inclined tube sedimentation tank, a defluorination agent is added to each coagulation reaction tank, and a flocculant is added to each flocculation reaction tank.

4. The method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to claim 3, characterized in that: The mass ratio of the added amount of the defluorinating agent in the primary coagulation reaction tank is 2.5-2.8‰, and the mass ratio of the added amount of the defluorinating agent in the secondary or higher coagulation reaction tank is 0.7-1.1‰.

5. The method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to any one of claims 2 to 4, characterized in that: The defluoridation agent is any combination of bone char, zeolite, calcium chloride, calcium hydroxide, sodium aluminum phosphate, disodium hydrogen phosphate, polyaluminum iron silicate, lanthanide rare earth elements, and iron-aluminum-manganese complex; The flocculant is any combination of polyacrylamide, polymerized aluminum oxide, aluminum sulfate, and polymerized ferric sulfate.

6. The method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to claim 3, characterized in that: The amount of flocculant added in the primary flocculation reaction tank is 3-5 mg / L, and the amount of flocculant added in the secondary or higher flocculation reaction tank is 1-3 mg / L.

7. The method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to claim 3, characterized in that: The pH value of the pH adjustment tank in the primary high-efficiency sedimentation tank is 7.5-10, the pH value of the pH adjustment tank in the secondary high-efficiency sedimentation tank is 6.5-9.0, and the pH value of the pH adjustment tank in the secondary high-efficiency sedimentation tank or above is 5.5-8.

8. The method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to any one of claims 1 to 7, characterized in that: The ozone reaction system in step S2 includes an ozone reaction tank and a deoxygenation tank. The ozone reaction tank is used to decompose the refractory organic matter in the wastewater into small molecular organic matter that is easy to biodegrade, and the deoxygenation tank is used to remove the ozone remaining in the water after oxidation.

9. The method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to any one of claims 1 to 7, characterized in that: The biochemical system in step S3 includes a three-dimensional ecological reaction tank and a secondary sedimentation tank. The three-dimensional ecological reaction tank is used to remove organic matter in water, and the secondary sedimentation tank is used for solid-liquid separation.

10. Use of the method for removing fluoride, phosphorus and chemical oxygen demand in wastewater according to any one of claims 1 to 9 in defluoridation of industrial wastewater.

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