Efficient magnetic medium coagulating sedimentation water treatment system and method thereof

Abstract

The invention discloses a high-efficiency magnetic medium coagulating sedimentation water treatment system which comprises a pre-sedimentation tank, an electro-Fenton oxidation device, a magnetic medium coagulating device, a calcining furnace, a secondary sedimentation tank, a magnetic recovery device and a modification mixing tank, an outlet of the pre-sedimentation tank is communicated with the electro-Fenton oxidation device, a water outlet of the electro-Fenton oxidation device is communicated with the magnetic medium coagulating device, and a water outlet of the magnetic medium coagulating device is communicated with the calcining furnace. A sludge outlet of the electro-Fenton oxidation device is communicated with the calcining furnace, a calcining outlet of the calcining furnace and a magnetic medium outlet of the magnetic medium coagulation device are both communicated with the magnetic recovery device, a magnetic medium outlet of the magnetic recovery device is communicated with the modified mixing pool, and a discharge port of the modified mixing pool is communicated with the magnetic medium coagulation device; and a water outlet of the magnetic medium coagulation device is communicated with the secondary sedimentation tank. The method has the advantages of being high in oxidation capacity, small in selectivity, high in reaction speed and thorough in reaction, has a good degradation effect on refractory organic pollutants, and meanwhile can effectively achieve modification and reutilization of recovered magnetic media.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a high-efficiency magnetic medium coagulation and sedimentation water treatment system and a method thereof. Background Art

[0002] With the continuous development of industrial parks, the proportion of industrial wastewater in the mixed influent of park sewage treatment plants is increasing. The increase of difficult-to-degrade organic matter causes the influent to deviate from the design value, the biodegradability of wastewater is reduced, the difficulty of biological treatment is increased, and the original treatment process cannot meet the stable discharge standards of effluent. Summary of the invention

[0003] The purpose of the present invention is to provide a high-efficiency magnetic medium coagulation and sedimentation water treatment system and method, which has the advantages of strong oxidation ability, low selectivity, fast reaction speed and thorough reaction, has a good degradation effect on difficult-to-degrade organic pollutants, and can effectively realize the modification and reuse of recovered magnetic media.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions: A high-efficiency magnetic medium coagulation and sedimentation water treatment system, characterized in that it comprises a pre-sedimentation tank, an electric Fenton oxidation device, a magnetic medium coagulation device, a calcining furnace, a secondary sedimentation tank, a magnetic recovery device and a modified mixing tank, the outlet of the pre-sedimentation tank is connected to the electric Fenton oxidation device, the water outlet of the electric Fenton oxidation device is connected to the magnetic medium coagulation device, the sludge outlet of the electric Fenton oxidation device is connected to the calcining furnace, the calcination outlet of the calcining furnace and the magnetic medium outlet of the magnetic medium coagulation device are both connected to the magnetic recovery device, the magnetic medium outlet of the magnetic recovery device is connected to the modified mixing tank, the discharge port of the modified mixing tank is connected to the magnetic medium coagulation device, and the water outlet of the magnetic medium coagulation device is connected to the secondary sedimentation tank.

[0005] Preferably, the magnetic medium coagulation device includes a coagulation tank, a magnetic medium mixing tank, a flocculation reaction tank and a clarification tank which are connected in sequence, the electro-Fenton oxidation device, the coagulation tank, the magnetic medium mixing tank and the flocculation reaction tank are all provided with electric agitators, the upper part of the clarification tank is provided with fillers and inclined plate clarification tanks, the bottom of the clarification tank is provided with a scraper, and the bottom of the clarification tank is provided with a sludge outlet.

[0006] Preferably, the magnetic recovery machine is a magnetic drum equipped with permanent magnets, and the inner ring of the magnetic drum is divided into an adsorption zone, a conveying zone 1, a conveying zone 2, a conveying zone 3 and a slag unloading zone upward. The magnetic field strength in the adsorption zone is 430-450mT, and the magnetic wrap angle is 120°. The magnetic field strength in the conveying zone 1 is 320-350mT, and the magnetic wrap angle is 60°. The magnetic field strength in the conveying zone 2 is 230-250mT, and the magnetic wrap angle is 30°. The magnetic field strength in the conveying zone 3 is between 140 and 160mT, and the magnetic wrap angle is 30°. The permanent magnets are arranged in an annular direction with the same poles and in an axial direction with SN alternatingly.

[0007] Preferably, an ultrasonic generator and an electric stirrer are provided in the modified mixing tank.

[0008] A high-efficiency magnetic medium coagulation sedimentation water treatment method, characterized in that it comprises the following steps: The wastewater first enters the pre-sedimentation tank, and after part of the sludge is precipitated, the wastewater is transported to the electro-Fenton oxidation device; After the wastewater enters the electro-Fenton oxidation device, the electric stirrer is turned on, the Fenton reagent is added and an electric current is applied; After the electro-Fenton treatment is completed, the wastewater is introduced into the magnetic medium coagulation device, the Fenton sludge produced by the electro-Fenton oxidation device enters the calciner for calcination, and the calcined product enters the magnetic recovery device; The wastewater enters the magnetic medium coagulation device, and coagulant, modified magnetic medium and flocculant are added in sequence under stirring, and finally enters the coagulation tank. The upper clear water enters the secondary sedimentation tank and is discharged after meeting the standards, and the magnetic medium sludge at the bottom enters the magnetic recovery device; After the magnetic recovery device magnetically separates the calcined product from the magnetic medium sludge, the magnetic medium to be treated is sent to the modified mixing tank, where a modifier and sodium hydroxide solution are added under stirring and ultrasonic conditions for modification, and the modified magnetic medium flows back to the magnetic medium mixing tank.

[0009] Preferably, the Fenton reagent is ferrous sulfate and hydrogen peroxide, the dosage of ferrous sulfate is 0.2-0.4 mmol / L, and the dosage of hydrogen peroxide is 2-3 mmol / L.

[0010] Preferably, the calcination temperature in the calcination furnace is 800° C. and the calcination time is 2 to 3 hours.

[0011] Preferably, the coagulant is PAC, the modified magnetic medium is lanthanum-loaded ferrosoferric oxide, the flocculant is PAM, and the modifier is lanthanum nitrate.

[0012] Preferably, the preparation method of the lanthanum-loaded ferroferric oxide in the modified mixing tank is: suspending the ferroferric oxide obtained by magnetic recovery in pure water in the modified mixing tank and ultrasonicating, then dissolving lanthanum nitrate in the ferroferric oxide suspension under mechanical stirring of an electric stirrer, adding sodium hydroxide solution dropwise to the generated mixture of lanthanum nitrate and magnetic medium, and obtaining the lanthanum-loaded ferroferric oxide after stirring and separation.

[0013] In summary, the present invention has the following beneficial effects: The present invention realizes deep treatment of wastewater by combining electro-Fenton and magnetic medium coagulation, and has a good removal effect on difficult-to-degrade industrial wastewater.

[0014] The present invention calcines Fenton sludge generated by electro-Fenton, wherein the main components of Fenton sludge are FeOOH, organic matter and some inorganic salts. The calcined product is basically in the form of ferroferric oxide, and the ferroferric oxide is separated by magnetic separation technology to complete the resource utilization of Fenton sludge.

[0015] Modified magnetic medium lanthanum ferroferric oxide can enhance the fluoride removal rate of coagulation sedimentation, and the fluoride concentration of the effluent can be stably lower than 1 mg / L. At the same time, the use of modified magnetic medium lanthanum ferroferric oxide reduces the amount of coagulant added to a certain extent, reduces the operating cost and avoids the secondary pollution that may be caused by the addition of reagents. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the internal structure of the magnetic recovery device of the present invention. DETAILED DESCRIPTION

[0017] The specific implementation manner of the present invention is further described below in conjunction with the accompanying drawings, and this embodiment does not constitute a limitation of the present invention.

[0018] like Figure 1 A high-efficiency magnetic medium coagulation and sedimentation water treatment system shown in the figure comprises a pre-sedimentation tank 1, an electro-Fenton oxidation device 2, a magnetic medium coagulation device 3, a calcining furnace 4, a secondary sedimentation tank 5, a magnetic recovery device 6 and a modified mixing tank 7. The outlet of the pre-sedimentation tank 1 is connected to the electro-Fenton oxidation device 2, the water outlet of the electro-Fenton oxidation device 2 is connected to the magnetic medium coagulation device 3, the sludge outlet of the electro-Fenton oxidation device 2 is connected to the calcining furnace 4, the calcination outlet of the calcining furnace 4 and the magnetic medium outlet of the magnetic medium coagulation device 3 are both connected to the magnetic recovery device 6, the magnetic medium outlet of the magnetic recovery device 6 is connected to the modified mixing tank 7, the discharge port of the modified mixing tank 7 is connected to the magnetic medium coagulation device 3, and the water outlet of the magnetic medium coagulation device 3 is connected to the secondary sedimentation tank 5.

[0019] The magnetic medium coagulation device 3 includes a coagulation tank 1, a magnetic medium mixing tank 2, a flocculation reaction tank 3 and a clarification tank 4 which are connected in sequence. The electric-Fenton oxidation device 2, the coagulation tank 1, the magnetic medium mixing tank 2 and the flocculation reaction tank 3 are all provided with electric agitators. The upper part of the clarification tank 4 is provided with a filler and an inclined plate clarification tank, the bottom of the clarification tank 4 is provided with a scraper, and the bottom of the clarification tank 4 is provided with a sludge outlet.

[0020] like Figure 2 As shown, the magnetic recovery machine is a magnetic drum equipped with permanent magnets. The inner ring of the magnetic drum is divided into an adsorption zone, a conveying zone 1, a conveying zone 2, a conveying zone 3 and a slag unloading zone. The magnetic field strength in the adsorption zone is 430-450mT, and the magnetic wrap angle is 120°. The magnetic field strength in the conveying zone 1 is 320-350mT, and the magnetic wrap angle is 60°. The magnetic field strength in the conveying zone 2 is 230-250mT, and the magnetic wrap angle is 30°. The magnetic field strength in the conveying zone 3 is between 140-160mT, and the magnetic wrap angle is 30°. In the process of conveying the magnetic medium to the slag unloading zone, the magnetic field is weakened. The background magnetic field magnetizes the magnetic medium to prevent the magnetic medium from forming magnetic chains due to magnetization during the reuse process; the zero magnetic field area in the slag unloading area is conducive to the unloading of the magnetic medium, ensuring that the magnetic medium can be properly magnetized without over-magnetization during the recovery process. While reducing the loss of the magnetic medium, the magnetization of the magnetic medium can maintain part of the "residual magnetic field strength". Under the magnetic field force generated by this part of the "residual magnetic field strength", the micro-flocs containing the magnetic medium are promoted to aggregate, which helps to form larger and denser flocs, thereby improving the coagulation effect. At the same time, the permanent magnets of the magnetic drum adopt the same polarity in the annular direction and the axial SN alternating arrangement, which can not only ensure the uniformity of the magnetic field strength on the surface of the permanent magnet, so that the magnetic medium adsorbed on the surface is not washed off by the water force, but also ensure the depth of the magnetic field strength on the surface of the permanent magnet, which is conducive to the adsorption of fine-grained magnetic media.

[0021] An ultrasonic generator and an electric stirrer are arranged in the modified mixing tank 7 .

[0022] A high-efficiency magnetic medium coagulation sedimentation water treatment method comprises the following steps: The wastewater first enters the pre-sedimentation tank 1, and after part of the sludge is precipitated, the wastewater is transported to the electro-Fenton oxidation device 2; After the wastewater enters the electro-Fenton oxidation device 2, the electric stirrer is turned on, the Fenton reagent is added and the current is applied; After the electro-Fenton treatment is completed, the wastewater is introduced into the magnetic medium coagulation device 3, the Fenton sludge produced by the electro-Fenton oxidation device 2 enters the calcining furnace 4 for calcination, and the calcined product enters the magnetic recovery device 6; The wastewater enters the magnetic medium coagulation device 3, and the coagulant, modified magnetic medium and flocculant are added in sequence under stirring, and finally enters the coagulation tank 1. The upper clear water enters the secondary sedimentation tank 5 and is discharged after meeting the standards. The magnetic medium sludge at the bottom enters the magnetic recovery device 6; After the magnetic recovery device 6 magnetically separates the calcined product from the magnetic medium sludge, the magnetic medium to be treated is sent to the modified mixing tank 7, where a modifier and sodium hydroxide solution are added under stirring and ultrasonic conditions for modification, and the modified magnetic medium flows back to the magnetic medium mixing tank 2.

[0023] Fenton's reagent is ferrous sulfate and hydrogen peroxide, the dosage of ferrous sulfate is 0.2-0.4mmol / L, and the dosage of hydrogen peroxide is 2-3mmol / L.

[0024] The calcination temperature in the calcination furnace 4 is 800° C. and the calcination time is 2 to 3 hours.

[0025] The coagulant is PAC, the modified magnetic medium is lanthanum-loaded ferrosoferric oxide, the flocculant is PAM, and the modifier is lanthanum nitrate.

[0026] The preparation method of lanthanum-loaded ferroferric oxide in the modified mixing tank 7 is as follows: the ferroferric oxide obtained by magnetic recovery is suspended in pure water in the modified mixing tank 7 and ultrasonicated, and then lanthanum nitrate is dissolved in the ferroferric oxide suspension under mechanical stirring of an electric stirrer, and sodium hydroxide solution is added dropwise to the generated mixture of lanthanum nitrate and magnetic medium, and lanthanum-loaded ferroferric oxide is obtained after stirring and separation.

[0027] The present invention realizes deep treatment of wastewater by combining electro-Fenton and magnetic medium coagulation, and has a good removal effect on difficult-to-degrade industrial wastewater.

[0028] The present invention calcines Fenton sludge generated by electro-Fenton, wherein the main components of Fenton sludge are FeOOH, organic matter and some inorganic salts. The calcined product is basically in the form of ferroferric oxide, and the ferroferric oxide is separated by magnetic separation technology to complete the resource utilization of Fenton sludge.

[0029] Modified magnetic medium lanthanum ferroferric oxide can enhance the fluoride removal rate of coagulation sedimentation, and the fluoride concentration of the effluent can be stably lower than 1 mg / L. At the same time, the use of modified magnetic medium lanthanum ferroferric oxide reduces the amount of coagulant added to a certain extent, reduces the operating cost and avoids the secondary pollution that may be caused by the addition of reagents.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions should also be deemed to fall within the protection scope of the technical solution of the present invention.

Claims

1. A high-efficiency magnetic medium coagulation and sedimentation water treatment system, characterized in that: The invention comprises a pre-sedimentation tank, an electric-Fenton oxidation device, a magnetic medium coagulation device, a calcining furnace, a secondary sedimentation tank, a magnetic recovery device and a modified mixing tank. The outlet of the pre-sedimentation tank is connected with the electric-Fenton oxidation device, the water outlet of the electric-Fenton oxidation device is connected with the magnetic medium coagulation device, the sludge outlet of the electric-Fenton oxidation device is connected with the calcining furnace, the calcination outlet of the calcining furnace and the magnetic medium outlet of the magnetic medium coagulation device are both connected with the magnetic recovery device, the magnetic medium outlet of the magnetic recovery device is connected with the modified mixing tank, the material discharge port of the modified mixing tank is connected with the magnetic medium coagulation device, and the water outlet of the magnetic medium coagulation device is connected with the secondary sedimentation tank.

2. A high-efficiency magnetic medium coagulation and sedimentation water treatment system according to claim 1, characterized in that: The magnetic medium coagulation device includes a coagulation tank, a magnetic medium mixing tank, a flocculation reaction tank and a clarification tank which are connected in sequence. The electric Fenton oxidation device, the coagulation tank, the magnetic medium mixing tank and the flocculation reaction tank are all provided with electric agitators. The upper part of the clarification tank is provided with fillers and inclined plate clarification tanks, the bottom of the clarification tank is provided with a scraper, and the bottom of the clarification tank is provided with a sludge outlet.

3. The high-efficiency magnetic medium coagulation and sedimentation water treatment system according to claim 1 is characterized in that: The magnetic recovery machine is a magnetic drum equipped with permanent magnets. The inner ring of the magnetic drum is divided into an adsorption zone, a conveying zone 1, a conveying zone 2, a conveying zone 3 and a slag unloading zone upward. The magnetic field strength in the adsorption zone is 430-450mT, and the magnetic wrap angle is 120°. The magnetic field strength in the conveying zone 1 is 320-350mT, and the magnetic wrap angle is 60°. The magnetic field strength in the conveying zone 2 is 230-250mT, and the magnetic wrap angle is 30°. The magnetic field strength in the conveying zone 3 is between 140 and 160mT, and the magnetic wrap angle is 30°. The permanent magnets are arranged in an axial SN alternating manner with the same poles in the annular direction.

4. The high-efficiency magnetic medium coagulation and sedimentation water treatment system according to claim 1 is characterized in that: An ultrasonic generator and an electric stirrer are arranged in the modified mixing tank.

5. A high-efficiency magnetic medium coagulation and sedimentation water treatment method, characterized in that: The steps include: The wastewater first enters the pre-sedimentation tank, and after part of the sludge is precipitated, the wastewater is transported to the electro-Fenton oxidation device; After the wastewater enters the electro-Fenton oxidation device, the electric stirrer is turned on, the Fenton reagent is added and an electric current is applied; After the electro-Fenton treatment is completed, the wastewater is introduced into the magnetic medium coagulation device, the Fenton sludge produced by the electro-Fenton oxidation device enters the calciner for calcination, and the calcined product enters the magnetic recovery device; The wastewater enters the magnetic medium coagulation device, and coagulant, modified magnetic medium and flocculant are added in sequence under stirring, and finally enters the coagulation tank. The upper clear water enters the secondary sedimentation tank and is discharged after meeting the standards, and the magnetic medium sludge at the bottom enters the magnetic recovery device; After the magnetic recovery device magnetically separates the calcined product from the magnetic medium sludge, the magnetic medium to be treated is sent to the modified mixing tank, where a modifier and sodium hydroxide solution are added under stirring and ultrasonic conditions for modification, and the modified magnetic medium flows back to the magnetic medium mixing tank.

6. A high-efficiency magnetic medium coagulation and sedimentation water treatment method according to claim 5, characterized in that: The Fenton reagent is ferrous sulfate and hydrogen peroxide, the dosage of ferrous sulfate is 0.2-0.4 mmol / L, and the dosage of hydrogen peroxide is 2-3 mmol / L.

7. A high-efficiency magnetic medium coagulation and sedimentation water treatment method according to claim 5, characterized in that: The calcination temperature in the calcination furnace is 800° C. and the calcination time is 2 to 3 hours.

8. The high-efficiency magnetic medium coagulation and sedimentation water treatment method according to claim 5 is characterized in that: The coagulant is PAC, the modified magnetic medium is lanthanum-loaded ferrosoferric oxide, the flocculant is PAM, and the modifier is lanthanum nitrate.

9. A high-efficiency magnetic medium coagulation and sedimentation water treatment method according to claim 8, characterized in that: The preparation method of lanthanum-loaded ferroferric oxide in a modified mixing tank is as follows: suspending the ferroferric oxide obtained by magnetic recovery in pure water in the modified mixing tank and ultrasonicating, then dissolving lanthanum nitrate in the ferroferric oxide suspension under mechanical stirring of an electric stirrer, adding sodium hydroxide solution dropwise to the generated mixture of lanthanum nitrate and magnetic medium, and obtaining lanthanum-loaded ferroferric oxide after stirring and separation.

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