Activated aluminum oxide defluorination filter tank and wastewater treatment method

Abstract

The invention discloses an activated aluminum oxide defluorination filter tank and a wastewater treatment method. Comprising a filter tank body, and a buffer water distribution area, a supporting layer, an activated aluminum oxide filter material layer and a water outlet area are sequentially arranged in the filter tank body from bottom to top; and a water inlet pipe and a backwashing device are arranged in the buffer water distribution area. According to the three-stage structural design, the water flow distribution uniformity can be improved, and the short flow phenomenon is avoided; the supporting layer adopts a quartz sand and activated aluminum oxide dynamic matching technology, so that the loss rate of a filter material can be reduced during back washing, and non-uniform regeneration of the filter material caused by insufficient local washing strength is avoided; compared with a traditional method, the regeneration period of the pH dynamic adjustment-gas-water pulse regeneration composite process can be prolonged, and the dosage of an aluminum sulfate regenerant is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluorine-containing wastewater treatment process, and more particularly to an active alumina defluorination filter and a wastewater treatment method. BACKGROUND

[0002] In the process of modern industrial production such as chemical industry, steel, cement, glass, smelting, etc., fluorine-containing minerals in nature are used as main production raw materials or auxiliary production raw materials. Especially in the production of solar cell panels, fluorine-containing polymer backboards are often used in the manufacture of photovoltaic modules in China. Although such materials improve the durability and performance of the modules, they are difficult to recycle and process after being discarded, which may cause environmental pollution. The fluorine-containing wastewater has large water quantity, wide distribution, and large difference in fluorine concentration. Different concentrations of fluorine-containing wastewater have different defluorination methods. The fluorine-containing wastewater usually contains inorganic acid, alkali, salt, etc., which increases the difficulty of treatment. In order to protect the health and safety of the environment and meet the national discharge standard of fluorine-containing wastewater, the wastewater needs to be defluorinated before being discharged. The treatment methods of fluorine-containing wastewater include precipitation method, adsorption method, ion exchange method, electrochemical method, electrodialysis method, liquid membrane method, reverse osmosis method, etc. The active alumina adsorption method removes fluorine ions in wastewater through physical adsorption and ion exchange on the surface of active alumina under acidic conditions. The fluorine concentration of the effluent after treatment can be reduced to below 1 mg / L, and the saturated filter material can be regenerated and reused by using aluminum sulfate solution or sodium hydroxide solution.

[0003] The traditional active alumina filter has problems such as high energy consumption of backwashing due to easy cementation of filter material, rapid decay of adsorption capacity after regeneration, and sudden drop of exchange capacity under the interference of high alkalinity (HCO3 - >150mg / L). SUMMARY

[0004] In view of the defects and deficiencies of the prior art, the present application provides an active alumina defluorination filter and a wastewater treatment method.

[0005] To achieve the above purpose, the active alumina defluorination filter of the present application comprises: a filter body, a buffer water distribution zone, a supporting layer, an active alumina filter material layer and a water outlet zone are sequentially arranged in the filter body from bottom to top; a water inlet pipe and a backwashing device are arranged in the buffer water distribution zone.

[0006] Further, a Venturi jet device is arranged in the water inlet pipe to realize the pre-mixing of raw water and CO2 gas.

[0007] Further, the backwashing device comprises a backwashing water inlet pipe arranged along one side of the buffer water distribution area and a backwashing air inlet pipe arranged along the opposite side of the buffer water distribution area; the backwashing air inlet pipe is arranged higher than the backwashing water inlet pipe and is located 200-300 mm below the supporting layer.

[0008] Further, the supporting layer comprises a filter plate, a plurality of long-handle filter heads are arranged on the filter plate; the lower end of the long-handle filter head is located in the buffer water distribution area, the upper end of the long-handle filter head is located on the filter plate, and the long-handle filter head, the backwashing water inlet pipe and the backwashing air inlet pipe form a small-resistance water distribution and air distribution system.

[0009] Further, a quartz sand layer with a thickness of 50-150 mm is arranged on the filter plate.

[0010] Further, a process aeration pipe is arranged on the quartz sand layer, and a single-hole membrane air diffuser is installed on the process aeration pipe.

[0011] Further, the water outlet area comprises a clear water area, an ultra-high area, a backwashing drainage channel and a water outlet channel.

[0012] Further, an emptying sump is arranged at the bottom of the buffer water distribution area, and an emptying pipe is arranged on one side of the emptying sump and is installed at an inclination of 30°.

[0013] To achieve the above purpose, the method for wastewater treatment by using the active alumina defluorination filter tank comprises a filtration and adsorption step. After adjusting the pH of the fluorine-containing raw water by CO2 gas, the fluorine-containing raw water is uniformly distributed through the buffer water distribution area. The fluorine-containing raw water eliminates water flow impact through the long-handle filter head of the supporting layer and the quartz sand layer. The fluorine-containing raw water uniformly enters the active alumina filter material layer through the supporting layer to perform ion exchange adsorption, and the fluorine ions specifically combine with the surface of the filter material. The treated clear water is uniformly collected through the water outlet weir (11) of the water outlet area, the height of the weir plate is adjusted to stabilize the filtration speed, and filter material particles are intercepted at the same time.

[0014] Further, a regeneration backwashing step is further included; when the filter material is saturated, the filter material is regenerated by adopting a gas-water combined backwashing technology and an aluminum sulfate regenerant through backwashing, regeneration and secondary backwashing, the fluorine ions and impurities adsorbed on the surface of the filter material are efficiently stripped through the synergistic effect of the water distribution and air distribution system in the buffer water distribution area, and the adsorption performance of the active alumina is restored.

[0015] The application adopts the active alumina fluoride removal filter tank composed of a buffer water distribution area, a supporting layer, an active alumina filter material layer and a water outlet area. Raw water enters the active alumina filter material layer through the supporting layer for ion exchange adsorption, and fluoride ions specifically combine with the surface of the filter material. The water outlet area collects clean water meeting the standard. When the filter material is saturated, the filter material is regenerated by using air-water combined backwashing technology. Through the synergistic effect of the water distribution and air distribution system in the buffer water distribution area, the pollutants are efficiently stripped. The three-level structure design of the application can improve the uniformity of water flow distribution and avoid the short flow phenomenon. The supporting layer adopts the dynamic matching technology of quartz sand and active alumina. During backwashing, the filter material loss rate is reduced, and the uneven regeneration of the filter material caused by insufficient local washing intensity is avoided. Compared with the traditional method, the regeneration cycle of the pH dynamic adjustment-air-water pulse regeneration composite process is prolonged, and the amount of aluminum sulfate regenerant is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic view of the application; In the figure: A, buffer water distribution area; B, supporting layer; C, active alumina filter material layer; D, water outlet area (including: a, clean water area, b, ultra-high area, c, backwashing drainage channel, d, water outlet channel). 1, water inlet pipe; 2, Venturi jet; 3, backwashing water inlet pipe; 4, backwashing air inlet pipe; 5, emptying sump; 6, emptying pipe; 7, long handle filter head; 8, filter plate; 9, process aeration pipe; 10, single-hole membrane air diffuser; 11, water outlet weir. DETAILED DESCRIPTION

[0017] The embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0018] In the description of the application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0019] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the application, unless otherwise specified, the meaning of "multiple" is two or more.

[0020] Example 1 From Figure 1It can be seen that the active alumina defluorination filter tank of the embodiment includes a buffer water distribution area (A), a supporting layer (B), an active alumina filter material layer (C), and a water outlet area (D).

[0021] The water outlet area (D) includes a clean water area (a), an ultra-high area (b), a backwashing drainage channel (c), and a water outlet channel (d).

[0022] The water inlet pipe (1) in the buffer water distribution area (A) is internally provided with a Venturi jet (2) to realize the premixing of raw water and CO2 gas.

[0023] The backwashing water inlet pipe (3) in the buffer water distribution area (A) is arranged along the side of the buffer water distribution area (A); the backwashing air inlet pipe (4) is arranged higher than the backwashing water inlet pipe (3) and is located 200-300 mm below the supporting layer (B). The two sets of pipe systems are independently installed to avoid cross interference.

[0024] The height of the buffer water distribution area (A) is preferably 1.35-1.5 m, and a venting sump (5) is arranged at the bottom of the tank, and the venting pipe (6) is installed at an inclination of 30°.

[0025] The buffer water distribution area (A) is communicated with the supporting layer (B) and the active alumina filter material layer (C) through a long-handle filter head (7), and the long-handle filter head (7) and the backwashing water inlet pipe (3) and the backwashing air inlet pipe (4) form a small-resistance water distribution and gas distribution system.

[0026] The long-handle filter head (7) has a anti-blocking and detachable washing function, which realizes uniform water and gas distribution, prevents the filter material from flowing back to the water distribution system, and improves the regeneration efficiency.

[0027] The filter plate (8) in the supporting layer (B) provides rigid support for the long-handle filter head (7) to prevent displacement or loss of the supporting layer (B) and the active alumina filter material layer (C) during backwashing.

[0028] The filter plate (8) is preferably a split type assembled filter plate, which should have appropriate bearing strength, horizontal precision, and corrosion resistance, and the filter plate joint is sealed with a filling material with good sealing performance.

[0029] The filter plate is paved with quartz sand with a particle size of 2-4 mm, and the paving thickness is 50-150 mm.

[0030] The process aeration pipe (9) is arranged above the supporting layer (B) to continuously supply oxygen to the water body during the filtration stage, maintain the dissolved oxygen concentration, prevent the accumulation of reducing substances such as Fe² + and Mn² + in the filter layer, and ensure the ion exchange activity of the hydroxyl group on the surface of the active alumina.

[0031] The aeration system formed by the process aeration pipe (9) adopts the single-hole membrane air diffuser (10) which has high oxygen transfer efficiency, is easy to install, is not easy to be blocked, can be flushed, and is stable in operation.

[0032] The active alumina filter material layer (C) is composed of active alumina with a particle size of 0.5-1.5 mm, and the thickness is determined according to the fluorine content of raw water.

[0033] The active alumina defluorination filter has two stages of filtering and adsorbing and regenerating backwashing in actual work. Firstly, after the CO2 gas adjusts the pH of the fluorine-containing raw water, the fluorine-containing raw water is uniformly distributed through the buffer water distribution area (A), the water flow impact is eliminated through the supporting layer (B), and the ion exchange adsorption is ensured to enter the active alumina filter material layer (C). The fluorine ions are specifically combined with the filter material surface, the treated clean water is uniformly collected through the outlet weir (11) of the outlet area (D), the weir height is adjusted to stabilize the filter speed, and the filter material particles are intercepted; then, when the filter material adsorption is saturated, the filter material is regenerated by adopting the air-water combined backwashing technology and the aluminum sulfate regenerant through backwashing, regeneration and secondary backwashing, and the fluorine ions and impurities adsorbed on the filter material surface are efficiently stripped through the synergistic effect of the water distribution and gas distribution system in the buffer water distribution area, so that the adsorption performance of the active alumina is restored.

[0034] The active alumina defluorination filter is composed of a buffer water distribution area, a supporting layer, an active alumina filter material layer and an outlet area. The raw water enters the active alumina filter material layer through the supporting layer to perform ion exchange adsorption, the fluorine ions are specifically combined with the filter material surface, and the outlet area collects the clean water meeting the standard. When the filter material adsorption is saturated, the filter material is regenerated by adopting the air-water combined backwashing technology, and the pollutants are efficiently stripped through the synergistic effect of the water distribution and gas distribution system in the buffer water distribution area. The three-level structure design of the present application can improve the uniformity of water flow distribution and avoid the short flow phenomenon. The supporting layer adopts the dynamic matching technology of quartz sand and active alumina, so that the filter material loss rate is reduced during backwashing, and the uneven regeneration of the filter material caused by insufficient local washing intensity is avoided. Compared with the traditional method, the regeneration cycle of the pH dynamic adjustment-air-water pulse regeneration composite process can be prolonged, and the amount of aluminum sulfate regenerant is reduced.

[0035] In the description of the present application, unless otherwise specified and limited, the terms "mounting", "connection" and "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected, it can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] In the description of the present application, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0037] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An active alumina defluoridation filter characterized in that: The filter tank body is provided with a buffer water distribution area, a supporting layer, an active alumina filter material layer and a water outlet area from bottom to top.

2. The active alumina oxidation defluoridation filter according to claim 1, characterized in that: The water inlet pipe is provided with a Venturi jet device to realize the pre-mixing of raw water and CO2 gas.

3. The activated alumina defluoridation filter according to claim 1, wherein: The backwashing device comprises a backwashing water inlet pipe arranged along one side of the buffer water distribution area and a backwashing air inlet pipe arranged along the opposite side of the buffer water distribution area.

4. The activated alumina defluoridation filter according to claim 1, wherein: The supporting layer comprises a filter plate provided with a plurality of long-handle filter heads.

5. The activated alumina defluoridation filter according to claim 4, wherein: A quartz sand layer with a thickness of 50-150mm is arranged on the filter plate.

6. The activated alumina defluoridation filter according to claim 5, wherein: A process aeration pipe is arranged on the quartz sand layer, and a single-hole membrane air diffuser is installed on the process aeration pipe.

7. The activated alumina defluoridation filter according to claim 1, wherein: The water outlet area comprises a clear water area, an ultra-high area, a backwashing drainage channel and a water outlet channel.

8. The activated alumina defluoridation filter according to claim 1, wherein: An emptying collection pit is arranged at the bottom of the buffer water distribution area, and an emptying pipe is arranged on one side of the emptying collection pit.

9. A method for treating wastewater using the active alumina defluoridation filter as claimed in claim 1, wherein: The method comprises a filtration and adsorption step. After adjusting the pH of the fluorine-containing raw water by CO2 gas, the fluorine-containing raw water is uniformly distributed in the buffer water distribution area. The fluorine-containing raw water passes through the long-handle filter heads of the supporting layer and the quartz sand layer to eliminate water flow impact. The fluorine-containing raw water uniformly enters the active alumina filter material layer through the supporting layer to perform ion exchange and adsorption, and the fluorine ions are specifically combined with the surface of the filter material. The treated clear water is uniformly collected through the water outlet weir (11) of the water outlet area, the weir plate height is adjusted to stabilize the filtration rate, and filter material particles are intercepted.

10. The method of claim 9, wherein the activated alumina defluoridation filter is used for wastewater treatment. The method further comprises a regeneration and backwashing step. When the filter material is saturated, the filter material is regenerated by a three-step process of backwashing, regeneration and secondary backwashing using a gas-water combined backwashing technology and aluminum sulfate regenerant, and the filter material surface adsorbed fluorine ions and impurities are efficiently stripped through the synergistic effect of the water distribution and gas distribution system in the buffer water distribution area, thereby restoring the adsorption performance of the active alumina.

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