Apparatus and method for removing phosphorus from eutrophic water

Abstract

The application discloses a device and method for removing phosphorus in eutrophication water body, comprising an algae decomposition pool, an electric flocculation pool, a sedimentation pool and an anoxic recovery pool; the algae decomposition pool is a vertically arranged decomposition pool body, a plurality of motors are arranged at the upper and lower ends of the decomposition pool body respectively, a filter plate is arranged in the decomposition pool body, a pulling rope is arranged between the upper end motor and the upper surface of the filter plate, a pulling rope is arranged between the lower end motor and the lower surface of the filter plate, and the movement of the filter plate in the vertical direction is controlled through the pulling ropes; a plurality of one-way holes are arranged on the filter plate. Part of the separated phosphorus is in the form of phosphate, and the anoxic recovery pool can recover the phosphate under the condition that the content of additives is small. The application is simple to operate, does not need to use a large amount of chemical agents, and avoids secondary pollution possibly caused by the chemical agents.

Description

Technical Field

[0001] This invention belongs to the field of water environment management and wastewater treatment technology, and relates to a method for removing phosphorus from high-algae water bodies. In particular, it relates to an apparatus and method for removing phosphorus from eutrophic water bodies without the need for large-scale use of chemical agents, thus avoiding potential secondary pollution. Background Technology

[0002] Phosphorus is irreplaceable in life on Earth. However, the availability of high-quality, mineable phosphate rock is gradually decreasing. 80% of the mined phosphate rock is used for agricultural production, while most of the phosphorus is transported to lakes via rivers, causing eutrophication. Statistics show that more than half of the lakes are in a state of eutrophication.

[0003] Eutrophication is often accompanied by the accumulation of algal biomass. The excessive absorption and storage of phosphorus by algae in the lake is stored in the form of phosphate. After decomposition, it will cause the water quality in the algal accumulation area to deteriorate sharply, affecting the environment and the lives of surrounding residents. Therefore, the recovery of algae and phosphate in this area is extremely important.

[0004] Algal blooms are often harvested manually, but this method is inefficient. Chemical flocculation is commonly used to quickly remove small particles of phosphorus and phosphate. However, chemical flocculation requires a large amount of chemicals, and the resulting large amount of chemical sludge is costly to treat and can cause secondary pollution. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an apparatus and method for removing phosphorus from eutrophic water bodies. The water first enters an algae decomposition tank, and after decomposition, it is pumped into an electrocoagulation tank. The phosphorus in the water is removed through the electrocoagulation tank and then precipitated. Finally, the phosphorus is released as phosphate in an anoxic tank and then recovered. The method of this invention does not require the use of large amounts of chemical agents, thus avoiding potential secondary pollution.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention first provides a device for removing phosphorus from eutrophic water bodies. The device includes an algae decomposition tank, an electrocoagulation tank, a sedimentation tank, and an anoxic recovery tank. The algae decomposition tank is a vertically arranged decomposition tank body. Several motors are respectively installed at the upper and lower ends of the decomposition tank body. A filter press plate is installed inside the decomposition tank body. Pull ropes are provided between the upper motor and the upper surface of the filter press plate, and pull ropes are provided between the lower motor and the lower surface of the filter press plate. The pull ropes control the vertical movement of the filter press plate. Several one-way holes are provided on the filter press plate.

[0008] The electrocoagulation tank includes a flocculation tank body, and an electrode plate support, an electrode plate and a constant voltage power supply are provided inside the flocculation tank body;

[0009] The sedimentation tank includes a sedimentation tank body, and a first exhaust pipe is provided at the upper end of the sedimentation tank body;

[0010] The anoxic recovery tank includes a recovery tank body, and a second exhaust pipe is provided at the upper end of the recovery tank body;

[0011] The algae decomposition tank is sequentially connected to the electrocoagulation tank, sedimentation tank, and anoxic recovery tank.

[0012] As a preferred embodiment of the present invention, the one-way hole includes a plurality of cover plates that can be opened vertically and a semi-permeable membrane, wherein the semi-permeable membrane is disposed below the cover plates.

[0013] As a preferred embodiment of the present invention, one end of the decomposition tank is provided with a first inlet pipe and a first outlet pipe, the first inlet pipe is provided with a first inlet valve and a first inlet water pump, and the first outlet pipe is provided with a first outlet valve and a first outlet water pump.

[0014] In a preferred embodiment of the present invention, the lower part of the flocculation tank is provided with a second outlet pipe, a first circulating water pipe, a second circulating water pipe and a first tee pipe, the first circulating water pipe and the first tee pipe are connected by a circulating water pump, one end of the second circulating water pipe is connected to the first tee pipe and the other end is connected to the upper part of the flocculation tank to form a circulation, and a circulating water valve is provided on the second circulating water pipe; a second outlet pipe is provided with a second outlet valve and a second outlet water pump; and an algae decomposition tank is connected to the upper part of the flocculation tank.

[0015] As a preferred embodiment of the present invention, the lower part of the sedimentation tank is provided with a third outlet pipe, the first exhaust pipe is provided with a first exhaust valve and a first exhaust pump, and the third outlet pipe is provided with a third outlet valve and a third outlet water pump; the upper part of the sedimentation tank is connected to an electrocoagulation tank.

[0016] As a preferred embodiment of the present invention, the lower end of the recycling tank is provided with a second three-way pipe, the second three-way pipe is connected to the sedimentation tank, and a pH detection device is provided inside the second three-way pipe; a second exhaust valve and a second air pump are provided on the second exhaust pipe.

[0017] As a preferred embodiment of the present invention, it further includes a pH reagent storage tank, wherein the pH reagent storage tank is provided with a partition plate to maintain the simultaneous storage of acidic and alkaline reagents; the lower part of the pH reagent storage tank is provided with a reagent valve and a reagent filling pipe, wherein the reagent valve is connected to the reagent filling pipe and the second three-way pipe.

[0018] In a preferred embodiment of the present invention, the motors are arranged opposite to each other.

[0019] The present invention also provides a method for removing phosphorus from eutrophic water bodies using the above-described apparatus, comprising the following steps:

[0020] 1) Water enters the algae decomposition tank. The motor and pull rope below the filter press plate cause the filter press plate to press downwards until the motor reaches the threshold. The motor and pull rope above the filter press plate cause the filter press plate to return to its original position. This process is repeated multiple times to fully break down and decompose the algae in the water.

[0021] 2) The fully decomposed water enters the electrocoagulation tank for electrocoagulation;

[0022] 3) After flocculation, the water enters the sedimentation tank for settling;

[0023] 4) After sedimentation, the flocculated concentrate at the bottom of the sedimentation tank enters the anoxic recovery tank, and the gas in the anoxic recovery tank is discharged to form an anoxic atmosphere, waiting for phosphate to form.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The present invention can rapidly and efficiently separate algae from lake water, thereby reducing lake phosphorus levels.

[0026] 2) The phosphorus separated in this invention is in the form of phosphate. The anoxic recovery tank of this invention can recover phosphate with a low additive content.

[0027] 3) The operation of this invention is simple, does not require the use of large amounts of chemical agents, and avoids the secondary pollution that may result. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the present invention.

[0029] Figure 2 This is a schematic diagram of an algae decomposition pond.

[0030] Figure 3 This is a cross-sectional view of section AA.

[0031] Figure 4 This is a cross-sectional view of BB.

[0032] Figure 5 This is a CC cross-sectional view.

[0033] Figure 6 This is a schematic diagram of a one-way hole.

[0034] Figure 7 This is a schematic diagram of an electrocoagulation cell.

[0035] Figure 8 This is a top view of an electrocoagulation cell.

[0036] Figure 9 This is a schematic diagram of a sedimentation tank.

[0037] Figure 10 This is a schematic diagram of an anoxic recovery tank.

[0038] Figure 11 This is a schematic diagram of a pH reagent storage tank.

[0039] In the diagram, 1. Decomposition tank; 1-1. First inlet pipe; 1-2. First inlet valve; 1-3. First inlet pump; 1-4. Filter press plate; 1-4-1 One-way hole; 1-4-1-1. Cover plate; 1-4-1-2. Semi-permeable membrane; 1-5. Motor; 1-6. Pull rope; 1-7. First outlet valve; 1-8. First outlet pump; 1-9. First outlet pipe.

[0040] 2. Flocculation tank body; 2-1. Electrode plate; 2-2. Constant voltage power supply; 2-3 First circulating water pipe; 2-4. Circulating water pump; 2-5. First tee pipe; 2-6. Second outlet valve; 2-7. Second outlet water pump; 2-8. Second outlet pipe; 2-9. Circulating water valve.

[0041] 3. Sedimentation tank body; 3-1. First vent pipe; 3-2. First vent pump; 3-3. First vent valve; 3-4. Third outlet pipe; 3-5. Third outlet valve; 3-6. Third outlet pump.

[0042] 4. Recovery tank; 4-1. Second exhaust pipe; 4-2. Second exhaust pump; 4-3. Second exhaust valve; 4-4. Second tee pipe; 4-5. pH detection device.

[0043] 5. pH reagent storage tank; 5-1. Reagent valve; 5-2. Reagent filling pipe; 5-3. Divider plate. Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] See Figure 1 The present invention first provides a device for removing phosphorus from eutrophic water bodies, the device comprising an algae decomposition tank, an electrocoagulation tank, a sedimentation tank and an anoxic recovery tank.

[0046] See Figures 2-5The algae decomposition tank is a vertically arranged decomposition tank body 1. Several motors 1-5 are installed at the upper and lower ends of the decomposition tank body 1. A filter press plate 1-4 is installed at the top inside the decomposition tank body 1. Pull ropes 1-6 are installed on the upper surfaces of the upper motors 1-5 and the filter press plate 1-4, and on the lower surfaces of the lower motors 1-4 and the filter press plate 1-5. The pull ropes 1-6 control the vertical movement of the filter press plate 1-4. Several one-way holes 1-4-1 are provided on the filter press plate 1-4. The default position of the filter press plate 1-4 is the top of the decomposition tank body 1, i.e., the side away from the first inlet pipe 1-1 and the first outlet pipe 1-9.

[0047] One end of the decomposition tank 1 is provided with a first inlet pipe 1-1 and a first outlet pipe 1-9. The first inlet pipe 1-1 is provided with a first inlet valve 1-2 and a first inlet water pump 1-3. The first outlet pipe 1-9 is provided with a first outlet valve 1-7 and a first outlet water pump 1-8.

[0048] See Figure 6 The one-way hole 1-4-1 includes multiple cover plates 1-4-1-1 that can be opened up and down and a semi-permeable membrane 1-4-1-2, wherein the semi-permeable membrane 1-4-1-2 is disposed below the cover plate 1-4-1-1.

[0049] See Figure 7 and Figure 8 The electrocoagulation tank includes a flocculation tank 2, and the flocculation tank 2 is provided with an electrode plate support 2-11 (the electrode plate support 2-11 should be made of non-metallic insulating material), an electrode plate 2-1 (the electrode plate is an aluminum electrode plate) and a constant voltage power supply 2-2 (the constant voltage power supply is a 15V constant voltage power supply).

[0050] The lower part of the flocculation tank body 2 is provided with a second outlet pipe 2-8, a first circulating water pipe 2-3, a second circulating water pipe 2-10, and a first tee pipe 2-5. The first circulating water pipe 2-3 and the first tee pipe 2-5 are connected by a circulating water pump 2-4. One end of the second circulating water pipe 2-10 is connected to the first tee pipe 2-5, and the other end is connected to the upper part of the flocculation tank body 2 to form a circulation. A circulating water valve 2-9 is provided on the second circulating water pipe 2-3. A second outlet valve 2-6 and a second outlet water pump 2-7 are provided on the second outlet pipe 2-8. The upper part of the flocculation tank body 2 is connected to the first outlet pipe 1-9.

[0051] See Figure 9 The sedimentation tank includes a sedimentation tank body 3, with a first vent pipe 3-1 at the upper end of the sedimentation tank body 3; a third outlet pipe 3-4 at the lower part of the sedimentation tank body 3; a first vent valve 3-3 and a first vent pump 3-2 on the first vent pipe 3-1; and a third outlet valve 3-5 and a third outlet pump 3-6 on the third outlet pipe 3-4; the upper part of the sedimentation tank body 3 is connected to a second outlet pipe 2-8.

[0052] See Figure 10 The anoxic recovery tank includes a recovery tank body 4, with a second exhaust pipe 4-1 at the upper end of the recovery tank body 4; a second three-way pipe 4-4 at the lower end of the recovery tank body 4, the second three-way pipe 4-4 being connected to the sedimentation tank body 3, and a pH detection device 4-5 being installed inside the second three-way pipe 4-4; and a second exhaust valve 4-3 and a second air pump 4-2 being installed on the second exhaust pipe 4-1.

[0053] See Figure 11 It also includes a pH reagent storage tank 5, which is equipped with a partition plate 5-3 to keep the pH reagent storage tank storing acidic and alkaline reagents at the same time; the pH reagent storage tank 5 is equipped with a reagent valve 5-1 and a reagent filling pipe 5-2 at the bottom, and the reagent valve 5-1 is connected to the second three-way pipe 4-4 through the reagent filling pipe 5-2.

[0054] Example 1

[0055] This embodiment provides a method for removing phosphorus from eutrophic water using the aforementioned device, including:

[0056] 1) During operation, firstly, the first inlet valve 1-2 and the first inlet pump 1-3 are opened, while the first outlet valve 1-7 and the first outlet pump 1-8 are closed. High-algae water is pumped into the decomposition tank 1 by the first inlet pump 1-3 through the first inlet pipe 1-1. Once full, the first inlet valve 1-2 and the first inlet pump 1-3 are closed, the motor 1-5 located at the lower end of the decomposition tank 1 is started, and the motor 1-5 at the upper end of the decomposition tank 1 is closed, with the pull rope 1-6 in a free state. This pulls the filter press plate 1-4 downwards. During this movement, water passes through the semi-permeable membrane 1-4-1-2 and the cover plate 1-4-1-1 into the area above the filter press plate 1-4, while algae, unable to pass through the semi-permeable membrane 1-4-1-2, remain below the filter press plate 1-4. Therefore, as the filter press plate 1-4 continues to move downwards, the algae space is continuously compressed, eventually causing the algae to break down. When the motor 1-5 at the lower end of the decomposition tank 1 reaches the threshold force, it stops operating and the pull rope 1-6 is in a free state. At this time, the motor 1-5 at the lower end of the decomposition tank 1 starts and pulls the filter press plate 1-4 to the top. This cycle is repeated several times to fully decompose the algae in the high-algae water (judged by the water's conductivity. If the degree of algae decomposition is high, the water's conductivity will also be relatively high).

[0057] After the algae are fully decomposed, the filter press 1-4 returns to the default position, the first inlet valve 1-2 and the first inlet pump 1-3 remain closed, and the first outlet valve 1-7 and the first outlet pump 1-8 are opened to pump the high-algae water in the decomposition tank 1 into the electrocoagulation tank through the first outlet pipe 1-9.

[0058] 2) When the first outlet valve 1-7 and the first outlet pump 1-8 are opened to pump high-algae water into the electrocoagulation tank, the constant voltage power supply 2-2, circulating water pump 2-4, circulating water valve 2-9, second outlet valve 2-6, and second outlet pump 2-7 are closed. When the electrocoagulation tank is full, the first outlet valve 1-7, the first outlet pump 1-8, the second outlet valve 2-6, and the second outlet pump 2-7 remain closed, while the constant voltage power supply 2-2, circulating water pump 2-4, and circulating water valve 2-9 are opened to carry out the electrocoagulation process (the current or voltage is set according to the area of ​​the electrode).

[0059] When electrocoagulation is complete, the first outlet pipe 1-7, the first outlet water pump 1-8, the constant voltage power supply 2-2 and the circulating water valve 2-9 remain closed, the circulating water pump 2-4 does not run but remains unobstructed, and the second outlet valve 2-6 and the second outlet water pump 2-8 are opened to pump the water containing a large amount of flocculent matter into the sedimentation tank.

[0060] 3) When the second outlet valve 2-6 and the second outlet pump 2-8 are opened to pump water containing flocculent particles into the sedimentation tank, the first vent pump 3-2, the first vent valve 3-3, the third outlet valve 3-5, and the third outlet pump 3-6 are closed. After the pumping is complete, the second outlet valve 2-6, the second outlet pump 2-7, the third outlet valve 3-5, and the third outlet pump 3-6 are closed, and the first vent pump 3-2 and the first vent valve 3-3 are opened. Gas in the tank is extracted by the first vent valve 3-2 to create an anoxic environment. After venting is completed, all valves and pumps are closed, and sedimentation is allowed to complete (obvious sedimentation can be observed in about 30 minutes. The flocculent particles generated by electrocoagulation have a clear boundary with the water body, and sedimentation is considered complete when the flocculent particles are observed to have settled to the bottom). After sedimentation is complete, the third outlet valve 3-5 and the third outlet pump 3-6 are opened to pump the concentrated flocculent liquid from the bottom of the sedimentation tank into the anoxic recovery tank.

[0061] 4) pH reagent storage tank 5 is used to store pH adjusting reagents. A partition plate 5-3 divides the pH reagent storage tank 5 into two parts: one part stores acidic reagents, and the other part stores alkaline reagents. The pH reagent storage tank 5 is externally connected to a reagent filling pipe 5-2, which is equipped with a reagent valve 5-1, allowing the reagent to flow out by gravity.

[0062] The second three-way pipe 4-4 connects to the outlet pipe 3-4, the recovery tank 4, and the chemical injection pipe 5-2.

[0063] Based on the results from pH detection devices 4-5, pH reagent storage tank 5 releases appropriate types and amounts of reagents and mixes them with the flocculated concentrate drawn by the third effluent pump 3-6, so that the pH of the water body is maintained at the level most suitable for phosphate release (pH between 7 and 10).

[0064] When the third outlet valve 3-5, the third outlet pump 3-6, and the chemical valve 5-1 are opened to send the flocculant concentrate with a suitable pH into the recovery tank 4, the second exhaust pump 4-2 and the second exhaust valve 4-3 are closed. After water injection is completed, the third outlet valve 3-5, the third outlet pump 3-6, and the chemical valve 5-1 are closed, and the second exhaust pump 4-2 and the second exhaust valve 4-3 are opened to extract the gas from the recovery tank 4 to create an oxygen-deficient environment. After the gas is extracted, the third outlet valve 3-5, the third outlet pump 3-6, the chemical valve 5-1, the second exhaust pump 4-2, and the second exhaust valve 4-3 are all closed to await phosphate release.

[0065] In anoxic environments, phosphates are released into the water, reaching their maximum on the sixth day. By extracting the liquid from the anoxic recovery tank, approximately 40% of the phosphates can be recovered.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An apparatus for removing phosphorus from an eutrophic water body, characterized by, The device comprises an algae decomposition tank, an electrocoagulation tank, a sedimentation tank and an anoxic recovery tank; the algae decomposition tank is a vertically arranged decomposition tank body, a plurality of motors are arranged at the upper and lower ends of the decomposition tank body respectively, a filter plate is arranged in the decomposition tank body, a pulling rope is arranged between the upper motor and the upper surface of the filter plate, and a pulling rope is arranged between the lower motor and the lower surface of the filter plate; the movement of the filter plate in the vertical direction is controlled through the pulling rope; the filter plate is pressed downward until the motor reaches a threshold value through the motor below the filter plate and the pulling rope; the filter plate is restored to the original position upward through the motor above the filter plate and the pulling rope; the algae in the water body is fully broken and decomposed through repeated operations; a plurality of one-way holes are arranged on the filter plate; the one-way hole comprises a plurality of upper and lower open cover plates and a semi-permeable membrane; and the semi-permeable membrane is arranged below the cover plate. The electrocoagulation tank comprises a coagulation tank body, an electrode plate support, an electrode plate and a constant voltage power supply arranged in the coagulation tank body. The sedimentation tank comprises a sedimentation tank body, and a first exhaust pipe is arranged at the upper end of the sedimentation tank body. The anoxic recovery tank comprises a recovery tank body, and a second exhaust pipe is arranged at the upper end of the recovery tank body; the flocculation concentrated liquid at the bottom of the sedimentation tank enters the anoxic recovery tank, the gas in the anoxic recovery tank is discharged to form an anoxic atmosphere, and the formation of phosphate is waited for; The algae decomposition tank is sequentially connected with the electrocoagulation tank, the sedimentation tank and the anoxic recovery tank.

2. The device for removing phosphorus in eutrophicated water according to claim 1, wherein One end of the decomposition tank body is provided with a first water inlet pipe and a first water outlet pipe; a first water inlet valve and a first water inlet pump are arranged on the first water inlet pipe; and a first water outlet valve and a first water outlet pump are arranged on the first water outlet pipe.

3. The device for removing phosphorus in eutrophicated water according to claim 1, wherein The lower part of the coagulation tank body is provided with a second water outlet pipe, a first circulating water pipe, a second circulating water pipe and a first three-way pipe; the first circulating water pipe and the first three-way pipe are connected through a circulating water pump; one end of the second circulating water pipe is connected with the first three-way pipe, and the other end is connected with the upper part of the coagulation tank body to form a circulation; a circulating water valve is arranged on the second circulating water pipe; a second water outlet valve and a second water outlet pump are arranged on the second water outlet pipe; and the upper part of the coagulation tank body is connected with the algae decomposition tank.

4. The device for removing phosphorus in eutrophicated water according to claim 1, wherein The lower part of the sedimentation tank body is provided with a third water outlet pipe; a first exhaust valve and a first exhaust pump are arranged on the first exhaust pipe; a third water outlet valve and a third water outlet pump are arranged on the third water outlet pipe; and the upper part of the sedimentation tank is connected with the electrocoagulation tank.

5. The device for removing phosphorus in eutrophicated water according to claim 1, wherein The lower end of the recovery tank body is provided with a second three-way pipe; the second three-way pipe is connected with the sedimentation tank; and a pH detection device is arranged in the second three-way pipe; a second exhaust valve and a second exhaust pump are arranged on the second exhaust pipe.

6. The device for removing phosphorus in eutrophicated water according to claim 5, wherein A pH medicament storage tank is further included; a partition plate is arranged in the pH medicament storage tank to store acidic medicament and alkaline medicament at the same time; a medicament valve and a medicament filling pipe are arranged at the lower part of the pH medicament storage tank; and the medicament valve is connected with the second three-way pipe through the medicament filling pipe.

7. The device for removing phosphorus in eutrophicated water according to claim 1, wherein The motors are oppositely arranged.

8. A method for removing phosphorus from an eutrophic water body, characterized by, The device of any one of claims 1-7 comprises the following steps: 1) The water body enters the algae decomposition tank, and the filter plate is pressed downward by the motor and pulling rope below the filter plate until the motor reaches the threshold value; the filter plate is restored to its original position by the motor and pulling rope above the filter plate, and the process is repeated several times to fully break and decompose the algae in the water body; 2) The fully decomposed water body enters the electric flocculation tank for electric flocculation; 3) The water body after flocculation enters the sedimentation tank for sedimentation; 4) After sedimentation is completed, the flocculation concentrate at the bottom of the sedimentation tank enters the anoxic recovery tank, the gas in the anoxic recovery tank is discharged to form an anoxic atmosphere, and the formation of phosphate is waited.

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