Self-driven electrochemical device for recycling nitrogen and phosphorus-containing wastewater resources

Abstract

The utility model provides a self-driven electrochemical device for recycling nitrogen and phosphorus-containing wastewater resources, which comprises a cylindrical precipitation and crystallization device and an anode rotating and stirring device, the anode rotating and stirring device is positioned in the cylindrical precipitation and crystallization device, and a magnesium anode slot is mounted at the bottom of the anode rotating and stirring device; an air cathode slot is designed on the cylindrical precipitation crystallization device, a conical precipitation collection device is mounted at the bottom of the cylindrical precipitation crystallization device, a sludge discharge port is formed in the bottom of the cylindrical precipitation crystallization device, a water outlet and a water inlet are formed in the side wall of the cylindrical precipitation crystallization device, and a cover plate with a hole is designed at the top of the cylindrical precipitation crystallization device. A hydraulic dead zone does not exist in the device due to the cylindrical structure and the anode rotary stirring device, so that the treatment efficiency is improved. The cylindrical magnesium anode eliminates the weak connection part of the convex electrode, and meanwhile, the wrapping structure of the bottom of the anode rotating and stirring device on the magnesium anode eliminates the fringe effect, so that the anode corrosion is more uniform.

Description

TECHNICAL FIELD

[0001] The utility model belongs to sewage treatment technical field especially relates to a kind of for recycling nitrogen phosphorus wastewater resource self-driven electrochemical device. BACKGROUND

[0002] With the growth of world population, the global food production scale expands year by year. In order to meet the increasing demand for human food, the application amount of chemical fertilizer is continuously improved. Nitrogen, phosphorus and potassium, as essential elements required for plant growth, are the main components of chemical fertilizer. Today, phosphorus and potassium mainly come from the mining of ore, while phosphorus ore and potassium ore are considered as non-renewable resources, and the distribution of phosphorus and potassium ore is extremely uneven in the world. Recycling nitrogen, phosphorus and potassium resources from waste streams not only can reduce environmental pollution, but also can provide certain support for maintaining the stability of world politics. There are many methods for recycling nitrogen, phosphorus and potassium from waste streams, among which the struvite precipitation method has attracted the attention of researchers due to its simple operation and relatively high recovery rate of struvite. However, due to the lack of sufficient alkalinity and magnesium ions in most wastewater, chemical substances need to be continuously added as magnesium source and alkali source in the traditional struvite precipitation method.

[0003] The existing patent 202010459575.5 provides a method for recycling phosphorus resources and electrical energy from urine based on magnesium-air fuel cell, which utilizes the principle of Mg 2+ and OH - generated during the operation of magnesium-air fuel cell, uses source-separated urine as electrolyte, combines nitrogen and phosphorus in urine with magnesium ions released by magnesium-air fuel cell to generate struvite precipitation or magnesium phosphate precipitation, and produces electricity at the same time. The cell cavity of the magnesium-air fuel cell designed in this patent is a cuboid structure, with a cavity volume of 60-210 mL and a spacing between the cathode and anode of the battery of 1.1-4.1 cm. The device uses a sheet-shaped air cathode and a magnesium anode in the form of a convex structure. Although the device has a stirring system, it is found that there is a hydraulic dead zone in the device during actual operation, which can cause struvite precipitation to agglomerate in the hydraulic dead zone. The device does not have a precipitation collection structure, and needs to be completely disassembled for precipitation cleaning and collection after each operation. The convex magnesium anode used in the device is not uniformly electrochemically corroded during use, and there is a probability of fracture at the connection between the top of the convex structure during continuous operation. The edge effect can make the edge corrosion of the flat plate electrode more serious.

[0004] The existing patent 202311717396.7 provides a device and method for recovering phosphorus in sludge filtrate of magnesium air battery, by mixing sludge and solid carbon source to obtain sludge filtrate containing high phosphate, then adding sludge filtrate into magnesium air battery, and additionally adding ammonium source to produce struvite. The magnesium anode plate of the technology uses magnesium plate with purity of more than 99%, which is more expensive than magnesium alloy plate, and cannot obtain better operation effect. The device does not design a stirring system, the hydraulic condition in the device is not good, and the electrolyte is not uniformly mixed, which will affect the treatment efficiency of the device. Utility model content

[0005] The utility model aims at solving the problem of uneven anode electrochemical corrosion in the prior art, and eliminating the hydraulic dead zone.

[0006] To achieve the above-mentioned purpose, the utility model provides a kind of self-driving electrochemical device for wastewater nitrogen and phosphorus resource recovery, including cylindrical body precipitation crystallization device and anode rotary stirring device;Cylindrical body precipitation crystallization device top is equipped with the cylindrical body precipitation crystallization device top cover plate with hole;Anode rotary stirring device is located in cylindrical body precipitation crystallization device, and the rotating shaft of anode rotary stirring device upper portion passes through the hole of cylindrical body precipitation crystallization device top cover plate, and anode rotary stirring device bottom is equipped with magnesium anode slot, and magnesium alloy anode is inserted into magnesium anode slot and is fixed, and the rotating shaft of anode stirring device is equipped with stirring vane, and the sidewall of cylindrical body precipitation crystallization device is respectively equipped with water inlet and water outlet;Cylindrical body precipitation crystallization device bottom has conical precipitation collection device, and conical precipitation collection device bottom has sludge discharge port;The circumferential surface of the sidewall of cylindrical body precipitation crystallization device is provided with air cathode slot, and air cathode is inserted into air cathode slot, and magnesium anode and air cathode are connected by wire and form closed loop with external resistance.

[0007] Further, the obtuse angle α formed by the conical precipitation collection device and the inner wall of the cylindrical body precipitation crystallization device is 135 °.

[0008] Further, the effective volume of the internal reaction zone of the cylindrical body precipitation crystallization device is 1650ml.

[0009] Further, the bottom radius x top radius x height of the conical precipitation collection device is 50mm x 10mm x 40mm, and the diameter of the sludge discharge port is 10mm.

[0010] Further, the magnesium anode is a cylinder with an outer diameter x inner diameter x height of 90mm x 80mm x 200mm, and the effective area of the magnesium anode is 56549mm 2 .

[0011] Further, the height x length x width of the air cathode is 220mm x 290mm x 0.5mm, and the effective area of the air cathode is 41888mm2

[0012] Advantages:

[0013] 1. The cylindrical structure and the anode rotating stirring device eliminate the hydraulic dead zone in the device, improving the treatment efficiency. The cylindrical magnesium anode eliminates the weak connection of the convex electrode, and the covering structure of the anode rotating stirring device at the bottom of the magnesium anode eliminates the edge effect, so that the anode corrosion is more uniform. The integration design of the air cathode and the device itself and the anode rotating stirring device make the disassembly and maintenance of the device simpler, and only the anode stirring device needs to be pulled out to replace the anode and clean the air cathode, and the sediment collection makes the device not need to be frequently disassembled to collect the sediment.

[0014] 2. The magnesium air cell is designed to be a reactor capable of operating in continuous flow or sequencing batch mode to meet the operating requirements of the reactor in different scenes, ensure the treatment performance of the reactor, and prolong the service life of the electrode; the sediment chamber at the bottom can accumulate a large amount of struvite sediment, and the accumulation of struvite crystals is beneficial to the crystallization and growth of struvite. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a self-driven electrochemical device structure schematic diagram of the utility model;

[0016] Figure 2 is a schematic diagram of the anode rotating stirring device (remove magnesium anode) of the utility model;

[0017] Figure 3 is a bottom schematic diagram of the utility model;

[0018] Figure 4 is a vertical section view of the self-driven electrochemical device (from front to back) of the utility model.

[0019] Fig. 1 is a cylindrical sediment crystallization device top cover plate, 2 is an anode rotating stirring device, 3 is a magnesium alloy anode; 4 is a cylindrical sediment crystallization device, 5 is an air cathode, 6 is a water outlet, 7 is a water inlet, 8 is a mud discharge port, 9 is an air cathode slot, 10 is a stirring blade, 11 is a magnesium anode slot, 12 is a conical sediment collection device. DETAILED DESCRIPTION

[0020] In order to further understand the invention content, characteristics and effects of the utility model, the following examples are given, and the detailed description is as follows in combination with the drawings.

[0021] The structure of the utility model will be described in detail below in combination with the drawings.

[0022] Please refer to Figures 1-4As shown, a self-driven electrochemical device for recycling nitrogen-containing phosphorus wastewater resources comprises a cylindrical sedimentation crystallization device 4 and an anode rotating stirring device 2. The effective volume of the internal reaction zone of the cylindrical sedimentation crystallization device 4 is 1650ml, and the cylindrical sedimentation crystallization device 4 is a single-chamber cavity composed of ABS plastic and an air cathode 5.

[0023] A cylindrical sedimentation crystallization device top cover plate 1 with holes is installed on the top of the cylindrical sedimentation crystallization device 4. The anode rotating stirring device 2 is located in the cylindrical sedimentation crystallization device 4, the rotating shaft of the anode rotating stirring device 2 passes through the hole in the cylindrical sedimentation crystallization device top cover plate 1, a magnesium anode insertion slot 11 is installed at the bottom of the anode rotating stirring device 2, a magnesium alloy anode 3 is inserted into the magnesium anode insertion slot 11 for fixation and rotation with the anode stirring device 2; a stirring blade 10 is installed on the rotating shaft of the anode stirring device 2 for enhancing hydraulic stirring. A water inlet 7 and a water outlet 6 are respectively arranged on the side wall of the cylindrical sedimentation crystallization device 4, and the water outlet 6 is located above the water inlet 7. A conical sediment collection device 12 is arranged at the bottom of the cylindrical sedimentation crystallization device 4, the obtuse angle α formed between the conical sediment collection device 12 and the inner wall of the cylindrical sedimentation crystallization device 4 is 135°, the bottom of the conical sediment collection device 12 is provided with a sludge discharge port 8, the radius at the bottom, the radius at the top and the height of the conical sediment collection device 12 are 50mm, 10mm and 40mm respectively, the diameter of the sludge discharge port 8 is 10mm, and a valve is installed on the sludge discharge port 8. The nitrogen-containing phosphorus wastewater enters the cylindrical sedimentation crystallization device 4 through the water inlet 7, is uniformly mixed under the action of the anode rotating stirring device 2, and finally flows out of different holes according to different operation modes, and under the condition of continuous flow operation, the wastewater flows out of the water outlet 6, and under the condition of sequencing batch operation, the wastewater is discharged from the sludge discharge port 8.

[0024] Air cathode insertion slots 9 are arranged on the circumference of the side wall of the cylindrical sedimentation crystallization device 4, the air cathode 5 is inserted into the air cathode insertion slots 9, the air cathode insertion slots 9 surround the top of the conical sediment collection device 12, the magnesium anode 3 and the air cathode 5 are connected by wires to form a closed loop with an external resistance, a multi-channel voltage acquisition device is connected in parallel with the external resistance, and voltage data is monitored and recorded in real time.

[0025] The effective area of the magnesium anode 3 is 56549mm 2 , the magnesium alloy is prepared, and the main part is a cylinder with an outer diameter of 90mm, an inner diameter of 80mm and a height of 200mm; the effective area of the air cathode 5 is 41888mm 2 , and the height, length and width of the air cathode 5 are 220mm, 290mm and 0.5mm respectively.

[0026] The working principle of the utility model is as follows:

[0027] Under the condition of continuous flow, the nitrogen and phosphorus containing wastewater is transported to the water inlet 7 by pipeline under the action of pump, with the wastewater continuously entering the device, the liquid level in the reactor rises to contact the magnesium anode 3 and the air cathode 5, at this time, the wastewater, the wire, the magnesium anode 3 and the air cathode 5 form a closed loop, a reaction zone is formed between the magnesium anode 3 and the air cathode 5, a precipitation reaction occurs in the reaction zone, the generated precipitate falls to the bottom conical sediment collection device 12, and when accumulated to a certain amount, it is discharged from the sludge discharge port 8, and the discharged precipitate is collected and dried. Under the action of the anode stirring device 2, the wastewater in the reactor is fully mixed, and after the liquid level rises to the water outlet 6, it is slowly discharged.

[0028] Under the condition of continuous flow, the nitrogen and phosphorus containing wastewater is transported to the water inlet 7 by pipeline under the action of pump, with the wastewater continuously entering the device, the liquid level in the reactor rises to contact the magnesium anode 3 and the air cathode 5, at this time, the wastewater, the wire, the magnesium anode 3 and the air cathode 5 form a closed loop, a reaction zone is formed between the magnesium anode 3 and the air cathode 5, a precipitation reaction occurs in the reaction zone, the generated precipitate falls to the bottom conical sediment collection device 12, and when accumulated to a certain amount, it is discharged from the sludge discharge port 8, and the discharged precipitate is collected and dried. Under the action of the anode stirring device 2, the wastewater in the reactor is fully mixed, and after the liquid level rises to the water outlet 6, it is slowly discharged.

[0029] The above only describes the preferred embodiments of the present application, and does not limit the present application in any form, any simple modification, equivalent change and modification made according to the technical essence of the present application to the above embodiments are within the scope of the technical scheme of the present application.

Claims

1. A self-powered electrochemical device for recovering nitrogen-containing phosphorous wastewater resources, characterized in that, The cylindrical body sedimentation crystallization device is provided with a cylindrical body sedimentation crystallization device top cover plate with holes at the top, and an anode rotary stirring device is arranged in the cylindrical body sedimentation crystallization device, the rotary shaft at the upper portion of the anode rotary stirring device passes through the holes in the cylindrical body sedimentation crystallization device top cover plate, a magnesium anode insertion slot is arranged at the bottom of the anode rotary stirring device, a magnesium alloy anode is inserted into the magnesium anode insertion slot for fixation, stirring blades are arranged on the rotary shaft of the anode stirring device, and a water inlet and a water outlet are respectively arranged on the side wall of the cylindrical body sedimentation crystallization device; a conical body sedimentation collection device is arranged at the bottom of the cylindrical body sedimentation crystallization device, and a sludge discharge port is arranged at the bottom of the conical body sedimentation collection device; an air cathode insertion slot is arranged on the circumference of the side wall of the cylindrical body sedimentation crystallization device, an air cathode is inserted into the air cathode insertion slot, and the magnesium anode and the air cathode are connected with an external resistance through wires to form a closed loop.

2. The self-powered electrochemical device for recovering nitrogen and phosphorus containing wastewater resource according to claim 1, characterized in that, The obtuse angle α formed between the conical body sedimentation collection device and the inner wall of the cylindrical body sedimentation crystallization device is 135°.

3. The self-powered electrochemical device for recovering nitrogen and phosphorus containing wastewater resource according to claim 1, characterized in that, The effective volume of the internal reaction zone of the cylindrical body sedimentation crystallization device is 1650ml.

4. The self-powered electrochemical device for recovering nitrogen and phosphorus containing wastewater resource according to claim 1, characterized in that, The bottom radius x top radius x height of the conical body sedimentation collection device is 50mm x 10mm x 40mm, and the diameter of the sludge discharge port is 10mm.

5. The self-powered electrochemical device for recovering nitrogen and phosphorus containing wastewater resource according to claim 1, characterized in that, The magnesium anode is a cylinder with an outer diameter x inner diameter x height of 90 mm x 80 mm x 200 mm, and the effective area of the magnesium anode is 56549 mm 2 .

6. The self-powered electrochemical device for recovering nitrogen and phosphorus containing wastewater resource according to claim 1, characterized in that, The air cathode has a height x length x width of 220 mm x 290 mm x 0.5 mm, and an effective area of 41888 mm 2 .

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