A miniaturized domestic sewage treatment device

Abstract

The application discloses a small-sized domestic sewage treatment device. The domestic sewage treatment device comprises, from upstream to downstream, a first anode, a first cathode, a second anode, a second cathode, a stirring unit and a post-treatment unit. Magnesium sulfite particles are arranged at the first anode, activated alumina is arranged at the first cathode, the first cathode is in communication with an external air source, the second anode adopts an iron electrode plate, the surface of the second cathode is loaded with a copper-doped inverse perovskite phase coating, and the post-treatment unit mainly comprises a stainless steel electrode pair and calcium carbonate particles. The treatment device is small in size, convenient to operate, short in treatment period and low in requirement for water quality fluctuation.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a domestic wastewater treatment device. Background Technology

[0002] Domestic sewage refers to wastewater generated in daily life, such as kitchen wastewater, laundry wastewater, bathroom wastewater, and toilet wastewater. If this wastewater is discharged directly into the environment without treatment, it will have a serious impact on surrounding water bodies and the environment, threatening public health. Therefore, domestic sewage needs to be treated to ensure that it meets discharge standards and is harmless to the environment.

[0003] Common wastewater treatment methods involve the following steps: First, hydraulic balancing: Due to the instability of domestic sewage discharge, hydraulic balancing is necessary before treatment to stabilize the flow and quality of the sewage, facilitating subsequent treatment. Second, pretreatment: Domestic sewage contains a large amount of suspended solids and impurities, requiring pretreatment to remove large particles such as sand, branches, stones, and fabric to avoid adverse effects on treatment equipment and subsequent processes. Third, biological treatment: Biological treatment is one of the mainstream wastewater treatment methods. It uses microbial communities to degrade organic matter in sewage, converting it into carbon dioxide and water, while simultaneously removing nutrients such as nitrogen and phosphorus. Common biological treatment processes include activated sludge processes and MBR (Membrane Bioreactor). Finally, advanced treatment: Advanced treatment refers to the deep purification of wastewater, removing trace amounts of organic matter, microorganisms, viruses, and other substances to ensure stable and compliant effluent quality. Commonly used advanced treatment processes include sedimentation, adsorption, oxidation, and membrane separation.

[0004] Biological treatment is a key component, utilizing the metabolic activity of microorganisms to transform dissolved and colloidal organic pollutants in wastewater into stable, harmless substances. While this process has relatively low operating costs, it still suffers from drawbacks such as long operating times, large footprint, high investment, long start-up times, and inconsistent treatment effectiveness. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a miniaturized domestic wastewater treatment device. This invention treats domestic wastewater using an electro-assisted catalytic oxidation method, which not only has advantages such as small size, convenient operation, and short treatment cycle, but also eliminates the need for continuous, timed, and quantitative addition of chemical reagents; the release of corresponding ions can be controlled simply by adjusting the voltage and current density.

[0006] The technical solution adopted in this invention is as follows:

[0007] I. A miniaturized domestic sewage treatment device

[0008] The domestic sewage treatment device includes a first anode, a first cathode, a second anode, a second cathode, a stirring unit, and a post-treatment unit arranged sequentially from upstream to downstream. Magnesium sulfite particles are arranged at the first anode, activated alumina is arranged at the first cathode, and the first cathode is connected to an external air source. The second anode uses an iron electrode plate, and the surface of the second cathode is loaded with a copper-doped anti-perovskite phase coating. The post-treatment unit mainly consists of stainless steel electrode pairs and calcium carbonate particles.

[0009] Preferably, the first anode, the first cathode, the second anode, and the second cathode are all sieve plate electrodes.

[0010] Preferably, the first anode, the first cathode, and the second cathode are all made of titanium electrode plates.

[0011] Preferably, the first cathode has an internal cavity containing a perforated tube. The perforated tube is used to introduce oxygen-containing gas (e.g., air) into the first cathode. One end of the perforated tube is connected to an external gas delivery device, and the other end extends into the internal cavity of the first cathode. The first cathode and the perforated tube are used to generate hydrogen peroxide by electrolyzing the oxygen-containing gas (e.g., air).

[0012] Preferably, the domestic sewage treatment device further includes a tank and a collection tank; the upper and lower ends of the tank are respectively provided with an outlet and an inlet, and the inside is arranged from bottom to top with a first anode, magnesium sulfite particles, a first cathode, activated alumina, a second anode, a second cathode and a stirring unit; the magnesium sulfite particles are stacked on the upper surface of the first anode and the activated alumina is stacked on the upper surface of the first cathode; the upper end of the collection tank is connected to the outlet, and the lower end of the collection tank is provided with a drain outlet; the stainless steel electrode pair in the post-treatment unit is arranged at the bottom of the collection tank, and the stainless steel electrode pair includes two stainless steel electrodes arranged opposite each other, with calcium carbonate particles piled around the stainless steel electrodes.

[0013] Preferably, the stirring unit includes a flared mouth and a paddle; the large-diameter end of the flared mouth is the inlet, located at the lower end, and the small-diameter end is the outlet, located at the upper end and arranged below the outlet; the paddle is located between the inlet and outlet of the flared mouth, and its top end is connected to the stirring shaft, which is connected to an external motor drive.

[0014] Preferably, the voltage between the first anode and the first cathode is 20-30V and the distance between them is 10-15cm; the voltage between the second anode and the second cathode is 20-30V and the distance between them is 10-15cm; in the stainless steel electrode pair, the voltage between the two stainless steel electrodes is 35V and the distance between them is 5-10cm.

[0015] II. A method for treating domestic sewage using the above-mentioned domestic sewage treatment device.

[0016] The domestic sewage treatment method includes the following steps: the domestic sewage to be treated flows sequentially through a first anode, a first cathode, a second anode, and a second cathode, is stirred by a stirring unit, and finally passes through a post-treatment unit to obtain the treated domestic sewage.

[0017] During the treatment process, nitrogen and phosphorus in the domestic sewage to be treated are converted into magnesium ammonium phosphate precipitate, and residual phosphorus is converted into calcium phosphate precipitate. The magnesium ammonium phosphate precipitate and calcium phosphate precipitate are adsorbed by calcium carbonate particles in the post-treatment unit.

[0018] Specifically, during the treatment process, the acidic environment generated after the first anode is energized dissolves magnesium sulfite particles, producing sulfite and magnesium ions; air is introduced into the first cathode through the perforated tube, and after the first cathode is energized, the oxygen in the air is reduced to hydrogen peroxide. Oxygen and hydrogen peroxide can oxidize sulfite to generate sulfate free radicals; ferrous ions are generated after the second anode is energized, and ferrous ions can activate hydrogen peroxide to generate hydroxyl free radicals; nitrates in the sewage to be treated are partially reduced to ammonia after the second cathode is energized; the oxygen, hydrogen peroxide, sulfate free radicals, and hydroxyl free radicals can oxidize polyphosphates in the sewage to be treated to produce orthophosphoric acid; and the sulfate free radicals and hydroxyl free radicals can convert trace chloride ions in the sewage to be treated into chloride free radicals under the catalysis of activated alumina.

[0019] Specifically, during the processing, at the stirring unit, phosphate, magnesium ions, and ammonia react to generate magnesium ammonium phosphate; in the post-processing unit, the acidic environment generated by the energization of the stainless steel electrode dissolves calcium carbonate particles, generating calcium ions, which can react with phosphate in the water to generate calcium phosphate; the calcium carbonate particles can adsorb magnesium ammonium phosphate and calcium phosphate.

[0020] The beneficial effects of this invention are:

[0021] 1. The treatment device of this invention uses an electro-assisted catalytic oxidation method to treat domestic sewage, which is smaller in size, easier to operate, has a shorter treatment cycle, and is less sensitive to water quality fluctuations than the traditional biological treatment method.

[0022] 2. The device of this invention is different from ordinary small biological treatment devices. It does not need to be started in advance and can be turned off after use. It does not need to maintain biological activity and does not occupy land.

[0023] 3. The device of this invention requires little investment, is easy to move, and is suitable for areas without centralized processing facilities, especially for temporary use scenarios;

[0024] 4. Compared with common chemical oxidation methods, the device of the present invention does not require the continuous, timed, and quantitative addition of chemical reagents. The release of corresponding ions can be controlled by controlling the voltage and current density, without the need for manual operation. Attached Figure Description

[0025] Figure 1 A cross-sectional view of the small-scale domestic sewage treatment device provided by the present invention;

[0026] Figure 2 Left sectional view (left) and right sectional view (right) of the small-scale domestic sewage treatment device provided by the present invention;

[0027] Figure 3 Right view (left) and right sectional view (right) of the small-scale domestic sewage treatment device provided by the present invention;

[0028] Figure 4 A top view (without a bucket lid) of the small-scale domestic sewage treatment device provided by the present invention;

[0029] Figure 5 A flowchart of a small-scale domestic sewage treatment method provided by the present invention.

[0030] In the diagram: 1. Barrel body, 2. Inlet, 3. Outlet, 4. First anode, 5. First cathode, 6. Perforated pipe, 7. Magnesium sulfite particles, 8. Second anode, 9. Second cathode, 10. Paddle, 11. Trumpet mouth, 12. Water collection tank, 13. Stainless steel electrode, 14. Calcium carbonate particles, 15. Drain, 16. Activated alumina. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] The first aspect of this invention provides a domestic sewage treatment device. This domestic sewage treatment device treats domestic sewage using an electro-assisted catalytic oxidation method. By controlling the voltage and current density, the release of corresponding ions can be controlled, eliminating the need for continuous, timed, and quantitative addition of chemical reagents. It is easy to operate and has a short treatment cycle.

[0033] like Figure 1 As shown, the domestic wastewater treatment device includes a first anode 4, a first cathode 5, a second anode 8, a second cathode 9, a stirring unit, and a post-treatment unit arranged sequentially from upstream to downstream. Magnesium sulfite particles 7 are arranged at the first anode 4. The first cathode 5 is connected to an external air source. The second anode 8 uses an iron electrode plate. The surface of the second cathode 9 is loaded with a copper (Cu)-doped anti-perovskite phase (Co4N) coating. The post-treatment unit mainly consists of stainless steel electrode pairs and calcium carbonate particles 14.

[0034] Specifically, the first anode 4, the first cathode 5, the second anode 8, and the second cathode 9 all employ sieve plate electrodes. In this invention, a sieve plate electrode refers to an electrode plate with sieve holes. The domestic sewage to be treated flows through the electrodes via the sieve holes on the electrode plate.

[0035] Preferably, the first anode 4, the first cathode 5, and the second cathode 9 are all made of titanium electrode plates.

[0036] Specifically, the first cathode 5, when energized, can electrolyze oxygen from an externally introduced oxygen-containing gas (e.g., air) into hydrogen peroxide.

[0037] Optionally, the first cathode 5 is connected to an external air source as follows: the first cathode 5 has an internal cavity, and a perforated tube 6 is installed in the cavity. The perforated tube 6 is used to introduce air into the first cathode 5. One end of the perforated tube 6 is connected to an external gas delivery device, and the other end extends into the internal cavity of the first cathode 5. When energized, the first cathode 5 can electrolyze oxygen in the gas introduced through the perforated tube 6 into hydrogen peroxide.

[0038] In the above embodiments, the perforated tube 6 is preferably arranged in parallel with the first cathode 5.

[0039] Preferably, the voltage between the first anode 4 and the first cathode 5 is 20-30V and the distance between them is 10-15cm; the voltage between the second anode 8 and the second cathode 9 is 20-30V and the distance between them is 10-15cm; in the stainless steel electrode pair, the voltage between the two stainless steel electrodes 13 is 35V and the distance between them is 5-10cm.

[0040] Furthermore, such as Figure 4 As shown, in an embodiment of the present invention, the domestic sewage treatment device further includes a tank 1 and a collection tank 12. The collection tank 12 is arranged on one side of the tank 1. Figures 1-2 As shown, the upper and lower ends of the barrel 1 are respectively provided with an outlet 3 and an inlet 2. Inside, from bottom to top, are arranged a first anode 4, magnesium sulfite particles 7 stacked on the upper surface of the first anode 4, a first cathode 5, activated alumina 16 stacked on the upper surface of the first cathode 5, a second anode 8, a second cathode 9, and a stirring unit. Figure 3 As shown, the upper end of the water collection tank 12 is connected to the water outlet 3, and the lower end is provided with a drain outlet 15. The stainless steel electrode pair in the post-treatment unit is arranged at the bottom of the tank. The stainless steel electrode pair includes two stainless steel electrodes 13 arranged opposite to each other. Calcium carbonate particles 14 are piled up around the stainless steel electrodes 13.

[0041] Furthermore, in embodiments of the present invention, such as Figure 1 and Figure 2As shown, the stirring unit includes a bell mouth 11 and a blade 10. The larger diameter end of the bell mouth 11 is the inlet, located at the lower end; the smaller diameter end is the outlet, located at the upper end and positioned below the outlet 3. The function of the bell mouth 11 is to concentrate the water flow, thereby improving the stirring efficiency and eliminating the need for a large propeller. The blade 10 is located between the inlet and outlet of the bell mouth 11, and its top end is connected to the stirring shaft, which is then connected to an external motor drive.

[0042] The installation method of the stirring unit can be as follows: the stirring shaft is connected to the top inner wall of the barrel 1 through a bearing, and the large diameter end of the flared mouth 11 is connected to the inner wall of the barrel 1.

[0043] Specifically, the first anode 4 and the first cathode 5 are electrically connected to the positive and negative terminals of the external power supply, respectively. The second anode 8 and the second cathode 9 are electrically connected to the positive and negative terminals of the external power supply, respectively.

[0044] Specifically, in the embodiments of the present invention, the first anode 4, the first cathode 5, the second anode 8, and the second cathode 9 are all arranged horizontally and sequentially from bottom to top vertically. The first anode 4 is located above the water inlet 2, the second cathode 9 is located below the stirring unit, and the stirring unit is located below the water outlet 3. Magnesium sulfite particles 7 are deposited above the first anode 4, and activated alumina 16 is deposited above the first cathode 5. The first anode 4, the first cathode 5, the second anode 8, the second cathode 9, and the flared mouth 11 are all connected to the inner wall of the tank body 1.

[0045] In an embodiment of the present invention, the stainless steel electrode 13 is arranged vertically relative to the inner wall of the bottom of the water collection tank 12 and is connected to the inner wall of the bottom of the tank. Calcium carbonate particles 14 are deposited between the two stainless steel electrodes 13 and between each stainless steel electrode 13 and the inner wall of the water collection tank 12.

[0046] Preferably, the stacking height of the calcium carbonate particles 14 is flush with the height of the stainless steel electrode 13.

[0047] In an embodiment of the present invention, the inlet 2 and the outlet 3 are respectively disposed on the first and second opposite sides of the barrel 1, the water collection tank 12 is arranged on the second side of the barrel 1, that is, the side of the outlet 3, and the drain outlet 15 is disposed on the second side of the water collection tank 12.

[0048] A second aspect of the present invention provides a method for treating domestic sewage using the above-described domestic sewage treatment device.

[0049] The domestic sewage treatment method provided by this invention mainly includes the following steps: The domestic sewage to be treated flows sequentially through a first anode 4, a first cathode 5, a second anode 8, and a second cathode 9, is stirred by a stirring unit, and finally passes through a post-treatment unit to obtain treated domestic sewage. During the treatment process, organic matter in the wastewater is completely oxidized; for example, polyphosphate is completely oxidized to orthophosphate. Furthermore, nitrogen is converted from nitrate nitrogen to ammonia nitrogen, which is then precipitated as magnesium ammonium phosphate, thus removing both nitrogen and phosphorus. Simultaneously, trace amounts of chloride ions present in the wastewater (such as salts in rural kitchen wastewater and chlorine from tap water entering the wastewater) are converted into various chloride free radicals (such as Cl·, Cl2·-, and ClO·), which can accelerate the oxidation of organic matter.

[0050] In this embodiment of the invention, solid wastewater is used as the domestic sewage to be treated. The domestic sewage flows into the tank 1 from the inlet 2, passes through the first anode 4, first cathode 5, second anode 8, and second cathode 9, and is stirred by the paddle 10 at the bell mouth 11 before flowing into the collection tank 12 from the outlet 3 of the tank 1. During this process, nitrogen and phosphorus elements in the domestic sewage are converted into magnesium ammonium phosphate precipitate. After the domestic sewage containing magnesium ammonium phosphate precipitate flows into the collection tank 12, the residual phosphorus element in the domestic sewage is converted into calcium phosphate precipitate. Both the magnesium ammonium phosphate precipitate and the calcium phosphate precipitate are adsorbed by calcium carbonate particles 14. Finally, the treated domestic sewage is discharged from the drain 15.

[0051] like Figure 5 As shown, the specific implementation principle of the above process is as follows:

[0052] When the first anode 4 is energized, an oxidation reaction occurs, generating H+ ions. This causes a local decrease in pH around the first anode 4, creating an acidic environment. The resulting acidic environment dissolves the magnesium sulfite particles 7, producing sulfite ions and magnesium ions.

[0053] Air is continuously introduced into the first cathode 5. After the first cathode 5 is energized, the oxygen O2 in the air is reduced to hydrogen peroxide H2O2. Both oxygen and hydrogen peroxide can oxidize sulfite ions to generate sulfate free radicals.

[0054] Under the catalytic action of the activated alumina stacked on the surface of the first cathode 5, the generated sulfate radicals and hydroxyl radicals can transform trace amounts of chloride ions in wastewater (such as salt in rural kitchen wastewater, chlorine in tap water entering the wastewater, etc.) into various chloride radicals (such as Cl·, Cl2·- and ClO·, etc.). These radicals can accelerate the oxidation of organic matter.

[0055] When the second anode 8 is energized, it generates ferrous ions, which can activate hydrogen peroxide and produce more hydroxyl radicals. When the second cathode 9 is energized, it reduces nitrates in the sewage to ammonia.

[0056] Oxygen, hydrogen peroxide, sulfate radicals, and hydroxyl radicals can oxidize organic matter and polyphosphate in domestic sewage to produce orthophosphate. Hydroxyl radicals also have a bactericidal effect.

[0057] At the stirring unit, after being gathered by the bell mouth 11 and stirred by the blades 10, phosphate, magnesium ions, ammonia and other substances in the water react to form magnesium ammonium phosphate solid particles.

[0058] In the post-treatment unit, the acidic environment generated by the energized stainless steel electrode 13 dissolves the particles 14. The resulting calcium ions react with the remaining unprecipitated phosphate ions in the water to form calcium phosphate solid particles. The calcium carbonate particles 14 can adsorb magnesium ammonium phosphate solid particles and calcium phosphate solid particles in the water, thereby removing phosphorus and nitrogen elements from domestic sewage.

[0059] The above description, based on the preferred embodiments of the present invention, provides inspiration. Those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification but must be determined according to the claims.

Claims

1. A method for treating domestic sewage, characterized in that: The process is carried out using a domestic sewage treatment device; the domestic sewage treatment device includes a first anode (4), a first cathode (5), a second anode (8), a second cathode (9), a stirring unit, and a post-treatment unit arranged sequentially from upstream to downstream; magnesium sulfite particles (7) are arranged at the first anode (4), activated alumina (16) is arranged at the first cathode (5), and the first cathode (5) is connected to an external air source; the second anode (8) is made of iron electrode plate; the surface of the second cathode (9) is loaded with a copper-doped anti-perovskite phase coating; the post-treatment unit is mainly composed of stainless steel electrode pairs and calcium carbonate particles (14); The domestic sewage treatment device also includes a tank (1) and a water collection tank (12); the upper and lower ends of the tank (1) are respectively provided with an outlet (3) and an inlet (2), and the inside is arranged from bottom to top with a first anode (4), magnesium sulfite particles (7), a first cathode (5), activated alumina (16), a second anode (8), a second cathode (9) and a stirring unit; the magnesium sulfite particles (7) are stacked on the upper surface of the first anode (4), and the activated alumina (16) is stacked on the upper surface of the first cathode (5); the upper end of the water collection tank (12) is connected to the outlet (3), and the lower end of the water collection tank (12) is provided with a drain outlet (15); the stainless steel electrode pair in the post-treatment unit is arranged at the bottom of the water collection tank (12), and the stainless steel electrode pair includes two stainless steel electrodes (13) arranged opposite to each other, and calcium carbonate particles (14) are piled around the stainless steel electrodes (13); The acidic environment generated by the first anode (4) after being energized dissolves magnesium sulfite particles (7), producing sulfite and magnesium ions; air is introduced into the first cathode (5) through the perforated tube (6), and the first cathode (5) reduces the oxygen in the air to hydrogen peroxide after being energized. Oxygen and hydrogen peroxide can oxidize sulfite and generate sulfate free radicals; ferrous ions are generated after the second anode (8) is energized, and ferrous ions can activate hydrogen peroxide and generate hydroxyl free radicals; nitrates in the domestic sewage to be treated are electroreduced to ammonia after the second cathode (9) is energized; the oxygen, hydrogen peroxide, sulfate free radicals, and hydroxyl free radicals can oxidize polyphosphate in the domestic sewage to be treated and generate orthophosphoric acid; the sulfate free radicals and hydroxyl free radicals can convert trace chloride ions in the domestic sewage to be treated into chloride free radicals under the catalytic action of activated alumina (16); At the stirring unit, phosphate, magnesium ions, and ammonia react to generate magnesium ammonium phosphate; in the post-treatment unit, the acidic environment generated by the energized stainless steel electrode (13) dissolves calcium carbonate particles (14) and generates calcium ions, which can react with phosphate in the water to generate calcium phosphate; the calcium carbonate particles (14) can adsorb magnesium ammonium phosphate and calcium phosphate.

2. The method for treating domestic sewage according to claim 1, characterized in that: The first anode (4), the first cathode (5), the second anode (8) and the second cathode (9) are all sieve plate electrodes; the first anode (4), the first cathode (5) and the second cathode (9) are all titanium electrode plates.

3. The method for treating domestic sewage according to claim 1, characterized in that: The first cathode (5) has a cavity inside, and a perforated tube (6) is provided in the cavity. The perforated tube (6) is used to introduce oxygen-containing gas into the first cathode (5). One end of the perforated tube (6) is connected to an external gas delivery device, and the other end extends into the cavity inside the first cathode (5). The first cathode (5) and the perforated tube (6) are used to generate hydrogen peroxide by electrolyzing the oxygen-containing gas.

4. The method for treating domestic sewage according to claim 1, characterized in that: The stirring unit includes a flared mouth (11) and a blade (10); the large diameter end of the flared mouth (11) is the inlet, located at the lower end, and the small diameter end is the outlet, located at the upper end, and arranged below the outlet (3); the blade (10) is located between the inlet and outlet of the flared mouth (11), and its top end is connected to the stirring shaft, which is connected to an external motor drive.

5. The method for treating domestic sewage according to claim 4, characterized in that: The voltage between the first anode (4) and the first cathode (5) is 20~30V and the distance between them is 10~15cm; the voltage between the second anode (8) and the second cathode (9) is 20~30V and the distance between them is 10~15cm; in the stainless steel electrode pair, the voltage between the two stainless steel electrodes (13) is 35V and the distance between them is 5~10cm.

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