Sewage treatment device and method based on self-filtering biological cathode aluminum-air battery

Abstract

The application provides a sewage treatment device and method based on a self-filtering biological cathode aluminum air cell, and belongs to the technical field of sewage treatment. The cavity is composed of a water inlet area, a reaction area and a water outlet area, and the reaction area is divided into different polar chambers by a partition. The self-filtering biological cathode aluminum air cell system is in an inverted U shape and is arranged on both sides of each partition in the reaction area. The fecal and urine wastewater flows through the cathode by capillary action and adsorption, and is automatically filtered to the next stage. After being processed in sequence, the wastewater is collected in the water outlet area. The application fully utilizes the high reduction of the activated carbon cathode, the biological cathode, the capillary action and the pollutant adsorption, realizes the automatic separation of solid and liquid, the automatic flow of wastewater, the automatic adsorption and biodegradation of pollutants in the entire cell system, and finally realizes the purposes of efficient water purification and power generation. The application provides a new idea for sustainable wastewater treatment and power generation technology development in a narrow space.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a wastewater treatment device and method based on a self-filtering biological cathode aluminum-air battery. Background Technology

[0002] In the context of transportation systems, high-speed rail toilets generate high-concentration wastewater containing large amounts of suspended solids, such as urine, organic matter, organic nitrogen, and phosphates. Traditional treatment methods need to address multiple tasks simultaneously, including solid-liquid separation, pollutant removal, nitrogen and phosphorus removal, and inhibition of urine hydrolysis. While individual methods such as membrane filtration, aerobic biological treatment, electrocatalytic oxidation, and advanced oxidation can solve some of these tasks, they cannot achieve the simultaneous completion of all of them. More importantly, traditional treatment methods and devices rely on additional energy sources such as electricity, pumps, and chemical agents to maintain system operation. Therefore, from a low-carbon perspective, they involve significant direct greenhouse gas emissions and are not sustainable water treatment processes overall.

[0003] Especially in the field of in-situ treatment of transportation wastewater, such as inside high-speed rail or RVs, there is a need for the development of more low-maintenance, low-cost, and efficient sustainable treatment technologies and equipment, particularly in confined spaces, to achieve new systems that can simultaneously purify water and generate electricity without any external energy. This is of great significance to the sustainability of transportation water systems.

[0004] To achieve sustainable treatment of wastewater from high-speed trains, it is necessary to address the issues of autonomous wastewater flow, autonomous solid-liquid separation, autonomous pollutant degradation, and in-situ power generation within the treatment system, relying solely on the system's internal chemical energy without external energy sources. Among these, water treatment technology based on metal-air batteries offers a new approach to sustainable wastewater treatment. While Chinese invention patent CN113060799B proposes the concept of a self-filtering, self-absorbing aluminum-air battery, several key issues remain unresolved when directly applied to urine treatment: 1) Degradation and in-situ removal of high-concentration organic pollutants. Previous removal methods primarily rely on absorbent separating materials such as kitchen paper and the flocculation effect of the aluminum-air battery. However, the adsorption capacity of these separating materials is limited, and once saturated, the adsorbed organic matter is difficult to degrade further. 2) The flow rate of the self-absorbed water depends mainly on the separating material. Increasing the flow rate requires increasing the thickness of the separating material, which in turn increases the electrode spacing, affecting power generation. These contradictions hinder system scaling. 3) Existing patents cannot remove urine quickly and effectively in a single step, requiring reactor optimization and design, which was not discussed in previous patents. Therefore, developing a sustainable water treatment device and method that enables autonomous wastewater flow, autonomous solid-liquid separation, autonomous pollutant degradation, and in-situ power generation within the treatment system is of great significance for wastewater treatment on high-speed trains. Summary of the Invention

[0005] The purpose of this invention is to provide a wastewater treatment device and method based on a self-filtering biological cathode aluminum air battery, so as to solve at least one of the technical problems existing in the background art.

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

[0007] On one hand, the present invention provides a wastewater treatment device based on a self-filtering biological cathode aluminum-air battery, comprising:

[0008] The cavity through which the sewage flows;

[0009] In the direction of sewage flow, the cavity is sequentially provided with an inlet zone, a reaction zone, and an outlet zone;

[0010] The reaction zone includes compartments separated by multiple partitions; there is a height difference between two adjacent compartments and the height decreases sequentially in the direction of sewage flow to ensure the water flows by gravity.

[0011] The water inlet zone and the first compartment of the reaction zone, the adjacent compartments, and the last compartment of the reaction zone and the water outlet zone are all connected by a self-filtering biocathode aluminum-air battery system.

[0012] The self-filtering biocathode aluminum-air battery system comprises, in sequence, a first insulating clamp, a first aluminum foil anode, a first separating material, an activated carbon fiber felt biocathode, a second separating material, a second aluminum foil anode, and a second insulating clamp; wherein the cathode and anode are electrically connected to an energy storage device for collecting the generated electrical energy.

[0013] Preferably, the area of ​​the separating material is the same as the apparent area of ​​the aluminum foil anode, and the apparent area of ​​the activated carbon fiber felt biocathode is 2-5 times that of the aluminum foil anode.

[0014] Preferably, the activated carbon fiber felt biocathode consists of an activated carbon fiber felt matrix, a catalyst supported on the activated carbon fiber felt matrix, and a microbial membrane that grows in the interaction between the activated carbon fiber felt matrix and urine.

[0015] Preferably, the catalyst supported on the activated carbon fiber felt matrix is ​​a composite of one or more metal oxides selected from Ir, Ti, Ru, Co, Mn, Sn, Sb, Pb, or Pt.

[0016] Preferably, the self-filtering biocathode aluminum-air battery system is arranged in an inverted U-shape on both sides of each partition in the reaction zone. One end of the activated carbon fiber felt biocathode is placed at the bottom of the previous compartment along its length, while the other end is suspended above the current compartment. A certain height difference is maintained on both sides of the activated carbon fiber felt biocathode to ensure that the wastewater can achieve autonomous filtration and flow under the combined action of capillary action and gravity.

[0017] Preferably, the surface area of ​​the activated carbon fiber felt is 1000 m². 2 / g-3000m 2 / g, thickness 0.2cm-5cm.

[0018] Preferably, the aluminum foil anode is kitchen aluminum foil with an aluminum purity greater than 95% and a thickness of 0.001mm-1mm.

[0019] Preferably, both the first and second separating materials are non-woven fabrics or paper made of pure cotton or pure polyester, with a thickness of 0.1mm-1mm.

[0020] Secondly, the present invention provides a method for wastewater treatment using the apparatus described above, comprising:

[0021] (1) In the self-filtering biocathode aluminum-air battery, one end of the activated carbon fiber felt biocathode is immersed at the bottom of the inlet water zone, and the other end is placed at the top of the first compartment of the reaction zone. Under the action of gravity and capillary action, the activated carbon fiber felt only allows dissolved pollutants and water molecules to be lifted through its interior and flow into the first compartment. During the autonomous flow process, dissolved organic matter is fully adsorbed by the activated carbon fiber felt, achieving the purpose of autonomous filtration. Suspended particulate matter cannot diffuse inside the activated carbon cathode by capillary action and is trapped in the inlet water zone, realizing in-situ sedimentation, in-situ filtration and autonomous flow of high turbidity wastewater and high suspended solids wastewater.

[0022] (2) Gradient autonomous filtration and flow of wastewater: The treated wastewater will repeat step (1) in each compartment of the reaction zone. Under the action of the self-filtering biocathode aluminum air battery system, it will be autonomously filtered and flowed into the next compartment, and finally flow into the effluent area. After multiple gradient treatments, organic matter, turbidity and suspended particulate matter in the wastewater will be adsorbed and filtered out.

[0023] (3) The simultaneous power generation and water purification functions of the self-filtering biocathode aluminum air battery system:

[0024] Electricity generation: As wastewater flows through the activated carbon fiber felt biocathode, it causes a corrosion discharge reaction at the aluminum foil anode, generating electrons. These electrons are then received by the activated carbon biocathode through an external circuit to generate electrical energy, which is then collected in the energy storage system.

[0025] In-situ electrocoagulation for COD and phosphate removal: The released aluminum ions generate aluminum hydroxide flocculants that are distributed around the separator material to flocculate organic pollutants in wastewater in situ; at the same time, aluminum ions react with phosphates in urine to produce aluminum phosphate precipitates, which are deposited on the separator material to form an aluminum phosphate flame retardant layer.

[0026] Inhibits wastewater hydrolysis and ammonia volatilization: The release of large amounts of aluminum ions causes a decrease in the pH of wastewater, inhibiting wastewater hydrolysis and preventing the generation of ammonia.

[0027] Biocathode synergistic organic matter degradation: With continuous operation, a biofilm will gradually grow on the surface of the activated carbon fiber felt cathode that has been exposed to air for a long time;

[0028] (4) Based on (2), the wastewater undergoes (3) reaction in each compartment of the reactor in sequence. Organic matter, nitrogen, phosphorus pollutants and suspended solids in the wastewater are effectively removed, and decolorization is achieved. The wastewater is then discharged into the effluent area.

[0029] Preferably, due to the limited mass transfer of oxygen within the activated carbon fiber felt, aerobic-anoxic-anaerobic regions gradually form from the outside to the inside of the activated carbon fiber felt, thus naturally cultivating aerobic, anoxic, and anaerobic biofilms. Under the dual action of the catalyst and the biofilm, the organic matter and organic nitrogen adsorbed on the cathode surface are decomposed into CO2 and N2, achieving in-situ regeneration of the cathode surface and promoting the continuous progress of subsequent adsorption reactions. In addition, the synergistic catalytic effect of the catalyst and the biofilm further accelerates the reduction reaction of oxygen on the cathode surface, increases the cathode potential, and promotes the increase of power generation.

[0030] Beneficial effects of this invention:

[0031] By simultaneously using activated carbon fiber felt cathodes as absorbent materials, electrode materials, filter materials, and the loading substrate for the biofilm treatment system, the battery cathode potential is improved, resulting in excellent power generation performance. Precise control of water flow rate and volume is achieved by modifying the pore size, thickness, and surface area of ​​the activated carbon fiber cathode. In-situ regeneration of the cathode is realized, providing a more continuous driving force for subsequent organic matter adsorption. It possesses highly efficient autonomous solid-liquid separation capabilities, turbidity removal capabilities, and simultaneous wastewater stabilization characteristics. It can autonomously retain solid matter, allowing only the liquid to flow autonomously without any external energy. While removing phosphates, it can also acidify and inhibit hydrolysis, preventing ammonia nitrogen production. This design eliminates odor overflow and avoids the extra steps of adding controlled chemicals such as sulfuric acid in traditional operations, enabling in-situ addition of inhibitors and improving the system's sustainability. The plug-flow continuous reactor design enhances the system's reaction driving force, ensuring effluent quality. It achieves continuous wastewater treatment and continuous power generation without requiring any external kinetic energy to drive wastewater flow, enabling autonomous wastewater flow, autonomous filtration of suspended solids and turbidity, autonomous adsorption of dissolved organic pollutants, and autonomous biodegradation on the cathode. Meanwhile, the aluminum-air battery uses wastewater as the electrolyte to continuously provide electricity, lowering the wastewater's pH and inhibiting hydrolysis in situ without the need for additional inhibitors.

[0032] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a structural diagram of a wastewater treatment device based on a self-filtering biological cathode aluminum-air battery, as described in an embodiment of the present invention.

[0035] Figure 2 for Figure 1 Enlarged view of the structure of the self-filtering biocathode aluminum-air battery at point A.

[0036] Figure 3 for Figure 2 Schematic diagram of the cathode reaction principle of activated carbon fiber felt at point B.

[0037] Figure 4 for Figure 2 A schematic diagram of the reaction principle of the self-filtering biocathode aluminum-air battery at point C.

[0038] Wherein: 1-cavity; 2-self-filtering biocathode aluminum-air battery system; 3-energy storage system; 4-water inlet area; 5-reaction area; 6-water outlet area; 7-separator; 8-activated carbon fiber felt biocathode; 9-first plastic clamp; 10-first aluminum foil anode; 11-first separating material; 12-second plastic clamp; 13-second aluminum foil anode; 14-second separating material. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0040] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0041] It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as here.

[0042] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or groups thereof.

[0043] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0044] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0045] In the description of this specification, the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this technology and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this technology.

[0046] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of these terms in this art according to the specific circumstances.

[0047] To facilitate understanding of the present invention, the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. However, the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0048] Those skilled in the art should understand that the accompanying drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily essential for implementing the present invention.

[0049] Example 1

[0050] This embodiment first provides a wastewater treatment device based on a self-filtering biological cathode aluminum-air battery, comprising: a cavity, a self-filtering biological cathode aluminum-air battery system, and an energy storage system. The cavity has a rectangular structure, consisting of an inlet zone, a reaction zone, and an outlet zone from front to back. The reaction zone is divided into 3-10 small compartments by built-in partitions. Each compartment has a temporary drain outlet at its bottom, as do the inlet zone and the reaction zone. There is a height difference between adjacent compartments, with the height decreasing sequentially in the direction of wastewater flow to ensure gravity-driven water flow; the height difference ranges from 2cm to 20cm.

[0051] The self-filtering biocathode aluminum-air battery system comprises, from the outside in, a double-anode, single-cathode, sandwich-structured battery assembly consisting of a plastic clamp, an aluminum foil anode, a separator, an activated carbon fiber felt biocathode, another separator, an aluminum foil anode, and an insulating clamp. The anode and cathode are connected via wires and an energy storage device to collect the generated electrical energy. The area of ​​the separator is the same as the apparent area of ​​the aluminum foil anode, while the apparent area of ​​the activated carbon fiber felt biocathode is 2-5 times that of the aluminum foil anode.

[0052] The activated carbon fiber felt biocathode consists of an activated carbon fiber felt matrix, a catalyst supported on the activated carbon fiber felt matrix, and a microbial membrane that grows naturally under the interaction of the activated carbon fiber felt matrix and urine.

[0053] The self-filtering biocathode aluminum-air battery system is arranged in an inverted U-shape on both sides of each partition in the reaction zone. One end of the activated carbon fiber felt biocathode is placed at the bottom of the previous compartment along its length, while the other end is suspended above the current compartment. A certain height difference is maintained on both sides of the activated carbon fiber felt biocathode to ensure that the sewage can achieve autonomous filtration and flow under the combined action of capillary action and gravity.

[0054] The surface area of ​​the activated carbon fiber felt is 1000m². 2 / g-3000m 2 / g, thickness ranging from 0.2cm to 5cm. The aluminum foil anode is commonly used kitchen aluminum foil, with an aluminum purity greater than 95%, and a thickness of 0.001mm to 1mm. The separator material is commonly used pure cotton, pure polyester non-woven fabric, or paper, with a thickness of 0.1mm to 1mm. The catalyst layer supported on the activated carbon fiber felt biocathode is one or more composites of Ir, Ti, Ru, Co, Mn, Sn, Sb, Pb, and Pt metal oxides.

[0055] In this embodiment 1, the method for treating urine wastewater using the above-mentioned self-filtering biocathode aluminum-air battery device includes:

[0056] (1) In-situ sedimentation and self-filtration of fecal wastewater: Fecal wastewater generated by the toilet is discharged into the inlet area. Under the action of gravity, the suspended solids in the fecal wastewater settle naturally at the bottom of the inlet area. The bottom drain is opened periodically to remove the above-mentioned sediments. In the self-filtration biocathode aluminum-air battery, one end of the activated carbon fiber felt biocathode is immersed at the bottom of the inlet area, and the other end is placed at the top of the first compartment of the reaction zone. Under the action of gravity and capillary action, the activated carbon fiber felt only allows dissolved pollutants and water molecules in the fecal wastewater to be lifted through its interior and flow into the first-stage compartment. During the autonomous flow process, the dissolved organic matter in the fecal wastewater is fully adsorbed by the activated carbon fiber felt, achieving the purpose of autonomous filtration. Secondly, the suspended particulate matter in the fecal wastewater cannot diffuse inside the activated carbon cathode by capillary action, so it is trapped in the inlet area, realizing in-situ sedimentation, in-situ filtration and autonomous flow of high turbidity wastewater and high suspended solids wastewater. Moreover, this process does not require additional power consumption such as water pumps.

[0057] (2) Gradient autonomous filtration and flow of fecal wastewater: The treated fecal wastewater will undergo step (1) in sequence in each compartment of the reaction zone. Under the action of the self-filtration biocathode aluminum air battery system, it will be autonomously filtered and flowed into the next compartment step by step, and finally flow into the effluent zone. After multiple gradient treatments, the organic matter, turbidity and suspended particulate matter in the wastewater will be gradually adsorbed and filtered out.

[0058] (3) The simultaneous power generation and water purification functions of the self-filtering biocathode aluminum air battery system:

[0059] Electricity generation: As the fecal wastewater flows through the activated carbon fiber felt biocathode, the high pH value of the wastewater causes a corrosion discharge reaction at the aluminum foil anode, generating electrons. These electrons are then received by the activated carbon biocathode through an external circuit, generating electrical energy, which is collected in the energy storage system.

[0060] In-situ electrocoagulation for COD and phosphate removal: The released aluminum ions generate aluminum hydroxide flocculants that are distributed around the separator material to flocculate organic pollutants in urine in situ; at the same time, the aluminum ions react with phosphates in the urine to produce aluminum phosphate precipitates, which are deposited on the separator material to form an aluminum phosphate flame retardant layer.

[0061] Inhibits urine hydrolysis and ammonia volatilization: The release of large amounts of aluminum ions causes a decrease in urine pH, which can inhibit urine hydrolysis and prevent the production of odors such as ammonia.

[0062] Biocathode-assisted organic matter degradation: With continuous operation, a biofilm gradually grows on the surface of the activated carbon fiber felt cathode, which is exposed to air for extended periods. Due to the limited mass transfer of oxygen within the activated carbon fiber felt, aerobic-anoxic-anaerobic zones gradually form from the outside in, naturally leading to the growth of aerobic, anoxic, and anaerobic biofilms. This microbial ecosystem produces substances that can degrade the organic matter adsorbed on the activated carbon fiber felt, achieving in-situ nitrification and denitrification. Under the dual action of the catalyst and the biofilm, the organic matter and organic nitrogen adsorbed on the cathode surface are decomposed into CO2 and N2, achieving in-situ regeneration of the cathode surface and promoting the continued progress of subsequent adsorption reactions. Furthermore, the synergistic catalytic effect of the catalyst and the biofilm further accelerates the reduction reaction of oxygen on the cathode surface, increases the cathode potential, and promotes increased power generation.

[0063] (4) Based on (2), the fecal wastewater undergoes (3) reaction in each compartment of the reactor in sequence. Organic matter, nitrogen, phosphorus pollutants and suspended solids in the wastewater are effectively removed, and decolorization is also achieved. The wastewater is discharged into the effluent area and can be reused for toilet flushing or direct discharge.

[0064] Example 2

[0065] like Figures 1 to 4 In this embodiment 2, a urine wastewater treatment device based on a self-filtering biocathode aluminum-air battery is provided, comprising: a cavity 1, a self-filtering biocathode aluminum-air battery system 2, and an energy storage system 3. The cavity 1 has a rectangular structure and consists of an inlet zone 4, a reaction zone 5, and an outlet zone 6 from front to back. The reaction zone is divided into 7 small compartments by an internal partition 7. The height difference between two adjacent compartments is 5 cm, and the height decreases sequentially in the direction of water flow to ensure the water flows under gravity. Temporary drain outlets are provided at the bottom of each compartment and at the bottom of the inlet zone and the reaction zone. The self-filtering biocathode aluminum-air battery system 2 consists of a double-anode single-cathode sandwich structure battery assembly composed of an insulating clamp, an aluminum foil anode, a separator material, an activated carbon fiber felt biocathode, a separator material, an aluminum foil anode, and an insulating clamp. The anode and cathode are connected by wires and an energy storage device to collect the generated electrical energy. The area of ​​the separator material is the same as the apparent area of ​​the aluminum foil anode, and the apparent area of ​​the activated carbon fiber felt biocathode is three times that of the aluminum foil anode.

[0066] In the aforementioned sandwich-structured battery assembly, the activated carbon fiber felt biocathode is located in the middle. One side of the biocathode consists of a first insulating clamp 9, a first aluminum foil anode 10, and a first separator 11; the other side consists of a second insulating clamp 12, a second aluminum foil anode 13, and a second separator 14. The corresponding insulating clamps, aluminum foil anodes, and separators on both sides are symmetrically arranged with respect to the activated carbon fiber felt biocathode. The first insulating clamp 9 and the second insulating clamp 12 can be made of plastic.

[0067] The activated carbon fiber felt biocathode consists of an activated carbon fiber felt matrix, a catalyst supported on the activated carbon fiber felt matrix, and a microbial membrane that grows naturally through interaction between the activated carbon fiber felt matrix and urine. The catalyst layer supported on the activated carbon fiber felt biocathode is MnO2.

[0068] The self-filtering biocathode aluminum-air battery system is arranged in an inverted U-shape on both sides of each compartment in the reaction zone. One end of the activated carbon fiber felt biocathode is placed at the bottom of the previous compartment along its length, while the other end is suspended above this compartment. A certain height difference is maintained on both sides of the activated carbon fiber felt biocathode to ensure that urine can achieve autonomous filtration and flow under the combined action of capillary action and gravity.

[0069] The surface area of ​​the activated carbon fiber felt used is 1000m². 2 / g, thickness 1cm, size 30cm×10cm. The aluminum foil anode is commonly used kitchen aluminum foil, aluminum purity 95%, thickness 0.1mm, size 10cm×10cm. The separator material is household kitchen paper, thickness 0.1mm, size 10cm×10cm.

[0070] This embodiment also provides a urine treatment method using the above-mentioned self-filtering biocathode aluminum-air battery device, including:

[0071] (1) In-situ sedimentation and self-filtration of fecal wastewater: Fecal wastewater generated by the toilet is discharged into the inlet area. Under the action of gravity, the suspended solids in the fecal wastewater settle naturally at the bottom of the inlet area. The bottom drain is opened periodically to remove the above-mentioned sediments. In the self-filtration biocathode aluminum-air battery, one end of the activated carbon fiber felt biocathode is immersed at the bottom of the inlet area, and the other end is placed at the top of the first compartment of the reaction zone. Under the action of gravity and capillary action, the activated carbon fiber felt only allows dissolved pollutants and water molecules in the fecal wastewater to be lifted through its interior and flow into the first-stage compartment. During the autonomous flow process, the dissolved organic matter in the fecal wastewater is fully adsorbed by the activated carbon fiber felt, achieving the purpose of autonomous filtration. Secondly, the suspended particulate matter in the fecal wastewater cannot diffuse inside the activated carbon cathode by capillary action, so it is trapped in the inlet area, realizing in-situ sedimentation, in-situ filtration and autonomous flow of high turbidity wastewater and high suspended solids wastewater. Moreover, this process does not require additional power consumption such as water pumps.

[0072] (2) Gradient autonomous filtration and flow of fecal wastewater: The treated fecal wastewater will undergo step (1) in sequence in each compartment of the reaction zone. Under the action of the self-filtration biocathode aluminum air battery system, it will be autonomously filtered and flowed into the next compartment step by step, and finally flow into the effluent zone. After multiple gradient treatments, the organic matter, turbidity and suspended particulate matter in the wastewater will be gradually adsorbed and filtered out.

[0073] (3) The simultaneous power generation and water purification functions of the self-filtering biocathode aluminum air battery system:

[0074] Electricity generation: As the fecal wastewater flows through the activated carbon fiber felt biocathode, the high pH value of the wastewater causes a corrosion discharge reaction at the aluminum foil anode, generating electrons. These electrons are then received by the activated carbon biocathode through an external circuit, generating electrical energy, which is collected in the energy storage system.

[0075] In-situ electrocoagulation for COD and phosphate removal: The released aluminum ions generate aluminum hydroxide flocculants that are distributed around the separator material to flocculate organic pollutants in urine in situ; at the same time, the aluminum ions react with phosphates in the urine to produce aluminum phosphate precipitates, which are deposited on the separator material to form an aluminum phosphate flame retardant layer.

[0076] Inhibits urine hydrolysis and ammonia volatilization: The release of large amounts of aluminum ions causes a decrease in urine pH, which can inhibit urine hydrolysis and prevent the production of odors such as ammonia.

[0077] Biocathode-assisted organic matter degradation: With continuous operation, a biofilm gradually grows on the surface of the activated carbon fiber felt cathode, which is exposed to air for extended periods. Due to the limited mass transfer of oxygen within the activated carbon fiber felt, aerobic-anoxic-anaerobic zones gradually form from the outside in, naturally leading to the growth of aerobic, anoxic, and anaerobic biofilms. This microbial ecosystem produces substances that can degrade the organic matter adsorbed on the activated carbon fiber felt, achieving in-situ nitrification and denitrification. Under the dual action of the catalyst and the biofilm, the organic matter and organic nitrogen adsorbed on the cathode surface are decomposed into CO2 and N2, achieving in-situ regeneration of the cathode surface and promoting the continued progress of subsequent adsorption reactions. Furthermore, the synergistic catalytic effect of the catalyst and the biofilm further accelerates the reduction reaction of oxygen on the cathode surface, increases the cathode potential, and promotes increased power generation.

[0078] (4) Based on (2), the fecal wastewater undergoes (3) reaction in each compartment of the reactor in sequence. Organic matter, nitrogen, phosphorus pollutants and suspended solids in the wastewater are effectively removed, and decolorization is also achieved. The wastewater is discharged into the effluent area and can be reused for toilet flushing or direct discharge.

[0079] Ultimately, the treated wastewater exhibited 90% removal of turbidity, 90% removal of phosphorus, and 85% removal of COD.

[0080] Example 3

[0081] like Figures 1 to 4 As shown in Embodiment 3, a wastewater treatment device based on a self-filtering biological cathode aluminum-air battery is provided, comprising: a cavity 1, a self-filtering biological cathode aluminum-air battery system 2, and an energy storage system 3. The cavity 1 has a rectangular structure and consists of an inlet zone 4, a reaction zone 5, and an outlet zone 6 from front to back. The reaction zone shown is divided into 7 small compartments by an internal partition 7.

[0082] In this embodiment, the height difference between two adjacent compartments is 20cm. Temporary drain outlets are provided at the bottom of each compartment and at the bottom of the water inlet and reaction zones. The self-filtering biocathode aluminum-air battery system 2, from the outside in, is a sandwich-structured battery assembly consisting of a first plastic clamp 9, a first aluminum foil anode 10, a first separating material 11, an activated carbon fiber felt biocathode 8, a second separating material 14, a second aluminum foil anode 13, and a second plastic clamp 12. The anode and cathode are connected by wires and an energy storage device to collect the generated electrical energy. The area of ​​the separating material is the same as the apparent area of ​​the aluminum foil anode, and the apparent area of ​​the activated carbon fiber felt biocathode is four times the area of ​​the aluminum foil anode.

[0083] The activated carbon fiber felt biocathode consists of an activated carbon fiber felt matrix, a catalyst supported on the activated carbon fiber felt matrix, and a microbial membrane that has been domesticated and grown under natural conditions through interaction between the activated carbon fiber felt matrix and urine. The catalyst layer supported on the activated carbon fiber felt biocathode is Pt.

[0084] The self-filtering biocathode aluminum-air battery system is arranged in an inverted U-shape on both sides of each compartment in the reaction zone. One end of the activated carbon fiber felt biocathode is placed at the bottom of the previous compartment along its length, while the other end is suspended above this compartment. A certain height difference is maintained on both sides of the activated carbon fiber felt biocathode to ensure that urine can achieve autonomous filtration and flow under the combined action of capillary action and gravity.

[0085] In this embodiment, the surface area of ​​the activated carbon fiber felt used is 2000 m². 2 / g, thickness 2cm, size 50cm×10cm. The aluminum foil anode is commonly used kitchen aluminum foil, aluminum purity 97%, thickness 0.3mm, size 10cm×10cm. The separator material is absorbent cotton cloth, thickness 0.05mm, size 10cm×10cm.

[0086] In this embodiment, the method for treating urine wastewater from high-speed trains using the aforementioned wastewater treatment device based on a self-filtering biological cathode aluminum-air battery is illustrated as an example, including:

[0087] (1) In-situ sedimentation and self-filtration of fecal wastewater: Fecal wastewater generated by the toilet is discharged into the inlet area. Under the action of gravity, the suspended solids in the fecal wastewater settle naturally at the bottom of the inlet area. The bottom drain is opened periodically to remove the above-mentioned sediments. In the self-filtration biocathode aluminum-air battery, one end of the activated carbon fiber felt biocathode is immersed at the bottom of the inlet area, and the other end is placed at the top of the first compartment of the reaction zone. Under the action of gravity and capillary action, the activated carbon fiber felt only allows dissolved pollutants and water molecules in the fecal wastewater to be lifted through its interior and flow into the first-stage compartment. During the autonomous flow process, the dissolved organic matter in the fecal wastewater is fully adsorbed by the activated carbon fiber felt, achieving the purpose of autonomous filtration. Secondly, the suspended particulate matter in the fecal wastewater cannot diffuse inside the activated carbon cathode by capillary action, so it is trapped in the inlet area, realizing in-situ sedimentation, in-situ filtration and autonomous flow of high turbidity wastewater and high suspended solids wastewater. Moreover, this process does not require additional power consumption such as water pumps.

[0088] (2) Gradient autonomous filtration and flow of fecal wastewater: The treated fecal wastewater will undergo step (1) in sequence in each compartment of the reaction zone. Under the action of the self-filtration biocathode aluminum air battery system, it will be autonomously filtered and flowed into the next compartment step by step, and finally flow into the effluent zone. After multiple gradient treatments, the organic matter, turbidity and suspended particulate matter in the wastewater will be gradually adsorbed and filtered out.

[0089] (3) The simultaneous power generation and water purification functions of the self-filtering biocathode aluminum air battery system:

[0090] Electricity generation: As the fecal wastewater flows through the activated carbon fiber felt biocathode, the high pH value of the wastewater causes a corrosion discharge reaction at the aluminum foil anode, generating electrons. These electrons are then received by the activated carbon biocathode through an external circuit, generating electrical energy, which is collected in the energy storage system.

[0091] In-situ electrocoagulation for COD and phosphate removal: The released aluminum ions generate aluminum hydroxide flocculants that are distributed around the separator material to flocculate organic pollutants in urine in situ; at the same time, the aluminum ions react with phosphates in the urine to produce aluminum phosphate precipitates, which are deposited on the separator material to form an aluminum phosphate flame retardant layer.

[0092] Inhibits urine hydrolysis and ammonia volatilization: The release of large amounts of aluminum ions causes a decrease in urine pH, which can inhibit urine hydrolysis and prevent the production of odors such as ammonia.

[0093] Biocathode-assisted organic matter degradation: With continuous operation, a biofilm gradually grows on the surface of the activated carbon fiber felt cathode, which is exposed to air for extended periods. Due to the limited mass transfer of oxygen within the activated carbon fiber felt, aerobic-anoxic-anaerobic zones gradually form from the outside in, naturally leading to the growth of aerobic, anoxic, and anaerobic biofilms. This microbial ecosystem produces substances that can degrade the organic matter adsorbed on the activated carbon fiber felt, achieving in-situ nitrification and denitrification. Under the dual action of the catalyst and the biofilm, the organic matter and organic nitrogen adsorbed on the cathode surface are decomposed into CO2 and N2, achieving in-situ regeneration of the cathode surface and promoting the continued progress of subsequent adsorption reactions. Furthermore, the synergistic catalytic effect of the catalyst and the biofilm further accelerates the reduction reaction of oxygen on the cathode surface, increases the cathode potential, and promotes increased power generation.

[0094] (4) Based on (2), the fecal wastewater undergoes (3) reaction in each compartment of the reactor in sequence. Organic matter, nitrogen, phosphorus pollutants and suspended solids in the wastewater are effectively removed, and decolorization is also achieved. The wastewater is discharged into the effluent area and can be reused for toilet flushing or direct discharge.

[0095] Ultimately, the treated fecal wastewater exhibited 93% turbidity removal, 95% phosphorus removal, and 90% COD removal.

[0096] In summary, the urine treatment device and method based on a self-filtering biocathode aluminum-air battery described in this embodiment of the invention have the following beneficial effects:

[0097] (1) The activated carbon fiber felt biocathode integrates numerous characteristics such as adsorption, water absorption, self-filtration, microflow, high-efficiency oxygen reduction reaction, and biodegradation. Compared to the self-filtration system in patent CN113060799B, where the water flow rate mainly relies on hydrophilic separating materials, this device innovatively utilizes the activated carbon fiber felt cathode simultaneously as a water-absorbing material, electrode material, filter material, and the load substrate for the biofilm treatment system. This design fully leverages the dual characteristics of the activated carbon fiber felt air cathode and biocathode, improving the battery cathode potential and exhibiting excellent power generation performance.

[0098] (2) In patent CN113060799B, increasing the water flow rate requires increasing the thickness of the separator material, which increases the battery's internal resistance. Furthermore, the increased water flow rate necessitates a thicker separator material, making this design unfavorable for battery scaling. This device, however, is more conducive to scaling because it changes the water-absorbing material from the separator material to an activated carbon fiber cathode, allowing the water to flow through the cathode. Therefore, the flow rate and volume can be precisely controlled by altering the pore size, thickness, and surface area of ​​the activated carbon fiber cathode. This change in the cathode does not adversely affect the anode-cathode spacing.

[0099] (3) Synergistic effect of in-situ adsorption and biodegradation of organic pollutants. In patent CN113060799B, the organic matter adsorbed by the self-filter is mainly on the separating material, which needs to be replaced once it becomes saturated. However, the self-filtering and self-absorbing activated carbon fiber felt biocathode constructed in this invention can decompose the adsorbed organic matter and organic nitrogen in situ under biological action, realizing the in-situ regeneration of the cathode and providing a more continuous driving force for subsequent organic matter adsorption.

[0100] (4) It possesses highly efficient autonomous solid-liquid separation capabilities, turbidity removal capabilities, and synchronous urine stabilization characteristics. Generally, fecal wastewater contains not only fresh urine but also a large amount of fecal solids and viscous, highly turbid substances. If a traditional membrane filtration process is used, it will inevitably cause rapid membrane fouling, leading to system collapse. Conversely, the self-filtering, self-absorbing aluminum-air battery system designed in this invention, based on the excellent pore effect, capillary action, and adsorption effect of the activated carbon fiber felt biocathode, can autonomously retain solid matter, allowing only the liquid to flow autonomously without any external energy. Simultaneously, the aluminum ions released by the aluminum-air system cause a decrease in water pH, removing phosphates while acidifying and inhibiting urine hydrolysis, preventing ammonia nitrogen production and odor emissions. These characteristics also avoid the additional operations of adding controlled chemicals such as sulfuric acid in traditional operations, enabling in-situ addition of inhibitors to the urine and further improving the system's sustainability.

[0101] (5) The plug-flow continuous flow reactor design enhances the driving force of the system reaction and ensures the quality of the effluent. By designing a terraced plug-flow hydraulic system, it can be ensured that the wastewater after each stage of treatment can react effectively, and the wastewater does not come into contact with each stage, thus ensuring the quality of the effluent. In particular, solid matter is efficiently removed through the previous stages of reaction, which provides a favorable guarantee for the efficient subsequent water purification.

[0102] (6) The water treatment method of the present invention can achieve continuous treatment and continuous power generation of fecal and urinary wastewater, while requiring no external kinetic energy to drive the wastewater flow. It can achieve autonomous wastewater flow, autonomous filtration of suspended solids and turbidity, autonomous adsorption of dissolved organic pollutants, and autonomous biodegradation on the cathode. At the same time, the aluminum-air battery uses urine as the electrolyte to continuously provide electricity, while causing the pH of the urine to decrease, inhibiting urine hydrolysis in situ, without the need to add additional inhibitors.

[0103] The urine treatment device based on a self-filtering biocathode aluminum-air battery described in this embodiment of the invention has a height difference between adjacent compartments ranging from 2cm to 20cm, with the height decreasing sequentially in the direction of water flow to ensure the water flows under gravity. However, in practical applications, the height difference between adjacent compartments is not limited to the above range, and those skilled in the art can set the height difference between two adjacent compartments according to the actual situation.

[0104] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solutions disclosed in the present invention, various modifications or variations that can be made by those skilled in the art without creative effort should be included within the scope of protection of the present invention.

Claims

1. A wastewater treatment device based on a self-filtering biological cathode aluminum-air battery, characterized in that, include: The cavity through which the sewage flows; In the direction of sewage flow, the cavity is sequentially equipped with an inlet zone, a reaction zone, and an outlet zone; The reaction zone includes compartments separated by multiple partitions; there is a height difference between two adjacent compartments and the height decreases sequentially in the direction of sewage flow to ensure the water flows by gravity. The water inlet zone and the first compartment of the reaction zone, the adjacent compartments, and the last compartment of the reaction zone and the water outlet zone are all connected by a self-filtering biocathode aluminum-air battery system. The self-filtering biocathode aluminum-air battery system comprises, in sequence, a first insulating clamp, a first aluminum foil anode, a first separating material, an activated carbon fiber felt biocathode, a second separating material, a second aluminum foil anode, and a second insulating clamp; wherein the cathode and anode are electrically connected to an energy storage device for collecting the generated electrical energy; The area of ​​the separating material is the same as the apparent area of ​​the aluminum foil anode, and the apparent area of ​​the activated carbon fiber felt biocathode is 2-5 times that of the aluminum foil anode. The activated carbon fiber felt biocathode consists of an activated carbon fiber felt matrix, a catalyst supported on the activated carbon fiber felt matrix, and a microbial membrane that grows in the interaction between the activated carbon fiber felt matrix and urine. The self-filtering biocathode aluminum-air battery system is arranged in an inverted U-shape on both sides of each partition in the reaction zone. One end of the activated carbon fiber felt biocathode is placed at the bottom of the previous compartment along its length, while the other end is suspended above the current compartment. A certain height difference is maintained on both sides of the activated carbon fiber felt biocathode to ensure that urine can achieve autonomous filtration and flow under the combined action of capillary action and gravity.

2. The wastewater treatment device based on a self-filtering biological cathode aluminum-air battery according to claim 1, characterized in that, The catalyst supported on the activated carbon fiber felt matrix is ​​a complex of one or more metal oxides of Ir, Ti, Ru, Co, Mn, Sn, Sb, Pb or Pt.

3. The wastewater treatment device based on a self-filtering biological cathode aluminum-air battery according to claim 1, characterized in that, The surface area of ​​the activated carbon fiber felt is 1000 m². 2 / g-3000m 2 / g, thickness 0.2cm-5cm.

4. The wastewater treatment device based on a self-filtering biological cathode aluminum-air battery according to claim 1, characterized in that, The aluminum foil anode is kitchen aluminum foil with an aluminum purity greater than 95% and a thickness of 0.001mm-1mm.

5. The wastewater treatment device based on a self-filtering biological cathode aluminum-air battery according to claim 1, characterized in that, Both the first and second separating materials are non-woven fabrics or paper made of pure cotton or pure polyester, with a thickness of 0.1mm-1mm.

6. A method for treating urine wastewater using the apparatus as described in any one of claims 1-5, characterized in that, include: (1) In the self-filtering biocathode aluminum-air battery, one end of the activated carbon fiber felt biocathode is immersed at the bottom of the inlet water zone, and the other end is placed at the top of the first compartment of the reaction zone. Under the action of gravity and capillary action, the activated carbon fiber felt only allows dissolved pollutants and water molecules to be lifted through its interior and flow into the first compartment. During the autonomous flow process, dissolved organic matter is fully adsorbed by the activated carbon fiber felt, achieving the purpose of autonomous filtration. Suspended particulate matter cannot diffuse inside the activated carbon cathode by relying on the capillary action of the activated carbon fiber felt and is trapped in the inlet water zone, realizing in-situ sedimentation, in-situ filtration and autonomous flow of wastewater. (2) Gradient autonomous filtration and flow of fecal wastewater: The treated fecal wastewater repeats step (1) in each compartment of the reaction zone. Under the action of the self-filtering biocathode aluminum air battery system, it is autonomously filtered step by step and flows into the next compartment, and finally flows into the effluent zone. After multiple gradient treatments, the organic matter, turbidity and suspended particulate matter in the wastewater are adsorbed and filtered out. (3) The simultaneous power generation and water purification functions of the self-filtering biocathode aluminum air battery system: Electricity generation: Fecal wastewater flows through the activated carbon fiber felt biocathode, causing a corrosion discharge reaction at the aluminum foil anode to generate electrons. These electrons are then received by the activated carbon biocathode through an external circuit to generate electrical energy, which is collected in the energy storage system. In-situ electrocoagulation for COD and phosphate removal: The released aluminum ions generate aluminum hydroxide flocculants that are distributed around the separator material to flocculate organic pollutants in urine in situ; at the same time, aluminum ions react with phosphates in urine to produce aluminum phosphate precipitates, which are deposited on the separator material to form an aluminum phosphate flame retardant layer. Inhibits urine hydrolysis and ammonia volatilization: The release of aluminum ions causes a decrease in urine pH, inhibiting urine hydrolysis and preventing the production of ammonia. Biocathode synergistic organic matter degradation: With continuous operation, a biofilm gradually grows on the surface of the activated carbon fiber felt cathode exposed to air; (4) Based on (2), the fecal wastewater undergoes (3) reaction in each compartment of the reactor in sequence. Organic matter, nitrogen, phosphorus pollutants and suspended solids in the wastewater are effectively removed, and decolorization is achieved. The wastewater is then discharged into the effluent area.

7. The method according to claim 6, characterized in that, Because oxygen mass transfer is limited within the activated carbon fiber felt, aerobic-anoxic-anaerobic regions gradually form from the outside to the inside of the activated carbon fiber felt, allowing aerobic, anoxic, and anaerobic biofilms to grow. Under the dual action of the catalyst and the biofilm, the organic matter and organic nitrogen adsorbed on the cathode surface are decomposed into CO2 and N2, achieving in-situ regeneration of the cathode surface and promoting the continuous progress of subsequent adsorption reactions. The synergistic catalytic effect of the catalyst and the biofilm increases the reduction reaction rate of oxygen on the cathode surface, enhances the cathode potential, and improves the power generation.

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