Wastewater treatment system coupled with multiple electrochemical treatment devices

Abstract

The utility model discloses a wastewater treatment system with coupled multiple electrochemical treatment devices. The wastewater treatment system comprises an electrolytic tank and an MFC-MEC coupling unit, the electrolytic tank comprises an electrolytic anode and an electrolytic cathode, and the electrolytic anode is connected with the electrolytic cathode through an external power supply; the MFC-MEC coupling unit comprises an MFC cathode chamber, a common anode chamber and an MEC cathode chamber which are sequentially arranged and mutually separated by proton exchange membranes; and an MFC cathode is arranged in the MFC cathode chamber. A common anode is arranged in the common anode chamber, and electroactive microorganisms are cultivated in the common anode chamber; an MEC cathode is arranged in the MEC cathode chamber, and a first liquid inlet and a first liquid outlet are formed in the MEC cathode chamber. The cathode of the MFC is electrically connected with the electrolytic anode, the cathode of the MEC is electrically connected with the electrolytic cathode and the common anode, and a resistor is connected in series between the cathode of the MEC and the electrolytic cathode. According to the utility model, the electric energy generated by the MFC is utilized in situ, and meanwhile, heavy metal ions in wastewater can be recovered and treated, so that the problem of heavy metal pollution is effectively solved, and the pollutant removal efficiency is relatively high.

Description

Technical Field

[0001] This utility model relates to the field of electrochemical technology, and in particular to a wastewater treatment system with multiple electrochemical treatment devices coupled together. Background Technology

[0002] In industrial production processes such as mining, metallurgy, machinery manufacturing, chemicals, and electronics, wastewater containing heavy metals such as cadmium, nickel, mercury, and zinc is frequently generated. Direct discharge of this heavy metal-containing wastewater can cause serious environmental pollution. Therefore, before discharge, methods such as chemical precipitation, electrolysis, ion exchange, membrane separation, and adsorption are typically used to separate and remove heavy metals. In the removal of heavy metals, microbial fuel cells and microbial electrolyzers have shown significant potential and effectiveness.

[0003] Microbial full cell (MFC) is a device that uses microorganisms as catalysts to convert organic matter into electrical energy. In an MFC, microorganisms catalyze the oxidation of organic matter under anaerobic conditions, producing carbon dioxide, electrons, and protons. Electrons are transferred to the cathode through an external circuit, where they combine with protons and oxygen to form water, simultaneously generating electrical energy. Because domestic sewage and industrial wastewater contain abundant organic waste that can serve as a raw material source, MFCs are widely used in wastewater treatment.

[0004] A microbial electrolysis cell (MEC) is a device that adds an external voltage to an MFC (microferrochemical fuel cell), transforming the cathode reaction into an electron-proton reaction to produce hydrogen or other reduction products. MECs offer greater flexibility in energy recovery; electrons at the cathode can combine with heavy metal ions in wastewater to form elemental metals or other low-toxicity substances, making them particularly suitable for recovering valuable substances such as heavy metals from wastewater.

[0005] Both MFCs and MECs can convert organic matter in wastewater into electrical energy or other bioenergy, while simultaneously treating various pollutants such as sewage and sludge, making them environmentally friendly. However, improving their pollutant removal efficiency remains one of the important research directions. Utility Model Content

[0006] The purpose of this invention is to provide a wastewater treatment system with multiple electrochemical treatment devices coupled together, which has a high pollutant removal efficiency.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0008] A wastewater treatment system with coupled multiple electrochemical treatment devices includes an electrolytic cell and an MFC-MEC coupling unit. The electrolytic cell includes an electrolytic anode and an electrolytic cathode, with the electrolytic anode connected to the electrolytic cathode via an external power source. The MFC-MEC coupling unit includes an MFC cathode chamber, a common anode chamber, and an MEC cathode chamber arranged sequentially and separated by a proton exchange membrane. An MFC cathode is disposed in the MFC cathode chamber. A common anode is disposed in the common anode chamber, and electroactive microorganisms are cultivated in the common anode chamber. An MEC cathode is disposed in the MEC cathode chamber, and a first inlet and a first outlet are provided at the MEC cathode chamber. The MFC cathode is electrically connected to the electrolytic anode, and the MEC cathode is electrically connected to the electrolytic cathode and the common anode, with a resistor connected in series between the MEC cathode and the electrolytic cathode.

[0009] Furthermore, it also includes a pretreatment unit, which includes an oxidation tank and an anaerobic tank. The oxidation tank, the anaerobic tank and the MFC cathode chamber are arranged sequentially and connected to each other. A second liquid inlet is provided at the oxidation tank and a second liquid outlet is provided at the MFC cathode chamber. Microalgae are cultivated in the MFC cathode chamber.

[0010] Furthermore, it also includes an aeration unit, which includes an aeration pipe, a blower, and an air pipe. One end of the aeration pipe is connected to the bottom of the oxidation tank, and the other end is connected to the oxygen outlet of the electrolytic cell. The blower is installed on the aeration pipe, and the air pipe is connected to the aeration pipe and is located between the electrolytic cell and the blower.

[0011] Furthermore, it also includes a methane preparation unit, which comprises a synthesis tower, a drying tower, and a separation tower; the inlet of the synthesis tower is connected to the outlet of the drying tower and the carbon dioxide outlet of the separation tower, and a liquefaction device is provided at the outlet of the synthesis tower; the inlet of the drying tower is connected to the hydrogen outlet of the electrolytic cell, and the drying tower is connected to an external hydrogen source; a first gas outlet pipe is connected to the top of the oxidation tank, and a second gas outlet pipe is connected to the top of the common anode chamber, and the first gas outlet pipe and the second gas outlet pipe are connected to the inlet of the separation tower.

[0012] Furthermore, the methane preparation unit also includes a waste gas treatment device connected to the separation tower.

[0013] Furthermore, the microalgae is Chlorella.

[0014] Furthermore, the MFC cathode chamber is equipped with a light-emitting element.

[0015] Furthermore, a metal grid is provided in the MEC cathode chamber, and the MEC electrode is disposed within the metal grid.

[0016] Furthermore, the shared anode chamber is inoculated with sludge from the clarifier of a wastewater treatment plant as electroactive microorganisms.

[0017] This utility model has the following beneficial effects:

[0018] 1. The system is equipped with an MFC-MEC coupling unit, which uses the electrical energy of the MFC to drive and couple the MEC. While utilizing the electrical energy generated by the MFC in situ, it can also recover and treat heavy metal ions in wastewater, effectively solving the problem of heavy metal pollution. The MFC and MEC share the same anode chamber and anode electrode, which not only helps to simplify the system structure, but also makes electron transfer smoother, enhances electrode reaction, helps to improve the power conversion efficiency, promotes the removal of pollutants, and improves the pollutant removal efficiency.

[0019] 2. The system is equipped with an electrolytic cell connected to an MFC-MEC coupling unit. The electrolytic cell can act as a buffer when there are fluctuations in the electrical energy generated by the MFC, ensuring the continuous operation of the system. Moreover, the gas produced by electrolysis can be used as a raw material for industrial gas synthesis or for aeration of the oxidation pond, realizing resource utilization.

[0020] 3. The system is equipped with a pretreatment unit and microalgae are cultivated in the MFC cathode chamber. Through this pretreatment unit, organic matter in wastewater can be degraded. The treated wastewater can flow into the MFC cathode chamber to cultivate microalgae and then be discharged after meeting the standards.

[0021] 4. The system is equipped with a methane preparation unit, which can use the gas generated by the electrolytic cell and the MFC-MEC coupling unit to prepare methane, realizing resource utilization. The whole system has good environmental, economic and social benefits. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of this utility model.

[0023] Figure 2 This is a schematic diagram showing the connection between the electrolytic cell, the pretreatment unit, and the MFC-MEC coupling unit of this utility model.

[0024] Key component symbols: 100, Electrolytic cell; 110, Electrolytic anode; 120, Electrolytic cathode; 200, MFC-MEC coupling unit; 210, MFC cathode chamber; 211, MFC cathode; 212, Second outlet; 220, Common anode chamber; 221, Common anode; 230, MEC cathode chamber; 231, MEC cathode; 232, First inlet; 233, First outlet; 300, Pre-treatment unit. Treatment unit; 310, oxidation tank; 311, second liquid inlet; 320, anaerobic tank; 400, aeration unit; 410, aeration pipe; 420, blower; 430, air pipe; 500, methane preparation unit; 510, synthesis tower; 520, drying tower; 530, separation tower; 540, hydrogen source; 550, first gas outlet pipe; 560, second gas outlet pipe; 570, waste gas treatment device; 580, storage device; R, resistor. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] like Figure 1 , 2 As shown, this utility model discloses a wastewater treatment system with multiple electrochemical treatment devices coupled together. The system includes an electrolytic cell 100 and an MFC-MEC coupling unit 200 that couples a microbial fuel cell (hereinafter referred to as MFC) with the microbial electrolytic cell 100 (hereinafter referred to as MEC).

[0027] The electrolytic cell 100 includes an electrolytic anode 110 and an electrolytic cathode 120, with the anode 110 connected to the cathode 120 via an external power source. The electrolytic cell 100 electrolyzes an aqueous solution, generating oxygen at the anode 110 and hydrogen at the cathode 120. Conduits, gas collection hoods, and other structures are provided at both the anode 110 and cathode 120 to collect the generated gases separately. This electrolytic cell 100 acts as a buffer when there are fluctuations in the electrical energy generated by the MFC, ensuring continuous operation of the system.

[0028] The MFC-MEC coupling unit 200 includes an MFC cathode chamber 210, a common anode chamber 220, and an MEC cathode chamber 230 arranged sequentially and separated by a proton exchange membrane. An MFC cathode 211 is disposed in the MFC cathode chamber 210; a common anode 221 is disposed in the common anode chamber 220, and electroactive microorganisms are cultivated in the common anode chamber 220; an MEC cathode 231 is disposed in the MEC cathode chamber 230, and a first inlet 232 and a first outlet 233 are provided at the MEC cathode chamber 230. The MFC cathode 211 is electrically connected to the electrolytic anode 110, and the MEC cathode 231 is electrically connected to the electrolytic cathode 120 and the common anode 221, with a resistor R connected in series between the MEC cathode 231 and the electrolytic cathode 120.

[0029] The MFC-MEC coupling unit 200 utilizes the electrical energy generated by the MFC to drive and couple the MEC. While utilizing the electrical energy generated by the MFC in situ, it can also treat industrial wastewater flowing into the MEC cathode chamber 230 from the first inlet 232, reducing heavy metal ions in the wastewater onto the MEC cathode 231, effectively solving the problem of heavy metal pollution in industrial wastewater. The treated industrial wastewater can be discharged from the system through the first outlet 233.

[0030] In the MFC-MEC coupling unit 200, the MFC and MEC share a single anode chamber and anode electrode. This not only simplifies the system structure but also facilitates smoother electron transfer, enhances electrode reactions, and improves energy conversion efficiency, thereby promoting pollutant removal and increasing overall pollutant removal efficiency. Furthermore, the shared anode chamber 220 allows for interaction between the microorganisms in the MFC and MEC, forming a more complex and diverse microbial community. This enhances the system's adaptability and treatment capacity for different pollutants, resulting in higher stability and resistance to shock loads. When faced with complex or changing wastewater compositions, the system better adapts to and maintains stable treatment performance.

[0031] The shared anode chamber 220 maintains an anaerobic environment during operation. It is inoculated with sludge from a wastewater treatment plant clarifier, which contains a large number of electroactive microorganisms. Using this sludge as an inoculum significantly shortens the start-up time of the MFC-MEC coupling unit 200. Furthermore, the microbial community in the sludge exhibits high diversity, which helps the MFC-MEC coupling unit 200 maintain stable operation under various environmental conditions. A metal grid is installed in the MEC cathode chamber 230, and the MEC electrodes are positioned within this grid to facilitate the collection of heavy metal ions.

[0032] The system also includes a pretreatment unit 300, which comprises an oxidation tank 310 and an anaerobic tank 320. The oxidation tank 310, anaerobic tank 320, and MFC cathode chamber 210 are arranged sequentially and interconnected. A second inlet 311 is provided at the oxidation tank 310, and a second outlet 212 is provided at the MFC cathode chamber 210, where microalgae are cultivated. During system operation, the domestic wastewater to be treated flows into the pretreatment unit 300 through the second inlet 311, where organic matter in the wastewater is degraded. The treated wastewater can then continue to flow into the MFC cathode chamber 210 to cultivate microalgae, and after reaching the required standards, it is discharged from the system through the second outlet 212. Preferably, the microalgae is Chlorella vulgaris, which has a strong absorption capacity for nutrients such as nitrogen and phosphorus, effectively removing these pollutants from the wastewater. The MFC cathode chamber 210 is also equipped with a light source to provide sufficient light for the growth and metabolism of the microalgae.

[0033] The system also includes an aeration unit 400, which comprises an aeration pipe 410 and a blower 420. One end of the aeration pipe 410 is connected to the bottom of the oxidation tank 310, and the other end is connected to the oxygen outlet of the electrolytic cell 100. The blower 420 is mounted on the aeration pipe 410. When the blower 420 is turned on, oxygen produced at the electrolytic anode 110 can be extracted and guided to the oxidation tank 310 for aeration to provide sufficient dissolved oxygen and achieve resource utilization. In addition, the aeration unit 400 is also equipped with an air pipe 430, which is connected to the aeration pipe 410 and located between the electrolytic cell 100 and the blower 420 to provide additional oxygen sources or to discharge excess oxygen.

[0034] The system also includes a methane preparation unit 500, which comprises a synthesis tower 510, a drying tower 520, a separation tower 530, and a waste gas treatment device 570. The inlet of the drying tower 520 is connected to the hydrogen outlet of the electrolytic cell 100 to collect hydrogen produced at the electrolytic cathode 120, and the drying tower 520 is connected to an external hydrogen source. A first vent pipe 550 is connected to the top of the oxidation tank 310, and a second vent pipe 560 is connected to the top of the common anode chamber 220. The first vent pipe 550 and the second vent pipe 560 are connected to the inlet of the separation tower 530, allowing waste gas generated by microbial metabolism to be directed to the separation tower 530 for utilization. The waste gas treatment device 570 is connected to the separation tower 530 to treat components in the waste gas other than carbon dioxide. The outlet of the drying tower 520 and the carbon dioxide outlet of the separation tower 530 are respectively connected to the inlet of the synthesis tower 510 to introduce oxygen and carbon dioxide to synthesize methane. A liquefaction device is installed at the outlet of the synthesis tower 510 to liquefy the methane. The liquefied methane enters the storage device 580. Through this methane preparation unit 500, methane can be prepared from the gas generated by the electrolytic cell 100 and the MFC-MEC coupling unit 200, realizing resource utilization.

[0035] In summary, the wastewater treatment system coupled with this multi-electrochemical treatment device has a high pollutant removal efficiency, can effectively remove heavy metal ions from industrial wastewater, degrade organic matter in domestic wastewater, and the gas generated during operation can be used for aeration and co-production of methane. The entire system has good environmental, economic and social benefits.

[0036] Although the present invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail to the present invention without departing from the spirit and scope of the present invention as defined in the appended claims are within the scope of protection of the present invention.

Claims

1. A wastewater treatment system coupled with multiple electrochemical treatment devices, characterized in that, The application relates to a MFC-MEC coupling unit and a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method.

2. The multiple electro-chemical treatment apparatus coupled wastewater treatment system of claim 1, wherein: The application also relates to a methane preparation method.

3. The multiple electro-chemical treatment apparatus coupled wastewater treatment system of claim 2, wherein: The application also relates to a methane preparation method.

4. The multiple electro-chemical treatment device coupled wastewater treatment system of claim 2 or 3, wherein: The application also relates to a methane preparation method.

5. The multiple electro-chemical treatment device coupled wastewater treatment system of claim 4, wherein: The application also relates to a methane preparation method.

6. The multiple electro-chemical treatment apparatus coupled wastewater treatment system of claim 2, wherein: The application also relates to a methane preparation method.

7. The multiple electro-chemical treatment apparatus coupled wastewater treatment system of claim 2, wherein: The application also relates to a methane preparation method.

8. The multiple electro-chemical treatment apparatus coupled wastewater treatment system of claim 1, wherein: The application also relates to a methane preparation method.

9. The multiple electro-chemical treatment apparatus coupled wastewater treatment system of claim 1, wherein: The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. The application also relates to a methane preparation method. 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