An apparatus and method for online automated detection of organic matter indicators using MEC sensors.

Abstract

This application relates to the field of wastewater treatment technology and provides an apparatus and method for online automated detection of organic matter indicators using an MEC sensor. The apparatus includes a bioelectrochemical system and a data acquisition and conversion system. The bioelectrochemical system comprises a microbial electrolysis cell and a three-electrode potentiostat. Electrogenic bacteria are placed in the anode chamber of the microbial electrolysis cell, oxidizing organic matter to generate electrons and outputting current. The data acquisition and conversion system includes a control computer, a data acquisition card, and programming software. The potentiostat is connected to the microbial electrolysis cell and the data acquisition card, collecting current signals and converting and transmitting them to the computer. The programming software calculates organic matter indicators based on the signals, and the computer displays and saves the results. This apparatus indirectly monitors organic matter through current changes, and combined with the programming software, achieves integrated monitoring and display, enabling real-time monitoring and saving time. It also offers a wide detection range and a simple structure. Furthermore, this application also provides a method for applying this apparatus.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to an apparatus and method for online automated detection of organic matter indicators using an MEC sensor. Background Technology

[0002] Persistent organic pollutants (POPs) and other recalcitrant substances degrade slowly and are highly resistant to degradation in aquatic environments, posing a potential threat to aquatic ecosystems and human health. Biochemical oxygen demand (BOD) and total organic carbon (TOC) are commonly used indicators for assessing the degree of organic pollution in water bodies, but traditional detection methods are usually cumbersome and time-consuming, making it difficult to meet the practical needs for real-time monitoring and rapid early warning of organic pollutants.

[0003] In recent years, bioelectrochemical systems have attracted attention as a novel detection technology based on electrochemical conversion processes. These systems utilize the catalytic activity of microorganisms to convert the chemical energy stored in biodegradable organic matter into measurable electrical signals. Among them, microbial fuel cells are considered a promising biosensing technology for wastewater treatment and energy recovery. Microbial electrolyzers offer higher stability and reliability compared to microbial fuel cells. The electroactive microorganisms in the anode generate current when degrading organic matter, and the magnitude of this current is related to the organic matter content in the wastewater. Therefore, microbial electrolyzers can serve as biosensors for rapidly estimating organic matter concentration. Existing technical solutions integrate bioelectrochemical systems with water sample delivery units, signal acquisition devices, and computers to form a monitoring system. This system monitors organic matter indicators in water bodies by collecting and transmitting electrical signals for analysis. Other solutions employ continuous-flow membrane-free biocathode microbial fuel cells, using both the bioanode and biocathode as detection elements for water quality monitoring. Still other solutions utilize microfluidic technology to integrate biofilm reactors and electrochemical electrodes onto a single chip to achieve sensor miniaturization and automated monitoring.

[0004] However, some existing organic matter detection schemes based on bioelectrochemical systems require incubation of biofilms, resulting in relatively long detection cycles; others have complex structures and low system integration, making it difficult to balance rapid detection with ease of operation in practical applications. Therefore, providing a rapid-response, relatively simple structure, and real-time online monitoring device and method for detecting organic matter indicators is a pressing technical problem to be solved in this field. Summary of the Invention

[0005] In view of this, this application aims to provide an apparatus and method for online automated detection of organic matter indicators using MEC sensors, in order to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows: Firstly, this application proposes a device for online automated detection of organic matter indicators using an MEC sensor, comprising: A bioelectrochemical system includes a microbial electrolytic cell and a three-electrode potentiostat. The microbial electrolytic cell includes an anode chamber and a cathode chamber. The anode chamber is used to contain electrogenic bacteria, which oxidize and decompose organic matter to generate electrons and output current. A data acquisition and conversion system is connected to the bioelectrochemical system. The data acquisition and conversion system includes a control computer, a data acquisition card connected to the control computer, and programming software installed in the control computer. The current signal input terminal of the three-electrode potentiostat is connected to the current output terminal of the microbial electrolysis cell, and the signal output terminal of the three-electrode potentiostat is connected to the signal input terminal of the data acquisition card. The three-electrode potentiostat is used to collect the current signal output by the microbial electrolysis cell and convert it into an acquireable electrical signal. The data acquisition card acquires the collectable electrical signals and transmits them to the control computer. The programming software is used to calculate the corresponding organic matter index based on the received collectable electrical signals. The control computer is used to display and save the monitoring results.

[0007] Furthermore, the microbial electrolysis cell also includes a proton exchange membrane disposed between the anode chamber and the cathode chamber, the anode chamber and the cathode chamber being separated by the proton exchange membrane, the anode chamber being inoculated with anaerobic sludge, and the electrogenic bacteria in the anode chamber generating electrons and outputting current when degrading organic matter.

[0008] Furthermore, the three-electrode potentiostat is characterized by comprising a working electrode, a counter electrode, and a reference electrode, wherein the working electrode, the counter electrode, and the reference electrode are all disposed inside the microbial electrolysis cell, the working electrode is a carbon fiber brush, the counter electrode is a platinum sheet, and the reference electrode is an Ag / AgCl electrode.

[0009] Furthermore, the surface of the carbon fiber brush is coated with a microbial film formed by electrogenic bacteria, which wraps around the carbon fiber interlaced structure of the carbon fiber brush.

[0010] Furthermore, the programming software is used to perform curve fitting between the output current and the corresponding organic matter index at different organic matter concentrations to establish a standard curve. The standard curve is stored in the control computer, and the control computer calculates the real-time organic matter index value based on the current value output by the wastewater to be tested and the standard curve.

[0011] Secondly, this application proposes a method for an apparatus used in the online automated detection of organic matter indicators using the aforementioned MEC sensor, comprising the following steps: S1, Construct an electrochemical working system with a three-electrode configuration including a working electrode, a counter electrode, and a reference electrode, wherein the working electrode, the counter electrode, and the reference electrode are all disposed inside a microbial electrolysis cell; S2, anaerobic sludge is added to the microbial electrolysis cell for inoculation, so that electrogenic bacteria attach to the surface of the working electrode; S3, acclimatize the anaerobic sludge in the microbial electrolysis cell to enrich the electrogenic bacteria and adapt them to the organic matter degradation environment; S4, a potential difference is applied between the working electrode and the reference electrode by a potentiostat, so that the positive extracellular electron transfer of electrogenic bacteria maintains energy metabolism and generates current. S5, keep the potentiostat connected to the control computer, record the current signal output by the microbial electrolysis cell in real time through the data acquisition card and transmit it to the control computer for storage; S6, replace the base solution and test the output current of wastewater with different known organic matter concentrations in the microbial electrolysis cell; S7, Perform curve fitting on the different known organic matter concentrations and their corresponding output currents to establish a standard curve between the organic matter index and the output current, and save the standard curve to the control computer; S8, the wastewater to be tested is introduced, and the control computer calculates and displays the corresponding real-time organic matter index value based on the real-time collected output current value and the standard curve.

[0012] Furthermore, in step S3, the domestication involves controlling the temperature at 30°C and the pH at 7-7.2 under anaerobic conditions, so that electrogenic bacteria accumulate on the surface of the working electrode to form a stable electroactive biofilm.

[0013] Furthermore, in step S4, the potential difference is -0.2V, so that the working electrode is in a constant potential state suitable for the extracellular electron transfer of electrogenic bacteria.

[0014] Furthermore, in step S6, the base solution is a mixed solution containing sodium acetate and dipotassium hydrogen phosphate, and different concentrations of sodium acetate solution are prepared to simulate wastewater with different organic matter concentrations.

[0015] Furthermore, in step S7, the organic matter index is the BOD value, the standard curve is the fitting curve between the BOD value and the output current, and after the control computer collects the output current value of the wastewater to be tested, it automatically calculates the corresponding BOD value based on the fitting curve between the BOD value and the output current and displays it on the display interface of the control computer.

[0016] Compared with existing technologies, the device and method for online automated detection of organic matter indicators using MEC sensors proposed in this application have the following advantages: (1) This application utilizes a bioelectrochemical system and a data acquisition and conversion system to generate current by oxidizing and decomposing organic matter in a microbial electrolysis cell. The signal is collected by a potentiostat and transmitted to a data acquisition card and a control computer. The corresponding organic matter index is calculated by programming software, thus realizing real-time acquisition and processing of the current signal. This device does not require incubation of biofilm, has a simple overall structure, and is easy to build, thereby effectively shortening the detection time. It can meet the needs of real-time online monitoring of organic matter indexes in wastewater and is suitable for various wastewater discharge scenarios.

[0017] (2) This application separates the anode and cathode chambers by setting a proton exchange membrane between them, thus isolating the anode-related microbial community from external environmental disturbances and effectively mitigating the negative impact of complex pollutants such as high concentrations of antibiotics on the activity of microorganisms in the reactor. Simultaneously, by using a carbon fiber brush as the working electrode, the microbial film formed by electrogenic bacteria attached to its surface, wrapped around the interwoven structure of the carbon fiber, provides ample attachment sites to enrich electroactive bacteria, ensuring the stable generation and transfer of electrons. Therefore, this application can maintain high detection stability even under complex water quality conditions, enhancing the sensor's resistance to water quality fluctuations.

[0018] (3) This application establishes a standard curve by performing curve fitting between the output current and the corresponding organic index at different organic concentrations in the programming software, and saves the standard curve in the control computer. This enables the control computer to automatically calculate and display the corresponding real-time organic index value based on the real-time collected output current value and the standard curve after the wastewater to be tested is introduced. This further simplifies the operation process and realizes full-process automated monitoring from signal acquisition, data processing to result output, ensuring the stability and reliability of the detection results. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the device for online automated detection of organic matter indicators using a MEC sensor, as described in an embodiment of this application. Figure 2 This is a schematic diagram of the carbon fiber brush described in an embodiment of this application; Figure 3 The graph shows the current data obtained by monitoring a 1 g / L sodium acetate solution (simulated wastewater) using the MEC sensor online automated detection device for organic matter indicators described in the embodiments of this application. Figure 4 The graph shows a comparison between the BOD results obtained by the MEC sensor online automated detection device for organic matter indicators described in this application and the results obtained by the conventional method when monitoring a 1 g / L sodium acetate solution (simulated wastewater) for 5 minutes; Figure 5 This is a schematic diagram of the structure of the proton exchange membrane described in the embodiments of this application; Figure 6 The image shows time-current fitting curves of the device for online automated detection of organic matter indicators using the MEC sensor described in the embodiments of this application at different TOC concentrations under antibiotic load.

[0020] Explanation of reference numerals in the attached figures: 1. Potentiostat; 2. Control computer; 3. Carbon fiber brush; 4. Microbial membrane; 5. Reference electrode; 6. Counter electrode; 7. Proton exchange membrane. Detailed Implementation

[0021] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0023] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0025] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0026] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0027] This application belongs to the field of wastewater treatment technology, specifically relating to an online automated detection system, and more particularly to an online automated detection device and method for organic matter indicators based on MEC sensors.

[0028] Against the backdrop of global focus on environmental protection, organic pollution has become a focal point of environmental governance. Persistent organic pollutants, such as antibiotics and polychlorinated biphenyls (PCBs), degrade slowly and are highly resistant to degradation, easily accumulating in the environment and threatening ecological security and human health. Traditional water quality testing methods, such as biochemical oxygen demand (BOD) and total organic carbon (TOC) testing, generally suffer from cumbersome procedures, long testing cycles, low operating efficiency, and high testing costs, making it difficult to meet the needs of real-time monitoring and precise treatment of organic pollutants.

[0029] Bioelectrochemical systems are a class of water quality detection technologies based on electrochemical conversion processes. They utilize the catalytic activity of microorganisms to convert the chemical energy stored in biodegradable organic matter into an electric current, reflecting the organic matter content in the water through the current response. In previous research, microbial fuel cells were considered a biotechnology with potential for both wastewater treatment and energy recovery. Their unique operating principle holds promise for achieving real-time and accurate detection of organic pollutants, providing technical support for environmental protection. Compared to microbial fuel cells, microbial electrolyzers offer higher operational stability and detection reliability. The electroactive microorganisms in their anode region can directly degrade organic matter, and there is a clear correlation between the current generated and the organic matter content in the wastewater. Therefore, microbial electrolyzers can serve as biosensors for rapidly estimating organic matter concentration. By combining biosensor elements composed of bacterial biofilms with electrochemical detection structures, rapid responses to organic matter concentrations can be achieved.

[0030] Among water quality assessment parameters, the ratio of five-day biochemical oxygen demand (BOD5) to chemical oxygen demand (COD5) can provide a preliminary assessment of wastewater's biodegradability. A higher ratio indicates stronger biodegradability, while a lower ratio indicates greater resistance to degradation of organic pollutants. Utilizing the electron-generating properties of bioelectrochemical technology during the degradation of organic pollutants allows for rapid detection and assessment of wastewater's resistance to degradation, which is of great significance for water environment protection and human health safeguards.

[0031] In microbial electrolysis cell systems, the performance of the anode material directly determines the microbial adhesion effect and electron transfer efficiency, which are core factors affecting the online monitoring effect of complex organic matter. Existing research has introduced a carbon nanotube sponge structure into the anode material. This material possesses excellent biocompatibility and a highly porous structure. The interlaced carbon fiber structure provides ample microbial attachment sites, effectively enriching electroactive bacteria and ensuring stable electron generation and efficient transfer. Simultaneously, the material's excellent conductivity and microbial adhesion can weaken the interference of other bacteria on the detection process, enhance the efficiency of the anodic oxidation reaction, improve the electrolytic cell's power generation performance and pollutant degradation efficiency, and shorten the detection response time. To further improve the adaptability of biosensors to complex organic wastewater environments and optimize the internal microenvironment of the reactor, existing research has also designed a dual-chamber microbial electrolysis cell device. Through structural optimization, the interference of impurities and side reactions on the detection process is reduced, the metabolic processes of functional bacteria and electron transfer efficiency are stabilized, and the sensor's detection stability and anti-interference ability under complex water quality conditions are improved.

[0032] Existing technologies for detecting organic matter in water, whether employing microfluidic electrochemical sensor chips or detection methods involving adjusted electrode potentials, generally suffer from drawbacks such as complex device structures and long detection times, making them unsuitable for applications requiring rapid, real-time on-site detection. Therefore, developing a real-time organic matter detection solution with rapid response capabilities is an important research direction in the field of aquatic environmental chemical analysis. To address the problems of complex structures, long detection cycles, and difficulty in achieving stable online monitoring in existing organic matter detection technologies, this application provides a device and method for online automated detection of organic matter indicators using a MEC sensor. The technical solution is described in detail below through two embodiments.

[0033] Example 1 This embodiment provides a device for online automated detection of organic matter indicators using an MEC sensor. The device comprises two main parts: a bioelectrochemical system and a data acquisition and conversion system. (Refer to...) Figure 1 The bioelectrochemical system and the data acquisition and conversion system are connected in sequence to form a complete online detection loop.

[0034] The bioelectrochemical system includes a microbial electrolytic cell and a three-electrode potentiostat 1. The microbial electrolytic cell, as the core carrier of the bioreaction, includes an anode chamber and a cathode chamber. The anode chamber houses electrogenic bacteria, which oxidize and decompose organic matter during metabolism, generating electrons and outputting current. The current signal input terminal of the three-electrode potentiostat 1 is connected to the current output terminal of the microbial electrolytic cell, and its signal output terminal is connected to the signal input terminal of a data acquisition card. The three-electrode potentiostat 1 collects the weak current signal output from the microbial electrolytic cell and converts it into a standard, collectable electrical signal, while simultaneously maintaining the potential stability of the working electrodes.

[0035] The data acquisition and conversion system is connected to the bioelectrochemical system. The data acquisition and conversion system includes a data acquisition card connected to the control computer 2, and programming software installed in the control computer 2. The data acquisition card acquires the collectable electrical signals output by the potentiostat and transmits them to the control computer 2. The programming software is used to calculate the corresponding organic matter index values ​​based on the received electrical signals. The control computer 2 is used to display and store all data and results during the monitoring process in real time.

[0036] Based on the invention's objective of enhancing the anti-interference capability of the device under complex water quality conditions, in this embodiment, the microbial electrolysis cell is further equipped with a proton exchange membrane 7. (Refer to...) Figure 5 A proton exchange membrane 7 is positioned between the anode and cathode chambers, providing fluid separation and proton conduction between them. The anode chamber is inoculated with anaerobic sludge as a source of electrogenic bacteria. These bacteria generate electrons during the degradation of organic matter, which are then transferred to the cathode via an external circuit. Protons migrate through the proton exchange membrane 7 to the cathode chamber to achieve charge balance. The proton exchange membrane 7 possesses high proton conductivity, accelerating the proton transfer kinetics. Simultaneously, it isolates the anode microbial community from the cathode chamber and external environmental disturbances, enabling the bioelectrochemical system to maintain detection sensitivity and achieve rapid response even in complex water quality environments with high antibiotic levels.

[0037] To achieve stable electrochemical potential control and signal acquisition, the three-electrode potentiostat 1 in this embodiment is configured as a three-electrode system including a working electrode, a counter electrode 6, and a reference electrode 5. Both the working electrode, counter electrode 6, and reference electrode 5 are located inside the microbial electrolysis cell. The working electrode is a carbon fiber brush 3, the counter electrode 6 is a platinum sheet, and the reference electrode 5 is an Ag / AgCl electrode. (Refer to...) Figure 2A carbon fiber brush 3 is vertically arranged in the central area of ​​the electrolytic cell, with a reference electrode 5 and a counter electrode 6 symmetrically arranged on either side of the carbon fiber brush 3. Together, they form a stable three-electrode detection circuit. The diameter of the carbon fiber brush 3 is set to 3 cm, and the counter electrode 6 is a 10×10 mm platinum sheet. This size provides sufficient reaction area within the limited volume of the electrolytic cell, while ensuring uniform flow of electrolyte between the electrodes. The carbon fiber brush 3 is made of a carbon nanotube sponge matrix, possessing good biocompatibility and a highly porous structure. The interlaced carbon fiber structure provides ample microbial attachment sites, effectively enriching electroactive bacteria, ensuring stable electron generation and efficient transfer. Its excellent conductivity also weakens interference from other bacteria, enhances the efficiency of the anodic oxidation reaction, and improves the detection response speed. The platinum sheet, as the counter electrode 6, possesses stable electrochemical inertness and can withstand cathodic reduction reactions for a long time without corrosion, ensuring the long-term stability of the detection circuit. The Ag / AgCl reference electrode 5 has low potential drift and high stability, providing a precise potential reference for the working electrode and ensuring the accuracy of constant potential control.

[0038] Based on the inventive objective of enhancing microbial adhesion and electrostatic stability, in this embodiment, the surface of the carbon fiber brush 3 is coated with a microbial film 4 formed by electrostatic bacteria. (Refer to...) Figure 2 The microbial membrane 4 is uniformly wrapped around the interwoven carbon fiber structure of the carbon fiber brush 3, forming a continuous electroactive biological layer. The interwoven porous structure of the carbon fibers provides a three-dimensional attachment space for microorganisms, which is conducive to the enrichment of electrogenic bacteria and the stable growth of the biofilm. The mature microbial membrane 4 can directly contact organic matter and undergo oxidation reaction, converting the chemical energy in the organic matter into electrical energy output, providing a signal basis for the quantitative detection of organic matter concentration.

[0039] To achieve automatic conversion of current signals to organic matter indicators, the programming software in this embodiment is configured with curve fitting and real-time calculation functions. The software can perform curve fitting between the output current and corresponding organic matter indicators at different organic matter concentrations, establish a standard curve, and save the standard curve parameters in the control computer 2. During actual detection, the control computer 2 automatically calculates the corresponding real-time organic matter indicator value based on the real-time current value output by the wastewater under test, calling the pre-stored standard curve. The programming software adopts a data flow architecture, supports parallel processing mode, and can simultaneously connect to multiple detection channels to achieve multi-parameter synchronous monitoring. The software provides a graphical user interface, supports custom calculation formulas to complete data conversion, and adapts to the usage requirements of different detection scenarios. Taking biochemical oxygen demand (BOD) detection as an example, the fitted curve expression obtained through gradient concentration experiments is: current equals 0.0001 multiplied by the BOD concentration plus 0.0638, with a fitting correlation coefficient of 0.9738. The corresponding BOD calculation method is: BOD equals the difference between the current and 0.0638 divided by 0.0001, with the concentration unit being mg / L. This standard curve has a high degree of fit, which can ensure the accuracy of quantitative detection.

[0040] The device provided in this embodiment combines a microbial electrolysis cell with a three-electrode constant potential system and an automated data acquisition and computing unit. It eliminates the need for separate biofilm preparation through in-situ cultivation, directly forming a functional biofilm and achieving integrated detection and display. Compared to traditional biochemical oxygen demand (BOD) detection methods, it significantly shortens the detection cycle, enables real-time online monitoring of organic matter indicators, and features a simple and easy-to-build structure with a wide detection coverage, adaptable to various wastewater discharge scenarios.

[0041] Example 2 This embodiment provides a method for online automated detection of organic matter indicators using a MEC sensor, implemented using the apparatus described in Embodiment 1, and specifically includes the following steps.

[0042] The first step involved constructing a three-electrode electrochemical working system containing a working electrode (counter electrode 6) and a reference electrode (reference electrode 5). Both the working electrode (counter electrode 6) and the reference electrode 5 were housed within the microbial electrolysis cell. The microbial electrolysis cell reactor was fabricated from acrylic material, with a single-chamber structure measuring 90mm in length, 90mm in width, and 50mm in height, an inner diameter of 56mm, and an effective working volume of 118mL. The use of acrylic material ensures good corrosion resistance and structural strength, while the transparent material facilitates observation of the internal reaction state. The miniaturized reactor volume reduces the amount of water used, shortens the detection response time, and improves detection efficiency.

[0043] The second step involves inoculating the anaerobic sludge into a microbial electrolysis tank, allowing the electrogenic bacteria in the anaerobic sludge to gradually attach to the surface of the working electrode. Anaerobic sludge contains abundant facultative and strict anaerobic microbial communities, providing a sufficient source of inoculum for electrogenic bacteria. After inoculation, the microbial community can gradually colonize the electrode surface under suitable conditions, providing a foundation for subsequent biofilm formation.

[0044] The third step involves acclimating the anaerobic sludge in the microbial electrolysis tank, allowing the electrogenic bacteria to gradually accumulate and adapt to the organic matter degradation environment. The acclimation process is conducted under anaerobic conditions, with the reactor internal temperature controlled at 30°C and the system pH maintained between 7 and 7.2. This temperature and pH range was chosen because it provides the optimal metabolic environment for most common electrogenic bacteria, effectively promoting the enrichment of functional bacterial communities and the maturation of the biofilm. Gradually increasing the substrate concentration during acclimation allows for the screening of highly efficient electrogenic functional strains, improving the biofilm's electrogenic stability and organic matter degradation efficiency. After acclimation, the electrogenic bacteria accumulate on the working electrode surface, forming a stable electroactive biofilm with stable organic matter degradation and electrogenic capabilities.

[0045] To drive the extracellular electron transfer of electrogenic bacteria and maintain a stable current output, a fixed potential difference is applied between the working electrode and the reference electrode 5 using a potentiostat in this embodiment. This ensures that the positive extracellular electron transfer of the electrogenic bacteria can maintain normal energy metabolism and continuously generate current. This potential difference is set to -0.2V. Choosing this potential level effectively drives the extracellular electron transfer while avoiding excessively high potentials that could inhibit microbial activity, thus ensuring the long-term metabolic activity and current output stability of the electrogenic bacteria and keeping the working electrode in a constant potential state suitable for the metabolism of the electrogenic bacteria.

[0046] Fifth, maintain the connection between the three-electrode potentiostat 1 and the control computer 2. Record the current signal output by the microbial electrolysis cell in real time using the data acquisition card, and transmit the acquired current data to the control computer 2 for storage. The data acquisition card can achieve high-frequency signal acquisition, ensuring the continuity and accuracy of the current data, and providing a reliable data foundation for subsequent quantitative calculations.

[0047] The sixth step involves replacing the substrate solution in the reactor and testing the output current of wastewater with different known organic matter concentrations in the microbial electrolysis cell. The substrate solution is a mixed solution containing sodium acetate and dipotassium hydrogen phosphate. Different concentrations of sodium acetate solution are prepared to simulate wastewater with varying organic matter concentrations. Sodium acetate, as a readily biodegradable organic substrate, can be rapidly utilized by electrogenic bacteria to generate a stable current response. Dipotassium hydrogen phosphate provides buffering capacity to maintain pH stability during the reaction. By setting gradients in sodium acetate concentration, multiple sets of experimental data on organic matter concentrations and corresponding current values ​​can be obtained, providing data support for establishing a standard curve.

[0048] Based on the invention's objective of achieving quantitative detection of organic matter, this embodiment requires curve fitting of different known organic matter concentrations and their corresponding output currents to establish a standard curve between the organic matter index and the output current. The parameters of the standard curve are then saved to the control computer 2. The organic matter index detected by this method is the biochemical oxygen demand (BOD) value, and the standard curve is the fitted curve between the BOD value and the output current. The standard curve obtained by fitting multiple sets of experimental data exhibits high linear correlation, ensuring the accuracy of subsequent quantitative calculations. After acquiring the output current value of the wastewater to be tested, the control computer 2 can automatically calculate the corresponding BOD value based on the fitted curve between the BOD value and the output current, and display the result in real time on the display interface of the control computer 2.

[0049] Step 8: The wastewater to be tested is introduced into the microbial electrolysis cell. The control computer 2 automatically calculates and displays the corresponding real-time organic matter index value based on the real-time collected output current value and the pre-stored standard curve, thus completing the online detection process.

[0050] To verify the detection effect of this method, a 1 g / L sodium acetate solution was used as simulated wastewater for testing. During the test, the reactor temperature was controlled at 30℃, the system pH was maintained at 7.1, and a three-electrode potentiostat 1 was used to apply a potential difference of -0.2V between the working electrode and the reference electrode 5. Electrogenic bacteria oxidized and decomposed organic matter in the solution, generating electrons. The system output current was 0.12152 mA, and the corresponding biochemical oxygen demand (BOD) value was calculated to be 520 mg / L using the standard curve calculated by the programming software. (Reference) Figure 3 During the detection process, the current data remains stable over time, quickly reaching a stable response state. (Refer to...) Figure 4 The detection results at the fifth minute of the test were compared with those of traditional detection methods. Three out of four parallel sample groups showed an accuracy rate exceeding 98%, while the accuracy rate of the remaining group was slightly lower but still above 91%. The effective monitoring range of this online detection system is 0-800 mg / L, with an overall detection accuracy exceeding 90%, demonstrating stable and reliable monitoring performance.

[0051] For complex wastewater scenarios containing high concentrations of antibiotics, a dual-chamber microbial electrolysis cell equipped with a proton exchange membrane 7 can be used for detection. During the test, synthetic wastewater containing sodium acetate, ammonium sulfate, sodium dihydrogen phosphate, sodium chloride, potassium chloride, magnesium sulfate, and calcium chloride is introduced into the anode chamber of the reactor. The pH value in the anode chamber is controlled to be maintained between 6.98 and 7.02. An acetate buffer solution is added to the cathode chamber to maintain pH stability. A high concentration of tetracycline is added to the reactor to simulate antibiotic-contaminated wastewater. A three-electrode potentiostat 1 applies a potential difference of -0.2V between the working electrode and the reference electrode 5, and the correlation between the current value and the total organic carbon concentration is recorded over 1 to 20 minutes under antibiotic loading conditions. (Reference) Figure 6 During the detection process, the correlation coefficient between the current value and the total organic carbon concentration in the dual-chamber microbial electrolysis cell remained above 0.9171 from the first minute to the 20th minute, demonstrating good detection stability. This result indicates that the proton exchange membrane 7 can effectively mitigate the negative impact of antibiotic load on reactor function, enabling the device to maintain stable response performance even in complex water quality environments, thus expanding the device's applicable scenarios.

[0052] The detection method provided in this embodiment can achieve rapid online detection of organic matter indicators by inoculating and acclimatizing to form a functional biofilm in situ, combined with constant potential control and automated data acquisition and calculation. This significantly shortens the detection cycle and has high detection accuracy and stability, making it suitable for detection needs in various water quality scenarios.

[0053] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A device for online automated detection of organic matter indicators using an MEC sensor, characterized in that, include: A bioelectrochemical system includes a microbial electrolytic cell and a three-electrode potentiostat (1). The microbial electrolytic cell includes an anode chamber and a cathode chamber. The anode chamber is used to contain electrogenic bacteria, which oxidize and decompose organic matter to generate electrons and output current. A data acquisition and conversion system is connected to the bioelectrochemical system. The data acquisition and conversion system includes a control computer (2), a data acquisition card connected to the control computer (2), and programming software installed in the control computer (2). The current signal input terminal of the three-electrode potentiostat (1) is connected to the current output terminal of the microbial electrolysis cell, and the signal output terminal of the three-electrode potentiostat (1) is connected to the signal input terminal of the data acquisition card. The three-electrode potentiostat (1) is used to collect the current signal output by the microbial electrolysis cell and convert it into an acquireable electrical signal. The data acquisition card acquires the collectable electrical signals and transmits them to the control computer (2). The programming software is used to calculate the corresponding organic matter index based on the received collectable electrical signals. The control computer (2) is used to display and save the monitoring results.

2. The device for online automated detection of organic matter indicators using an MEC sensor according to claim 1, characterized in that, The microbial electrolysis cell also includes a proton exchange membrane (7) disposed between the anode chamber and the cathode chamber, the anode chamber and the cathode chamber being separated by the proton exchange membrane (7), the anode chamber being inoculated with anaerobic sludge, and the electrogenic bacteria in the anode chamber generating electrons and outputting current when degrading organic matter.

3. The device for online automated detection of organic matter indicators using an MEC sensor according to claim 1, characterized in that, The three-electrode potentiostat (1) includes a working electrode, a counter electrode (6) and a reference electrode (5). The working electrode, the counter electrode (6) and the reference electrode (5) are all located inside the microbial electrolysis cell. The working electrode is a carbon fiber brush (3), the counter electrode (6) is a platinum sheet, and the reference electrode (5) is an Ag / AgCl electrode.

4. The device for online automated detection of organic matter indicators using a MEC sensor according to claim 3, characterized in that, The surface of the carbon fiber brush (3) is covered with a microbial film (4) formed by electrogenic bacteria, and the microbial film (4) wraps around the carbon fiber interlaced structure of the carbon fiber brush (3).

5. The device for online automated detection of organic matter indicators using an MEC sensor according to claim 1, characterized in that, The programming software is used to perform curve fitting between the output current and the corresponding organic index under different organic concentrations to establish a standard curve. The standard curve is stored in the control computer (2). The control computer (2) calculates the real-time organic index value based on the current value output by the wastewater to be tested and the standard curve.

6. A method for online automated detection of organic matter indicators using an MEC sensor, characterized in that, The apparatus used as described in any one of claims 1 to 5 comprises the following steps: S1, construct an electrochemical working system with a three-electrode configuration including a working electrode, a counter electrode (6) and a reference electrode (5), wherein the working electrode, the counter electrode (6) and the reference electrode (5) are all disposed inside a microbial electrolysis cell; S2, anaerobic sludge is added to the microbial electrolysis cell for inoculation, so that electrogenic bacteria attach to the surface of the working electrode; S3, acclimatize the anaerobic sludge in the microbial electrolysis cell to enrich the electrogenic bacteria and adapt them to the organic matter degradation environment; S4, by applying a potential difference between the working electrode and the reference electrode (5) through a potentiostat (1), the positive extracellular electron transfer of electrogenic bacteria is used to maintain energy metabolism and generate current. S5, keep the potentiostat (1) connected to the control computer (2), record the current signal output by the microbial electrolysis cell in real time through the data acquisition card and transmit it to the control computer (2) for storage; S6, replace the base solution and test the output current of wastewater with different known organic matter concentrations in the microbial electrolysis cell; S7, perform curve fitting on the different known organic concentrations and their corresponding output currents, establish a standard curve between the organic index and the output current, and save the standard curve to the control computer (2). S8, the wastewater to be tested is introduced, and the control computer (2) calculates and displays the corresponding real-time organic matter index value based on the real-time collected output current value and the standard curve.

7. The method for online automated detection of organic matter indicators using a MEC sensor according to claim 6, characterized in that, In step S3, the acclimatization involves controlling the temperature at 30°C and the pH at 7-7.2 under anaerobic conditions, so that electrogenic bacteria accumulate on the surface of the working electrode to form a stable electroactive biofilm.

8. The method for online automated detection of organic matter indicators using a MEC sensor according to claim 6, characterized in that, In step S4, the potential difference is -0.2V, so that the working electrode is in a constant potential state suitable for the extracellular electron transfer of electrogenic bacteria.

9. The method for online automated detection of organic matter indicators using a MEC sensor according to claim 6, characterized in that, In step S6, the base solution is a mixed solution containing sodium acetate and dipotassium hydrogen phosphate. Different concentrations of sodium acetate solution are prepared to simulate wastewater with different organic matter concentrations.

10. The method for online automated detection of organic matter indicators using a MEC sensor according to claim 6, characterized in that, In step S7, the organic matter index is the BOD value, the standard curve is the fitting curve between the BOD value and the output current, and after the control computer (2) collects the output current value of the wastewater to be tested, it automatically calculates the corresponding BOD value according to the fitting curve between the BOD value and the output current and displays it on the display interface of the control computer (2).

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