Water quality comprehensive biological toxicity on-line monitoring system

Abstract

This invention discloses an online monitoring system for comprehensive biotoxicity of water. The system uses an open-type three-electrode bioelectrolysis cell as a culture device during the monitoring phase, directly employing microbial membrane electrodes cultured in the monitored water body for sensing biotoxic substances. This enables real-time water quality monitoring and toxicity determination under electrochemical control conditions. Furthermore, the system exhibits highly sensitive responses to toxins, with extremely rapid reaction rates and fast activity recovery.

Description

Technical Field

[0001] This invention relates to the field of real-time online water quality monitoring technology, and in particular to an online monitoring system for comprehensive biotoxicity of water. Background Technology

[0002] Water resources are a fundamental condition for the stable maintenance of human survival and social activities. In modern production and daily life, water resources come into close contact with humans in the form of drinking water, domestic and industrial wastewater, landscape water, and other natural water bodies. During the utilization of water resources, chemicals entering the aquatic environment in various forms pose varying degrees of potential threats to human health. Due to the extensive contact between human production and daily life activities and water bodies, the types of chemicals entering the aquatic environment as pollutants are extremely numerous. In addition to conventional pollutants currently under national control, hundreds and thousands of new pollutants, including persistent organic pollutants, endocrine disruptors, antibiotics, and microplastics, are widely present in various aquatic environments. Many of these chemical pollutants have significant health hazards to humans, including toxicity, endocrine disruption effects, carcinogenicity, and teratogenicity.

[0003] Analyzing and detecting various toxic and hazardous pollutants in aquatic environments is essential for understanding their health hazards. However, to achieve early warning, it is necessary to develop detection technologies for in-situ, real-time online analysis of pollutants. Electrochemical sensing technology is an ideal choice to meet this requirement, and its application in the online monitoring of chemicals such as lead ions, fluoride ions, cyanide, and sulfur-containing anions has been proven. For the numerous types of organic pollutants, specifically distinguishing their concentrations one by one during online monitoring is neither feasible nor necessary; therefore, directly monitoring their potential biotoxicity is of greater practical significance. By immobilizing electroactive microorganisms on the surface of a basic electrode to form a bioelectrochemical sensor based on biological metabolic activity, and utilizing the principle that toxic and hazardous pollutants affect the physiological metabolism of microorganisms to generate identifiable sensing electrical signals, a specialized online monitoring technology system for comprehensive biotoxicity of water quality can be constructed.

[0004] This invention utilizes natural microbial communities in various water bodies, artificially cultivating and acclimatizing them in an electrochemical system to form an electroactive microbial film on the surface of a basic electrode. This results in a comprehensive bioelectrochemical water quality toxicity sensing system for monitoring events of sudden entry of toxic pollutants into the aquatic environment. The system is easy to start and operate, has low maintenance costs, responds rapidly to toxic and harmful substances in water, and exhibits stable activity. It is suitable for monitoring drinking water sources and water transmission networks, monitoring the operational status of wastewater treatment plants, monitoring water quality in aquaculture systems, and other water bodies, and has broad prospects for widespread application. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a comprehensive online monitoring system for water quality biotoxicity, which enables real-time online monitoring of toxic pollutants invading the aquatic environment.

[0006] To address the aforementioned technical problems, the first aspect of this invention proposes an online monitoring system for comprehensive biotoxicity of water, comprising:

[0007] An electrochemical control system includes a potentiostat, a host computer connected to the potentiostat, and electrode wires connected to the output terminal of the potentiostat.

[0008] An open-type three-electrode bioelectrolysis cell is connected to the electrode line and controlled by the potentiostat. The open-type three-electrode bioelectrolysis cell includes a shell with openings at both ends. A cylindrical working electrode is disposed inside the shell. The surface of the working electrode is covered with a layer of microbial film. A counter electrode and a reference electrode are respectively disposed on the side of the shell. The counter electrode and the reference electrode pass through the shell and the working electrode in sequence and enter the cavity formed by the working electrode. The working electrode is connected to the electrode line via a working electrode connecting line. The counter electrode and the reference electrode are directly connected to the electrode line.

[0009] In some embodiments, one end of the housing serves as a water inlet and the other end as a water outlet, and the water inlet is provided with a water inlet filter.

[0010] In some embodiments, the working electrode connecting wire is a titanium wire or a stainless steel wire.

[0011] In some embodiments, the working electrode is made of carbon felt, carbon fiber, graphite or stainless steel, the counter electrode is made of platinum, gold, titanium, stainless steel or graphite, and the reference electrode is made of silver / silver chloride electrode, saturated calomel electrode or mercury / mercurous sulfate electrode.

[0012] In some embodiments, an electrostatic shielding layer is provided on the outside of the electrode wire.

[0013] A second aspect of this invention provides a method for cultivating microbial membrane electrodes for use in the aforementioned online monitoring system for integrated biotoxicity of water quality, comprising the following steps:

[0014] The outlet of the open three-electrode bioelectrolysis cell is set downward and sealed, and the liquid inside the open three-electrode bioelectrolysis cell is in a mixed state.

[0015] Sufficient water samples were collected from the monitored water body, and high-concentration microbial strains were collected by centrifugation or filtration. The concentrated microbial strains were redispersed in the water sample as electrolyte and injected into the interior of the open three-electrode bioelectrolysis cell. A preset concentration of organic carbon source was added to the electrolyte.

[0016] The open three-electrode bioelectrolysis cell is connected to a potentiostat via the electrode wire. The inlet is kept open, and the operating temperature is between 25-30℃. The potentiostat continuously applies an anode potential to the open three-electrode bioelectrolysis cell, monitors and records the time curve of the current output, and replaces the electrolyte with fresh water samples according to a preset cycle to remove suspended sludge, retaining only the microbial film deposited on the surface of the working electrode. At the same time, the organic carbon source is replenished until the electrolyte output current tends to stabilize, at which point the microbial film electrode culture is considered complete.

[0017] A third aspect of this invention provides a method for detecting biological poisoning, used in the aforementioned integrated online monitoring system for water quality biological toxicity, comprising the following steps:

[0018] The open three-electrode bioelectrolysis cell is horizontally immersed and fixed in the water body to be monitored, wherein the electrode wires and their connectors to each electrode are kept dry above the water surface, the output of the potentiostat is kept within a preset range and the current dynamics are monitored, and no organic carbon source is added during the process.

[0019] The host computer outputs the monitoring current generated by the biological oxidation of organic matter in the monitored water body in real time, and dynamically determines the presence of toxic chemicals based on the time of the monitoring current.

[0020] In some embodiments, the criteria for determining whether a chemical is toxic include:

[0021] Calculate the average rate of change of the monitored current per unit time. The rate of change before the toxic chemical enters the system is defined as (t). 0-60min The average rate of change of current is denoted as ν0, and the toxic chemical enters the system after t0, t0). 0+n The average rate of change of current over the time period is denoted as ν1.

[0022] When ν1≤0.5ν0, it is determined that toxic chemicals have entered the system, and t0 is taken as the time when toxic chemicals enter the system.

[0023] The beneficial effects of this invention are as follows: by using the open three-electrode bioelectrolysis cell used in the monitoring stage as a culture device, and directly employing microbial membrane electrodes to cultivate microorganisms in the monitored water, water quality monitoring and toxicity determination can be achieved under electrochemical control conditions; furthermore, this system has an extremely fast response rate to toxins and a rapid recovery rate of activity after interaction with toxins, making it suitable for real-time water quality monitoring of drinking water sources, water supply networks, aquaculture, sewage treatment, and natural water bodies. It features rapid response to toxins, stable activity, simple operation, and low maintenance costs, and has broad prospects for promotion and application. Attached Figure Description

[0024] Figure 1This is a schematic diagram of the structure of the integrated biotoxicity online monitoring system for water quality disclosed in Embodiment 1 of the present invention;

[0025] Figure 2a This is a three-dimensional schematic diagram of the open-type three-electrode bioelectrolyte cell disclosed in Embodiment 1 of the present invention. Figure 1 ;

[0026] Figure 2b 2 is a three-dimensional schematic diagram of the open three-electrode bioelectrolysis cell disclosed in Embodiment 1 of the present invention;

[0027] Figure 2c This is a left view of the open-type three-electrode bioelectrolysis cell disclosed in Embodiment 1 of the present invention;

[0028] Figure 3 This is a schematic diagram of an open three-electrode bioelectrolysis cell used to cultivate microbial membrane electrodes, as disclosed in Embodiment 2 of the present invention;

[0029] Figure 4 A schematic diagram illustrating the relationship between current and time after adding poison in Application Example 1;

[0030] Figure 5 This is a schematic diagram showing the relationship between different concentrations of 2,4-dichlorophenol and current in Application Example 1, where carbon felt is used as the working electrode.

[0031] Figure 6 This is a schematic diagram showing the relationship between different concentrations of 2,4-dichlorophenol and current in Application Example 1, where graphite is used as the working electrode.

[0032] Figure 7 This is a schematic diagram showing the relationship between different concentrations of 2,4-dichlorophenol and current in Application Example 2, where carbon felt is used as the working electrode.

[0033] Figure 8 This is a schematic diagram showing the relationship between different concentrations of 2,4-dichlorophenol and current in Application Example 2, where graphite is used as the working electrode.

[0034] Among them: 100-Electrochemical control system, 200-Open three-electrode bioelectrolysis cell, 101-Potential constant, 102-Host computer, 103-Electrode wire, 1-Outer shell, 2-Working electrode, 3-Counter electrode, 4-Reference electrode, 5-Working electrode connection wire, 6-Inlet filter. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the content of this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to this invention are shown in the accompanying drawings, not all of them.

[0036] Example 1

[0037] This embodiment proposes an online monitoring system for comprehensive biotoxicity of water quality, such as... Figure 1 As shown, it includes:

[0038] The electrochemical control system 100 includes a potentiostat 101, a host computer 102 (such as a PC) connected to the potentiostat 101, and electrode lines 103 connected to the output terminal of the potentiostat 101. Optionally, an electrostatic shielding layer is provided on the outside of the electrode lines 103.

[0039] An open-type three-electrode bioelectrolysis cell 200 is connected to electrode wire 103 and controlled by a potentiostat 101.

[0040] The potentiostat 101 is a device that controls the potential of the working electrode 2 in the open three-electrode bioelectrolysis cell 200 with high precision and high stability through the terminal software of the host computer 102. Specifically, the potentiostat 101 is connected to the host computer 102 through a communication line and controls the open three-electrode bioelectrolysis cell 200 through the electrode line 103.

[0041] like Figure 2a , 2bAs shown in Figure 2c, the open-type three-electrode bioelectrolysis cell 200 includes a shell 1 with openings at both ends. A cylindrical working electrode 2 is disposed inside the shell 1, and the surface of the working electrode 2 is covered with a microbial film. A counter electrode 3 and a reference electrode 4 are respectively disposed on the sides of the shell 1. The counter electrode 3 and the reference electrode 4 pass sequentially through the shell 1 and the working electrode 2, entering the cavity formed by the working electrode 2. The working electrode 2 is connected to the electrode wire 103 via a working electrode connecting wire 5, and the counter electrode 3 and the reference electrode 4 are directly connected to the electrode wire 103. Optionally, the shell 1 can be made of a polytetrafluoroethylene cylinder, and the working electrode 2 can be made of conductive carbon material, such as carbon felt, carbon fiber, graphite, or stainless steel mesh, rolled into a cylindrical shape with a mesh structure to facilitate microbial film adhesion. The working electrode 2 is connected to the electrode wire 103 via a working electrode connecting wire 5 (such as titanium wire or stainless steel wire). The reference electrode 4 (such as a silver / silver chloride electrode, a saturated calomel electrode, or a mercury / mercurous sulfate electrode, filled with a mixed saturated solution of silver chloride and potassium chloride, and separated from the electrolytic cell solution by a ceramic diaphragm) passes through the outer shell 1 and is immersed in the electrolyte (the electrolyte is filled with a mixed saturated solution of silver chloride and potassium chloride, and separated from the electrolytic cell solution by a ceramic diaphragm). The counter electrode 3 (such as platinum, gold, titanium, stainless steel, or graphite) passes through the outer shell and is immersed in the electrolyte. Furthermore, one end of the outer shell 1 serves as a water inlet, and the other end as a water outlet. The water inlet is equipped with an inlet filter 6 to intercept large solid particles. This open design allows the open three-electrode bioelectrolyte 200 to continuously allow water to flow over the electrode surfaces during use in flowing water, thereby continuously monitoring the dynamic signals of water quality. The control software of potentiostat 101 controls the potential of the working electrode 2 relative to the reference electrode 4 to be constant, and records, outputs and analyzes the generated current-time data.

[0042] Example 2

[0043] This embodiment proposes a method for culturing microbial membrane electrodes for use in the online monitoring system for integrated biotoxicity of water quality described in Embodiment 1. The method involves culturing electroactive microbial membrane electrodes under electrochemical conditions, specifically under non-flow conditions. Figure 3 As shown, it includes the following steps:

[0044] Step 1: The outlet of the open three-electrode bioelectrolysis cell 200 is set downward and sealed. For example, a polytetrafluoroethylene plug is used to seal the outlet of the outer shell 1, and the liquid inside the open three-electrode bioelectrolysis cell 200 is in a mixed state.

[0045] Step 2: Collect sufficient water samples from the monitored water body (river, lake or pond, tap water network, sewage treatment structure, etc.), collect high concentration of microbial strains by centrifugation or filtration, redisperse the concentrated microbial strains in the water sample as electrolyte, inject them into the interior of the open three-electrode bioelectrolysis cell 200, and add a preset concentration of organic carbon source to the electrolyte.

[0046] Step 3: Drive the magnetic stirrer to slowly stir the electrolyte to maintain the spatial uniformity of the suspended microbial community, nutrients, and other chemical components, and to provide mild hydraulic shear to the working electrode surface to improve the mechanical strength of the cultured biofilm. Furthermore, connect the open three-electrode bioelectrolysis cell 200 to the potentiostat 101 via electrode wire 103, keeping the inlet open to facilitate the replenishment of oxygen and organic carbon sources. Operating at a temperature between 25-30°C, the potentiostat 101 continuously applies an anodic potential (0 to +0.4V relative to the reference electrode) to the electrolyte, monitoring and recording the current output time curve. Replace the electrolyte with fresh water samples at preset intervals to remove suspended sludge, retaining only the microbial film deposited on the surface of the working electrode 2, while simultaneously replenishing the organic carbon source until the electrolyte output current stabilizes, indicating that the microbial film electrode cultivation is complete.

[0047] Example 3

[0048] This embodiment proposes a method for detecting biological poisoning, used in the online monitoring system for integrated biological toxicity of water quality described in Embodiment 1, comprising the following steps:

[0049] Step 1: The open three-electrode bioelectrolysis cell 200 is horizontally immersed and fixed in the water body to be monitored. The electrode wires 103 and their connectors to each electrode are kept dry above the water surface. The inlet water is filled and can flow freely and continuously through the open three-electrode bioelectrolysis cell 200. The output of the potentiostat 101 is kept within the preset range and the current dynamics are monitored. No organic carbon source is added during the process.

[0050] Step 2: The host computer 102 outputs the monitoring current generated by the biological oxidation of organic matter in the monitored water body in real time, and determines the presence of toxic chemicals based on the time dynamics of the monitoring current.

[0051] Specifically, the criteria for determining whether a chemical is toxic include:

[0052] Step 201: Calculate the average rate of change of the monitored current per unit time. The rate of change before the toxic chemical enters the system is defined as (t...). 0-60min The average rate of change of current is denoted as ν0 (mA / min). After toxic chemicals enter the system (t0, t0), the average rate of change of current is denoted as ν0 (mA / min). 0+n The average rate of change of current over the time period is denoted as ν1 (mA / min).

[0053] Step 202: When ν1≤0.5ν0, it is determined that toxic chemicals have entered the system, and t0 is taken as the time when toxic chemicals enter the system.

[0054] Application Example 1

[0055] This application example illustrates a comprehensive online biotoxicity monitoring system for urban wastewater treatment plants:

[0056] The outer shell 1 of the open-type three-electrode bioelectrolysis cell 200 has a volume of 300 mL. The working electrode 2 is designed in two ways: one uses a conductive carbon felt measuring 205 mm in length, 60 mm in width, and 4 mm in thickness, tightly laid around the inner wall of the outer shell 1 for fixation; the other uses a graphite ring (inner diameter 57 mm, wall thickness 5 mm, height 20 mm) instead of the carbon felt as the working electrode 2. The potentiostat 101 uses a multi-channel potentiostat CHI1030C manufactured by Shanghai Chenhua Instrument Co., Ltd., which controls the potential of multiple open-type three-electrode bioelectrolysis cells 200 as 0V (relative to the reference electrode 4) via computer, recording the changes in current. During the system startup phase, a 2L sludge-water mixture sample was prepared from equal volumes of aerobic activated sludge, anaerobic digested sludge, and nitrification / denitrification sludge from various water treatment structures in a Guangzhou water treatment plant during its daily operation. This mixture was used directly to cultivate the microbial membrane electrode without centrifugation, supplemented with 50mM sodium acetate as an organic carbon source, and slowly stirred at room temperature (20-25℃) for long-term operation. This process was repeated for four weeks, with the organic carbon source supplemented weekly. Afterward, the electrolyte was replaced weekly with fresh tap water containing 50mM sodium acetate to remove excess sludge. During this phase, the organic carbon source was supplemented weekly.

[0057] The integrated online monitoring system for biological toxicity of water quality conducted toxicity response tests when the microbial membrane electrode reached maturity (output current stabilized at around 15 mA). An open three-electrode bioelectrolysis cell 200, using carbon felt as the working electrode 2, was used. 100 μM cadmium chloride, 2,4-dichlorophenol, and aniline were added to the cell, and the current changes over time were recorded. Figure 4Data shows that from the time t0 when the toxin was added, the current generated by the control electrochemical cell, which was not affected by the toxin, continued to increase at a rate of +0.035 mA / min (ν0), while the three groups of electrochemical cells with added toxins all showed a decline in current over a certain period of time. This proves that the open three-electrode bioelectrolysis cell constructed according to this scheme successfully responded to multiple types of toxins. The initial response rates ν1 for cadmium ions, 2,4-dichlorophenol, and aniline were -0.103, -0.424, and -0.003 mA / min, respectively, far below 0.5ν0. The entire poisoning reaction period lasted for more than 8 minutes, after which activity began to recover, demonstrating the tolerance of the microbial membrane electrode to poisoning by multiple different types of toxins. Based on this response speed and intensity, this system can be used in continuous water quality monitoring of various water bodies to achieve the purpose of rapid and effective early warning of toxic substances represented by the above pollutants.

[0058] The relationship between the response intensity of a microbial membrane electrode and the concentration of toxic chemicals not only reflects the sensitivity of the electrode but also helps in the immediate estimation of toxicant concentrations, which is of obvious significance for water quality management. To analyze the relationship between the current response and toxicant concentration in this system, different concentrations (1-400 μM) of 2,4-dichlorophenol were added to an electrolytic cell with carbon felt as the working electrode, and the current response curves were recorded. Figure 5 As shown, the microbial membrane electrode cultivated under the experimental conditions exhibits a significant current response to concentrations of 2,4-dichlorophenol above 10 μM (consistent with common pollutant concentrations in actual wastewater), and the response amplitude is positively correlated with the concentration of 2,4-dichlorophenol. This result demonstrates that the designed microbial membrane electrode can technically and rapidly determine the approximate concentration of a suddenly appearing toxin.

[0059] To examine the response of the designed microbial membrane electrode to lower concentrations of toxins, the design of working electrode 2 was modified by using a graphite ring working electrode 2 to improve detection sensitivity. Microbial membranes were cultured on the graphite surface until a stable current was generated. Different concentrations (0.1-80 μM) of 2,4-dichlorophenol were added to the electrolytic cell, confirming that the microbial membrane electrode responded to low concentrations (0.1-2 μM) of 2,4-dichlorophenol. Figure 6 Although the overall current response amplitude of the new microbial membrane electrode is lower than that of the aforementioned carbon felt-based microbial membrane electrode (this is related to the difference between the two electrodes and does not represent a decrease in activity), the current response intensity is still generally positively correlated with the concentration of 2,4-dichlorophenol. However, further increasing the concentration of 2,4-dichlorophenol does not produce a higher response. These results indicate that the graphite ring-based microbial membrane electrode has a higher level of sensitivity and is suitable for early warning detection specifically targeting low concentrations of toxic substances.

[0060] Application Example 2

[0061] This application example illustrates a comprehensive online monitoring system for biotoxicity in aquaculture ponds.

[0062] The design of the open three-electrode bioelectrolysis cell 200, the working electrode 2, and the culture conditions of the microbial membrane electrode are the same as in "Application Example 1". During the system startup phase, 4L of mixed fish and shrimp aquaculture water sample from an aquaculture pond in the vicinity of Guangzhou was collected by centrifugation and used as a microbial inoculum to inoculate four 300mL electrolysis cells. The microbial membrane electrode was cultured at a potential of 0V (relative to the reference electrode).

[0063] When the microbial membrane electrode reached maturity (the output current of the carbon felt electrode sensor stabilized at around 45 mA, and the output current of the graphite ring electrode stabilized at around 30 mA), the relationship between the response intensity of the microbial membrane electrode and the concentration of toxic chemicals was analyzed. 0.1-400 μM 2,4-dichlorophenol was used as a representative toxicant for testing. For bioelectrochemical sensors based on carbon felt electrodes (see...),... Figure 7 The presence of 2,4-dichlorophenol at a concentration of 20 μM was clearly detectable, and its response current was distinguishable from background current fluctuations. At higher concentrations, the amplitude of the response current was positively correlated with the concentration of 2,4-dichlorophenol. A bioelectrochemical sensor with a graphite ring electrode as its core also showed a significant response to 2,4-dichlorophenol (see...). Figure 8 Its sensitivity is higher than that of sensors based on carbon felt, and it can clearly detect 2,4-dichlorophenol at concentrations above 2 μM. At the same time, the linear relationship between the response current amplitude and the concentration of 2,4-dichlorophenol is better over a wide concentration range of 2-400 μM, thus demonstrating a superior quantitative ability for poisons.

[0064] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for detecting microbial poisoning, using a comprehensive online monitoring system for microbial toxicity of water quality, the comprehensive online monitoring system for microbial toxicity of water quality comprising an electrochemical control system, the electrochemical control system comprising a potentiostat, a host computer connected to the potentiostat, and electrode lines connected to the output terminal of the potentiostat; an open three-electrode bioelectrolysis cell connected to the electrode lines and controlled by the potentiostat, the open three-electrode bioelectrolysis cell comprising a shell open at both ends, a cylindrical working electrode disposed inside the shell, the surface of the working electrode being covered with a layer of microbial film, and a counter electrode and a reference electrode respectively disposed on the sides of the shell, wherein... The counter electrode and the reference electrode both pass sequentially through the outer shell and the working electrode, entering the cavity formed by the working electrode. The working electrode is connected to the electrode wire via a working electrode connecting wire. The counter electrode and the reference electrode are directly connected to the electrode wire. The method is characterized by including the following steps: The open three-electrode bioelectrolysis cell is horizontally immersed and fixed in the water body to be monitored, wherein the electrode wires and their connectors to each electrode are kept dry above the water surface, the output of the potentiostat is kept within a preset range and the current dynamics are monitored, and no organic carbon source is added during the process. The host computer outputs the monitoring current generated by the biological oxidation of organic matter in the monitored water body in real time, and dynamically determines the presence of toxic chemicals based on the time of the monitoring current. The criteria for determining whether a chemical is toxic include: calculating the average rate of change of the monitoring current per unit time; the toxic chemical is defined as the rate of change of the current before it enters the system (t). 0-60min The average rate of change of current is denoted as ν0. After toxic chemicals enter the system (t0, t0), the average rate of change of current is denoted as ν0. 0+n During the time period, the average rate of change of current is denoted as ν1; when ν1 ≤ 0.5ν0, it is determined that toxic chemicals have entered the system, and t0 is taken as the time when toxic chemicals enter the system.

2. The method for detecting microbial poisoning as described in claim 1, characterized in that, One end of the outer casing serves as a water inlet, and the other end serves as a water outlet. The water inlet is equipped with a water filter screen.

3. The method for detecting microbial poisoning as described in claim 1, characterized in that, The working electrode connecting wire is made of titanium wire or stainless steel wire.

4. The method for detecting microbial poisoning as described in claim 1, characterized in that, The working electrode is made of carbon felt, carbon fiber, graphite or stainless steel, the counter electrode is made of platinum, gold, titanium, stainless steel or graphite, and the reference electrode is made of silver / silver chloride electrode, saturated calomel electrode or mercury / mercurous sulfate electrode.

5. The method for detecting microbial poisoning as described in claim 1, characterized in that, An electrostatic shielding layer is provided on the outside of the electrode wire.

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