Microbial sensor applied to online water quality monitoring instrument

Abstract

The utility model belongs to the technical field of water quality monitoring, and particularly relates to a microbial sensor applied to an online water quality monitoring instrument, which comprises a sensor shell, and a liquid storage chamber and a reaction chamber are arranged in the sensor shell; a microbial reactor is arranged in the reaction chamber, the microbial reactor is communicated with the liquid storage chamber, the microbial reactor is a single-chamber reactor, a spherical anode is arranged in an inner cavity of the single-chamber reactor, and electroactive microorganisms are attached to the spherical anode; an air cathode is arranged on the side wall of the single-chamber reactor; the spherical anode is sequentially connected with a resistance wire, a cathode wire and an air cathode through an anode wire to form a closed-loop reactor; two ends of the resistance wire are connected with a signal collector. The spherical anode and the air cathode are arranged in the reaction bin, the special electroactive microorganisms are attached to the spherical anode, voltage is applied to the spherical anode to decompose the microorganisms, an expensive cathode catalyst does not need to be used, and the cost is low.

Description

Technical Field

[0001] The utility model belongs to the technical field of water quality monitoring, and in particular relates to a microbial sensor applied to an online water quality monitoring instrument. Background Art

[0002] The statements in this section merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Biochemical oxygen demand (BOD) is a comprehensive indicator that reflects the concentration of organic matter in water and sewage. It is the amount of dissolved oxygen consumed by microorganisms to decompose organic matter in water within a certain period of time, usually expressed in mg / l. The higher the BOD value, the higher the concentration of organic pollutants in the water.

[0004] In recent years, there have been a lot of studies on BOD sensors, such as the pressure-detecting coulometer method, the short-time day method, the platform value method, the microbial electrode method, the luminescent bacteria method, and the ultraviolet fluorescence method. However, these BOD detection methods have not been widely used in the field of water body detection. How to accurately and quickly determine the BOD concentration has always been a major problem in water body detection. The research on BOD sensors based on the working principle of the bioelectrochemical system is also the focus of researchers. The changes in the electrical signals of the bioelectrochemical system intuitively reflect the changes in the water body.

[0005] The bioelectrochemical system is a device that uses microorganisms to directly convert the chemical energy of organic matter in water into electrical energy. Its basic working principle is: in the anode chamber, organic matter is decomposed by microorganisms and releases electrons and protons. The electrons are transferred to the cathode through the external circuit to form current / voltage, while the protons are transferred to the cathode through the ion exchange membrane and reduced. Since there is a corresponding relationship between the current (voltage) or electron coulomb of the bioelectrochemical system and the content of the electron donor, the bioelectrochemical system can be used to determine the content of certain substrates, such as organic carbon, wastewater BOD, and toxic substances. The current, voltage or amount of electricity generated by the metabolism of organic substrates by microorganisms is linearly proportional to the content of organic matter in the sample. Therefore, the BOD content in the sample can be determined by detecting the output current, voltage or electricity of the bioelectrochemical system.

[0006] So far, the best bioelectrochemical system technology is HABS-2000 and HABS-2001 developed by the Korea Advanced Institute of Science and Technology, which have been used in countries around the world. However, they use dissolved oxygen as the cathode electron acceptor, and the cathode becomes the limiting factor of the battery. They have the following disadvantages: (1) The cathode chamber requires continuous aeration, which consumes a lot of energy; (2) The cathode catalyst pt is easily poisoned, and the pt reserves are scarce and expensive; (3) The structure and operation are relatively complex, and the maintenance cost is high; (4) Expensive proton exchange membranes are required; (5) The test results are easily affected by the cathode performance; (6) Due to the ion exchange membrane between the anode and cathode chambers, the anode chamber has limited pressure resistance. Utility Model Content

[0007] In order to overcome the above-mentioned deficiencies of the prior art, the utility model provides a microbial sensor applied to an online water quality monitoring instrument. The microbial sensor is applied to online water quality detection to achieve online monitoring of indicators such as biochemical oxygen demand of the water body to be tested.

[0008] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0009] The first aspect of the utility model provides a microbial sensor applied to an online water quality monitoring instrument, comprising a sensor housing, wherein a liquid storage chamber and a reaction chamber are provided inside the sensor housing;

[0010] The reaction chamber is provided with a microbial reactor, a signal collector and a main control module, and the signal collector is connected to the microbial reactor and the main control module respectively;

[0011] The microbial reactor is connected to the liquid storage chamber. The microbial reactor is a single-chamber reactor. A spherical anode is arranged in the internal cavity of the single-chamber reactor. Electroactive microorganisms are attached to the spherical anode. An air cathode is arranged on the side wall of the single-chamber reactor.

[0012] The spherical anode is connected to a resistance wire, a cathode wire and an air cathode in sequence through an anode wire to form a closed-loop reactor; and both ends of the resistance wire are connected to a signal collector.

[0013] Furthermore, a solenoid valve and a liquid storage container are provided in the liquid storage chamber;

[0014] The microbial reactor is connected to a water inlet pipe via a solenoid valve, and the water inlet pipe is connected to a liquid storage container and an external water sample to be tested.

[0015] Furthermore, the water inlet pipe includes a water sample inlet pipe to be tested, a distilled water inlet pipe and a standard liquid inlet pipe;

[0016] One end of the water sample inlet pipe to be tested extends out of the sensor housing and is connected to the external water sample to be tested;

[0017] The distilled water inlet pipe and the standard liquid inlet pipe are used to connect the distilled water container and the standard liquid container respectively.

[0018] Furthermore, the solenoid valve is also connected to a water outlet pipe, one end of which extends out of the sensor housing and is used to discharge waste liquid.

[0019] Furthermore, a PLC control module for controlling the solenoid valve is also provided in the liquid storage chamber.

[0020] Furthermore, the main control module includes a processor and a transmitter, and the processor is used to transmit the electrical signal collected by the signal collector to the host computer through the transmitter.

[0021] Furthermore, the electroactive microorganism is Geobacter.

[0022] Furthermore, the spherical anode is a porous spherical carbon felt.

[0023] Furthermore, a partition plate is provided inside the sensor housing, the lower part of the partition plate is a liquid storage chamber, and the upper part of the partition plate is a reaction chamber.

[0024] Furthermore, a display screen is provided on the sensor housing, and the display screen is electrically connected to the main control module.

[0025] One or more of the above technical solutions have the following beneficial effects:

[0026] (1) The utility model arranges a spherical anode and an air cathode in a reaction chamber. Electroactive microorganisms are attached to the spherical anode to form a biofilm. Voltage is applied to the spherical anode to decompose the biofilm. Expensive cathode catalysts are not required, and the cost is low.

[0027] (2) The utility model provides sufficient microbial adsorption area by using a porous spherical carbon felt anode, thereby increasing the contact area between the biofilm and the sewage and improving the removal efficiency of the bioreactor for pollutants.

[0028] (3) The sensor of the utility model does not require aeration during operation, which solves the problem that the cathode chamber of the current microbial sensor needs continuous aeration and consumes a lot of energy. It does not need to use expensive proton exchange membranes and directly uses oxygen in the air as an electron acceptor, greatly reducing the manufacturing cost.

[0029] Advantages of additional aspects of the present invention will be partially given in the following description, and partially become apparent from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0031] Figure 1 This is a schematic diagram of a microbial sensor used in an online water quality monitoring instrument according to Example 1.

[0032] Figure 2 This is a schematic diagram of the current signal generated by the microbial sensor of Example 1 in response to different BOD concentrations.

[0033] Figure 3 (a), (b), (c), and (d) are schematic diagrams of current signals generated by monitoring different types of wastewater.

[0034] In the figure, 1. microbial reactor, 2. spherical anode, 3. air cathode, 4. anode wire, 5. resistance wire, 6. cathode wire, 7. electroactive microorganisms, 8. wire, 9. signal collector, 10. processor, 11. transmitter, 12. host computer, 13. display screen, 14. solenoid valve, 15. PLC air module, 16. distilled water inlet pipe, 17. standard liquid inlet pipe, 18. waste liquid outlet pipe, 19. standard liquid storage bottle, 20. distilled water storage bottle, 21. water sample to be tested. DETAILED DESCRIPTION

[0035] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0036] Embodiment 1

[0037] like Figure 1 As shown, the utility model proposes a microbial sensor for use in an online water quality monitoring instrument, comprising: a sensor housing, a partition plate is provided inside the sensor housing, the partition plate divides the internal chamber of the sensor shell into a liquid storage chamber (located at the lower part of the partition plate) and a reaction chamber (located at the upper part of the partition plate), and the liquid storage chamber and the reaction chamber are connected to each other.

[0038] The reaction chamber is provided with a microbial reactor 1, a signal collector 9 and a main control module, and the signal collector 9 is connected to the microbial reactor 1 and the main control module respectively;

[0039] The microbial reactor is a single-chamber reactor, which avoids the pressure balance problem of a double-chamber reactor; an air cathode 3 and a spherical anode 2 are arranged in the single-chamber reactor, the spherical anode 2 is placed at the center of the internal cavity of the microbial reactor 1, and electroactive microorganisms 7 are attached to the spherical anode 2, and the microorganisms attach to the spherical anode to form a biofilm; an air cathode is arranged on the side wall of the single-chamber reactor, and the air cathode 3 is waterproof on one side, one side of which is placed in the inner cavity of the microbial reactor 1 to contact the water therein, and the other side is exposed to the air, using oxygen in the air as an electron acceptor, and the waterproof material used is PTFE.

[0040] The spherical anode 2 is connected to the resistance wire 5, the cathode wire 6 and the air cathode 3 in sequence through the anode wire to form a closed-loop reactor; the two ends of the resistance wire 5 are connected to the signal collector 9; the main control module includes a processor 10 and a transmitter 11, the processor 10 is used to transmit the electrical signal collected by the signal collector 9 to the host computer 12 through the transmitter 11, and the signal collector 9 is a current sensor for collecting current signals in the circuit.

[0041] The principle of the microbial reactor in the utility model is as follows: in the microbial reactor 1, a spherical anode 2 is attached with a unique electroactive microorganism 7, a typical example being Geobacter, and the electroactive microorganism 7 decomposes organic matter to release hydrogen ions, carbon dioxide and electrons. After the electrons move to the spherical anode 2, they move to the air cathode 3 driven by the potential difference between the cathode and cathode, and reduce the hydrogen ions and oxygen to water on the surface of the air cathode 3;

[0042] During the degradation of organic matter by the microbial reactor 1, an electric signal is generated at the resistor 5 by the flow of electrons. The two sides of the resistor are connected to the signal collector 9 by wires 8. The signal collector 9 is used to collect the current signal. The current signal generated by the microbial sensor for different BOD concentrations is as follows: Figure 2 As shown, the current signals generated by monitoring different types of wastewater are as follows Figure 3 As shown in (a), (b), (c) and (d).

[0043] The signal collector 9 transfers the collected signal to the signal processor 10, which is sent to the host computer 12 via the transmitter 11 after processing. The signal is automatically edited by the host computer 12 to produce specific monitoring indicators, and is fed back to the display screen 13. The display screen 13 is arranged on the upper part of the sensor housing, and the display screen is electrically connected to the main control module to display the BOD and COD concentration values.

[0044] The utility model applies an electric field to generate redox reactions at the cathode and anode to promote the removal effect of the system on pollutants. The microbial community structure in the reactor can change with the change of voltage intensity, and the activation of microorganisms can enhance the biotransformation ability, accelerate the migration and transformation of pollutants, and improve the removal efficiency of pollutants by the bioreactor. In addition, electrolysis can change the chemical form of pollutants and remove pollutants through oxidation, reduction and other effects.

[0045] As a further technical solution, the liquid storage chamber is provided with a solenoid valve 14, a PLC control module 15 and a liquid storage container. The microbial reactor 1 is connected to a water inlet pipe through the solenoid valve 14, and the water inlet pipe is connected to the liquid storage container and an external water sample to be tested. The PLC control module 15 is electrically connected to the main control module for controlling the on and off of the solenoid valve 14.

[0046] The liquid storage container includes a distilled water storage bottle 20 and a standard liquid storage bottle 17, and the water inlet pipe includes a water sample inlet pipe 22 to be tested, a distilled water inlet pipe 19 and a standard liquid inlet pipe 16; one end of the water sample inlet pipe 22 to be tested extends out of the sensor housing and is connected to an external water sample 21 to be tested; the distilled water inlet pipe 19 and the standard liquid inlet pipe 16 are used to connect the distilled water storage bottle 20 and the standard liquid storage bottle 17 respectively.

[0047] The solenoid valve is also connected to a water outlet pipe 18, one end of which extends out of the sensor housing and is used to discharge waste liquid.

[0048] The calibration process of the sensor of the present invention is as follows: first, the standard liquid is sucked into the microbial reactor 1 through the standard liquid inlet pipe 16, and then distilled water is sucked into the microbial reactor 1 through the distilled water inlet pipe 19 as required to dilute it to a specified concentration; the standard solution is a standard COD / BOD standard concentration solution, which is used to calibrate the microbial signal to draw a concentration standard curve; generally, four different concentrations are required for calibration, and calibration is required once 1-3 months after the test machine is stable.

[0049] After calibration, the standard solution is discharged from the microbial sensor 1 through the outlet pipe 18, and the water sample 21 to be tested is sucked into the microbial sensor 1 through the water sample inlet pipe 22 to extract the electrical signal for 10-30 minutes. After being edited by the host computer 12, the measured data is fed back to the display screen 13 to realize online monitoring of the water sample to be tested; after measuring the first water sample, the time can be set according to demand to continue real-time monitoring.

[0050] Although the above describes the specific implementation methods of the utility model in combination with the accompanying drawings, it is not intended to limit the scope of protection of the utility model. Technical personnel in the relevant field should understand that on the basis of the technical solution of the utility model, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the utility model.

Claims

1. A microbial sensor used in an online water quality monitoring instrument, characterized in that: It comprises a sensor housing, wherein a liquid storage chamber and a reaction chamber are provided inside the sensor housing; The reaction chamber is provided with a microbial reactor, a signal collector and a main control module, and the signal collector is connected to the microbial reactor and the main control module respectively; The microbial reactor is connected to the liquid storage chamber. The microbial reactor is a single-chamber reactor. A spherical anode is arranged in the internal cavity of the single-chamber reactor. Electroactive microorganisms are attached to the spherical anode. An air cathode is arranged on the side wall of the single-chamber reactor. The spherical anode is connected to a resistance wire, a cathode wire and an air cathode in sequence through an anode wire to form a closed-loop reactor; and both ends of the resistance wire are connected to a signal collector.

2. The microbial sensor used in an online water quality monitoring instrument according to claim 1, characterized in that: The liquid storage chamber is provided with a solenoid valve and a liquid storage container; The microbial reactor is connected to a water inlet pipe via a solenoid valve, and the water inlet pipe is connected to a liquid storage container and an external water sample to be tested.

3. The microbial sensor used in an online water quality monitoring instrument according to claim 2, characterized in that: The water inlet pipes include a water sample inlet pipe to be tested, a distilled water inlet pipe and a standard liquid inlet pipe; One end of the water sample inlet pipe to be tested extends out of the sensor housing and is connected to the external water sample to be tested; The distilled water inlet pipe and the standard liquid inlet pipe are used to connect the distilled water container and the standard liquid container respectively.

4. The microbial sensor used in an online water quality monitoring instrument according to claim 2, characterized in that: The solenoid valve is also connected to a water outlet pipe, one end of which extends out of the sensor housing and is used to discharge waste liquid.

5. The microbial sensor used in an online water quality monitoring instrument according to claim 1, characterized in that: The liquid storage chamber is also provided with a PLC control module for controlling the solenoid valve.

6. The microbial sensor used in an online water quality monitoring instrument according to claim 1, characterized in that: The main control module includes a processor and a transmitter, and the processor is used to transmit the electrical signal collected by the signal collector to the host computer through the transmitter.

7. The microbial sensor used in an online water quality monitoring instrument according to claim 1, characterized in that: The electroactive microorganism is Geobacter.

8. The microbial sensor used in an online water quality monitoring instrument according to claim 1, characterized in that: The spherical anode is a porous spherical carbon felt.

9. The microbial sensor used in an online water quality monitoring instrument according to claim 1, characterized in that: A partition plate is arranged inside the sensor housing, the lower part of the partition plate is a liquid storage chamber, and the upper part of the partition plate is a reaction chamber.

10. The microbial sensor used in an online water quality monitoring instrument according to claim 1, characterized in that: The sensor housing is provided with a display screen, and the display screen is electrically connected to the main control module.

Images