Circulating microbial electrolysis cell sewage treatment system

Abstract

The invention discloses a circulating type microbial electrolysis cell sewage treatment system which comprises a water inlet pipe, a water outlet pipe, a water storage bin and a microbial electrolysis cell, the tail end of the water inlet pipe is connected with the bottom of the microbial electrolytic tank; the head end of the water outlet pipe is connected with the upper part of the microbial electrolytic tank; an anode and a cathode are arranged in the microbial electrolysis cell at intervals, the anode and the cathode are connected with a detector through wires, and the detector is electrically connected with a display; a plurality of semi-permeable membrane bags are arranged in the microbial electrolysis cell, and nitrifying bacteria are contained in the semi-permeable membrane bags; a closed-loop circulating treatment mechanism is adopted, microorganisms are packaged through a semi-permeable membrane technology, meanwhile, non-intrusive real-time monitoring is achieved, the intelligence and automation level of the system is enhanced, the sewage treatment efficiency and the water quality purification standard are improved, energy consumption is reduced, and the sewage treatment cost is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental engineering, relates to sewage treatment, and specifically relates to a circulating microbial electrolysis cell sewage treatment system. Background Art

[0002] With the acceleration of urbanization, the amount of domestic sewage discharge is increasing. Traditional sewage treatment technology faces problems such as low treatment efficiency, high cost, and secondary pollution. Microbial electrolysis cell (MEC) technology, as an emerging method for treating organic sewage, directly converts organic pollutants into electrical energy by using the metabolic activities of microorganisms, effectively removes organic matter in sewage, reduces environmental pollution, and improves the reuse rate of water resources. It has the advantages of high efficiency, energy saving, and environmental protection.

[0003] Research on microbial electrolysis (MEC) technology has covered key links such as microbial community optimization, reactor design innovation, electrode material improvement and operating parameter adjustment.

[0004] The researchers constructed MEC electrode microbial flora through different domestication methods, improved the reactor design configuration, selected stable materials with higher conductivity and larger surface area as electrodes, and optimized the electrode structure design to increase the adhesion ability of microorganisms and the rate of electron transfer. In addition, the activity of microorganisms and system performance were optimized by adjusting the operating parameters of pH, temperature, substrate concentration and applied voltage. These studies provide reference directions for the selection of microbial communities, reactor design, electrode materials and optimization of operating parameters.

[0005] Traditional sewage treatment technologies often lack precise methods when determining key parameters (such as voltage and electrode layout) in the electrolytic treatment process. Parameters are usually selected based on experience or some preliminary experiments, without comprehensive consideration of multiple factors such as current density, electrochemical reaction kinetics, and the characteristics of electrode materials. This results in the inability to achieve the best electrolysis effect in actual operation, and the inability to monitor in real time and adjust parameters, affecting the sewage treatment efficiency; at the same time, when treating sewage, the existing technology does not have an effective method to confine microorganisms to a specific reaction environment. Microorganisms usually grow directly on the surface of the electrode or the surface of the culture medium and are in direct contact with the external environment. This will not only lead to the loss of microorganisms and reduce biomass, but may also cause secondary pollution, thereby reducing the efficiency of sewage treatment. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a circulating microbial electrolysis pool sewage treatment system, which adopts a closed-loop circulation treatment mechanism and encapsulates microorganisms through semi-permeable membrane technology, while realizing non-invasive real-time monitoring, enhancing the intelligence and automation level of the system, improving sewage treatment efficiency and water quality purification standards, reducing energy consumption, and saving sewage treatment costs.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A circulating microbial electrolytic cell sewage treatment system comprises a water inlet pipe, a water outlet pipe, a water storage tank and a microbial electrolytic cell;

[0009] The head end of the water inlet pipe is connected to the upper part of the water storage tank, and the tail end is connected to the bottom of the microbial electrolysis cell;

[0010] The head end of the water outlet pipe is connected to the upper part of the microbial electrolysis cell, and the tail end is connected to the inside of the water storage tank;

[0011] An anode and a cathode are arranged in the microbial electrolysis cell at intervals, the anode and the cathode are connected to a detector via a wire, and the detector is electrically connected to a display;

[0012] The anode is connected to the positive electrode of the current path of the detector, and the cathode is connected to the negative electrode of the current path of the detector;

[0013] The detector comprises a power module, a detection module and a calculation module;

[0014] The power module is used to provide electrolysis voltage, the detection module is used to detect the current, voltage and charge signal of the microbial electrolysis cell in real time, and the calculation module is used to calculate the ammonia nitrogen concentration and COD concentration and display them on the display;

[0015] A plurality of semipermeable membrane bags are arranged in the microbial electrolysis cell, and nitrifying bacteria are contained in the semipermeable membrane bags.

[0016] The present invention also has the following technical features:

[0017] Preferably, a water valve is provided on the water inlet pipe.

[0018] Preferably, a circulating water pump is provided on the water outlet pipe.

[0019] Preferably, the microbial electrolysis cell is further provided with an aeration device;

[0020] The aeration device comprises an air outlet arranged inside the microbial electrolysis cell, and the air outlet is connected to an aeration pump through a gas pipeline.

[0021] Preferably, the nitrifying bacteria include nitrite bacteria and nitrate bacteria.

[0022] Preferably, the multiple semipermeable membrane bags are fixed in the microbial electrolysis cell at intervals via fixed columns.

[0023] Preferably, the calculation method of the calculation module includes:

[0024] The power range is determined based on the real-time captured power data. When the power Q is less than or equal to 5.06E-9C, the COD concentration is calculated by formula (I):

[0025] C COD =-8E+10Q+448.55,R 2 =0.9132(Ⅰ)

[0026] When the electricity quantity Q>5.06E-9C, the COD concentration is calculated by formula (Ⅱ):

[0027] C COD =-1E+9Q+48.728,R 2 =0.9618 (Ⅱ)

[0028] At the same time, the current value measured in real time is used to calculate the corresponding ammonia nitrogen concentration through the linear relationship (III):

[0029] C 氨氮 =9.22E+5I+3.69,R 2 =0.7839 (III)

[0030] Among them, the unit of electric quantity Q is C, the unit of current I is A, and the unit of substance concentration of COD and ammonia nitrogen is mg / L.

[0031] The circulating microbial electrolytic tank sewage treatment system of the present invention establishes a model through COMSO to determine the system parameters;

[0032] The parameters include the distance between the anode and the cathode, the voltage, the arrangement of the microbial strains, and the water flow in and out of the water storage tank and the microbial electrolysis cell.

[0033] Furthermore, in the process of determining the system parameters, a secondary current distribution model is used to define the insulating surface, the initial voltage value, the cathode surface, the anode surface and the electrolyte composition of the electrode, the physical field of dilute material transfer and the temperature field are introduced, and the material charge is defined by the electron transfer amount in the oxidation reaction formula. The diffusion coefficient is set to 1e-9 [m^2 / s] and satisfies the isotropic state.

[0034] Furthermore, the dilute species transfer satisfies Fick's law, Nernst-Planck equation and coupled reaction equation;

[0035] The temperature field satisfies the fluid mass transfer and heat transfer energy equation.

[0036] Compared with the prior art, the present invention has the following technical effects:

[0037] The circulating microbial electrolytic pool sewage treatment system of the present invention, firstly, adopts a closed-loop circulation treatment mechanism to ensure that pollutants in wastewater are fully treated through continuous circulation, thereby improving treatment efficiency and water purification standards; secondly, introduces semi-permeable membrane technology to encapsulate microorganisms in a specific reaction environment to avoid secondary contamination of microorganisms, improve sewage treatment efficiency, and reduce energy consumption; thirdly, by tracking the changes in electrical signals and then monitoring the removal efficiency of ammonia nitrogen and COD, non-invasive real-time monitoring of sewage treatment is achieved, the intelligence and automation level of the system is enhanced, thereby improving sewage treatment efficiency and saving sewage treatment costs;

[0038] Furthermore, the present invention uses simulation technology to optimize key parameters in the electrolytic treatment process, such as voltage, electrode layout, arrangement of microbial strains, and water flow in and out of the water storage tank and the microbial electrolytic cell, to improve reaction efficiency;

[0039] The device of the present invention has a simple structure, is easy to construct and replicate, and can be realized by using simple materials such as graphite electrodes and acrylic materials, thereby reducing system costs and improving durability. It is suitable for use in small communities or homes, and also provides the possibility for large-scale applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic structural diagram of the circulating microbial electrolysis tank sewage treatment system of the present invention;

[0041] Figure 2 is a cross-sectional view of a microbial electrolysis cell of the present invention;

[0042] Figure 3 A top view of the microbial electrolysis cell of the present invention;

[0043] Figure 4 A graph showing the variation of the maximum current density on the anode surface with the electrode spacing during the process of determining the system parameters of the present invention;

[0044] Figure 5 The graph of electrolysis rate changing with time at different voltages for the same initial concentration;

[0045] Figure 6 It is a comparison chart of the degradation efficiency of the bacterial flora of the embodiment and the comparative example;

[0046] Figure 7 The real-time concentration change trend chart of ammonia nitrogen and COD detected by the detector;

[0047] Figures 1 to 3 The meanings of the numbers are as follows: 1-water inlet pipe, 2-water outlet pipe, 3-water storage tank, 4-microbial electrolysis cell, 5-anode, 6-cathode, 7-detector, 8-display, 9-semipermeable membrane bag, 10-water valve, 11-circulating water pump, 12-air outlet, 13-gas pipeline, 14-aeration pump, 15-fixed column. DETAILED DESCRIPTION

[0048] The specific contents of the present invention are further explained in detail below in conjunction with embodiments.

[0049] Example

[0050] like Figures 1 to 3 As shown, this embodiment provides a circulating microbial electrolytic tank sewage treatment system, including an inlet pipe 1, an outlet pipe 2, a water storage tank 3 and a microbial electrolytic tank 4; the microbial electrolytic tank 4 is a single-chamber square reactor, with a water inlet located at the bottom and a water outlet located at the top, so as to realize a continuous water inlet upward flow reaction mode, thereby increasing the hydraulic retention time.

[0051] The head end of the water inlet pipe 1 is connected to the upper part of the water storage tank 3, and the tail end is connected to the bottom of the microbial electrolysis cell 4; a water valve 10 is provided on the water inlet pipe 1;

[0052] The head end of the water outlet pipe 2 is connected to the upper part of the microbial electrolysis cell 4 , and the tail end is connected to the inside of the water storage tank 2 ; a circulating water pump 11 is arranged on the water outlet pipe 2 .

[0053] An anode 5 and a cathode 6 are arranged in the microbial electrolysis cell 4 at intervals. The anode 5 and the cathode 6 are connected to a detector 7 through a wire. The detector 7 is electrically connected to a display 8. The microbial electrolysis cell 4 is also provided with an aeration device.

[0054] The aeration device includes a gas outlet 12 disposed inside the microbial electrolysis cell 4 , and the gas outlet 12 is connected to an aeration pump 14 via a gas pipeline 13 .

[0055] A plurality of semipermeable membrane bags 9 are arranged in the microbial electrolysis cell 4 , and nitrifying bacteria are contained in the semipermeable membrane bags 9 . The plurality of semipermeable membrane bags 9 are fixed in the microbial electrolysis cell 4 at intervals by fixing columns 15 .

[0056] Nitrifying bacteria include nitrite bacteria and nitrate bacteria.

[0057] The anode 5 is connected to the positive pole of the current path of the detector 7, and the cathode 6 is connected to the negative pole of the current path of the detector;

[0058] The detector 7 includes a power module, a detection module and a calculation module;

[0059] The power supply module is used to provide electrolysis voltage, the detection module is used to detect the current and charge amount signals of the microbial electrolysis cell 4 in real time, and the calculation module is used to calculate the ammonia nitrogen concentration and COD concentration and display them through the display 8;

[0060] The calculation method of the calculation module includes:

[0061] The power range is determined based on the real-time captured power data. When the power Q is less than or equal to 5.06E-9C, the COD concentration is calculated by formula (I):

[0062] C COD =-8E+10Q+448.55,R 2 =0.9132(Ⅰ)

[0063] When the electricity quantity Q>5.06E-9C, the COD concentration is calculated by formula (Ⅱ):

[0064] C COD =-1E+9Q+48.728,R 2 =0.9618 (Ⅱ)

[0065] At the same time, the current value measured in real time is used to calculate the corresponding ammonia nitrogen concentration through the linear relationship (III):

[0066] C 氨氮 =9.22E+5I+3.69,R 2 =0.7839 (III)

[0067] Among them, the unit of electric quantity Q is C, the unit of current I is A, and the unit of substance concentration of COD and ammonia nitrogen is mg / L.

[0068] In the electrolysis reaction, the anode glucose is oxidized to produce hydrogen ions and electrons. The equation is:

[0069] C 6 H 12 O 6 +6H 2 O→6CO 2 +24H + +24e - ;

[0070] When nitrifying bacteria convert ammonia nitrogen into nitrate under aerobic conditions, hydrogen ions and electrons are also produced.

[0071] The reaction is divided into two basic steps:

[0072] 1. Nitrite reaction: Ammonia nitrogen is oxidized into nitrite under the action of nitrite bacteria. The reaction equation is:

[0073]

[0074] 2. Nitrification reaction: Nitrite is further oxidized into nitrate under the action of nitrate bacteria. The reaction equation is:

[0075]

[0076] The overall equation is:

[0077]

[0078] Electrons are transferred to the cathode through an external circuit, while hydrogen ions migrate to the cathode through the electrolyte and eventually combine to generate hydrogen. Electrolysis and microbial decomposition synergistically promote the degradation of ammonia nitrogen and chemical oxygen demand (COD).

[0079] During this process, the aeration pump 14 continuously aerates the microbial electrolysis tank 4 to provide the necessary oxygen environment for nitrifying bacteria to promote their survival and reproduction and improve the degradation efficiency of organic matter. The sewage rises from the bottom, fully contacts the electrodes and microorganisms, and is discharged from the upper outlet after undergoing the biological degradation and electrolysis process. The treated water is transported to the circulating water pump 11 through the outlet pipe 2, and then circulated back to the water storage tank 3 at a flow rate equivalent to the inlet water, realizing continuous circulation treatment until the pollutants in the sewage are completely decomposed. The entire current, voltage, charge and other signals are received, recorded and calculated in real time by the detector 7, and the change trend of ammonia nitrogen and COD is output.

[0080] In this embodiment, acrylic material is used to manufacture the main body of the microbial electrolysis cell 4. A cover is provided on the top of the microbial electrolysis cell 4. Precise holes are opened on the cover to install electrodes and an aeration device, thereby ensuring electrical insulation and chemical stability.

[0081] In order to detect the treatment efficiency of the system, pour 2L of sewage into the water storage tank 3. At this time, the water valve 10 is tightly closed. Then turn on the power module of the detector 8 and adjust the voltage to 1.5V. Then turn on the circulating water pump 11 and set the speed to 55-60r / s. Finally, turn on the aeration pump 14 and the water valve 10. Adjust the latter so that the inlet and outlet water flow rates are consistent to start the reaction. After 4 hours of reaction time and about 240 cycles, the COD degradation rate was measured to be 99.13%, and the ammonia nitrogen degradation rate was 97.47%. The pollutants in the sewage have been significantly degraded, indicating that the reaction process is basically completed. During the reaction process, the detection module of the detector 7 monitors and records the current and charge data in real time, which are converted into real-time concentration change trends of ammonia nitrogen and COD after processing by the calculation module, such as Figure 7 , the results are basically consistent with the experimental measurements.

[0082] The circulating microbial electrolytic tank sewage treatment system of this embodiment uses comsol to establish a model to determine system parameters;

[0083] The parameters include the distance between the anode 5 and the cathode 6, the voltage, the arrangement of the microbial strains, and the water flow in and out of the water storage tank 3 and the microbial electrolysis cell 4.

[0084] In the process of determining the system parameters, the initial temperature and pressure of the environment are specified, the electrode spacing, voltage, and initial concentration are set as variable parameters, the initial model of the system is constructed and the material parameters are imported into the material library, and the secondary current distribution model is used to define the insulating surface, initial voltage value, cathode surface, anode surface and electrolyte composition of the electrode. The physical field and temperature field of dilute material transfer are introduced, and the material charge is defined by the electron transfer amount in the oxidation reaction equation. The diffusion coefficient is set to 1e-9 [m^2 / s] and satisfies the isotropic requirement.

[0085] The dilute species transfer satisfies Fick's law, Nernst-Planck equation and coupled reaction equation;

[0086] With ammonium and glucose as substrates, the following reaction occurs at the anode:

[0087]

[0088] The reaction at the cathode is as follows:

[0089]

[0090] The transport equation of the substrate is obtained from Fick's second law:

[0091]

[0092] Where Dc is the diffusion coefficient (cm 2 h -1 ), C is the concentration of the substrate in the reactor (mol·L -1 ), is the consumption rate of substrate (mol·L -1 ·h -1 ).

[0093] During the simulation, the transfer of matter is affected by convection, diffusion, and the Coulomb force (electric field migration) on charged particles. 6 H 12 O 6 , H+ and The diffusion transport of is described by the Nemst-Planck equation:

[0094]

[0095] And satisfy:

[0096]

[0097] Ji is the flux, zi is the charge of the substance, um,i is the force per unit electric field, F is the Faraday constant, that is, the number of ions per mole, and R is the ideal gas constant (J·mol -1 K-1 )

[0098] The electric field migration equation is obtained from the Nernst-Einstein relationship:

[0099]

[0100] At the same time, the flux conservation principle is satisfied (the model is defined as flux-free, and the convection velocity field is used to replace the flow velocity change caused by the peristaltic pump):

[0101]

[0102] The buffer is hydrogen phosphate, which reacts:

[0103]

[0104] Therefore, during the delivery process:

[0105]

[0106] In the formula, Indicated in the reactor Diffusion coefficient (cm 2 ·h + ), Represents the reaction rate.

[0107] The substrate in the biofilm is degraded by microorganisms to produce H + , part of which The other part flows to the cathode, so the transport equation for hydrogen ions is:

[0108]

[0109] In the formula, Yes H + Diffusion coefficient (cm 2 ·h -1 );in,

[0110]

[0111] In the formula, ρ represents the H + The yield constant (mol-H + ·mol-Ac -1 ).

[0112] The temperature field satisfies the fluid mass transfer and heat transfer energy equation. The heat balance equation for electrochemical heat, resistance heat and heat absorbed by the fluid temperature rise during the process is as follows:

[0113]

[0114] Where k is thermal conductivity, Cp is specific heat capacity, is the temperature divergence, is the rate of change of temperature with time.

[0115] Organic matter is decomposed by oxidation and reduction to produce hydrogen ions and electrons. In the electrolyte, the potential caused by the equilibrium potential difference of the primary cell is called the electrolyte potential, that is, the electrolyte potential. The current of the electrolyte depends on the gradient of the electrolyte potential, and the current density of the electrode depends on the gradient of the electrode electrolyte potential. According to the law of conservation of current:

[0116]

[0117] φ l =phil,φ s =phis

[0118] σ l is the electrolyte conductivity, σ s is the electrode conductivity, i l is the electrolyte current, i s is the electrode current, φ l is the electrolyte potential, φ s is the electrode electrolyte potential.

[0119] The local current density at the anode surface is calculated based on the concentration-dependent kinetics:

[0120]

[0121] The calculation expression of the local current density on the cathode surface is based on the linear Butler-Volmer equation:

[0122]

[0123] The cathode and anode surface reactions both reach a steady state, satisfying:

[0124] η=E ct -E eq ,E ct =φ s,ext -φ-l

[0125] The initial potential of the electrolyte can be expressed as:

[0126] phil=(e cell -e a -e c ) / 2phis=0

[0127] There is the equation:

[0128] η=E ct -E eq ,E ct =φs,ext -G l

[0129] The surface current density of the anode and cathode electrodes satisfies the equation:

[0130]

[0131] where i 0 is the current exchange density, the parameter is set to 100 (A / m 2 ),η is the activation overpotential (V),α a is the anode transfer coefficient, the parameter is set to 0.5, α c is the cathode transfer coefficient, the parameter is set to 0.5, C R is the reduction expression, and the parameter is set to c / c i n,C O is the oxide expression, the parameter is set to 1, F is the Faraday constant (C / mol), R is the universal gas constant (J / mol·K), T is the absolute temperature (K), e c ell is the voltage, e c is the cathode equilibrium potential, e a is the anode equilibrium potential, φ s ,ext is the external potential, the parameter is set to 0 (V) and the electrode surface coupling reaction satisfies the equation:

[0132]

[0133] The stoichiometric coefficients satisfy:

[0134]

[0135] ν ox <0ν red >0

[0136] n is the number of participating electrons, ν C is the stoichiometric coefficient.

[0137] Boundary condition setting

[0138] On the insulating surface of the system, the current flows according to the equation:

[0139] -n·i L =0; -n·i S =0

[0140] The mass transfer in the system follows the equation:

[0141] -n·(J i +uc i )=0

[0142] In the initial state:

[0143] V L =0; V S =0

[0144] c 0 =c in

[0145] p 0 =p in .

[0146] Figure 4 is the variation of the maximum current density on the anode surface with the electrode spacing, according to Figure 4 Determine the most suitable electrode distance, Figure 5 The optimal voltage is determined by comparing the electrolysis rate at the same time for the same initial concentration over time. The initial conditions of the experimental equipment are specified based on these two points, and a concentration curve is drawn over time to observe the effect of microbial oxidation and decomposition of organic matter during the reaction. The concentration surface, streamlines, and multi-section diagrams are observed to improve the arrangement of microbial strains and the direction of water inflow and outflow. Finally, the concentration surface and the dynamic distribution diagram of temperature over time are derived, and the temperature and concentration change trends during the process are summarized to obtain the optimal system parameters.

[0147] The present invention adopts a closed-loop circulation treatment mechanism, and through a continuous circulation process, ensures that pollutants in sewage are fully treated, achieving a COD degradation rate of up to 99.13% and an ammonia nitrogen degradation rate of 97.47%. By optimizing the circulation process, a higher water purification standard is achieved, which can meet strict emission requirements.

[0148] The present invention introduces semi-permeable membrane technology to encapsulate microorganisms in a specific reaction environment, thereby avoiding direct contact between the microorganisms and the external environment, being beneficial to the enrichment and reproduction of the microorganisms and preventing the loss of the microorganisms.

[0149] The present invention successfully optimizes key parameters in the electrolysis process, including voltage and electrode layout, through simulation technology. The reaction efficiency is significantly improved by accurately controlling the distance between electrodes and the applied voltage. The simulation model comprehensively considers multiple factors, such as current density, electrochemical reaction kinetics, and electrode material properties to ensure that the best electrolysis effect can be achieved in actual operation.

[0150] The present invention selects 1.5V as the optimal electrolysis voltage to achieve efficient degradation of sewage at the lowest energy consumption. The reactor has specifications of 100×100×90mm and a capacity of nearly 1L. Acrylic material is used, which has good chemical stability and high impact strength and hardness, making the manufactured product durable and wear-resistant, easy to disassemble, assemble, carry and place. At the same time, graphite electrodes and nitrifying bacteria are easy to obtain, which greatly reduces the energy consumption and overall cost of the system.

[0151] The present invention uses an electrical signal real-time monitoring module to accurately track the changes in current and charge during the electrolysis process, thereby indirectly but accurately reflecting the composition change trends of ammonia nitrogen and COD. This method uses the correlation between current and chemical component concentration to achieve non-invasive real-time monitoring of sewage treatment effects, improving the transparency and predictability of system operation.

[0152] Comparative Example

[0153] 492 ml of waste liquid was placed in the system, the voltage was set to 1.5 V, then the circulating water pump 11 was turned on, the speed was set to 55-60 r / s, and finally the aeration pump 14 and the water valve 10 were turned on, and the latter were adjusted to make the inlet and outlet water flow rates consistent to start the reaction. The capsules containing the same mass of nitrifying bacteria, denitrifying bacteria, composite bacteria and activated sludge were placed in 4 parallel systems. After 4 hours of reaction time and about 240 cycles, the degradation efficiency was calculated as follows: Figure 6 As shown by Figure 6 It can be seen that nitrifying bacteria have the highest degradation efficiency.

[0154] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it; without departing from the concept of the present invention, deductions or substitutions made by those skilled in the art shall all fall within the protection scope of the present invention.

Claims

1. A circulating microbial electrolytic cell sewage treatment system, characterized in that: It comprises a water inlet pipe (1), a water outlet pipe (2), a water storage tank (3) and a microbial electrolysis cell (4); The head end of the water inlet pipe (1) is connected to the upper part of the water storage tank (3), and the tail end is connected to the bottom of the microbial electrolysis cell (4); The head end of the water outlet pipe (2) is connected to the upper part of the microbial electrolysis cell (4), and the tail end is connected to the inside of the water storage tank (2); An anode (5) and a cathode (6) are arranged in the microbial electrolysis cell (4) at intervals, and the anode (5) and the cathode (6) are connected to a detector (7) via a wire, and the detector (7) is electrically connected to a display (8); The anode (5) is connected to the positive pole of the current path of the detector (7), and the cathode (6) is connected to the negative pole of the current path of the detector; The detector (7) comprises a power module, a detection module and a calculation module; The power supply module is used to provide electrolysis voltage, the detection module is used to detect the current and charge amount signals of the microbial electrolysis cell (4) in real time, and the calculation module is used to calculate the ammonia nitrogen concentration and COD concentration and display them on the display (8); The microbial electrolysis cell (4) is further provided with a plurality of semi-permeable membrane bags (9), wherein nitrifying bacteria are contained in the semi-permeable membrane bags (9); The calculation method of the calculation module includes: The power range is determined based on the real-time captured power data. When the power Q is less than or equal to 5.06E-9C, the COD concentration is calculated by formula (I): C COD =-8E+10Q+448.55,R 2 =0.9132(Ⅰ) When the electricity quantity Q>5.06E-9C, the COD concentration is calculated by formula (Ⅱ): C COD =-1E+9Q+48. 728,R 2 =0.9618 (Ⅱ) At the same time, the current value measured in real time is used to calculate the corresponding ammonia nitrogen concentration through the linear relationship (III): C 氨氮 =9.22E+5I+3.69,R 2 =0.7839 (Ⅲ) Among them, the unit of electric quantity Q is C, the unit of current I is A, and the unit of substance concentration of COD and ammonia nitrogen is mg / L.

2. The circulating microbial electrolysis pool sewage treatment system according to claim 1, characterized in that: The water inlet pipe (1) is provided with a water valve (10).

3. The circulating microbial electrolytic cell sewage treatment system according to claim 1, characterized in that: The water outlet pipe (2) is provided with a circulating water pump (11).

4. The circulating microbial electrolytic cell sewage treatment system according to claim 1, characterized in that: The microbial electrolysis cell (4) is also provided with an aeration device; The aeration device comprises an air outlet (12) disposed inside the microbial electrolysis cell (4), and the air outlet (12) is connected to an aeration pump (14) via a gas pipeline (13).

5. The circulating microbial electrolysis tank sewage treatment system according to claim 1, characterized in that: The nitrifying bacteria include nitrite bacteria and nitrate bacteria.

6. The circulating microbial electrolytic cell sewage treatment system according to claim 1, characterized in that: The multiple semi-permeable membrane bags (9) are fixed in the microbial electrolysis cell (4) at intervals via fixing columns (15).

7. The circulating microbial electrolytic cell sewage treatment system according to claim 1, characterized in that: Establish a model through comsol to determine the system parameters; The parameters include the distance between the anode (5) and the cathode (6), the voltage, the arrangement of the microbial strains, and the water flow in and out of the water storage tank (3) and the microbial electrolysis cell (4).

8. The circulating microbial electrolytic cell sewage treatment system according to claim 7, characterized in that: In the process of determining the system parameters, a secondary current distribution model is used to define the insulating surface, the initial voltage value, the cathode surface, the anode surface and the electrolyte composition of the electrode, the physical field of dilute material transfer and the temperature field are introduced, and the material charge is defined by the electron transfer amount in the oxidation reaction formula. The diffusion coefficient is set to 1e-9 [m^2 / s] and satisfies the isotropic direction.

9. The circulating microbial electrolytic cell sewage treatment system according to claim 8, characterized in that: The dilute species transfer satisfies Fick's law, Nernst-Planck equation and coupled reaction equation; The temperature field satisfies the fluid mass transfer and heat transfer energy equation.

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