Method for electrically cleaning anaerobic membrane bioreactor in situ

Abstract

The invention relates to a method for electrically cleaning an anaerobic membrane bioreactor in situ. The anaerobic membrane bioreactor comprises a digestion tank and a membrane tank, the membrane pool comprises a working electrode and a counter electrode; the method comprises the following steps: applying pulse voltage between a working electrode and a counter electrode in a membrane pool, and cleaning the working electrode; and the magnitude of the pulse voltage ranges from 5V to 10V. According to the method, the anaerobic membrane bioreactor is cleaned by adopting pulse high voltage, the damage to enzymes, cell structures and microbial metabolism is relieved by adopting pulse type (intermittent type) instead of direct-current voltage, a strong electrochemical reaction is initiated in the anaerobic membrane bioreactor to realize efficient in-situ cleaning of the membrane, extra dosing or membrane cleaning is not needed in the process, the operation is simple, and the cost is low. And the membrane is not required to be taken out, the system is not required to be independently cleaned, and the system can continuously run and is uninterrupted only by increasing high voltage, so that the working efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly to a method for in-situ electro-cleaning an anaerobic membrane bioreactor. Background Art

[0002] The anaerobic membrane bioreactor (AnMBR) combines anaerobic biological treatment and membrane separation technologies, overcomes the disadvantage of easy sludge loss in traditional anaerobic reactors, strengthens the removal of organic pollutants, and realizes the recovery of clean energy (biogas). However, the expensive membrane modules and membrane fouling are bottleneck problems restricting its large-scale promotion.

[0003] The traditional treatment method for irreversible fouling is mainly to take out the membrane for intensive chemical cleaning or directly replace the membrane module. Current research believes that if in-situ cleaning of the membrane can be achieved, infrequent off-line chemical cleaning can effectively improve the performance of AnMBR. In-situ cleaning refers to membrane anti-fouling cleaning during operation without removing the membrane from the AnMBR. This method reduces the downtime of the system, ensures a continuous and stable anaerobic process, prolongs the service life of the membrane module, and reduces the replacement cost.

[0004] Electrochemical AnMBR has been considered an effective and promising anti-fouling method. However, applying an electric field often only repels SMP and EPS to the membrane surface and promotes microorganisms to reduce the EPS concentration. For example, carbohydrates are degraded into monosaccharides and proteins are converted into amides. The effect of low voltage on EPS is limited, while with the increase of voltage in electrochemistry, the electrode surface has redox ability, which can make the generated reducing substances interact with unsaturated bonds and halogenated organic compounds and undergo hydrogenation reduction, reducing their biological toxicity and making them metabolizable. On the other hand, electrochemical oxidation reactions occur near the anode, which can produce oxygen, chlorine, and other oxidation compounds (such as ·OH, ClO - and O 2- ), and these substances can oxidize refractory organic compounds. It has recently been found that the application of high-voltage electrochemical methods in sludge pretreatment effectively degrades and releases the EPS layer around the activated sludge, facilitating further compression and dehydration.

[0005] However, there are few studies on the application of high voltage for in-situ cleaning in membrane bioreactors. This is because, although it has the potential to react with EPS, high voltage will simultaneously have an adverse impact on the microbial community and metabolism. In particular, anaerobic digestion is an anoxic degradation process, and methane production is often strictly anaerobic. When the voltage exceeds 1.0 V, the oxygen and chlorine gas generated will destroy the anaerobic environment and hinder the metabolism of methanogens and other functional bacterial genera. Some researchers have found that when the applied voltage exceeds 1.0 V, the COD removal rate decreases and the metabolism of microorganisms is inhibited. Due to the continuous high current density, the hydrophobicity of the cell membrane is damaged. The enzyme secretion for methane production is inactivated under the change of redox environment. For example, when a voltage exceeding 1.0 V is applied in an AnMBR, the dehydrogenase activity decreases. When the voltage exceeds 1.5 V, there is a significant inhibition of the abundance of specific functional genes. In addition, when the electrode voltage reaches the oxidation-reduction potential of the organic matter, the substrate is consumed and converted into inert or harmful substances, such as haloalkanes. So far, the destruction mechanism of high voltage on anaerobic digestion is still unclear, and how to alleviate this destruction is also an issue worthy of research.

[0006] Therefore, studying the feasibility of high voltage in AnMBR and finding a method that can both utilize the electrochemical reaction to remove EPS and prevent the inhibition of methane production (microbial metabolism) has become an urgent problem to be solved at present. Summary of the Invention

[0007] To solve the above technical problems, the purpose of the present invention is to provide a method for in-situ electro-cleaning of an anaerobic membrane bioreactor. The method for in-situ electro-cleaning of an anaerobic membrane bioreactor provided by the present invention uses intermittent or pulsed high voltage, which alleviates the damage to enzymes, cell structures, and microbial metabolism. The present invention provides a solution (intermittent high voltage) that can trigger a strong electrochemical reaction in AnMBR without inhibiting the process of functional microorganisms. Through this method, not only can the in-situ cleaning of the membrane be achieved, but it also provides the possibility of introducing other electrochemical reactions in the future development of AnMBR.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a method for in-situ electro-cleaning of an anaerobic membrane bioreactor, where the anaerobic membrane bioreactor includes a digestion tank and a membrane tank; the membrane tank includes a working electrode and a counter electrode; the method includes the following steps:

[0010] Apply a pulsed voltage between the working electrode and the counter electrode in the membrane tank to clean the working electrode.

[0011] The magnitude of the pulsed voltage is 5V - 10V. For example, it can be 5V, 5.2V, 5.5V, 5.8V, 6V, 6.2V, 6.5V, 6.8V, 7V, 7.5V, 8V, 8.5V, 9V, 9.5V or 10V, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0012] The present invention uses pulsed high voltage to clean the anaerobic membrane bioreactor. On the one hand, the high voltage can greatly improve the cleaning efficiency of the membrane. During the process, no additional chemicals need to be added or the membrane needs to be removed from the system for separate cleaning. Only by increasing the high voltage, the continuous operation of the system can be ensured without interruption, reducing the downtime of the system, ensuring a continuous and stable anaerobic process, while prolonging the service life of the membrane module, reducing the replacement cost, and improving work efficiency. On the other hand, by using pulsed (intermittent) rather than DC voltage, the damage to enzymes, cell structures, and microbial metabolism is alleviated. The method provided by the present invention can initiate strong electrochemical reactions in the AnMBR to achieve efficient in-situ cleaning of the membrane without inhibiting the functional microbial process, and also provides the possibility of introducing other electrochemical reactions in the future development of AnMBR.

[0013] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved.

[0014] Preferably, the duty cycle ratio of the pulsed voltage is 1 / 20 - 1 / 8. For example, it can be 1 / 20, 1 / 18, 1 / 16, 1 / 15, 1 / 14, 1 / 10 or 1 / 8, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0015] Preferably, the frequency of the pulsed voltage is 10Hz - 2000Hz. For example, it can be 10Hz, 100Hz, 200Hz, 500Hz, 1000Hz, 1500Hz or 2000Hz, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0016] Preferably, the direction of the pulsed voltage is with the working electrode as the anode or with the working electrode as the cathode.

[0017] Preferably, the direction of the pulsed voltage is with the working electrode as the cathode.

[0018] Preferably, the material of the working electrode includes any one or at least two combinations of titanium film, ceramic or metal film. Typical but non-limiting combinations include the combination of titanium film and ceramic, the combination of ceramic and metal film, the combination of titanium film and metal film, and the combination of titanium film, ceramic and metal film.

[0019] Preferably, the pore diameter of the working electrode is 0.01 μm - 1 μm. For example, it can be 0.01 μm, 0.02 μm, 0.05 μm, 0.1 μm, 0.2 μm, 0.4 μm, 0.5 μm, 0.8 μm, 0.9 μm or 1 μm, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0020] The schematic structural diagram of the anaerobic membrane bioreactor device used in the present invention is as Figure 1 shown. The anaerobic membrane bioreactor consists of 4 reactors with the same structure, and each group shares a feed tank 8. Each reactor group includes a 3.0 L CSTR digestion tank 1 (inner diameter 150 mm, height 180 mm) and a 0.80 L cuboid membrane tank 2 (100 mm × 80 mm × 120 mm). The operating conditions of each digestion tank are kept consistent, while the operating conditions of the membrane tank are adjusted according to experimental requirements. The digestion tank agitator 5 maintains uniform mixing at a rotational speed of 50 rpm - 100 rpm, and is also equipped with a pH electrode 6 and a redox potential electrode 7 for real-time monitoring of the operation stability of the reactor. The top of the anaerobic membrane bioreactor device is connected to a gas bag 9 for collecting the biogas generated by the anaerobic digestion tank and the membrane tank.

[0021] Four working electrodes 3 are arranged in the membrane tank. Parallel to the titanium membrane electrode is the counter electrode 4, and the material of the counter electrode is a graphite plate. A pulsed voltage is applied between the working electrode and the counter electrode through a power supply 10. During the interval of applying the pulsed voltage, an operating voltage of 0.6 V is maintained between the working electrode and the counter electrode. Operating at a low voltage can achieve the most basic cleaning conditions for the working electrode. A pressure sensor 11 is used for real-time monitoring of the transmembrane pressure difference change. The effluent peristaltic pump 12 and the sludge circulation peristaltic pump 13 are respectively used for pumping out water from the membrane tank and circulating sludge into the anaerobic tank.

[0022] The degree of membrane fouling is monitored and evaluated in real time through the change of transmembrane pressure (TMP), that is, by the pressure sensor 11.

[0023] In the present invention, the influent of the digestion tank is simulated aquaculture wastewater. When the effluent flow rate is too low to maintain the target hydraulic retention time (HRT), the membrane is considered to be completely fouled and needs to be replaced.

[0024] Preferably, the rotational speed of the agitator is 50 rpm - 100 rpm. For example, it can be 50 rpm, 55 rpm, 60 rpm, 65 rpm, 70 rpm, 75 rpm, 80 rpm, 85 rpm, 90 rpm, 95 rpm or 100 rpm, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0025] As a preferred technical solution of the preparation method of the present invention, the preparation method comprises the following steps:

[0026] Apply a pulsed voltage of 5V - 10V with a duty cycle ratio of 1 / 20 - 1 / 12 between the working electrode and the counter electrode in the membrane tank of the in-situ electro-cleaning anaerobic membrane bioreactor to clean the working electrode.

[0027] The numerical ranges described in the present invention include not only the above-listed point values, but also any point values between the above numerical ranges not listed. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] (1) The present invention constructs a new electro-cleaning AnMBR technology, which performs in-situ cleaning by applying a pulsed high voltage to the conductive membrane and adjusts the EPS pollution. It not only improves the membrane cleaning efficiency, but also hardly affects the efficiency of microbial degradation of pollutants due to the intermittent high voltage.

[0030] (2) The method provided by the present invention does not require additional dosing or membrane cleaning. The operation is simple. There is no need to remove the membrane from the system for separate cleaning. Only by increasing the high voltage, it can ensure continuous operation of the system without interruption. The energy required for membrane filtration is low, and the membrane does not need to be frequently replaced, resulting in lower operation energy consumption and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of the anaerobic membrane bioreactor device used in the embodiments of the present invention, wherein, 1 - digestion tank 1, 2 - membrane tank, 3 - working electrode, 4 - counter electrode, 5 - digestion tank stirrer, 6 - pH electrode, 7 - redox potential electrode, 8 - feed tank, 9 - air bag, 10 - power supply, 11 - pressure sensor, 12 - effluent peristaltic pump, 13 - sludge circulation peristaltic pump;

[0032] Figure 2 is the transmembrane pressure magnitude in Embodiment 1 - Embodiment 2 and Comparative Example 1 - Comparative Example 2 of the present invention;

[0033] Figure 3 is the content of EPS (extracellular polymeric substances) and organic matter in the membrane pores in Embodiment 1 - Embodiment 2 and Comparative Example 1 - Comparative Example 2 of the present invention;

[0034] Figure 4 is the COD removal rate in Embodiment 1 - Embodiment 2 and Comparative Example 1 - Comparative Example 2 of the present invention;

[0035] Figure 5 is the COD removal rate of the method provided in Comparative Example 3 of the present invention;

[0036] Figure 6 is the COD removal rate of the method provided in Comparative Example 4 of the present invention. Specific Embodiments

[0037] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific embodiments. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0038] In the following examples and comparative examples, unless otherwise specified, all reagents and consumables are purchased from conventional reagent manufacturers in the art; unless otherwise specified, the experimental methods and technical means used are conventional methods and means in the art.

[0039] The structural schematic diagram of the experimental device used in the present invention is as Figure 1 shown. The anaerobic membrane bioreactor consists of 4 reactors with the same structure, and each group shares a feed tank. Each reactor includes a 3.0L CSTR digestion tank (inner diameter 150mm, height 180mm) and a 0.80L cuboid membrane tank (100mm×80mm×120mm). The operating conditions of each digestion tank are kept consistent, while the operating conditions of the membrane tank are adjusted according to the experimental requirements. The digestion tank stirrer maintains uniform mixing at a rotational speed of 50rpm - 100rpm, and is equipped with pH and redox potential electrodes for real-time monitoring of the operation stability of the reactor. Four working electrodes are arranged in the membrane tank, and the counter electrode parallel to the titanium membrane electrode is a graphite plate.

[0040] The top of the reactor is connected to an air bag for collecting the biogas generated by the anaerobic digestion tank and the membrane tank. The influent flows into the reactor by gravity, and the effluent is discharged under the control of a peristaltic pump. The hydraulic retention time (HRT) of the system is set to 7.3 days. The degree of membrane fouling is monitored and evaluated in real time through the change of transmembrane pressure (TMP). Influent represents the influent COD concentration, and effluent represents the effluent COD concentration.

[0041] Example 1

[0042] This example provides a method for in-situ electrocleaning an anaerobic membrane bioreactor. The schematic diagram of the device for in-situ electrocleaning the anaerobic membrane bioreactor is as Figure 1 shown. The preparation method of the method for in-situ electrocleaning the anaerobic membrane bioreactor provided in this example includes the following steps:

[0043] A pulsed voltage of 6V with a duty cycle ratio of 1 / 12 and a frequency of 500Hz is applied between the working electrode and the counter electrode in the membrane tank of the in-situ electro-cleaning anaerobic membrane bioreactor. The direction of the pulsed voltage is such that the working electrode is the cathode for cleaning the working electrode, which is denoted as cathode cleaning.

[0044] Example 2

[0045] The preparation method of the method for in-situ electro-cleaning an anaerobic membrane bioreactor provided in this example includes the following steps:

[0046] A pulsed voltage of 6V with a duty cycle ratio of 1 / 20 and a frequency of 500Hz is applied between the working electrode and the counter electrode in the membrane tank of the in-situ electro-cleaning anaerobic membrane bioreactor. The direction of the pulsed voltage is such that the working electrode is the anode for cleaning the working electrode, which is denoted as anode cleaning.

[0047] Example 3

[0048] The preparation method of the method for in-situ electro-cleaning an anaerobic membrane bioreactor provided in this example includes the following steps:

[0049] A pulsed voltage of 10V with a duty cycle ratio of 1 / 15 and a frequency of 1500Hz is applied between the working electrode and the counter electrode in the membrane tank of the in-situ electro-cleaning anaerobic membrane bioreactor. The direction of the pulsed voltage is such that the working electrode is the cathode for cleaning the working electrode.

[0050] Example 4

[0051] This example provides a method for in-situ electro-cleaning an anaerobic membrane bioreactor, with the pulsed voltage magnitude adjusted to 3V and other conditions the same as in Example 1.

[0052] Example 5

[0053] This example provides a method for in-situ electro-cleaning an anaerobic membrane bioreactor, with the pulsed voltage magnitude adjusted to 15V and other conditions the same as in Example 1.

[0054] Comparative Example 1

[0055] This comparative example provides a method for electro-cleaning an anaerobic membrane bioreactor. The difference from Example 1 is that no pulsed voltage is additionally applied between the working electrode and the counter electrode, and there is only a DC operating voltage of 0.6V, which is denoted as pure electric field.

[0056] Comparative Example 2

[0057] This comparative example provides a method for cleaning an anaerobic membrane bioreactor. The difference from Example 1 is that no pulsed voltage is additionally applied between the working electrode and the counter electrode, and the DC operating voltage is 0, which is denoted as AnMBR.

[0058] Comparative Example 3

[0059] This comparative example provides a method for electrochemically cleaning an anaerobic membrane bioreactor. The difference from Example 1 is only that the cleaning voltage of the membrane is 6 V DC, the cleaning frequency is once per hour, and the cleaning time each time is 5 minutes.

[0060] Comparative Example 4

[0061] This comparative example provides a method for electrochemically cleaning an anaerobic membrane bioreactor. The difference from Comparative Example 3 is only that the cleaning voltage of the membrane is 6 V DC, the cleaning frequency is twice per hour, and the cleaning time each time is 2.5 minutes.

[0062] Test method: The influent of the digester is simulated aquaculture wastewater, and its components include glucose, sodium acetate, ammonium chloride, potassium dihydrogen phosphate, tryptophan, and trace elements. The designed concentration of the influent is chemical oxygen demand (COD) 20,000 mg / L, ammonia nitrogen 600 mg / L, and total phosphorus (TP) 80 mg / L. The original sludge as the inoculum comes from the digester of the Gaobeidian Sewage Treatment Plant in Beijing. When the effluent flow rate of the membrane is too low to maintain the target hydraulic retention time (HRT), the membrane is considered to be completely fouled and needs to be replaced.

[0063] The final effects of the cleaning methods in the examples and comparative examples were tested, and the test results are as Figures 2 - 4 shown.

[0064] Figure 2 In [reference], first, the four reactors were connected and operated for 30 days to ensure that they had the same sludge concentration and fouling potential in the subsequent experiments, so that the subsequent experimental results were comparable.

[0065] In the examples and comparative examples, the results of the transmembrane pressure are as Figure 2 shown, demonstrating the influence of electrochemical cleaning on the alleviation effect of membrane fouling. The results show that both anodic cleaning (Example 2) and cathodic cleaning (Example 1) show better effects than Comparative Examples 1 - 2 in terms of membrane fouling control, and the cleaning TMP of Example 1 is the lowest.

[0066] By applying a pulsed voltage, the average TMP of anodic electrocleaning and cathodic electrocleaning decreased to 14.7 kPa and 10.2 kPa respectively, which were 54.1% and 69.7% lower than that of the pure electric field. It can be seen that the electrochemical cleaning method with high voltage applied can significantly improve the effect of alleviating membrane fouling, and this effect will not disappear with the change of cleaning frequency. Specifically, the TMP of anodic electrocleaning and cathodic electrocleaning decreased by 45% and 64% respectively. It is speculated that when a higher voltage is applied, the electrochemical reactions occurring on the membrane-electrode surface can effectively transform pollutants, such as transforming extracellular polymeric substances (EPS) into forms with lower fouling potential or directly degrading them, thus significantly improving the anti-fouling ability of the membrane. This mechanism may involve electrochemical redox reactions, which can destroy the structure of EPS and reduce its adsorption ability on the membrane surface by generating reactive oxygen species (such as hydroxyl radicals ·OH) or direct electron transfer. Research shows that electrochemical oxidation can effectively degrade organic components such as proteins and polysaccharides in EPS, thereby reducing the formation of membrane fouling. In addition, the electrochemical reaction may also change the surface charge characteristics of EPS, weaken the interaction between it and the membrane material, and further reduce the attachment of pollutants.

[0067] Figure 3 The EPS (extracellular polymeric substances) and organic matters in the membrane pores of the four reactors were measured by TOF-SIMS. Green represents protein-like substances, and yellow represents the total organic carbon content. The membrane pores of AnMBR were filled with organic matters, while in the pure electric field, the spatial concentration of organic matters was significantly reduced compared with AnMBR. This indicates that under the influence of electrostatic repulsion, EPS is repelled, reducing the entry and deposition of EPS into the membrane pores. The organic matters in the membrane pores of cathodic electrocleaning were significantly lower than those in the other three reactors, indicating that cathodic electrochemical cleaning effectively reduced the amount of EPS residue in the membrane pores.

[0068] Figure 4 The COD (chemical oxygen demand) removal rate is shown. The COD removal rate reflects the removal ability of wastewater treatment facilities for organic matters in wastewater, and it is an important indicator to measure the wastewater treatment effect. Generally speaking, the higher the COD removal rate of the treated wastewater, the better the wastewater treatment effect. By increasing the cleaning frequency, the inhibition of anaerobic digestion by electrochemical cleaning was alleviated. First, the four reactors were connected together and adapted to the sludge under the same conditions to maintain the initial state of each reactor. When the COD removal rate reached more than 90% and the biogas production was stable, the four reactors were disconnected and operated under different conditions.

[0069] Figure 5 and Figure 6 are the COD removal rate curves of the methods provided in Comparative Example 3 and Comparative Example 4 of the present invention respectively. By comparison, it can be seen that on the premise of ensuring the same total cleaning time, with the increase of the cleaning frequency, the COD removal rate will increase.

[0070] Example 1: Under pulsed voltage, the effluent COD concentration of cathodic electrochemically cleaning is basically the same as that of AnMBR and pure electric field, and the COD removal rate increases by 19% compared with that using DC power supply (Comparative Example 3).

[0071] Table 1

[0072]

[0073]

[0074] It can be seen from the test results that:

[0075] (1) It can be seen from Examples 1 - 3 that the present invention cleans the anaerobic membrane bioreactor by using pulsed high voltage, adopting pulse type (intermittent type) rather than DC voltage, alleviates the damage to enzymes, cell structure and microbial metabolism, triggers a strong electrochemical reaction in AnMBR to achieve efficient in-situ cleaning of the membrane. During the process, no additional medicine is needed to be added or the membrane is needed to be cleaned separately, and only the high voltage needs to be increased, which can ensure the continuous operation of the system without interruption, improve the working efficiency, and achieve the dual effects of efficient cleaning without damaging microorganisms.

[0076] (2) It can be seen from the comparison between Example 1 and Examples 4 - 5 that the present invention can better achieve the excellent cleaning effect while saving energy by further optimizing the range of pulsed voltage magnitude. When the pulsed voltage is too small, the cleaning effect cannot be satisfied. If the pulsed voltage is too large, it will not only not enhance the cleaning effect but also cause waste of energy.

[0077] (3) It can be seen from Example 1, Comparative Example 1 and Comparative Example 2 that the electrochemical cleaning method with high voltage applied can significantly improve and alleviate the membrane fouling effect. It can be seen from Example 1, Comparative Example 3 and Comparative Example 4 that the improvement and alleviation of the membrane fouling effect by the electrochemical cleaning method with high voltage applied will not disappear with the change of cleaning frequency. This is because the high voltage significantly changes the composition of archaeal and bacterial communities and also affects the metabolic pathways in the anaerobic digestion process by inhibiting the growth of acetate-utilizing methanogens and certain propionate-producing bacteria.

[0078] In summary, the present invention performs in-situ electro-cleaning on an anaerobic membrane bioreactor by applying pulsed high voltage. On the one hand, the high voltage can greatly improve the cleaning efficiency of the membrane. During the process, no additional chemicals need to be added or the membrane needs to be removed from the system for separate cleaning. Only by increasing the high voltage can the continuous operation of the system be ensured without interruption, reducing the downtime of the system, ensuring a continuous and stable anaerobic process, prolonging the service life of the membrane module, reducing the replacement cost, and improving the working efficiency. On the other hand, pulsed (intermittent) rather than DC voltage is used to alleviate the damage to enzymes, cell structures, and microbial metabolism. The method provided by the present invention can initiate strong electrochemical reactions in the AnMBR to achieve efficient in-situ cleaning of the membrane without inhibiting the functional microbial process, and also provides the possibility of introducing other electrochemical reactions in the future development of AnMBR.

[0079] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for in-situ electrocleaning of an anaerobic membrane bioreactor, characterized in that: The anaerobic membrane bioreactor comprises a digestion tank and a membrane tank; the membrane tank comprises a working electrode and a counter electrode; The method comprises the following steps: A pulse voltage is applied between the working electrode and the counter electrode in the membrane cell to clean the working electrode; The magnitude of the pulse voltage is 5V-10V.

2. The method according to claim 1, characterized in that The duty cycle ratio of the pulse voltage is 1 / 20-1 / 8; The frequency of the pulse voltage is 10 Hz-2000 Hz.

3. The method according to claim 1 or 2, characterized in that: The direction of the pulse voltage is to use the working electrode as the anode or the working electrode as the cathode.

4. The method according to any one of claims 1 to 3, characterized in that: The direction of the pulse voltage is such that the working electrode is the cathode.

5. The method according to any one of claims 1 to 4, characterized in that: The material of the working electrode includes any one of titanium film, ceramic or metal film, or a combination of at least two of them.

6. The method according to any one of claims 1 to 5, characterized in that: The pore size of the working electrode is 0.01 μm-1 μm.

7. The method according to any one of claims 1 to 6, characterized in that: The material of the counter electrode includes graphite plate.

8. The method according to any one of claims 1 to 7, characterized in that: The digestion tank and the membrane tank are connected via a peristaltic pump.

9. The method according to any one of claims 1 to 8, characterized in that: The digestion tank comprises a stirrer, a pH electrode and a redox potential electrode.

10. The method according to claim 9, characterized in that The rotation speed of the stirrer is 50 rpm-100 rpm.

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