CN112607852A - Membrane bioreactor and water purification method - Google Patents
Membrane bioreactor and water purification method Download PDFInfo
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- CN112607852A CN112607852A CN202011283156.7A CN202011283156A CN112607852A CN 112607852 A CN112607852 A CN 112607852A CN 202011283156 A CN202011283156 A CN 202011283156A CN 112607852 A CN112607852 A CN 112607852A
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Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/12—Activated sludge processes
- C02F3/1236—Particular type of activated sludge installations
- C02F3/1268—Membrane bioreactor systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
- B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
- B01D65/10—Testing of membranes or membrane apparatus; Detecting or repairing leaks
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/722—Oxidation by peroxides
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/03—Pressure
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/42—Liquid level
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2303/00—Specific treatment goals
- C02F2303/14—Maintenance of water treatment installations
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Abstract
The invention discloses a membrane bioreactor and a water purification method, wherein the membrane bioreactor comprises a reactor, an aeration system, a catalytic ceramic membrane component, a dosing system and a water outlet control system; the aeration system is connected with the reactor; the catalytic ceramic membrane component is arranged in the reactor and comprises at least one catalytic ceramic membrane; the catalytic ceramic membrane is provided with a plurality of membrane holes, the wall of each membrane hole is loaded with oxidation catalyst particles, and the catalytic ceramic membrane is also provided with a water outlet and a drug feeding port which are communicated with the membrane holes; the medicine adding system is connected with the medicine adding port and is used for adding an oxidant into the membrane hole; the water outlet control system is connected with the water outlet through a water outlet pipe. According to the membrane bioreactor, the oxidation catalyst is loaded on the wall of the catalytic ceramic membrane pores, the ceramic membrane separation technology and the advanced oxidation technology are highly integrated, the floor area is reduced, the pollution resistance of the membrane bioreactor is enhanced, the membrane pollution control efficiency is improved, the operation cost is reduced, and the effluent quality can be guaranteed.
Description
Technical Field
The invention relates to the technical field of water purification, in particular to a membrane bioreactor and a water purification method.
Background
In water purification, the membrane bioreactor is widely applied by virtue of the advantages of high sludge-water separation efficiency, good effluent quality and the like. However, most of the existing ceramic membranes only provide a simple physical separation function in the membrane bioreactor, such as the traditional alumina ceramic membrane, the pollution resistance is poor, and in the using process, as the membrane filtration is carried out, organic pollutants in water can be gradually adsorbed and deposited on the surface of the membrane, even block the membrane pores, and further form membrane pollution. And after the ceramic membrane is polluted, the membrane flux is reduced, the membrane needs to be frequently cleaned, the cost of the agent for cleaning the membrane pollution is high, and frequent membrane cleaning operation can influence the improvement of the water production efficiency and the water yield of the membrane, so that the operation cost is increased.
Strong oxidizing agents (such as ozone and hydrogen peroxide) have a strong oxidizing removal capacity for organic pollutants. In order to effectively control membrane fouling, oxidation techniques are used to remove organic pollutants, such as ozone oxidation and hydrogen peroxide oxidation, from water bodies or from membrane surfaces.
Wherein, the ozone oxidation technology is divided into two application forms, including ozone pre-oxidation and ozone in-situ oxidation. When adopting ozone preoxidation control membrane to pollute, need increase the preoxidation treatment pond in membrane bioreactor design, carry out preoxidation treatment to the sewage that gets into the membrane pond, remove the organic pollutant in the sewage and slow down the emergence of membrane pollution through passing, but this has prolonged water treatment process undoubtedly, and has increased membrane bioreactor's area and water treatment cost. When the membrane pollution is controlled by ozone in-situ oxidation, ozone aeration can be directly carried out at the bottom of a ceramic membrane component in the membrane bioreactor, organic pollutants in sewage can be removed by oxidation of ozone so as to slow down membrane pollution, and pollutants on the surface of the membrane can be removed by direct oxidation of ozone bubbles so as to clean the membrane pollution. However, in sewage treatment, biological treatment of sewage by activated sludge is the key point for reaching the standard of nitrogen and phosphorus removal of sewage, and when an oxidant is directly added into a water body, the strong oxidant action of the oxidant (such as ozone) can influence the microbial activity of the activated sludge in the sewage, even cause cell rupture, and further aggravate pollution; for example, long-term ozone oxidation treatment can affect the functional microbial activity of activated sludge in the membrane bioreactor, especially the activity of nitrifying bacteria can be inhibited by ozone oxidation, so as to affect the removal of total nitrogen in sewage, therefore, the long-term direct addition of a strong oxidant in the membrane bioreactor can affect the effluent quality of the membrane bioreactor, and cause the risk potential that sewage treatment does not reach the standard.
Hydrogen peroxide oxidation is also used to clean ceramic membrane fouling in sewage treatment where hydrogen peroxide solution can be oxidized by back-flushing to remove accumulated organic contaminants from the membrane after the membrane fouling has occurred. The traditional aluminum oxide ceramic membrane has limited self-catalytic performance, and cannot effectively catalyze an oxidizing agent to oxidize and remove organic pollutants, so that the prior oxidation technology (especially hydrogen peroxide oxidation) is low in membrane pollution cleaning efficiency and long in cleaning time, the requirement on adding amount of the oxidizing agent for membrane pollution cleaning is high, the agent cost is high, and the risk of water quality deterioration is also caused.
Therefore, the pollution resistance of the ceramic membrane is improved, the removal efficiency of organic pollutants removed by oxidizing the catalytic oxidant of the ceramic membrane is improved, the microbial activity of the activated sludge in the membrane bioreactor is protected from being damaged by strong oxidation, and the occupied area for implementing the oxidation technology is reduced, so that the problem to be solved in the prior art of controlling the membrane pollution in the membrane bioreactor by the oxidation technology is solved urgently.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. To this end, the invention proposes a membrane bioreactor and a method for purifying water.
In a first aspect of the invention, there is provided a membrane bioreactor comprising:
a reactor;
an aeration system connected to the reactor;
the catalytic ceramic membrane component is arranged in the reactor; the catalytic ceramic membrane component comprises at least one catalytic ceramic membrane, a plurality of membrane holes are formed in the catalytic ceramic membrane, and oxidation catalyst particles are loaded on the wall of each membrane hole; the catalytic ceramic membrane is also provided with a water outlet and a medicine feeding port which are communicated with the membrane hole;
the dosing system is connected with the dosing port and is used for injecting an oxidant into the membrane hole;
and the water outlet control system is connected with the water outlet through a water outlet pipe.
The membrane bioreactor provided by the embodiment of the invention has at least the following beneficial effects: the membrane bioreactor can effectively improve the pollution resistance of the ceramic membrane by loading the oxidation catalyst particles on the membrane pores of the catalytic ceramic membrane; the oxidation catalyst particles can catalyze the oxidizing agent to oxidize and remove the organic pollutants adsorbed on the ceramic membrane, and the oxidation efficiency of the oxidizing agent for oxidizing the organic pollutants is improved. Moreover, the catalytic ceramic membrane contains a large number of membrane pores, the membrane pores loaded with the oxidation catalyst particles can be used as a reactor for controlling membrane pollution by an oxidation technology by loading the oxidation catalyst particles on the pore walls of the membrane pores of the catalytic ceramic membrane, so that a limited-domain catalysis function is provided for catalytic oxidation reaction, when the catalytic ceramic membrane loaded with the oxidation catalyst particles is polluted, organic pollutants are blocked and enriched in the membrane pores of the catalytic ceramic membrane, a dosing system is connected with a dosing port communicated with the membrane pores on the catalytic ceramic membrane, an oxidant is filled into the membrane pores of the catalytic ceramic membrane through the dosing system, the oxidation catalyst particles on the pore walls of the membrane pores oxidize the catalytic oxidant to remove the organic pollutants enriched on the catalytic ceramic membrane, the online cleaning of the membrane pollution in a purification process can be realized, and the pollution efficiency of the oxidation cleaning membrane can be further improved by fully utilizing the limited-domain catalysis function of the membrane pores, the filling amount of the oxidant is reduced, and the reaction time for oxidizing and cleaning membrane pollution is shortened. In addition, oxidation catalyst particles are loaded on the pore walls of the membrane pores of the catalytic ceramic membrane, and the catalytic oxidation reaction for oxidizing a catalytic oxidant to remove organic pollutants is designed in the membrane pores, so that a pre-oxidation unit required by the traditional oxidation technology can be omitted, the occupied area of the membrane bioreactor is reduced, and the microbial activity of activated sludge in the reactor can be prevented from being damaged by the strong oxidation reaction, so that the effluent quality of the membrane bioreactor can be guaranteed to reach the standard stably.
In conclusion, the membrane bioreactor improves the self anti-pollution performance and the control efficiency of membrane pollution by loading the oxidation catalyst on the pore wall of the catalytic ceramic membrane pore and enhancing the anti-pollution performance, the catalytic activity and the pore confinement effect of the ceramic membrane, can realize the high integration of the ceramic membrane separation technology and the advanced oxidation technology in the membrane bioreactor, reduces the floor area, reduces the operation cost required by the membrane bioreactor, simultaneously protects the microorganisms in the reactor from the harm of strong oxidation reaction, and ensures the effluent quality.
According to some embodiments of the invention, the oxidation catalyst particles are transition metal oxide particles; preferably, the transition metal oxide particles are selected from at least one of manganese sesquioxide, copper oxide, iron oxide.
According to some embodiments of the invention, the water outlet control system comprises a water outlet valve, a pressure gauge, a first flowmeter and a water outlet pump, wherein the pressure gauge, the water outlet pump, the first flowmeter and the water outlet valve are sequentially arranged on the water outlet pipe along the water outlet flow direction;
the dosing system comprises a valve, a second flowmeter, a suction pump and an oxidant storage container; the oxidant storage container is connected with the dosing port through a pipeline; the suction pump, the second flowmeter and the valve are sequentially arranged on the pipeline along the conveying flow direction;
the aeration system comprises an air pump, an aeration pipe, an aeration valve, a gas flow meter and a gas pipe, wherein the aeration pipe is arranged at the lower part in the reactor and is connected with the air pump through the gas pipe, and the air pump, the gas flow meter, the aeration valve and the aeration pipe are sequentially arranged along the gas conveying direction.
According to some embodiments of the invention, the membrane bioreactor further comprises a water inlet control system, said water inlet control system being connected to said reactor via a water inlet pipe; preferably, the water inlet control system comprises a water inlet pump, a third flow meter and a water inlet valve, the water inlet pump is connected with the reactor through the water inlet pipe, and the third flow meter and the water inlet valve are arranged on the water inlet pipe.
According to some embodiments of the invention, a liquid level meter, an oxidant concentration detector, and a dissolved oxygen detector are disposed within the reactor.
According to some embodiments of the present invention, the membrane bioreactor further comprises an automatic control system, and the automatic control system is in communication with the aeration system, the water inlet control system, the level gauge, the oxidant concentration detector, the dissolved oxygen detector, the dosing system, and the water outlet control system, respectively.
In a second aspect of the present invention, a water purification method is provided, which uses any one of the membrane bioreactors provided in the first aspect of the present invention, and specifically includes the following steps:
s1, feeding water to be purified into the reactor;
s2, starting the aeration system to aerate the reactor, and filling oxidant into the membrane pores through the dosing system;
and S3, filtering the water to be purified through the catalytic ceramic membrane module, and pumping out the water through the water outlet control system. In the filtering treatment process, the trapped organic pollutants are adsorbed on the membrane pores of the catalytic ceramic membrane and are oxidized and removed under the catalytic action of the oxidation catalyst particles loaded on the pore walls of the membrane pores.
The water purification method provided by the embodiment of the invention has at least the following beneficial effects: the water purification method can ensure the quality of the effluent water by adopting the membrane bioreactor, realize the control of membrane pollution and reduce the water purification cost.
According to some embodiments of the invention, in step S2, the concentration of the oxidant in the water in the reactor is monitored during the process of injecting the oxidant into the membrane pores through the dosing system, and the oxidant injection is stopped when the oxidant concentration is greater than 0.001 mM. The oxidizing agent may employ hydrogen peroxide and/or persulfate.
In addition, in step S2, the dissolved oxygen concentration of the water in the reactor is controlled to be not less than 4mg/L during the aeration process into the reactor.
According to some embodiments of the invention, in step S3, the filtration process is performed by controlling the catalytic ceramic membrane to operate in a constant flux pumping-off mode by the effluent control system; and controlling the transmembrane pressure difference increase amount of the catalytic ceramic membrane within a set threshold range, wherein the set threshold range is 40-45 kPa.
The filtration flux of the catalytic ceramic membrane is subcritical flux (generally 40-100L/m)2And/h), controlling the membrane filtration pumping-stopping ratio to be 10-15 min: 1-2 min, not limiting the pumping-stopping ratio, but ensuring that the membrane filtration pumping-stopping ratio stops for at least 1min each time.
The transmembrane pressure difference is defined as the pressure required to drive the water to be treated through the catalytic ceramic membrane, typically the difference between the feed water pressure and the filtration pressure. The membrane with smaller pore size requires a larger transmembrane pressure difference, and the transmembrane pressure difference is higher when the water temperature is lower, the flux is higher and pollution occurs. The transmembrane pressure difference increase is the difference between the transmembrane pressure difference at the beginning of membrane filtration and the real-time transmembrane pressure difference of membrane filtration. As the membrane becomes contaminated, the pressure increases, with the amount of growth being taken to indicate the degree of membrane contamination. The transmembrane pressure difference increment is controlled within a certain range, so that the safe operation of the catalytic ceramic membrane suction filtration can be ensured. Due to the mechanical strength factor of the catalytic ceramic membrane, the transmembrane pressure difference borne by the membrane body has a certain limit value, and beyond the limit value, damage such as membrane breakage and the like can be caused, so that the transmembrane pressure difference required by water production is higher after the membrane is polluted, and the energy consumption is increased. Therefore, the transmembrane pressure difference is controlled to increase within a certain range, membrane pollution can be controlled within a certain degree, and energy consumption for water production can be reduced.
According to some embodiments of the invention, in step S3, a transmembrane pressure difference recovery rate of the catalytic ceramic membrane during the filtration treatment is detected, wherein the transmembrane pressure difference recovery rate is equal to a ratio of a difference between transmembrane pressure differences before and after filling an oxidant to a transmembrane pressure difference increase amount in a filtration cycle;
(1) when the transmembrane pressure difference recovery rate is equal to or higher than 50%, injecting an oxidizing agent in a normal water outlet intermittent gap manner in step S2; the method specifically comprises the following steps: controlling the catalytic ceramic membrane to operate according to the constant-flux pumping stop mode, and injecting an oxidant into the membrane hole through the dosing system in a gap where the effluent control system stops pumping filtration so as to perform an oxidation reaction with the organic pollutants adsorbed and retained on the catalytic ceramic membrane; the filling frequency of the oxidant is once every 1-6 hours;
(2) when the transmembrane pressure difference recovery rate is higher than or equal to 30% and lower than 50%, in step S2, the filling of the oxidizing agent is performed in a manner of suspending normal water outlet and extending the filling, specifically including: pausing the water outlet control system to enable the catalytic ceramic membrane to stop operating according to the constant flux pumping-stopping mode, wherein the pause time is longer than the pause time of the catalytic ceramic membrane in the operating process according to the constant flux pumping-stopping mode, then injecting an oxidant into the membrane hole through the dosing system to perform oxidation reaction with the organic pollutants adsorbed and intercepted on the catalytic ceramic membrane, and then starting the water outlet control system to enable the catalytic ceramic membrane to operate according to the constant flux pumping-stopping mode;
adding an oxidant at intervals of 1-6 h according to the mode of suspending normal water outlet and prolonging the adding; the amount of the oxidant added in the mode of suspending normal water outlet and prolonging the adding is larger than that of the oxidant added in the mode of suspending the interval of normal water outlet;
(3) and when the transmembrane pressure difference recovery rate is lower than 30 percent and the transmembrane pressure difference increase of the catalytic ceramic membrane exceeds the set threshold range, stopping the operation of the membrane bioreactor, and taking out the catalytic ceramic membrane for cleaning.
The more severe the membrane fouling, the higher the oxidant concentration required for cleaning, and the longer the cleaning time, the slower the membrane filtration performance recovery. Specifically, the concentration of the oxidant and the reaction time of the oxidant required by the next membrane cleaning can be predicted and set according to the transmembrane pressure difference recovery rate result of the previous membrane pollution cleaning in the filtration treatment process.
When the oxidant is added in the mode of suspending normal water outlet and prolonging the adding, the oxidant can be added specifically according to the adding concentration of the oxidant being 1-2 mM, the flux being 2 times of the filtering flux of the catalytic ceramic membrane, and the adding time being 30 s;
when the oxidant is added according to the mode of suspending normal water outlet prolonged adding, specifically, adding can be carried out according to the adding concentration of the oxidant being 5-20 mM, the flux being 2 times of the filtering flux of the catalytic ceramic membrane, and the adding time being 30 s; after the filling is finished, under the catalytic action of the oxidation catalyst particles loaded on the catalytic ceramic membrane, oxidizing reaction is carried out on the oxidant and the organic pollutants adsorbed and trapped on the catalytic ceramic membrane for 10-60 min, and then the effluent control system is started to enable the catalytic ceramic membrane to operate according to the constant-flux pumping-stopping mode.
Drawings
The invention is further described with reference to the following figures and examples, in which:
FIG. 1 is a schematic structural diagram of a membrane bioreactor according to an embodiment of the present invention;
FIG. 2 is an SEM image of a catalytic ceramic membrane of the membrane bioreactor of FIG. 1;
FIG. 3 is a graph showing the experimental results of the degradation of hydrogen peroxide catalyzed by ceramic membranes used in membrane bioreactors of a control group and an experimental group in an application example;
FIG. 4 is a graph showing the transmembrane pressure difference of the ceramic membrane used in the membrane bioreactors of the control group and the experimental group in the application example as a function of the operation time.
Reference numerals: 11-reactor, 12-aeration system, 121-air pump, 122-aeration pipe, 123-aeration valve, 124-gas flowmeter, 13-catalytic ceramic membrane module, 131-catalytic ceramic membrane, 14-dosing system, 141-valve, 142-second flowmeter, 143-suction pump, 144-oxidant storage container, 145-pipeline, 15-water outlet control system, 151-water outlet pipe, 152-water outlet valve, 153-pressure gauge, 154-first flowmeter, 155-water outlet pump, 16-water inlet control system, 161-water inlet pipe, 162-water inlet pump, 163-third flowmeter, 164-water inlet valve, 17-liquid level meter, 18-oxidant concentration detector, 19-dissolved oxygen detector, 20-mud valve.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, the meaning of a plurality is one or more, the meaning of a plurality is two or more, and the above, below, exceeding, etc. are understood as excluding the present numbers, and the above, below, within, etc. are understood as including the present numbers. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.
In the description of the present invention, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Referring to FIG. 1, FIG. 1 is a schematic structural diagram of a membrane bioreactor according to an embodiment of the present invention. As shown in FIG. 1, the membrane bioreactor comprises: the device comprises a reactor 11, an aeration system 12, a catalytic ceramic membrane component 13, a dosing system 14 and a water outlet control system 15; wherein, the aeration system 12 is connected with the reactor 11 and is used for aerating the reactor 11; the catalytic ceramic membrane component 13 is arranged in the reactor 11, the catalytic ceramic membrane component 13 comprises at least one catalytic ceramic membrane 131, a plurality of membrane holes are formed in the catalytic ceramic membrane 131, and oxidation catalyst particles are loaded on the wall of each membrane hole; the catalytic ceramic membrane 131 is also provided with a water outlet and a dosing port which are communicated with the membrane hole, and the dosing system 14 is connected with the dosing port on the catalytic ceramic membrane 131 and is used for injecting an oxidant into the membrane hole of the catalytic ceramic membrane 131; the water outlet control system 15 is connected with the water outlet of the catalytic ceramic membrane 131 through a water outlet pipe 151.
In this embodiment, the aeration system 12 includes an air pump 121, an aeration pipe 122, an aeration valve 123, a gas flow meter 124 and an air pipe 125, the aeration pipe 122 is disposed at the lower portion in the reactor 11, the aeration pipe 122 is connected to the air pump 121 through the air pipe 125, and the air pump 121, the gas flow meter 124, the aeration valve 123 and the aeration pipe 133 are sequentially disposed along the air conveying direction. Sufficient dissolved oxygen is provided for the microbial activity of the activated sludge in the reactor 11 through the aeration system 12, and meanwhile, the physical scouring action of the air bubbles on the surface of the catalytic ceramic membrane 131 can play a certain membrane pollution control effect.
The dosing system 14 comprises a valve 141, a second flowmeter 142, a suction pump 143 and an oxidant storage container 144, the oxidant storage container 144 is connected with the dosing port through a pipeline 145, and the suction pump 143, the second flowmeter 142 and the valve 141 are sequentially arranged on the pipeline 145 along the material flow direction. The water outlet control system 15 includes a water outlet valve 152, a pressure gauge 153, a first flow meter 154, and a water outlet pump 155, wherein the pressure gauge 153, the water outlet pump 155, the first flow meter 154, and the water outlet valve 152 are sequentially disposed on the water outlet pipe 151 along a water outlet flow direction. The first flow meter 154 and the second flow meter 142 may specifically employ electromagnetic flow meters. In order to improve the treatment efficiency, the dosing port and the water outlet on the catalytic ceramic membrane 131 can be respectively arranged at two ends of the catalytic ceramic membrane 131, and further can be arranged at two diagonal ports of the catalytic ceramic membrane 131, so as to facilitate the continuous water outlet and dosing oxidation cleaning stable operation of the membrane bioreactor.
The catalytic ceramic membrane 131 has a large number of membrane pores, and the pore diameter of the membrane pores is generally 50 to 500 nm. The pore walls of the pores of the catalytic ceramic membrane 131 are loaded with oxidation catalyst particles, the oxidation catalyst particles may be transition metal oxide particles, for example, at least one of manganese trioxide, copper oxide and iron oxide, the loading amount of the oxidation catalyst particles on the catalytic ceramic membrane 131 is generally controlled to be 0.5 to 5.0 wt%, and the loading amount specifically refers to the percentage of the mass of the loaded oxidation catalyst particles in the total mass of the catalytic ceramic membrane 131. In this embodiment, the main material of the catalytic ceramic membrane 131 is an alumina ceramic membrane, which includes a supporting layer and a membrane layer stacked together, the membrane layer and the supporting layer have a plurality of membrane pores, and the membrane pores on the membrane layer are loaded with manganese sesquioxide oxidation catalyst particles. A scanning electron microscope image of the catalytic ceramic membrane 131, as shown in fig. 2; in addition, X-ray energy spectrum analysis (EDS) was performed on M and N on the support layer of the catalytic ceramic membrane, respectively, and the results are shown in table 1, and it can be seen from table 1 that 0.7% (atomic percent) of manganese was loaded in the membrane layer of the catalytic ceramic membrane. In other embodiments, the catalytic ceramic membrane may be configured in other configurations, for example, the catalytic ceramic membrane may be prepared by directly mixing the oxidation catalyst particles with the catalytic ceramic membrane host material.
TABLE 1
In this embodiment, the membrane bioreactor further comprises a water inlet control system 16, and the water inlet control system 16 is connected to the reactor 11 through a water inlet pipe 161 for delivering the water to be purified into the reactor 11. In this embodiment, the water inlet control system 16 includes a water inlet pump 162, a third flow meter 163 and a water inlet valve 164, the water inlet pump 162 is connected to the reactor 11 through a water inlet pipe 161, and the third flow meter 163 and the water inlet valve 164 are sequentially disposed on the water inlet pipe 161 along the flow rate of the inlet water; the third flow meter 163 may be an electromagnetic flow meter.
In this embodiment, a liquid level meter 17 is further disposed in the reactor, so as to observe the liquid level in the reactor 11 in real time, and control the water inlet and outlet according to the liquid level, so as to ensure the stable operation of the water inlet and outlet in the reactor 11. In addition, in order to avoid that the oxidant excessively enters the water in the reactor 11 when the dosing system 14 is used for dosing, and the functional microbial activity of the activated sludge in the reactor 11 is affected, in the embodiment, an oxidant concentration detector 18 is further arranged in the reactor 11 and used for detecting the oxidant in the water in the reactor 11, so as to regulate and control the dosing system 14 to dose the oxidant when the oxidant or the concentration thereof is detected to exceed a preset value. In this embodiment, the reactor 11 is further provided with a sludge discharge valve 20, and the excess sludge in the reactor 11 can be periodically discharged through the sludge discharge valve 20. A dissolved oxygen detector 19 is also arranged in the reactor 11 for monitoring the dissolved oxygen concentration of the water body in the reactor 11 in real time.
In addition, in order to realize automatic control, the membrane bioreactor can be provided with an automatic control system which is respectively in communication connection with the aeration system 12, the water inlet control system 16, the liquid level meter 17, the oxidant concentration detector 18, the dissolved oxygen detector 19, the dosing system 14 and the water outlet control system 15.
The membrane bioreactor can be used for water purification, for example, the membrane bioreactor shown in FIG. 1 is used for water purification, and specifically comprises the following steps:
s1, feeding the water to be purified into the reactor 11. Specifically, the water inlet valve 164 of the water inlet control system 16 may be opened, and then the water inlet pump 162 may be activated to pump the water to be purified into the reactor 11, while the liquid level in the reactor 11 is monitored by the liquid level meter 17.
S2, starting the aeration system 12 to aerate the reactor, and filling the oxidant into the membrane holes of the catalytic ceramic membrane 131 through the dosing system 14. Specifically, the aeration valve 123 may be opened first, the air pump 121 is started to aerate the reactor 11 through the aeration pipe 122, and the dissolved oxygen concentration of the water body in the reactor may be monitored by a dissolved oxygen detector in the reactor, and the dissolved oxygen concentration of the water body in the reactor 11 is generally controlled to be not less than 4 mg/L; simultaneously, opening a valve 141 of the dosing system 14, starting a suction pump 143, filling an oxidant into the membrane pores of the catalytic ceramic membrane 131, monitoring the oxidant concentration in the water body in the reactor 11 through an oxidant concentration detector 18 in the reactor 11, and stopping filling the oxidant when detecting that the oxidant concentration is greater than 0.001mM so as to prevent excess oxidant from entering the reactor 11 and damaging the microbial activity of the activated sludge; the oxidizing agent may be hydrogen peroxide and/or a persulfate.
S3, filtering the water to be purified through the catalytic ceramic membrane module 13, pumping out the water through the water outlet control system 15, adsorbing the trapped organic pollutants on the membrane pores of the catalytic ceramic membrane 131 in the filtering process, and removing the organic pollutants by oxidation under the catalytic action of the oxidation catalyst particles loaded on the pore walls of the membrane pores.
In the above treatment process, the catalytic ceramic membrane 131 can be controlled to operate in a constant-flux pumping stop mode by the effluent control system 15, and the pumping filtration flux of the catalytic ceramic membrane 131 is subcritical flux (40-100L/m)2H); the membrane filtration pumping-stopping ratio can be 10-15 min: 1-2 min, but not limited to the pumping-stopping ratio, but at least 1min of stopping each time is guaranteed. Specifically, the water pump can be controlled by an automatic control system to adjust and control the pumping-out operation mode of the catalytic ceramic membrane 131.
In addition, in the treatment process, the transmembrane pressure difference change of the catalytic ceramic membrane 131 can be monitored in real time through a pressure gauge 153 in the effluent control system 15, and the transmembrane pressure difference increase of the catalytic ceramic membrane 131 is controlled to stably operate within a set threshold range of 40-45 kPa through chemical adding and cleaning treatment. In addition, the transmembrane pressure difference recovery rate of the catalytic ceramic membrane 131 after the chemical cleaning treatment in the filtration treatment process can be detected, and the transmembrane pressure difference recovery rate is equal to the ratio of the difference between transmembrane pressure differences before and after the addition of the oxidant to the transmembrane pressure difference increase amount in the filtration period.
When the transmembrane pressure difference recovery rate is equal to or higher than 50%, the oxidizing agent is added in step S2 in a normal water outlet dead space manner, which specifically includes: controlling the catalytic ceramic membrane 131 to operate according to a constant-flux pumping stop mode, filling an oxidant into a membrane hole through the dosing system 14 at a gap of an effluent control system for intermittent pumping filtration, wherein the filling concentration of the oxidant is 1-2 mM, the flux is 2 times of the filtering flux of the catalytic ceramic membrane, the filling time is 30s, and then, under the catalytic action of oxidation catalyst particles loaded on the catalytic ceramic membrane 131, the oxidant and organic pollutants adsorbed and trapped on the catalytic ceramic membrane 131 are subjected to oxidation reaction; adding an oxidant according to the normal water outlet intermittent gap mode, wherein the adding frequency is once every 1-6 hours;
when the transmembrane pressure difference recovery rate is higher than or equal to 30% and lower than 50%, in step S2, the step of filling the oxidizing agent in a manner of suspending normal water outlet and prolonging filling includes: suspending the effluent control system to stop the catalytic ceramic membrane 131 from operating according to a constant-flux pumping stop mode, filling an oxidant into the membrane hole through the dosing system 14, specifically, according to the filling concentration of the oxidant being 5-20 mM and the flux being 2 times of the filtering flux of the catalytic ceramic membrane, the duration being 30s, then stopping filling, under the catalytic action of the oxidation catalyst particles loaded on the catalytic ceramic membrane 131, carrying out an oxidation reaction on the oxidant and the organic pollutants adsorbed and trapped on the catalytic ceramic membrane 131 for 10-60 min, and then starting the effluent control system 15 to enable the catalytic ceramic membrane 131 to continue operating according to the constant-flux pumping stop mode; adding an oxidant at intervals of 1-6 h according to the mode of suspending normal water outlet and prolonging the adding; the pause time of the water outlet control system when the oxidant is filled is longer than the pause time of the catalytic ceramic membrane in the operation process of the constant-flux pumping-stopping mode; and the amount of the oxidant added in the mode of suspending normal water outlet and prolonging the adding is larger than that of the oxidant added in the mode of suspending normal water outlet and stopping the gap.
And when the transmembrane pressure difference recovery rate is lower than 30% and the transmembrane pressure difference increase of the catalytic ceramic membrane 131 exceeds the set threshold range of 40-45 kPa, stopping the operation of the membrane bioreactor, and taking out the catalytic ceramic membrane for cleaning.
The water purification process can be automatically controlled through an automatic control system in the specific treatment process, water to be purified is conveyed into the reactor 11 through the water inlet control system 16, meanwhile, the water level in the reactor 11 is monitored in real time through the liquid level meter 17 and is transmitted to the automatic control system, when the water level in the reactor 11 exceeds the preset water level by 0.5cm, the automatic control system stops the water inlet pump 162, closes the water inlet valve 164, water inlet is suspended, and when the water level is reduced to the preset range, the automatic control system starts the water inlet pump 162 and the water inlet valve 164 again. The reactor 11 is aerated by the aeration system 12, the dissolved oxygen concentration of the water in the reactor 11 is monitored by the dissolved oxygen detector and is transmitted to the automatic control system, and the aeration amount of the aeration system 12 is further controlled to control the dissolved oxygen concentration of the water in the reactor 11 not to be lower than 4 mg/L. The water to be purified is filtered by the catalytic ceramic membrane component 13, then is pumped out by the water outlet control system 15, and the automatic control system controls the water outlet valve 152 and the water outlet pump 155 of the water outlet control system 15 so as to regulate and control the pumping-out operation mode of the catalytic ceramic membrane 131; in the water outlet process, the first flow meter 154 detects the water flow on line, and when the water outlet flow is lower than the set membrane water outlet flow, the automatic control system controls and increases the rotating speed of the water outlet pump 155 to ensure that the membrane water outlet flow is stable; when the catalytic ceramic membrane enters a stop or cleaning state, the automatic control system controls to close the water outlet valve 152 and the water outlet pump 155. When the catalytic ceramic membrane 13 is cleaned, the automatic control system controls to open the valve 141 and the suction pump 143 of the chemical adding system 14 to inject the oxidizing agent into the membrane pores of the catalytic ceramic membrane 131, monitors the oxidizing agent concentration in the water body in the reactor 11 through the oxidizing agent concentration detector 18 in the reactor 11, and transmits the oxidizing agent concentration to the automatic control system, and when the detected oxidizing agent concentration is greater than 0.001mM, the automatic control system controls to close the valve 141 and the suction pump 143 of the chemical adding system 14 to stop injecting the oxidizing agent. In the water purification process, the transmembrane pressure difference of the catalytic ceramic membrane 131 is monitored in real time through the pressure gauge 153, the transmembrane pressure difference is transmitted to the automatic control system, the transmembrane pressure difference recovery rate of the catalytic ceramic membrane 131 is calculated, and then the medicine adding system 14 and the effluent control system 15 are regulated and controlled according to the transmembrane pressure difference and the transmembrane pressure difference recovery rate to switch different cleaning modes.
Application example
The membrane bioreactor shown in the figure 1 and a membrane bioreactor formed by replacing a traditional alumina ceramic membrane with a catalytic ceramic membrane in the membrane bioreactor shown in the figure 1 are respectively used as an experimental group and a control group, the membrane bioreactor of the experimental group and the membrane bioreactor of the control group are respectively adopted to repeatedly pump and filter 1mM hydrogen peroxide solution at the flux of 60LMH, the ratio of the hydrogen peroxide concentration in water in the reactor and the effluent of the membrane bioreactor to the initial concentration is measured under different running times, so as to investigate the effect of catalyzing the degradation of hydrogen peroxide by the ceramic membrane in the membrane bioreactor of the comparative experimental group and the membrane bioreactor of the control group, and the obtained result is shown in figure 3.
As can be seen from fig. 3, the conventional alumina ceramic membrane in the control group has no significant promoting effect on the degradation of hydrogen peroxide, while when a 1mM hydrogen peroxide solution passes through the pores of the manganese sesquioxide-loaded ceramic membrane, the hydrogen peroxide is rapidly catalytically degraded, and the hydrogen peroxide content in the membrane effluent of the catalytic ceramic membrane in the experimental group is substantially 0. Because the manganese sesquioxide loaded by the ceramic membrane in the experimental group has a strong catalytic degradation effect on the hydrogen peroxide, the concentration of the hydrogen peroxide in the reactor containing the manganese sesquioxide-loaded ceramic membrane is gradually reduced along with the membrane filtration, and therefore, the manganese sesquioxide-loaded ceramic membrane can efficiently catalyze the hydrogen peroxide reaction. In addition, compared with the traditional alumina ceramic membrane adopted by the control group, the ceramic membrane loaded with the manganese sesquioxide in the experimental group has higher hydrophilicity and stronger surface charge negativity, so that the ceramic membrane loaded with the manganese sesquioxide has stronger pollution resistance in water purification.
The experimental group and the control group membrane bioreactors are respectively adopted for purifying domestic water, and are divided into four groups for purifying experiments as follows:
the method comprises the following steps: purifying the domestic water by adopting a control group membrane bioreactor, and taking membrane effluent as cleaning fluid of a ceramic membrane in the treatment process;
group II: purifying the domestic water by adopting a control group membrane bioreactor, and adopting a 1mM hydrogen peroxide solution as a cleaning solution of a ceramic membrane in the treatment process;
group III: the membrane bioreactor of the experimental group is adopted for purifying domestic sewage, and 1mM hydrogen peroxide solution is adopted as cleaning solution of the ceramic membrane in the treatment process;
and fourthly: the membrane bioreactor of the experimental group is adopted for purifying domestic sewage, and membrane effluent is used as cleaning liquid of a ceramic membrane in the treatment process.
Except that the ceramic membrane material and the membrane cleaning liquid are different, the residual operating conditions of all groups of membrane bioreactors are controlled to be all consistent. In the treatment process, the filtration flux of the membrane is controlled to be 60LMH, the ceramic membrane is filtered by adopting a constant flux pumping stopping mode of pumping for 9min and stopping for 1min, the ceramic membrane is subjected to online medicine adding and cleaning once every 6h, the medicine adding flux is 120LMH, the medicine adding time is 30s, and the ceramic membrane is subjected to oxidation cleaning after being added with medicine and reacting for 10 min. The transmembrane pressure difference changes of the ceramic membranes under different running times are respectively detected, and the obtained results are shown in figure 4.
As can be seen from FIG. 4, after the four groups of membrane bioreactors stably operate for 24 hours, the transmembrane pressure difference of the membrane bioreactor in the group I is increased to 38.8 kPa; the transmembrane pressure difference of the middle membrane bioreactor is increased to 37.3 kPa; the transmembrane pressure difference of the middle membrane bioreactor is increased to 27.7 kPa; and the transmembrane pressure difference of the group III medium-film bioreactor only increases to 22.2 kPa.
Compared with the membrane bioreactor of the group I, the transmembrane pressure difference of the membrane bioreactor of the group II is reduced by 28.6 percent. Obviously, compared with the traditional alumina ceramic membrane, the manganese-containing catalytic ceramic membrane reactor has better pollution resistance, and the transmembrane pressure difference is increased more slowly in the actual sewage filtration process.
Compared with the membrane bioreactor of the group II, the transmembrane pressure difference of the membrane bioreactor of the group III is reduced by 40.5 percent. Clearly, a membrane bioreactor containing a confined catalytic hydrogen peroxide oxidation ceramic membrane achieves better membrane fouling control. When the online medicine adding and cleaning of the membrane pollution are carried out, the manganese-containing catalytic ceramic membrane can efficiently catalyze hydrogen peroxide to oxidize so as to remove organic pollutants blocked in membrane pores, so that the transmembrane pressure difference recovery rate of the manganese-containing catalytic ceramic membrane is higher than 30% after each medicine adding and cleaning, and the transmembrane pressure difference recovery rate of the traditional aluminum oxide ceramic membrane is lower than 10%.
In addition, the sludge mixed liquid in the reactor and the effluent quality of the membrane bioreactor are respectively detected after the domestic water purification treatment is finished, and the obtained results are respectively shown in tables 2 and 3.
TABLE 2 results of measuring the properties of the sludge mixture in the reactor
TABLE 3 Water quality test results of Membrane bioreactor effluent
As can be seen from Table 2, after the two groups of membrane bioreactors stably operate for 24 hours, the properties of the sludge mixed liquor are the same, particularly the specific oxygen consumption rate (SOUR) values representing the biological activity of the activated sludge are the same, no obvious difference occurs, and no hydrogen peroxide is detected in the two groups of membrane bioreactors, which indicates that the catalytic ceramic membrane in the experimental group of membrane bioreactors successfully controls the reaction of removing the organic matters by catalyzing the hydrogen peroxide in the membrane pores of the catalytic ceramic membrane, and no hydrogen peroxide enters the reactors, so that the microbial activity is protected from being influenced by the strong oxidation reaction. As can be seen from Table 3, the effluent quality of the two groups of membrane bioreactors after 24 hours of operation is the same, and no obvious difference occurs.
In summary, the membrane bioreactor shown in fig. 1 has better anti-pollution performance, wherein the pore wall of the pore of the ceramic membrane is loaded with oxidation catalyst particles, so that advanced oxidation reaction is efficiently integrated in the pore of the ceramic membrane, the floor area of the membrane bioreactor is reduced, organic pollutants are successfully removed by catalyzing oxidation of hydrogen peroxide in the pore of the catalytic ceramic membrane, the online efficient membrane pollution control can be realized, the microbial activity of activated sludge in the membrane bioreactor can be protected from being influenced by strong oxidation, and the stable effluent quality in the membrane bioreactor is ensured. In addition, it is understood that, based on a similar mechanism, other oxidation catalyst particles may be loaded in the pores of the ceramic membrane instead of manganese sesquioxide to form a catalytic ceramic membrane; the oxidizing agent used in the treatment process may also be other oxidizing agents, such as persulfates.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention. Furthermore, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.
Claims (10)
1. A membrane bioreactor, comprising:
a reactor;
an aeration system connected to the reactor;
the catalytic ceramic membrane component is arranged in the reactor; the catalytic ceramic membrane component comprises at least one catalytic ceramic membrane, a plurality of membrane holes are formed in the catalytic ceramic membrane, and oxidation catalyst particles are loaded on the wall of each membrane hole; the catalytic ceramic membrane is also provided with a water outlet and a medicine feeding port which are communicated with the membrane hole;
the dosing system is connected with the dosing port and is used for injecting an oxidant into the membrane hole;
and the water outlet control system is connected with the water outlet through a water outlet pipe.
2. The membrane bioreactor of claim 1, wherein said oxidation catalyst particles are transition metal oxide particles.
3. The membrane bioreactor of claim 1, wherein the water outlet control system comprises a water outlet valve, a pressure gauge, a first flow meter and a water outlet pump, and the pressure gauge, the water outlet pump, the first flow meter and the water outlet valve are sequentially arranged on the water outlet pipe along the water outlet flow direction;
the dosing system comprises a valve, a second flowmeter, a suction pump and an oxidant storage container; the oxidant storage container is connected with the dosing port through a pipeline; the suction pump, the second flowmeter and the valve are sequentially arranged on the pipeline along the conveying flow direction;
the aeration system comprises an air pump, an aeration pipe, an aeration valve, a gas flow meter and a gas pipe, wherein the aeration pipe is arranged at the lower part in the reactor and is connected with the air pump through the gas pipe, and the air pump, the gas flow meter, the aeration valve and the aeration pipe are sequentially arranged along the gas conveying direction.
4. A membrane bioreactor according to any one of claims 1 to 3, further comprising a water inlet control system connected to the reactor via a water inlet pipe.
5. The membrane bioreactor of claim 4, wherein a level gauge, an oxidant concentration detector and a dissolved oxygen detector are provided in the reactor.
6. The membrane bioreactor according to claim 5, further comprising an automatic control system, wherein said automatic control system is in communication with said aeration system, said water inlet control system, said level gauge, said oxidant concentration detector, said dissolved oxygen detector, said dosing system, and said water outlet control system, respectively.
7. A method for water purification, characterized in that a membrane bioreactor according to any one of claims 1 to 6 is used, comprising the following steps:
s1, feeding water to be purified into the reactor;
s2, starting the aeration system to aerate the reactor, and filling oxidant into the membrane pores through the dosing system;
and S3, filtering the water to be purified through the catalytic ceramic membrane module, and pumping out the water through the water outlet control system.
8. The water purification method according to claim 7, wherein in step S2, the concentration of the oxidant in the water body in the reactor is monitored during the process of injecting the oxidant into the membrane pores through the dosing system, and when the concentration of the oxidant is more than 0.001mM, the oxidant injection is stopped.
9. The water purification method of claim 7, wherein in step S3, the filtration process is controlled by the effluent control system to operate the catalytic ceramic membrane in a constant flux pump-down mode; and controlling the transmembrane pressure difference increase amount of the catalytic ceramic membrane within a set threshold range, wherein the set threshold range is 40-45 kPa.
10. The water purification method according to claim 9, wherein in step S3, a transmembrane pressure difference recovery rate of the catalytic ceramic membrane during the filtration treatment is detected, the transmembrane pressure difference recovery rate being equal to a ratio of a difference between transmembrane pressure differences before and after the addition of an oxidizing agent to a transmembrane pressure difference increase amount in a filtration cycle;
(1) when the transmembrane pressure difference recovery rate is equal to or higher than 50%, in step S2, the oxidant is injected in a normal water outlet dead space manner, specifically including: controlling the catalytic ceramic membrane to operate according to the constant-flux pumping stop mode, and injecting an oxidant into the membrane hole through the dosing system in a gap where the effluent control system stops pumping filtration so as to perform an oxidation reaction with the organic pollutants adsorbed and retained on the catalytic ceramic membrane; the filling frequency of the oxidant is once every 1-6 hours;
(2) when the transmembrane pressure difference recovery rate is higher than or equal to 30% and lower than 50%, in step S2, the filling of the oxidizing agent is performed in a manner of suspending normal water outlet and extending the filling, specifically including: pausing the water outlet control system to enable the catalytic ceramic membrane to stop operating according to the constant flux pumping-stopping mode, wherein the pause time is longer than the pause time of the catalytic ceramic membrane in the operating process according to the constant flux pumping-stopping mode, then injecting an oxidant into the membrane hole through the dosing system to perform oxidation reaction with the organic pollutants adsorbed and intercepted on the catalytic ceramic membrane, and then starting the water outlet control system to enable the catalytic ceramic membrane to operate according to the constant flux pumping-stopping mode;
adding an oxidant at intervals of 1-6 h according to the mode of suspending normal water outlet and prolonging the adding; the amount of the oxidant injected in the mode of suspending normal water outlet and prolonging the injection is larger than that of the oxidant injected in the mode of suspending the interval of normal water outlet;
(3) and when the transmembrane pressure difference recovery rate is lower than 30 percent and the transmembrane pressure difference increase of the catalytic ceramic membrane exceeds the set threshold range, stopping the operation of the membrane bioreactor, and taking out the catalytic ceramic membrane for cleaning.
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