Wastewater treatment device and wastewater treatment method

Abstract

The present invention discloses a wastewater treatment device, comprising a membrane bioreactor, an electrocatalytic anode membrane assembly, and a direct current power supply. The electrocatalytic anode membrane assembly is connected to the outlet of the membrane bioreactor, and the electrocatalytic anode membrane assembly comprises a microfiltration membrane anode and a porous cathode. The microfiltration membrane anode is electrically connected to the positive electrode of the direct current power supply, and the porous cathode is electrically connected to the negative electrode of the direct current power supply. The present invention also discloses a wastewater treatment method, which uses the above-mentioned wastewater treatment device to treat wastewater, comprising: introducing the wastewater into the membrane bioreactor, decontaminating the wastewater in the membrane bioreactor, filtering the wastewater through the electrocatalytic anode membrane assembly, and then discharging the wastewater. The wastewater treatment device and wastewater treatment method proposed in the present invention can effectively alleviate the problem of membrane fouling.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a wastewater treatment device and a wastewater treatment method. Background Art

[0002] With the continuous development of the global economy and the increasing population, water pollution has attracted widespread attention. Traditional biological wastewater treatment technologies include the anaerobic-anoxic-aerobic wastewater treatment process (A2O process), the sequencing batch activated sludge process (SBR process), and the oxidation ditch process. All of these utilize activated sludge microorganisms to degrade pollutants, often requiring large secondary sedimentation tanks. The membrane bioreactor (MBR) combines the activated sludge process with membrane separation technology. Through the interception and filtration of ultrafiltration or microfiltration membranes, the activated sludge remains in the reactor for a longer period of time for sufficient biosorption and biodegradation. This enhances the reactor's biological treatment of pollutants, eliminates the need for large secondary sedimentation tanks, and significantly improves solid-liquid separation efficiency. It is currently a widely used wastewater treatment technology. MBR can effectively treat different types of wastewater, and its high mixed liquor suspended solids concentration (MLSS) and long sludge retention time (SRT) make it highly resistant to shock loads.

[0003] However, in recent years, the country's requirements for wastewater treatment and discharge standards have gradually increased. Traditional biological treatment technologies can no longer meet increasingly stringent wastewater discharge standards. People are urgently in need of biological treatment technologies that are easy to operate, have high wastewater treatment efficiency, resist membrane fouling, and effectively degrade new pollutants. Although MBR wastewater treatment technology can be effectively applied to wastewater treatment, it still has some defects and technical challenges. For example, low membrane fouling control efficiency, poor phosphorus removal, and inability to effectively remove new pollutants (such as personal care products (PPCPs)) have made it difficult for effluent water quality to meet standards.

[0004] The disclosure of the above background technology content is only used to assist in understanding the concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention proposes a wastewater treatment device and a wastewater treatment method, which can effectively alleviate the problem of membrane fouling.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention discloses a wastewater treatment device, comprising a membrane bioreactor, an electrocatalytic anode membrane assembly and a direct current power supply, wherein the electrocatalytic anode membrane assembly is connected at the outlet of the membrane bioreactor, the electrocatalytic anode membrane assembly comprises a microfiltration membrane anode and a porous cathode, the microfiltration membrane anode is electrically connected to the positive pole of the direct current power supply, and the porous cathode is electrically connected to the negative pole of the direct current power supply.

[0008] Preferably, the microfiltration membrane anode adopts a cylindrical structure with one end open and the other end closed, and the porous cathode adopts a cylindrical structure with both ends open. The porous cathode is sleeved on the outside of the microfiltration membrane anode and a preset gap is left between the porous cathode and the microfiltration membrane anode.

[0009] Preferably, a preset gap of 0.5 to 1 cm is left between the porous cathode and the microfiltration membrane anode.

[0010] Preferably, the height of the porous cathode is greater than the height of the microfiltration membrane anode, and quartz rings are provided between the outer side of the closed end of the microfiltration membrane anode and the inner wall of the porous cathode, as well as between the outer side of the open end of the microfiltration membrane anode and the inner wall of the porous cathode, so that a preset gap is left between the porous cathode and the microfiltration membrane anode.

[0011] Preferably, the microfiltration membrane anode adopts a microfiltration ceramic membrane.

[0012] Furthermore, the microfiltration membrane anode is made of titanium dioxide.

[0013] Preferably, the porous cathode is made of stainless steel mesh.

[0014] Furthermore, the pore size of the stainless steel mesh is 3 to 4 mm.

[0015] Preferably, the wastewater treatment device further comprises a transmembrane differential pressure meter, which is connected to the microfiltration membrane anode to measure the transmembrane differential pressure of the microfiltration membrane anode.

[0016] Furthermore, the membrane bioreactor includes a reaction container, a water inlet device, a water outlet device, a first dissolved oxygen concentration regulating device, a second dissolved oxygen concentration regulating device, a third dissolved oxygen concentration regulating device, a reflux device, a mud discharge device and a control device, wherein the control device is respectively connected to and controls the water inlet device, the water outlet device, the first dissolved oxygen concentration regulating device, the second dissolved oxygen concentration regulating device, the third dissolved oxygen concentration regulating device, the reflux device and the mud discharge device, wherein:

[0017] The reaction vessel is provided with a facultative anaerobic bio-tank, a first aerobic bio-tank, and a second aerobic bio-tank, which are separated from each other, in sequence. A first baffle is provided between the facultative anaerobic bio-tank and the first aerobic bio-tank, and a second baffle is provided between the first aerobic bio-tank and the second aerobic bio-tank. The upper ends of the first baffle and the second baffle are both lower than the upper port of the reaction vessel.

[0018] The first dissolved oxygen concentration regulating device is disposed in the facultative biological pool to regulate the dissolved oxygen concentration in the facultative biological pool, the second dissolved oxygen concentration regulating device is disposed in the first aerobic biological pool to regulate the dissolved oxygen concentration in the first aerobic biological pool, and the third dissolved oxygen concentration regulating device is disposed in the second aerobic biological pool to regulate the dissolved oxygen concentration in the second aerobic biological pool;

[0019] The water inlet device is connected to the inlet of the facultative aerobic biological pool, the electrocatalytic anode membrane assembly is arranged in the second aerobic biological pool, and the outlet of the electrocatalytic anode membrane assembly is connected to the water outlet device, the inlet of the reflux device and the mud discharge device are respectively connected to the lower end of the second aerobic biological pool, and the outlet of the reflux device is connected to the inlet of the facultative aerobic biological pool.

[0020] In a second aspect, the present invention discloses a wastewater treatment method, which uses the wastewater treatment device described in the first aspect to treat wastewater, including: introducing the wastewater into the membrane bioreactor, decontaminating the wastewater through the membrane bioreactor, and then filtering it through the electrocatalytic anode membrane assembly and discharging it.

[0021] Preferably, during the wastewater treatment process, the DC power supply is powered on 1 to 2 times per day, with a current density of 2 to 5 mA / cm 2 Each power-on time is 2 to 5 minutes.

[0022] Preferably, the wastewater treatment device of the preferred scheme of the first aspect is used to treat the wastewater, including: introducing the wastewater into the facultative biological pool through the water inlet device, with a hydraulic retention time of 4 to 5 hours, the effluent overflowing through the top of the first baffle to the first aerobic biological pool, and the hydraulic retention time in the first aerobic biological pool is 8 to 9 hours, the effluent overflowing through the top of the second baffle to the second aerobic biological pool, and the hydraulic retention time in the second aerobic biological pool is 7 to 8 hours, and the effluent is filtered through the electrocatalytic anode membrane assembly and discharged from the water outlet device, wherein a part of the sludge mixed liquid at the bottom of the second aerobic biological pool is refluxed to the facultative biological pool through the reflux device, and the other part is discharged through the sludge discharge device, and the sludge return ratio is 300% to 400%.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: the wastewater treatment device proposed in the present invention couples an electrocatalytic anode membrane assembly in a membrane bioreactor, wherein the microfiltration membrane anode as an anode has synergistic effects such as direct oxidation, electrophoresis and electroosmosis mechanisms, thereby not only improving the removal efficiency of pollutants (including new pollutants such as antibiotics), but also controlling membrane pollution by in-situ oxidation and cleaning, significantly delaying membrane pollution, and achieving the goal of not having to clean the membrane within the operating range.

[0024] In a further embodiment, the present invention also has the following beneficial effects:

[0025] (1) The treatment efficiency and mechanism of action of electrode assemblies of different configurations in membrane bioreactors will vary greatly. The present invention innovatively proposes to adopt an electrocatalytic anode membrane assembly with a sleeve-type structure of anode and cathode. The effluent will first pass through the porous cathode and then through the microfiltration membrane anode. The sleeve-type structure makes the distance between the anode and cathode closer, reducing the resistance and voltage, and further realizing the organic combination of the electrocatalytic anode membrane assembly and the membrane bioreactor, achieving better resistance to membrane fouling and degradation of new pollutants in wastewater.

[0026] (2) A preset gap of 0.5 to 1 cm is left between the microfiltration membrane anode and the porous cathode, which further reduces the resistance and voltage, and better integrates the electrocatalytic anode membrane assembly into the membrane bioreactor. While effectively alleviating the problem of membrane fouling, it also further improves the removal of new pollutants and phosphorus removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure of the wastewater treatment device disclosed in the first embodiment of the present invention;

[0028] Figure 2 yes Figure 1 Schematic diagram of the structure of the electrocatalytic anode membrane assembly;

[0029] Figure 3 The wastewater treatment device disclosed in the first embodiment of the present invention is in the non-powered control group (MBR control ), power supply frequency 1 time / day (MBR e1 ), power supply frequency 2 times / day (MBR e2 ) changes in transmembrane pressure difference;

[0030] Figure 4 It is a redundancy analysis diagram of the correlation between electrocatalysis, sludge mixed liquor properties and membrane fouling resistance. DETAILED DESCRIPTION

[0031] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and circuit / signal communication.

[0033] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0035] Studies have found that membrane fouling is mainly caused by extracellular polymeric substances (EPS) and soluble microbial products (SMP). The occurrence of membrane fouling will lead to a decrease in membrane flux, deterioration of effluent water quality and shortened membrane service life, affecting the normal operation of MBR. Therefore, membrane fouling is one of the main reasons hindering the widespread application of MBR.

[0036] Because activated sludge microorganisms are mostly negatively charged, the use of anodic membranes in membrane bioreactors (MBRs) can lead to electrostatic adsorption, theoretically leading to more severe membrane fouling. Furthermore, the currently commonly used anodic membrane operation method is suitable for treating high-salinity, high-conductivity wastewater (such as ammonium sulfate solutions), which is not suitable for the MBR field. Therefore, the electrocatalytic membrane modules currently being studied and applied to MBRs are cathodic membranes, which have been reported to have the ability to degrade new pollutants and mitigate membrane fouling.

[0037] However, through further research, the inventors discovered that the cathode membrane is primarily an electroreduction membrane and cannot directly electrooxidize new pollutants and pollutants on the membrane. While the electrocatalytic anode membrane has an electrostatic adsorption effect on microorganisms, it primarily undergoes electrooxidation, directly capturing electrons at the anode to oxidize organic matter. This is beneficial for degrading organic pollutants and new pollutants in wastewater, while also directly degrading organic pollutants adsorbed and deposited on the membrane, thereby bringing about the original self-cleaning effect and effectively controlling membrane fouling. Before discharge, wastewater is fully exposed to the electrocatalytic anode membrane, making full use of electrooxidation, electrophoresis, and electroosmosis mechanisms, which is beneficial for further improving the degradation efficiency of organic pollutants and new pollutants in wastewater. At the same time, electrocatalysis can effectively control the concentrations of SMP and EPS in the sludge mixture and the degree of microbial adhesion on the membrane, thereby further reducing membrane fouling.

[0038] In order to solve the defects of traditional biological treatment technology such as difficult to meet effluent water quality standards, low membrane fouling control efficiency, and poor removal of new pollutants, the wastewater treatment device of the present invention (i.e., electrocatalytic membrane bioreactor) couples electrocatalysis with membrane bioreactor in order to achieve the purpose of resisting membrane fouling and degrading new pollutants in wastewater.

[0039] like Figure 1 As shown, the first embodiment of the present invention discloses a wastewater treatment device, including a membrane bioreactor, an electrocatalytic anode membrane assembly, a DC power supply 14 and a transmembrane pressure differential meter 12, that is, the wastewater treatment device adopts an electrocatalytic membrane bioreactor.

[0040] The membrane bioreactor includes a reaction container, a water inlet device, a water outlet device, a first dissolved oxygen concentration regulating device, a second dissolved oxygen concentration regulating device, a third dissolved oxygen concentration regulating device, a reflux device, a sludge discharge device and a control device, and the control device is respectively connected to and controls the water inlet device, the water outlet device, the first dissolved oxygen concentration regulating device, the second dissolved oxygen concentration regulating device, the third dissolved oxygen concentration regulating device, the reflux device and the sludge discharge device.

[0041] Specifically, the reaction vessel is provided with a facultative anaerobic biological pool 1, a first aerobic biological pool 2 and a second aerobic biological pool 3 separated from each other in sequence, a first baffle is provided between the facultative anaerobic biological pool 1 and the first aerobic biological pool 2, and a second baffle is provided between the first aerobic biological pool 2 and the second aerobic biological pool 3, and the upper ends of the first baffle and the second baffle are both lower than the upper port of the reaction vessel.

[0042] The water inlet device includes a water inlet pump 4 and a liquid level relay 9. The water inlet pump 4 is connected to the inlet of the facultative anaerobic biological pool 1 to introduce wastewater into the facultative anaerobic biological pool 1. The liquid level relay 9 is used to control the pumping and stopping of the water inlet pump 4 to achieve automatic water inlet and prevent liquid from overflowing the reaction container.

[0043] The water outlet device includes a water outlet pump 11 and a time relay 13. The water outlet pump 11 is connected to the outlet of the electrocatalytic anode membrane assembly so that the sewage treated in the facultative biological pool 1, the first aerobic biological pool 2 and the second aerobic biological pool 3 in sequence is filtered through the electrocatalytic anode membrane assembly and then discharged. The time relay 13 is used to control the pumping and stopping of the water outlet pump.

[0044] The first dissolved oxygen concentration regulating device includes an agitator 5 and a first dissolved oxygen detector 6. The end of the agitator 5 extends into the facultative anaerobic biological pool 1 for continuous stirring. The end of the first dissolved oxygen detector 6 extends into the facultative anaerobic biological pool 1 for real-time detection of the dissolved oxygen concentration in the facultative anaerobic biological pool 1, and controls the dissolved oxygen concentration to be ≤0.5 mg / L to maintain the facultative anaerobic state.

[0045] The second dissolved oxygen concentration regulating device includes a first air aeration pump 7, a first air flow meter 8, a first aeration device 19, and a second dissolved oxygen detector 10. The first aeration device 19 is disposed within the first aerobic biological tank 2 and is sequentially connected by hoses. The first air aeration pump 7 continuously releases oxygen, which is then controlled by the first air flow meter 8 before entering the first aeration device 19. Finally, the oxygen bubbles formed by the first aeration device 19 are aerated into the first aerobic biological tank 2. The end of the second dissolved oxygen detector 10 extends into the first aerobic biological tank 2 to monitor the dissolved oxygen concentration within the first aerobic biological tank 2 in real time, controlling the dissolved oxygen concentration to 1.5 to 2.5 mg / L to maintain an aerobic state.

[0046] The third dissolved oxygen concentration regulating device includes a second air aeration pump 17, a second air flow meter 18, and a second aeration device 20. The second aeration device 20 is disposed within the second aerobic biological tank 3. The second air aeration pump 17, the second air flow meter 18, and the second aeration device 20 are sequentially connected by a hose. The second air aeration pump 17 continuously aerates oxygen, the gas flow of which is controlled by the second air flow meter 18 before entering the second aeration device 20. Finally, the second aeration device 20 forms oxygen bubbles that are aerated into the second aerobic biological tank 3. In this embodiment, the third dissolved oxygen concentration regulating device does not need to include a dissolved oxygen detector. This is because the first aeration device 19 used in the first aerobic biological tank 2 and the second aeration device 20 used in the second aerobic biological tank 3 are the same type of aeration heads, and the aeration rates of the first air aeration pump 7 and the second air aeration pump 17 are also the same. Therefore, the second dissolved oxygen detector 10 can be installed only in the first aerobic biological tank 2. Furthermore, a power supply and other equipment need not be installed at the top of the second aerobic biological tank 3, thereby avoiding space congestion.

[0047] The reflux device utilizes a reflux pump 21, and the sludge discharge device utilizes a sludge discharge valve 22. The inlet of the reflux pump 21 and the sludge discharge valve 22 are respectively connected to the lower end of the second aerobic biological tank 3, and the outlet of the reflux pump 21 is connected to the inlet of the facultative biological tank 1. The control device utilizes an automatic control cabinet 23, which is connected to each device to achieve automatic long-term operation of the electrocatalytic membrane bioreactor.

[0048] The electrocatalytic anode membrane assembly is connected to the outlet of the membrane bioreactor. The electrocatalytic anode membrane assembly includes a microfiltration membrane anode 15 and a porous cathode 16. The microfiltration membrane anode 15 is electrically connected to the positive electrode of the DC power supply 14, and the porous cathode 15 is electrically connected to the negative electrode of the DC power supply 14. Figure 2 The microfiltration membrane anode 15 adopts a cylindrical structure with one end open and the other end closed, and the porous cathode 16 adopts a cylindrical structure with both ends open. The porous cathode 16 is fitted on the outside of the microfiltration membrane anode 15 and a preset gap is left between the porous cathode 16 and the microfiltration membrane anode 15. The transmembrane differential pressure meter 12 is connected to the microfiltration membrane anode 16 to measure the transmembrane pressure difference of the microfiltration membrane anode 16.

[0049] Specifically, the microfiltration membrane anode 15 is made of titanium dioxide (Ti4O7), a titanium dioxide ceramic tubular membrane, with the membrane and electrode coupled together. The active area of ​​the microfiltration membrane anode 15 has a diameter of 2 to 3 cm and a height of 12 to 14 cm. One end is open and the other is closed. The open end is connected to the outlet pipe. After being filtered by the microfiltration membrane anode 15, the wastewater is discharged through peristalsis to the outlet pump 11. A conductive column 151 is provided at the open end of the microfiltration membrane anode 15, which is 4 to 5 cm long. The conductive column 151 is connected to the positive terminal of the DC power supply 14 via an alligator clip cable.

[0050] The porous cathode 16 is made of a wound stainless steel mesh (specifically, a high-purity titanium mesh) with a pore size of 3-4 mm, an active area diameter of 3-4 cm, and a height of 13-15 cm. A conductive post 161 6-7 cm long is provided at one end of the porous cathode 16 (the end corresponding to the open end of the microfiltration membrane anode 15). This post 161 is connected to the negative electrode of the DC power supply 14 via an alligator clip cable.

[0051] The microfiltration membrane anode 15 is located inside, and the porous cathode 16 is located outside, forming a sleeve configuration. The porous cathode 16 is taller than the microfiltration membrane anode 15. Quartz rings 162 are located between the closed end of the microfiltration membrane anode 15 and the inner wall of the porous cathode 16, as well as between the open end of the microfiltration membrane anode 15 and the inner wall of the porous cathode 16. This ensures a preset gap of 0.5 to 1 cm between the porous cathode 16 and the microfiltration membrane anode 15. By providing a smaller preset gap between the anode and cathode, the resistance and voltage can be reduced, making it suitable for the membrane bioreactor in the embodiments of the present invention.

[0052] The operating parameters of the electrocatalytic anode membrane assembly in this embodiment are: anode membrane area 120-140 cm 2 , membrane flux 10-15LMH. Preferably, the current density is 2-5mA / cm 2 The power-on time is 2 to 5 minutes, and the power-on frequency is 1 time / day or 2 times / day.

[0053] The wastewater treatment device (electrocatalytic membrane bioreactor) proposed in this embodiment couples electrocatalysis, membrane filtration and biological treatment into one, and can achieve continuous and automatic operation. At the same time, the water quality of the effluent is better than that of traditional membrane bioreactors.

[0054] A second embodiment of the present invention discloses a wastewater treatment method, which uses the wastewater treatment device provided in the first embodiment to treat wastewater, wherein the wastewater is one of domestic sewage, industrial wastewater, and biopharmaceutical wastewater, and comprises the following steps:

[0055] S1. The wastewater is lifted by the water inlet pump 4 and enters the facultative aerobic biological pool 1. In the facultative aerobic biological pool 1, the agitator 5 continuously stirs the wastewater and biological sludge to mix evenly and fully contact the reaction, while allowing the organisms to perform facultative aerobic reactions. Denitrifying bacteria use the undecomposed carbon-containing organic matter in the sewage as a carbon source to reduce the nitrate and nitrite ions circulating from the first aerobic biological pool 2 and the second aerobic biological pool 3 into nitrogen gas and release it to achieve denitrification. At the same time, polyphosphate microorganisms (polyphosphate bacteria, etc.) release phosphorus anaerobically. This process removes some organic pollutants in the sewage. The hydraulic retention time in the facultative aerobic biological pool 1 is 4 to 5 hours, and the effluent overflows from the top of the first baffle to the first aerobic biological pool 2. The dissolved oxygen concentration of the facultative aerobic biological pool 1 is detected in real time by the first dissolved oxygen detector 6, and the dissolved oxygen concentration is controlled to be ≤0.5 mg / L to maintain the facultative aerobic state.

[0056] S2. The sludge mixture from the facultative aerobic biological tank 1 overflows into the first aerobic biological tank 2, with a hydraulic retention time of 8 to 9 hours. In the first aerobic biological tank 2, a first air aeration pump 7, a first air gas flowmeter 8, and a first aeration device 19 are provided to aerate the first aerobic biological tank 2 and stir the sludge mixture. A second dissolved oxygen detector 10 is also provided to regulate the first air aeration pump 7, maintaining the dissolved oxygen concentration in the first aerobic biological tank 2 within a suitable range for aerobic organisms to carry out aerobic reactions. Specifically, the dissolved oxygen concentration in the first aerobic biological tank 2 is monitored in real time by the second dissolved oxygen detector 10, and the dissolved oxygen concentration is controlled to 1.5 to 2.5 mg / L to maintain an aerobic state. In the first aerobic biological tank 2, nitrifying bacteria oxidize ammonia nitrogen in the wastewater into nitrate and nitrite through nitrification. Simultaneously, phosphorus-accumulating microorganisms aerobically absorb phosphorus, enriching it within the microorganisms. The sludge is then discharged from the system as phosphorus-rich sludge via the subsequent sludge pump, achieving phosphorus removal.

[0057] S3, the sludge mixture from the first aerobic biological pool 2 overflows into the second aerobic biological pool 3, with a hydraulic retention time of 7 to 8 hours. The effluent is filtered through a microfiltration membrane anode 15 and pumped out by an effluent pump 11. In the second aerobic biological pool 3, the upper half is designed as two sets of electrocatalytic anode membrane assemblies, each consisting of a microporous titanium dioxide (Ti4O7) ceramic tubular membrane as the anode (i.e., the microfiltration membrane anode 15) and a high-purity titanium mesh as the cathode (i.e., the porous cathode 16). These assemblies are connected to a DC power supply 14 for control, which intermittently supplies power to the electrocatalytic anode membrane assemblies. Similar to the first aerobic biological pool 2, an aeration device (including a second air aeration pump 17, a second air gas flowmeter 18, and a second aeration device 20) is provided to maintain aerobic conditions in the second aerobic biological pool 3. In the second aerobic biological pool 3, the electrocatalytic anode membrane assembly couples the membrane and electrode into one unit. Electrocatalysis not only stimulates sludge microorganisms but also controls membrane fouling and improves the removal rate of PPCPs.

[0058] S4. After the wastewater in the second aerobic biological pool 3 is treated, the top open end of the electrocatalytic anode membrane assembly is connected to the outlet pipe. The wastewater is filtered and pumped out through the electrocatalytic anode membrane assembly by the outlet pump 11. A transmembrane pressure gauge 12 monitors the transmembrane pressure differential across the microfiltration membrane anode 15 in real time. When the transmembrane pressure differential (ΔTMP) (ΔTMP = transmembrane pressure minus membrane resistance) reaches 30 kPa, wastewater treatment is suspended and the membrane is cleaned. A time relay 13 controls the pumping and stopping of the outlet pump 11, achieving automated operation. The outlet pump has a constant pumping and stopping ratio of (8-9 min): (1-2 min), for example, 9 min:1 min. Simultaneously, the bottom sludge from the second aerobic biological pool 3 is returned to the facultative biological pool 1 via the sludge return pump 21, with the sludge return ratio controlled at 300%-400%. The sludge mixture from the bottom of the second aerobic biological pool 3 is discharged via the sludge discharge valve 22, with the sludge retention time controlled at 30-35 days. Each operating device in the membrane bioreactor is automatically operated through the automatic control cabinet 23.

[0059] In this embodiment, the volume of the facultative anaerobic biotank 1 in the membrane bioreactor is 2.0 to 2.5 L, the volume of the first aerobic biotank is 3.5 to 4.0 L, and the volume of the second aerobic biotank 3 is 2.5 to 3.0 L, for a total volume of 8 to 9.5 L for the membrane bioreactor. The hydraulic retention time of the wastewater in the membrane bioreactor is 20 to 24 hours.

[0060] During the wastewater treatment process, the agitator of the facultative aerobic biological pool 1 continuously stirs, and the aeration devices of the first aerobic biological pool 2 and the second aerobic biological pool 3 continuously aerate, so as to control the dissolved oxygen concentration of the facultative aerobic biological pool 1 to be ≤0.5 mg / L, and the dissolved oxygen concentration of the first aerobic biological pool 2 and the second aerobic biological pool 3 to be 1.5-2.5 mg / L.

[0061] The effects of the wastewater treatment device and wastewater treatment method proposed in the embodiments of the present invention are further illustrated below with reference to specific experimental cases.

[0062] The wastewater treatment device provided in Example 1, which includes an electrocatalytic ceramic membrane, was operated for 130 days according to the wastewater treatment method of Example 2. The effluent quality indicators, including total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP), were measured. The experimental effluent quality results are shown in Table 1. Table 1 lists the effluent quality of the wastewater treatment device (electrocatalytic membrane bioreactor) in the control group (MBR) without power supply. control ), power supply frequency 1 time / day (MBR e1 ), power supply frequency 2 times / day (MBR e2 )’s effluent water quality results.

[0063] Table 1

[0064]

[0065] Among them, MBR control 、MBR e1 and MBR e2 The effluent TOC concentrations were 2.63±0.41mg / L, 2.65±0.58mg / L and 2.90±0.44mg / L, respectively. The TOC removal effects of each membrane bioreactor were similar. The effluent TN concentrations were 11.15±2.41mg / L, 10.93±1.99mg / L and 10.65±2.23mg / L, respectively. e1 and MBR e2 The removal efficiency of TN increased by 1.97% and 4.48% respectively. The results showed that electrocatalysis enhanced the denitrification of activated sludge and thus enhanced the treatment effect of membrane bioreactor on TN. control 、MB R e1 and MBR e2 The TP removal rates were 87.41%, 89.51% and 81.79% respectively, among which MBR e1 The treatment effect on TP is the best. The results show that the effluent quality of the electrocatalytic membrane bioreactor is good and it is beneficial to improve the removal rate of TP.

[0066] The wastewater treatment device provided in Example 1, which includes an electrocatalytic ceramic membrane, was operated according to the wastewater treatment method of Example 2 under the condition of a constant flux of 15LMH. The wastewater treatment device was operated in the control group (MBR) without power supply. control ), power-on frequency 1 time / day (MB R e1 ), power supply frequency 2 times / day (MBR e2 ) under the conditions of the membrane bioreactor, the changes in the transmembrane pressure (TMP) of each membrane bioreactor are as follows Figure 3 As shown. Figure 3 It can be seen that in the non-powered control group (MBR control ) for 11 consecutive days, the TMP reached 30kPa, and the power supply frequency was once a day (MBR e1 ) for 21 days, the TMP reaches 30kPa, and the power supply frequency is 2 times / day (MBR e2 ) under the conditions of first rising and then falling, showing a fluctuating state and not yet reaching 30 kPa. According to the transmembrane pressure difference of each membrane bioreactor, it can be seen that the electrocatalytic effect of the microfiltration membrane anode 15 (titanium suboxide anode membrane) directly acts on the membrane, which is conducive to slowing down the increase of the transmembrane pressure difference, delaying the critical time of membrane fouling, and facilitating the mitigation of membrane fouling. At the same time, the higher the power supply frequency, the stronger the ability to mitigate membrane fouling, and the membrane can achieve a self-cleaning effect.

[0067] The redundancy analysis method (RDA) was used to quantitatively analyze the correlation between electrocatalysis, sludge mixed liquor properties and membrane fouling resistance, in order to explain the membrane fouling control mechanism of electrocatalytic membrane bioreactor. Figure 4 As shown in Figure 2, the first and second axes explain 75.24% and 22.97% of the total variance of membrane fouling resistance, respectively. t ) including the cake layer pollution resistance (R c ), gel layer contamination resistance (R g ) and pore contamination resistance (R p ). For the total resistance to membrane fouling, Zeta potential, extracellular polymeric substances (EPS) and fluorescent characteristic organic matter (EEM) are positively correlated, and EPS has the highest positive correlation; while sludge particle size, sludge concentration, dissolved organic matter (DOC) and dissolved microbial products (SMP) are negatively correlated, and DOC has the highest negative correlation. Studies have shown that lower EPS concentration and lower Zeta potential will lead to reduced repulsion between sludge particles and show a stronger aggregation tendency, thereby reducing the adsorption of sludge on the membrane surface to alleviate the formation of membrane fouling cake layer, thereby alleviating membrane fouling. Combined with the results of redundancy analysis, EPS and Zeta potential have a high positive correlation with the total resistance to membrane fouling, indicating that electrocatalysis can control membrane fouling by significantly reducing EPS concentration and Zeta potential in sludge mixed liquor. Membrane bioreactor MBR without electricity control They are all in the right half of the first axis, which is consistent with the direction of the total membrane fouling resistance and the cake layer fouling resistance, while the gel layer fouling resistance and the pore fouling resistance are in the opposite direction, indicating that MBR control The reduction of the total resistance of membrane fouling and the resistance of the filter cake layer is limited. The filter cake layer deposited on the membrane surface has a slowing effect on the formation of gel layer pollution and pore pollution. e1 and MBR e2They are all in the left half of the first axis, indicating that electrocatalysis has an obvious effect on reducing the total resistance of membrane fouling and the resistance of the filter cake layer.

[0068] Table 2 below shows the power-on frequency of 2 times / day (MBR e2 ) electrocatalytic membrane bioreactor under the conditions of influent PPCPs concentration of 200ng / L, 2000ng / L and 20000ng / L.

[0069] Table 2

[0070]

[0071] Table 2 shows the removal efficiency of five antibiotic PPCPs, including ofloxacin (OFX), tetracycline (TC), roxithromycin (ROX), sulfadiazine (SFD), and sulfamethoxazole (SFM), using the wastewater treatment apparatus and method according to an embodiment of the present invention. The results in Table 2 demonstrate that an electrocatalytic membrane bioreactor operating at a power supply frequency of twice per day exhibits excellent PPCP removal efficiency. Specifically, when the influent PPCPs concentration is 200 ng / L, the PPCPs removal rate is greater than 91.6% in the initial stage of operation (20 days), greater than 74.3% in the middle stage of operation (50 days), and slightly decreased at the end of operation (90 days) but still greater than 66.9%; when the influent PPCPs concentration is 2000 ng / L, the PPCPs removal rate is greater than 87.0% in the initial stage of operation (20 days), greater than 85.5% in the middle stage of operation (50 days), and slightly decreased at the end of operation (90 days) but still greater than 68.5%; when the influent PPCPs concentration is 20000 ng / L, the PPCPs removal rate of the electrocatalytic membrane bioreactor is significantly reduced, and the PPCPs removal capabilities are equivalent in the initial stage (20 days), middle stage (50 days) and end stage (90 days), with a removal rate greater than 50.2%. Specifically, among different antibiotics, the electrocatalytic membrane bioreactor had the worst removal efficiency for ofloxacin (OFX), and the removal efficiency decreased significantly with increasing operation time. Overall, the electrocatalytic membrane bioreactor has a stable and efficient removal effect on PPCPs, and it is feasible to apply the wastewater treatment device provided by this embodiment of the invention to the treatment of wastewater containing new pollutants.

[0072] The background section of the present invention may contain background information about the problem or environment of the present invention rather than describing prior art by others. Therefore, the inclusion of content in the background section is not an admission by the applicant that the prior art is available.

[0073] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features from different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of the appended claims.

Claims

1. A wastewater treatment method, wherein wastewater is treated using a wastewater treatment device, characterized in that: The wastewater treatment device includes a membrane bioreactor, which includes an electrocatalytic anode membrane assembly and a direct current power supply. The electrocatalytic anode membrane assembly is connected to the outlet of the membrane bioreactor. The electrocatalytic anode membrane assembly includes a microfiltration membrane anode and a porous cathode. The microfiltration membrane anode adopts a cylindrical structure with one end open and the other end closed, and the porous cathode adopts a cylindrical structure with two ends open. The porous cathode is sleeved on the outside of the microfiltration membrane anode, and a preset gap of 0.5 to 1 cm is left between the porous cathode and the microfiltration membrane anode. The microfiltration membrane anode is electrically connected to the positive electrode of the direct current power supply, and the porous cathode is electrically connected to the negative electrode of the direct current power supply. The microfiltration membrane anode adopts a microfiltration ceramic membrane, and the microfiltration membrane anode is made of titanium dioxide so that the membrane does not need to be cleaned within the operating range. The wastewater treatment method includes introducing wastewater into the membrane bioreactor for decontamination, filtering through the electrocatalytic anode membrane assembly, and then discharging. During the wastewater treatment process, the direct current power supply is energized 1 to 2 times per day, and the current density is 2 to 5 mA / cm 2 Each power-on time is 2 to 5 minutes, thereby achieving the removal of antibiotic pollutants.

2. The wastewater treatment method according to claim 1, wherein The height of the porous cathode is greater than the height of the microfiltration membrane anode, and quartz rings are provided between the outer side of the closed end of the microfiltration membrane anode and the inner wall of the porous cathode, as well as between the outer side of the open end of the microfiltration membrane anode and the inner wall of the porous cathode, so that a preset gap is left between the porous cathode and the microfiltration membrane anode.

3. The wastewater treatment method according to claim 1, characterized in that The porous cathode is made of stainless steel mesh.

4. The wastewater treatment method according to claim 3, characterized in that The pore size of the stainless steel mesh is 3-4 mm.

5. The wastewater treatment method according to any one of claims 1 to 3, characterized in that: The wastewater treatment device further comprises a transmembrane pressure differential meter, which is connected to the microfiltration membrane anode to measure the transmembrane pressure difference of the microfiltration membrane anode.

6. The wastewater treatment method according to any one of claims 1 to 3, characterized in that: The membrane bioreactor comprises a reaction container, a water inlet device, a water outlet device, a first dissolved oxygen concentration regulating device, a second dissolved oxygen concentration regulating device, a third dissolved oxygen concentration regulating device, a reflux device, a mud discharge device and a control device, wherein the control device is respectively connected to and controls the water inlet device, the water outlet device, the first dissolved oxygen concentration regulating device, the second dissolved oxygen concentration regulating device, the third dissolved oxygen concentration regulating device, the reflux device and the mud discharge device, wherein: The reaction vessel is provided with a facultative anaerobic bio-tank, a first aerobic bio-tank, and a second aerobic bio-tank, which are separated from each other, in sequence. A first baffle is provided between the facultative anaerobic bio-tank and the first aerobic bio-tank, and a second baffle is provided between the first aerobic bio-tank and the second aerobic bio-tank. The upper ends of the first baffle and the second baffle are both lower than the upper port of the reaction vessel. The first dissolved oxygen concentration regulating device is disposed in the facultative biological pool to regulate the dissolved oxygen concentration in the facultative biological pool, the second dissolved oxygen concentration regulating device is disposed in the first aerobic biological pool to regulate the dissolved oxygen concentration in the first aerobic biological pool, and the third dissolved oxygen concentration regulating device is disposed in the second aerobic biological pool to regulate the dissolved oxygen concentration in the second aerobic biological pool; The water inlet device is connected to the inlet of the facultative aerobic biological pool, the electrocatalytic anode membrane assembly is arranged in the second aerobic biological pool, and the outlet of the electrocatalytic anode membrane assembly is connected to the water outlet device, the inlet of the reflux device and the mud discharge device are respectively connected to the lower end of the second aerobic biological pool, and the outlet of the reflux device is connected to the inlet of the facultative aerobic biological pool.

7. The wastewater treatment method according to claim 6, characterized in that: include: The wastewater is introduced into the facultative biological pool through the water inlet device, and hydraulically retained for 4 to 5 hours. The effluent overflows into the first aerobic biological pool through the top of the first baffle, and the hydraulic retention time in the first aerobic biological pool is 8 to 9 hours. The effluent overflows into the second aerobic biological pool through the top of the second baffle, and the hydraulic retention time in the second aerobic biological pool is 7 to 8 hours. The effluent is filtered through the electrocatalytic anode membrane assembly and then discharged from the water outlet device, wherein a portion of the sludge mixed liquid at the bottom of the second aerobic biological pool is returned to the facultative biological pool through the reflux device, and the other portion is discharged through the sludge discharge device, and the sludge return ratio is 300% to 400%.

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