A sewage treatment device with MBR membrane group having piezoelectric photocatalytic in-situ self-cleaning

Abstract

The utility model provides a sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group, the tank body is divided into an anaerobic tank, an anoxic tank and an aerobic tank by a partition; the sewage flows through the anaerobic tank, the anoxic tank and the aerobic tank in sequence to achieve degradation of organic matter and removal of nitrogen and phosphorus; a stirring device is provided in the anaerobic tank and the anoxic tank; an MBR membrane group is provided in the aerobic tank, the aerobic tank and the anaerobic tank are connected through an external reflux circulation system, which is used to circulate the activated sludge at the bottom of the membrane tank to the anaerobic tank; the aerobic tank and the anoxic tank are connected through an internal reflux circulation system, which is used to reflux the nitrification liquid in the aerobic tank to the anoxic tank; an ultrasonic generator and a microporous aerator are also provided at the bottom of the aerobic tank; the MBR membrane group is provided with a PLC controller, which is used to control the self-cleaning process of the MBR membrane group. The utility model applies light and mechanical force to the MBR membrane group in the aerobic tank to achieve self-degradation and stripping of pollutants on the surface of the membrane, saves chemical backwashing agents, and also achieves in-situ online cleaning of the membrane.

Description

Technical Field

[0001] The utility model belongs to the field of sewage treatment, in particular to a sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group. Background Art

[0002] Membrane Bioreactor (MBR) is a new type of sewage treatment device developed by combining membrane separation technology and biological treatment technology. People usually use MBR membrane to replace the secondary sedimentation tank for solid-liquid separation to achieve separate control of hydraulic retention time and sludge retention time. At the same time, MBR membrane also has the advantages of good treatment effect, low energy consumption, compact structure, less residual sludge, small footprint, and easy automatic management, but there is also a problem of membrane pollution.

[0003] Common membrane pollution is mainly divided into inorganic pollution and organic pollution. Common inorganic pollution of membranes mainly refers to scaling substances formed by the bridging effect of metal salts and inorganic salt ions, among which calcium carbonate, calcium sulfate, magnesium hydroxide, etc. are common inorganic pollution. Common organic pollution mainly comes from macromolecular organic matter (polysaccharides, proteins, etc.), humic acids, microbial flocs, cell fragments, etc. in the mixed liquid. At the same time, the growth of microorganisms on the membrane surface and inside the membrane pores also belongs to organic pollution of the membrane.

[0004] Common treatment methods for membrane fouling are mainly divided into physical methods and chemical methods. Among them, physical methods often use ultrasonic cleaning, aeration cleaning, etc.; chemical cleaning often uses sodium hypochlorite and citric acid backwashing to improve the fouling on the surface of the MBR membrane in order to restore the membrane flux of the MBR membrane. However, whether it is physical cleaning or chemical cleaning, the recovery of membrane flux is limited.

[0005] Photocatalysis refers to the separation of electrons and holes on the surface of semiconductor photocatalysts under the action of light, thereby activating water molecules and molecular oxygen in water to generate active oxygen (such as ·OH, ·O2 - 、H2O2、 1O2, etc.), thereby degrading pollutants in water or oxidizing and reducing heavy metals in water to achieve the mineralization of pollutants. Piezoelectric catalysis refers to the deformation of piezoelectric catalysts under the action of external mechanical forces (such as water flow, wind energy, ultrasound, and the energy of instantaneous bursting of micro-nano bubbles), resulting in the separation of electrons and holes inside them, and activating water molecules and molecular oxygen in water to generate active oxygen, thereby degrading pollutants in water or oxidizing and reducing heavy metals in water to achieve the mineralization of pollutants. In recent years, studies have shown that some photocatalytic semiconductors and piezoelectric catalysts (such as zinc oxide, transition metal sulfides, graphite phase carbon nitride, etc.) have piezoelectric properties while having photocatalytic properties, that is, piezoelectric photocatalysts separate photogenerated electrons and holes under light conditions. At the same time, under the action of mechanical force, the built-in electric field generated by piezoelectricity further promotes the separation of electrons and holes, so that the catalytic ability of piezoelectric photocatalysts is further enhanced, in order to improve the ability to remove pollutants.

[0006] Therefore, since piezoelectric photocatalytic materials can completely degrade organic matter in water into harmless carbon dioxide and water, they have attracted widespread attention. In addition, piezoelectric photocatalytic materials have certain antibacterial properties and can effectively prevent the growth of microorganisms on the surface of MBR membranes. A layer of piezoelectric photocatalytic material is coated and grown on the surface of the MBR membrane, so that the piezoelectric photocatalytic material can mineralize all inorganic and organic pollutants on the surface of the MBR membrane through strong redox reaction under the action of light and mechanical force, and turn them into harmless substances such as water, carbon dioxide, and inorganic particles, which are peeled off from the surface of the MBR membrane, that is, the surface of the MBR membrane is physically cleaned, and the inorganic and organic pollutants on the surface of the MBR membrane are degraded by chemical methods, achieving deep self-cleaning of the MBR membrane, thereby realizing in-situ online cleaning of the MBR membrane.

[0007] However, how to successfully combine piezoelectric photocatalytic materials and MBR membranes to achieve in-situ self-cleaning of MBR membranes is an urgent problem to be solved. Utility Model Content

[0008] In view of this, the utility model aims to propose a sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group, which realizes self-degradation and stripping of pollutants on the surface of the MBR membrane by applying light and mechanical force to the MBR membrane group in the aerobic tank, which not only saves chemical backwashing agents, but also realizes in-situ online cleaning of the MBR membrane.

[0009] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0010] A sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group, comprising a tank body, wherein the tank body is divided into an anaerobic tank, an anoxic tank and an aerobic tank by a partition; sewage flows through the anaerobic tank, the anoxic tank and the aerobic tank respectively to achieve degradation of organic matter and removal of nitrogen and phosphorus;

[0011] The anaerobic tank and the anoxic tank are both provided with stirring devices;

[0012] The aerobic tank is provided with an MBR membrane group, and the aerobic tank is connected to the anaerobic tank through an external reflux circulation system, which is used to circulate the activated sludge at the bottom of the aerobic tank to the anaerobic tank; the aerobic tank is connected to the anoxic tank through an internal reflux circulation system, which is used to reflux the nitrified liquid in the aerobic tank to the anoxic tank;

[0013] An ultrasonic generator and a microporous aerator are also provided at the bottom of the aerobic pool;

[0014] The MBR membrane group is provided with a PLC controller for controlling the self-cleaning process of the MBR membrane group.

[0015] Furthermore, the MBR membrane group includes a membrane frame, a membrane sheet and an ultraviolet visible lamp tube;

[0016] A plurality of the membranes and ultraviolet visible light tubes are installed on the membrane frame.

[0017] Furthermore, the membrane frame includes four support rods, an upper connecting plate and a lower connecting plate, and the upper connecting plate and the lower connecting plate are connected by the four support rods.

[0018] Furthermore, a plurality of parallel diaphragms are installed between the upper connecting plate and the lower connecting plate, and the spacing between the plurality of diaphragms is 5-10 cm;

[0019] The upper connecting plate and the lower connecting plate are also provided with ultraviolet-visible lamp tubes, and the upper ultraviolet-visible lamp tubes and the lower ultraviolet-visible lamp tubes are arranged in groups correspondingly.

[0020] Furthermore, the grouped UV-visible lamp tubes and diaphragms are arranged at intervals, the number of diaphragms is 5-10, and the number of grouped UV-visible lamp tubes is 6-11.

[0021] Furthermore, a wiring hub is provided on the top of the upper connecting plate, and the UV-visible lamp, the ultrasonic generator and the microporous aerator are connected to the PLC controller.

[0022] Furthermore, the circulation system includes a circulation pipe and a circulation water pump. The circulation pipe connects the bottom of the aerobic tank and the anaerobic tank, and the circulation water pump is arranged on the circulation pipe.

[0023] Compared with the prior art, the sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group described in the utility model has the following advantages:

[0024] (1) The utility model provides a sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group, which further saves the amount of chemical backwashing agents and reduces operating costs.

[0025] (2) The utility model discloses a sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group, which realizes in-situ online cleaning, makes the cleaning process more convenient, the cleaning speed more efficient, and the cleaning effect more obvious.

[0026] (3) The utility model provides a sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group, which can avoid the problem of microbial growth on the surface and inside of the MBR membrane;

[0027] The strong redox effect during the piezoelectric photocatalytic process can effectively degrade the inorganic and organic pollutants on the membrane surface and completely degrade them into harmless carbon dioxide and water, effectively improving the fouling of the membrane.

[0028] Through mechanical effects such as ultrasound or aeration, the pollutants on the membrane surface are peeled off to achieve membrane cleaning;

[0029] Through strong oxidation, water molecules are activated to produce highly oxidizing reactive oxygen species to improve water quality, thus eliminating the need to set up an independent advanced oxidation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0031] Figure 1 A schematic diagram of the use process of a sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group according to an embodiment of the utility model;

[0032] Figure 2 This is a schematic structural diagram of a sewage treatment device having a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group described in an embodiment of the utility model.

[0033] Description of reference numerals:

[0034] 1. Ultrasonic generator; 2. Microporous aerator; 3. Membrane frame; 4. Diaphragm; 5. UV-visible lamp; 6. PLC controller; 7. Cable collection socket; 8. Circulating water pump; 9. MBR membrane group. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0038] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0039] A sewage treatment device 9 with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group, such as Figure 1 Figure 2 As shown, it includes a tank body, which is divided into an anaerobic tank, an anoxic tank and an aerobic tank by a partition; sewage flows through the anaerobic tank, the anoxic tank and the aerobic tank respectively to achieve degradation of organic matter and removal of nitrogen and phosphorus;

[0040] The anaerobic tank and the anoxic tank are both provided with stirring devices;

[0041] The aerobic tank is provided with an MBR membrane group 9, and the aerobic tank is connected to the anaerobic tank through an external reflux circulation system, which is used to circulate the activated sludge at the bottom of the aerobic tank to the anaerobic tank; the aerobic tank is connected to the anoxic tank through an internal reflux circulation system, which is used to reflux the nitrified liquid in the aerobic tank to the anaerobic tank;

[0042] The bottom of the aerobic pool is also provided with an ultrasonic generator 1 and a microporous aerator 2;

[0043] The MBR membrane group 9 is provided with a PLC controller 6 for controlling the self-cleaning process of the MBR membrane group 9 .

[0044] Furthermore, the MBR membrane group 9 includes a membrane frame 3, a membrane sheet 4 and an ultraviolet visible lamp 5;

[0045] A plurality of the membranes 4 and the UV-visible lamp tubes 5 are mounted on the membrane frame 3 .

[0046] Furthermore, the film frame 3 includes four support rods, an upper connecting plate and a lower connecting plate, and the upper connecting plate and the lower connecting plate are connected by the four support rods.

[0047] Furthermore, a plurality of parallel diaphragms 4 are installed between the upper connecting plate and the lower connecting plate, and the spacing between the plurality of diaphragms 4 is 5-10 cm;

[0048] The upper connecting plate and the lower connecting plate are also provided with ultraviolet-visible lamp tubes 5, and the upper ultraviolet-visible lamp tubes 5 and the lower ultraviolet-visible lamp tubes 5 are arranged in groups correspondingly.

[0049] Furthermore, the grouped UV-visible lamp tubes 5 and the membranes 4 are arranged at intervals, the number of the membranes 4 is 5-10, and the number of the grouped UV-visible lamp tubes 5 is 6-11.

[0050] Furthermore, a wiring hub 7 is provided on the top of the upper connecting plate, and the UV-visible lamp 5 , the ultrasonic generator 1 and the microporous aerator 2 are connected to a PLC controller 6 .

[0051] Furthermore, the circulation system includes a circulation pipe and a circulation water pump. The circulation pipe connects the bottom of the aerobic tank and the anaerobic tank, and the circulation water pump is arranged on the circulation pipe.

[0052] First, a layer of loose and porous piezoelectric photocatalytic material is grown on the surface of the MBR membrane by sputtering, coating, bonding, dipping or spraying, so as to achieve an organic combination of the piezoelectric photocatalytic material and the MBR membrane;

[0053] Secondly, insert the MBR membrane 4 with piezoelectric photocatalyst on the surface into the membrane frame 3 with ultraviolet visible light tube, and place the membrane assembly into the membrane pool with ultrasonic generator 1 and microporous aerator 2 arranged at the bottom; at the same time, insert the ultraviolet visible light tube 5 into the membrane frame 3, wherein the ultraviolet visible light tube 5 and the MBR membrane 4 are alternately arranged, and the ultrasonic generator 1 and microporous aerator 2 are arranged at the bottom of the aerobic pool;

[0054] The water outlet of the membrane pool is provided with a vacuum pressure gauge, which is used to detect the transmembrane pressure difference and transmit the detection information to the PLC controller 6;

[0055] When the transmembrane pressure difference exceeds -0.035MPa, turn on the UV-visible lamp 5, the ultrasonic generator 1, and the microporous aerator 2 to start the piezoelectric photocatalytic self-cleaning of the membrane surface; after the membrane is cleaned for a period of time and the membrane flux is restored, turn off the UV-visible lamp 5, the ultrasonic generator 1, and the microporous aerator 2 to restart the water production of the MBR membrane;

[0056] Among them, the membrane cleaning time can be automatically controlled by PLC according to the fouling condition of the membrane.

[0057] In order to improve the effluent quality, traditional sewage treatment will set up a primary advanced oxidation treatment process (such as ozone oxidation, Fenton oxidation, electrochemical catalytic oxidation, wet oxidation, supercritical water oxidation, photocatalytic oxidation, ultrasonic oxidation, etc.) before the effluent is discharged, and the effluent quality is further improved through the strong redox effect of the advanced oxidation process. This method combines the advanced oxidation technology with the MBR membrane efficiently, and in the process of realizing the MBR membrane water production, it effectively realizes the in-situ online cleaning of the MBR membrane and realizes the high-throughput water production of the MBR membrane.

[0058] Common piezoelectric photocatalytic materials include zinc oxide, cadmium sulfide, cuprous oxide, graphite carbon nitride, transition metal sulfides, etc.

[0059] Preferably, the wavelength range of the UV-visible lamp 5 is 200-900 nm.

[0060] Preferably, the ultrasonic frequency of the ultrasonic generator 1 is preferably 40 kHz, and the power is 0-100W.

[0061] Preferably, the ultrasonic generator 1 and the microporous aerator 2 can be integrated into the membrane frame 3 in addition to being designed separately in the membrane tank.

[0062] Preferably, the automatic online cleaning device can use photocatalysis, piezoelectric catalysis or piezoelectric photocatalysis alone to achieve a self-cleaning process on the membrane surface.

[0063] Preferably, the photocatalytic material, the piezoelectric material, and the piezoelectric photocatalytic material can be mixed into the PVDF material for preparing the MBR membrane during the production process of the MBR membrane, and then the MBR membrane 4 with piezoelectric photocatalytic properties can be prepared.

[0064] Preferably, the automatic online cleaning device can be applied to processes involving membranes such as AAO+MBR, MBBR, and SBBR.

[0065] Example

[0066] Firstly, the transition metal sulfide molybdenum disulfide was prepared by a hydrothermal method, that is, a certain concentration of ammonium molybdate and thiourea solution was hydrothermally treated at 200°C for 24 hours. After the hydrothermal product was cooled, it was separated, washed and dried to obtain molybdenum disulfide with piezoelectric photocatalytic properties.

[0067] Vinyl acetate resin is used as a binder to bond molybdenum disulfide to the surface of the MBR membrane 4 by a bonding method; and the MBR membrane 4 is inserted into the MBR membrane group 9 containing the UV-visible lamp tube 5.

[0068] The MBR membrane group 9 is placed in an aerobic tank of a sewage treatment system containing an ultrasonic generator 1 and a microporous aerator 2. The MBR membrane group 9 is divided into a membrane frame 3, a membrane sheet 4 and an ultraviolet visible lamp 5. The ultraviolet visible lamp 5 is respectively installed at the upper and lower positions of the membrane frame 3, and the ultraviolet visible lamp 5 and the membrane sheet 4 are alternately distributed. At the same time, the wavelength range of the ultraviolet visible lamp 5 is 200-900nm.

[0069] A rechargeable waterproof wiring socket 7 is installed on the membrane assembly to supply power to the UV-visible lamp tube 5 , and the UV-visible lamp tube 5 is controlled by a PLC controller 6 .

[0070] The PLC controller 6 determines whether the membrane implements the self-cleaning process based on the set trans-membrane pressure difference threshold (-0.035MPa); once the trans-membrane pressure difference exceeds -0.035MPa, the PLC controller 6 automatically controls the opening of the UV-visible lamp 5, the ultrasonic generator 1 and the microporous aerator 2, thereby starting the piezoelectric photocatalytic self-cleaning process of the MBR diaphragm 4.

[0071] The light irradiation of the ultraviolet visible lamp 5 causes the generation of photogenerated electron-hole pairs on the surface of molybdenum disulfide, and the energy released by the ultrasonic action and the instantaneous rupture of micro-nano bubbles causes the molybdenum disulfide to undergo a slight deformation, thereby generating a built-in electric field, so that the electrons and holes on the surface of the molybdenum disulfide are further separated, so as to activate water molecules and molecular oxygen in the water to produce active oxygen species to oxidize and reduce inorganic or organic pollutants on the surface of the MBR membrane. Finally, the pollutants are peeled off from the membrane surface through the oscillation of ultrasonic waves and micro-nano bubbles, thereby achieving self-cleaning of the membrane surface.

[0072] After the membrane flux is restored, the PLC controller 6 automatically turns off the UV-visible lamp 5, the ultrasonic generator 1 and the microporous aerator 2 to restart the water production of the membrane.

[0073] In order to achieve higher effluent standards, traditional sewage treatment processes often add a first-level advanced oxidation treatment procedure. This system effectively combines advanced oxidation and membrane cleaning, achieving effective mineralization of pollutants while restoring membrane flux, which is beneficial to improving effluent water quality.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group, characterized in that: The tank body comprises a tank body, wherein the tank body is divided into an anaerobic tank, an anoxic tank and an aerobic tank by a partition; sewage flows through the anaerobic tank, the anoxic tank and the aerobic tank in sequence to achieve degradation of organic matter and removal of nitrogen and phosphorus; The anaerobic tank and the anoxic tank are both provided with stirring devices; The aerobic tank is provided with an MBR membrane group, and the aerobic tank is connected to the anaerobic tank through an external reflux circulation system, which is used to circulate the activated sludge at the bottom of the aerobic tank to the anaerobic tank; the aerobic tank is connected to the anoxic tank through an internal reflux circulation system, which is used to reflux the nitrified liquid in the aerobic tank to the anoxic tank; An ultrasonic generator and a microporous aerator are also provided at the bottom of the aerobic pool; The MBR membrane group is provided with a PLC controller for controlling the self-cleaning process of the MBR membrane group.

2. A sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group according to claim 1, characterized in that: The MBR membrane group includes a membrane frame, a membrane sheet and an ultraviolet visible lamp tube; A plurality of the membranes and ultraviolet visible light tubes are installed on the membrane frame.

3. A sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group according to claim 2, characterized in that: The film frame comprises four supporting rods, an upper connecting plate and a lower connecting plate, and the upper connecting plate and the lower connecting plate are connected by the four supporting rods.

4. A sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group according to claim 3, characterized in that: A plurality of parallel diaphragms are installed between the upper connecting plate and the lower connecting plate, and the spacing between two adjacent diaphragms is 5-10 cm; The upper connecting plate and the lower connecting plate are also provided with ultraviolet-visible lamp tubes, and the upper ultraviolet-visible lamp tubes and the lower ultraviolet-visible lamp tubes are arranged in groups correspondingly.

5. A sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group according to claim 4, characterized in that: The grouped UV-visible lamp tubes and diaphragms are arranged at intervals, the number of diaphragms is 5-10, and the number of grouped UV-visible lamp tubes is 6-11.

6. A sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group according to claim 5, characterized in that: A wiring hub is arranged on the top of the upper connection plate, and the ultraviolet visible lamp tube, the ultrasonic generator and the microporous aerator are connected to the PLC controller.

7. The sewage treatment device with a piezoelectric photocatalytic in-situ self-cleaning MBR membrane group according to claim 1, characterized in that: The circulation system comprises a circulation pipe and a circulation water pump. The circulation pipe is connected with the bottom of the aerobic tank and the anaerobic tank, and the circulation water pump is arranged on the circulation pipe.

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