MBR filter and container type wastewater purification system thereof

Abstract

The invention discloses an MBR filter and a container type wastewater purification system thereof, and the MBR filter is provided with a multi-layer device composed of a first filter membrane layer, a first cloth cushion layer, a first purified water cavity layer, a support skeleton layer, a second purified water cavity layer, a second cloth cushion layer and a second filter membrane layer which are sequentially arranged in parallel. The periphery of the multi-layer device is provided with a closed frame which is made of plastic materials, and the upper side face of the closed frame is provided with a water outlet. The filter membrane layer can filter wastewater, the cloth cushion layer is carbon fiber cloth, a power supply electrode can be connected to the cloth cushion layer, and an electric field formed between a plurality of adjacent MBR filters which are arranged in parallel can oscillate to remove sludge adhered to respective filter membranes. The equipment is high in wastewater treatment capacity, the filter membrane is easy to self-clean, and the equipment can be made into mobile integrated wastewater treatment equipment.

Description

Technical Field

[0001] The invention relates to wastewater treatment equipment and a treatment technology thereof. Background Art

[0002] In the field of wastewater treatment, the membrane filtration system relies on the pressure difference of water on both sides of the membrane to make the wastewater pass through membranes of different pore sizes to achieve the purpose of filtration. It is widely popular because of its strong treatment capacity, good water output effect, and no secondary pollution. In actual use, membrane surface contamination and membrane pore blockage are the most common problems. Therefore, how to clean the filter membrane is a very critical link. There are two main methods for membrane cleaning: physical method and chemical method. In specific operations, the cleaning method should be selected according to the configuration of the component, membrane material, type of pollutant and degree of contamination.

[0003] MBR filter membrane is a new water treatment technology that combines membrane separation unit and / or biological treatment unit. The membrane structure types used are mainly flat membrane and hollow fiber membrane. How to apply it to the treatment of different types of wastewater and the recovery of the filter membrane's own function requires more ingenious design and improvement.

[0004] The invention of application number 202011530790.6 discloses a wastewater treatment container equipment, including a container body, a filter device is fixedly connected to the inner bottom of the container body, an insulation box is installed on the right side of the filter device, an aeration tank is connected to the interior of the insulation box, an airflow pipe is connected to the bottom of the inner cavity of the aeration tank, and an aeration device is fixedly connected to the upper end of the airflow pipe. The invention provides a movable wastewater treatment equipment, and this structure can be used for reference in this application.

[0005] The "Research Progress of Electric Field Controlled MBR Membrane Fouling Technology" in the April 2020 issue of "Membrane Science and Technology" introduced a membrane bioreactor (MBR) with excellent effluent quality that can be directly reused. However, the membrane fouling problem that exists during long-term operation is still the main factor hindering its further development and commercial application. The electric field is one of the effective and clean ways to alleviate membrane fouling and improve effluent quality. The key to using the self-generated electric field of MBR to alleviate membrane fouling is the preparation of conductive microfiltration membranes. The electric field structure and its raw materials in this article are not clearly disclosed, but they can provide useful inspiration for the filtration facilities of this application. Summary of the invention

[0006] Purpose of the invention: To provide an MBR filter which can be flexibly moved and used, is particularly suitable for the treatment of printing and dyeing wastewater, has a self-cleaning function and a container-type wastewater purification system thereof.

[0007] Technical solution: The MBR filter of the present invention comprises a multilayer device consisting of a first filter membrane layer, a first cushion layer, a first purified water cavity layer, and a supporting skeleton layer arranged in parallel in sequence; or a multilayer device consisting of a first filter membrane layer, a first cushion layer, a first purified water cavity layer, a supporting skeleton layer, a second purified water cavity layer, a second cushion layer, and a second filter membrane layer arranged in sequence.

[0008] The outer periphery of the multilayer device is provided with a sealed frame surrounded by a plastic material (such as ABS material); the upper side surface of the sealed frame is provided with a water outlet which can be connected to a water outlet pipeline.

[0009] When in use, the MBR filter is immersed in a wastewater pool, where there may be biologically active sludge, which contains aerobic microorganisms that can oxidize and degrade organic matter in the wastewater; then, the wastewater is filtered through the filter membrane layer and enters the purified water cavity layer; the organic matter is blocked outside the filter membrane layer and continues to be degraded by the biologically active sludge. Then, the formed clean water (or the formed recycled water that can be recycled in the printing and dyeing production line) is discharged through the outlet to the outlet pipe for transportation.

[0010] An aeration device is pre-installed at the bottom of the wastewater pool. Aeration blows the biologically activated sludge, supplies oxygen to aerobic microorganisms, and stirs the sludge to prevent sludge accumulation or even clogging the filter membrane surface.

[0011] The filter membrane layer is a polymer filter membrane, and the filter membrane is divided into microfiltration membrane (MF), ultrafiltration membrane (UF), nanofiltration membrane (NF) or reverse osmosis membrane (RO) from coarse to fine according to the size of the membrane pores. The wastewater filter membrane is a corrosion-resistant and temperature-resistant polymer membrane such as PVDF (preferably polyvinylidene chloride PVDC, which has high barrier properties and is suitable for making selective permeability filter membranes; it has lower manufacturing costs than tetrafluoroethylene, is more heat-resistant and aging-resistant than polyvinyl chloride, and has a larger polarity in the molecule. When used in conjunction with an electric field, it is beneficial to the movement of polar organic molecules, anions and cations, anion and cation groups and water molecules and their separation from the filter membrane surface).

[0012] The support skeleton layer is made of non-metallic material (non-conductive, preventing leakage, preferably ABS material with good formability and high cost performance).

[0013] The cloth pad layer is thicker than the filter membrane layer, has a larger pore size than the filter membrane, and is closely attached to or close to the filter membrane layer, and has a lining or buffering effect on the filter membrane layer. The support skeleton layer has a supporting and fixing effect on the other two layers.

[0014] After long-term use, the surface of the above-mentioned MBR filter membrane may adhere to sludge. In addition to the bubbles blown out by aeration to stir the sludge to prevent sedimentation, there are also the following self-cleaning methods: The cloth pad layer is a carbon fiber cloth pad layer (carbon fiber cloth or felt, which has the functions of both lining and conductive electrode), on which an electrode of a power supply (pulse DC or AC with a larger period, and a controller and a power switch) can be connected. Multiple MBR filters are arranged in parallel in the wastewater pool adjacent to each other (the adjacent spacing is less than the thickness of the purified water chamber layer), and the adjacent carbon fiber cloth pad layers are respectively connected (or arranged in sequence) to the positive and negative electrodes of the power supply. Multiple positive power supply electrodes are connected together to connect the positive electrode of the total power supply; multiple negative power supply electrodes are connected together to connect the negative electrode of the total power supply. So that the filter membrane layers of two adjacent filters form a parallel plate electric field A with a smaller spacing, and the two filter membrane layers of the same filter form a parallel plate electric field B with a larger spacing; the electric field between adjacent MBR filters (and the electric field is between the two filter membranes, the electrolyte in the wastewater or sludge does not contact the electrode, will not be adsorbed on the electrode surface of the carbon fiber cloth or felt pad layer, and maintains good conductivity) has a greater adsorption or repulsion force on the electrolyte ions or ion clusters in the sludge than the electric field in the same MBR filter.

[0015] Since the field strength of parallel plate electric field A is greater than the field strength of parallel plate electric field B (constant or oscillating, the oscillation causes the positive and negative poles to exchange frequently, and the anions, cations and their groups are accompanied by oscillation), the anions, cations or their groups in the activated sludge or wastewater will move toward the positive or negative pole or vibrate back and forth under the action of the electric field, making it difficult for the activated sludge to accumulate or adhere to the outer wall surface of the filter membrane.

[0016] In the present invention, there can be 2-3 wastewater pools, which are the first oxidation pool, or the second oxidation pool (two are connected in series for further oxidation degradation and increase the degradation effect of organic molecules) and the filtration pool according to the wastewater entry route; the microbial oxidation and membrane filtration functions are carried out separately, so that the oxidation decomposition is thorough, the microorganisms basically do not contact the power electrode, and maintain good biological activity.

[0017] Moreover, the voltage at the two poles of the electric field (the voltage can overcome the ionization potential of most polluting compounds in the sludge - the voltage required for ionization, less than 36V safety voltage) forms an electric field or current in the sludge or wastewater, which removes the sludge accumulated or adhering to the filter membrane, while causing the microorganisms in the sludge to die by electric shock in the filter membrane pool, thereby reducing the pollution caused by remaining microorganisms.

[0018] In the present invention, the wastewater tank and its control unit, water inlet pipeline, water inlet pump, water outlet pipeline, water outlet pump, aeration pipeline, and air compressor pump can be placed in a container shell in a certain position sequence, which is convenient for lifting and transportation and used for wastewater treatment in different places. After the wastewater in the wastewater tank is emptied (a small amount of wastewater sludge can be reserved to maintain the activity of microorganisms), the empty container is hoisted, and the wastewater enters the purification treatment after it is in place.

[0019] Preferably, a thermal insulation layer is embedded between the stainless steel thin-walled wastewater pool and the outer shell of the container, which not only provides thermal insulation but also forms a sandwich composite material structure to enhance the mechanical properties of the wastewater pool wall and the outer shell of the container, thereby reducing the wall thickness and lightening the weight.

[0020] Further preferably, the water inlet pipe, the water outlet pipe and the aeration pipe are respectively buried in the insulation layer, which is not only hidden and beautiful, but also protects the pipes from freezing in winter. The water inlet pump, the water outlet pump and the air compressor pump are exposed in the equipment room for easy operation and maintenance.

[0021] In the present invention, the top of the electric control room is not cut, and a door for operators to enter and exit is opened on the side box; the top of the equipment room is not cut, and a door for operators to enter and exit is opened on the side box; the tops of the oxidation tank and the membrane filter tank are open for easy placement (cover plates can be provided).

[0022] In the present invention, the container is provided with a heightened cofferdam around the upper part to protect the safety of adding microorganisms and maintenance operators above; a water retaining plate is welded on the edge of the container opening to prevent rainwater from flowing back into the container. The top of the oxidation pool and the filter membrane pool inside the container is flanged and can be connected to the heightened cofferdam with bolts, which is convenient for lifting and transportation or fixed connection.

[0023] Beneficial effects: Containerized integrated wastewater treatment equipment has the advantages of stable and reliable technical performance, good treatment effect, low investment, small footprint, and convenient maintenance. The equipment can be connected to a car to make a mobile integrated wastewater treatment equipment, which is easy to carry and move.

[0024] The MBR filter has a large specific surface area and a strong filter membrane adhesion capacity. Under the same organic matter load conditions, it has a high organic matter filtration and removal rate.

[0025] The carbon fiber cloth pads of two adjacent MBR filters are connected to the positive and negative electrodes of a pulsed DC or AC power supply respectively. The pulsed electric field or alternating electric field formed in between causes the polar substances in the sludge or the electrolytes in the wastewater to be subjected to the pulsed or alternating electric field force, causing them to move (positive ions move to the negative electrode, negative ions move to the positive electrode) or oscillate. The sludge is not easy to adhere to the surface of the filter membrane or is easy to desorb, thus avoiding sludge particles from clogging the filter pores of the filter membrane and ensuring that the filter membrane can be reused for a long time.

[0026] The electrical control room can test and control the temperature of the incoming wastewater. The microorganisms in the oxidation tank are adsorbed in the sludge, and the organic matter in the wastewater becomes nutrients for the microorganisms. With the aeration device to supplement fresh air, the survival rate of microorganisms is high, which has the characteristics of the activated sludge method. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the three-dimensional structure of an MBR filter of the present invention when it is partially used; Figure 2 It is a schematic diagram of a partial three-dimensional structure of another MBR filter of the present invention; Figure 3 It is a schematic diagram of the structure in which multiple MBR filters of the present invention are arranged in parallel in a wastewater tank; Figure 4 It is a schematic diagram of the partial internal structure of the containerized wastewater treatment system of the present invention; Figure 5 yes Figure 4 Schematic diagram of the partial longitudinal section structure of a medium container.

[0028] In all the figures, 1-water outlet pipe; 2-water outlet; 3-MBR filter; 4-frame; 5-first filter membrane layer; 6-first cushion layer; 7-first purified water chamber layer; 8-support skeleton layer; 9-second purified water chamber layer; 10-second cushion layer; 11-second filter membrane layer; 12-bubbles; 13-sludge; 14-aeration pipe; 15-positive power supply; 16-negative power supply; 17-first oxidation tank; 18-second oxidation tank; 19-filtration tank (membrane tank); 20-electrical control room; 21-equipment room; 24-container cofferdam; 25-water retaining plate; 26-container bottom plate; 27-inlet pump; 28-outlet pump; 29-air compressor pump. DETAILED DESCRIPTION

[0029] Embodiment 1: like Figure 1 The MBR filter shown has seven layers of devices arranged in parallel, which are a multilayer device consisting of a first filter membrane layer 5, a first cloth cushion layer 6, a first purified water chamber layer 7, a thermoplastic plastic support skeleton layer 8, a second purified water chamber layer 9, a second cloth cushion layer 10, and a second filter membrane layer 11 arranged in sequence; the seven-layer device is provided with a closed frame 4 surrounded by plastic material on the periphery, and a water outlet 2 is provided on the upper side of the closed frame 4.

[0030] The filter membrane layers 5 and 11 are polymer filter membranes PVDF ultrafiltration membranes, which can filter organic wastewater from the textile or chemical industry to obtain purified water; the purified water cavity layers 7 and 9 can collect purified water that passes through the filter membrane layers 5 and 11 and discharge it from the water outlet 2 on the frame 4.

[0031] When used in wastewater, the activated sludge particles containing microorganisms in contact with the surface of the ultrafiltration membrane can oxidize and degrade organic matter in the wastewater; at the same time, under the aeration blowing entering the aeration pipeline 14, oxygen is supplemented to make the microorganisms active and the sludge particles roll up and down, so as not to be adsorbed on the surface of the filter membrane to block the filter holes, thereby maintaining a good filtration capacity.

[0032] Embodiment 2: like Figure 2The two MBR filters shown are arranged in parallel and facing each other (the filter membrane layers are close to each other), and each MBR filter 3 has four layers of devices arranged in parallel, which are the first filter membrane layer 5, the first cloth cushion layer 6, the first purified water cavity layer 7, and the ABS support skeleton layer 8 arranged in sequence; the four-layer device has a closed frame 4 surrounded by ABS material, and the upper side of the closed frame 4 has a water outlet 2. The filter membrane layer 5 is a polymer PVDC nanofiltration membrane, which can filter the organic wastewater of the printing and dyeing industry to obtain purified water; the purified water cavity layer 7 can collect the purified water that passes through the filter membrane layer 5 and discharge it from the water outlet 2 on the frame 4.

[0033] The cloth pad layer 6 is a pad layer of carbon fiber felt. The carbon fiber cloth pad layer in one MBR filter 3 is connected to a positive electrode 15 of a pulse power supply, and the carbon fiber cloth pad layer in another MBR filter 3 is connected to a negative electrode 16 of the power supply. When the filtering capacity of the filter 3 decreases, the pulse power supply is turned on, and a pulse electric field is formed between the positive electrode 15 and the negative electrode 16. The positive ions and negative ions of the electrolyte in the wastewater or activated sludge move toward the electrodes of the object respectively, so that the impurities adhering to the two nanofiltration membranes are desorbed, the filter pores of the filter membranes are unblocked, and the wastewater filtering function is restored.

[0034] Embodiment three: like Figure 3 The wastewater treatment device shown is composed of seven MBR filters 3 arranged in parallel, and a wastewater inlet space is reserved between adjacent MBR filters 3. The water outlet holes above each MBR filter 3 are connected to the purified water pipeline.

[0035] The wastewater treatment device is placed in the membrane filter pool 19. According to the wastewater entry route, the first oxidation pool 17, or the second oxidation pool 18, and the membrane filter pool 19 are arranged in order, and the microbial oxidation degradation of the wastewater and the filtration function of the wastewater are separated.

[0036] The wastewater treatment device described above constitutes a containerized wastewater purification system of the MBR filter 3. The electric control room 20, oxidation tanks 17, 18, membrane filter tank 19, and equipment room 21 are sequentially arranged on the bottom plate 26 of the container and inside the outer shell.

[0037] The first oxidation pool 17, the second oxidation pool 18 and the filter pool 19 made of stainless steel have dimensions of 2m (width) x 2m (length) x 2.5m (height). The width and height of the outer shell of the container are slightly larger than the dimensions of the above-mentioned stainless steel pools, and the length is 10 meters.

[0038] On one side of the container shell, a 2-meter-long electric control room 20 is set. The electric control room 20 has personnel entrances and exits and electric control instruments. The electric control instruments are connected with signal lines and collect status parameters of oxidation tanks 17, 18 and membrane filter tank 19. The electric control instruments are connected with control lines and control the start and stop of water inlet pump 27, water outlet pump 28 and air compressor pump 29.

[0039] On the other side of the container shell, a 2-meter-long equipment room 21 is set up. The equipment room 21 has a personnel entrance and exit and an inlet pump 27, an outlet pump 28, and an air compressor pump 29; the inlet pump 27 is connected to the oxidation ponds 17 and 18 through an inlet pipeline, the outlet pump 28 is connected to the filter membrane pond 19 through an outlet pipeline 1, and the air compressor pump 29 is connected to the oxidation ponds 17 and 18 through an aeration pipeline 14 at the bottom of the oxidation ponds 17 and 18.

[0040] On one side of the container in the width direction, leave a space of about 30 cm for installing pipes, including a water inlet pipe in the middle of the space, a water outlet pipe 1 at the top, and an aeration pipe 14 at the bottom.

[0041] Such a containerized wastewater purification system can be moved to the required location to carry out flexible and mobile small-scale wastewater treatment projects.

Claims

1. An MBR filter, comprising a multi-layer device, a sealed frame (4) made of plastic material on the periphery of the multi-layer device, and a water outlet (2) on the side of the sealed frame (4); The multilayer device comprises a first filter membrane layer (5), a first cushion layer (6), a first purified water cavity layer (7), a support skeleton layer (8), a second purified water cavity layer (9), a second cushion layer (10), and a second filter membrane layer (11) which are arranged in parallel in sequence; the filter membrane layer (5 or 11) is a polymer filter membrane capable of filtering wastewater to obtain purified water; the support skeleton layer (8) has a supporting and fixing effect on the other layers; the purified water cavity layer (7 or 9) can collect purified water that passes through the filter membrane layer (5 or 11) and discharge it from the water outlet (2) on the frame (4); Features: The cloth pad layer (6 or 10) is a pad layer of carbon fiber cloth or carbon fiber felt, one cloth pad layer (6 or 10) is connected to the positive electrode (15) of the power supply, and the other cloth pad layer is connected to the negative electrode (16) of the power supply, and the voltage between the two electrodes of the power supply is greater than the voltage required for ionization of most polluting compounds in the sludge and less than the safety voltage of 36V.

2. The MBR filter according to claim 1, characterized in that: The filter membrane is made of PVDC material.

3. A wastewater treatment device for an MBR filter according to claim 1, characterized in that: According to the route of wastewater entering, the first oxidation pond (17), or the second oxidation pond (18), and the membrane filter pond (19) are arranged in sequence, and the microbial oxidation degradation of wastewater and the filtering function of wastewater are carried out separately; aerobic microbial strains are placed in the oxidation pond (17 or 18), and a plurality of parallel-arranged MBR filters (3) are placed in the membrane filter pond (19); one of the adjacent carbon fiber cloth pad layers (6 or 10) is connected to the positive electrode (15) of the power supply, and the other is connected to the negative electrode (16) of the power supply; multiple positive electrodes (15) of the power supply are connected together to connect to the positive electrode of the total power supply; multiple negative electrodes (16) of the power supply are connected together to connect to the negative electrode of the total power supply; and multiple MBR filters (3) are connected in parallel.

4. The wastewater treatment device of the MBR filter according to claim 3, characterized in that: A parallel plate electric field A with a smaller spacing is formed between the filter membrane layers of two adjacent filters, and a parallel plate electric field B with a larger spacing is formed between the two filter membrane layers of the same filter; the field strength of parallel plate electric field A is greater than the field strength of parallel plate electric field B.

5. The wastewater treatment device of the MBR filter according to claim 3 or 4, characterized in that: The electric control room (20), the oxidation pond (17 or 18), the membrane filter pond (19), and the equipment room (21) are sequentially arranged on the bottom plate (26) of the container and inside the outer shell; the electric control room (20) has a personnel entrance and exit and an electric control instrument, the electric control instrument has signal lines connected to collect state parameters of the oxidation pond (17 or 18) and the membrane filter pond (19), and the electric control instrument has control lines connected to control the start and stop of the water inlet pump (27), the water outlet pump (28), and the air compressor pump (29); the equipment room (21) has a personnel entrance and exit and a water inlet pump (27), a water outlet pump (28), and an air compressor pump (29); the water inlet pump (27) is connected to the oxidation pond (17 or 18) through an inlet pipeline, the water outlet pump (28) is connected to the membrane filter pond (19) through an outlet pipeline (1), and the air compressor pump (29) is connected to the oxidation pond (17 or 18) through an aeration pipeline (14) at the bottom of the oxidation pond (17 or 18).

6. The wastewater treatment device of the MBR filter according to claim 5, characterized in that: An insulation layer is provided between the outer walls of the oxidation pool (17 or 18) and the membrane filter pool (19) and the outer shell of the container, forming a sandwich composite material structure to strengthen the wastewater pool wall and the outer shell of the container; an inlet pipe and an outlet pipe (1) are respectively buried in the insulation layer.

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