A filtration membrane assembly, coagulation-coupled polyethylene battery diaphragm bioreactor and use method

Abstract

The present invention provides a filtration membrane assembly, a coagulation-coupled polyethylene battery membrane bioreactor and a method of use, wherein the filtration membrane assembly comprises a filtration membrane; the filtration membrane is a polyethylene lithium battery membrane; the porosity of the polyethylene lithium battery membrane is 35-45%; and the contact angle of the polyethylene lithium battery membrane is 75-85°. Beneficial effects of the present invention: After a simple coagulation-coupled process, the present application can enable the polyethylene battery membrane bioreactor to operate stably for a long time under normal flux, and the addition of a coagulant does not significantly increase the cost, which reflects the feasibility and applicability of the present invention.

Description

Technical Field

[0001] The invention belongs to the technical field of MBR membranes, and in particular relates to a filtration membrane assembly, a coagulation-coupled polyethylene battery diaphragm bioreactor and a use method thereof. Background Art

[0002] MBR is a wastewater treatment process that combines membrane filtration with biological treatment and has been widely used in various industries. However, it is currently facing two major problems. First, the membrane pollution problem: as the MBR is running, the membrane will gradually be polluted, which will increase energy costs, cause deterioration of effluent water quality and shorten the life of the membrane. The addition of coagulants can significantly improve the properties of the sludge mixed liquid and thus slow down the development of membrane pollution; second, the membrane cost problem: currently the most commonly used membrane material for MBR is PVDF, and hollow fiber is the most popular membrane form. Another major use of PVDF is as a positive electrode binder and diaphragm coating in lithium batteries. However, in the past two years, the demand for lithium battery materials has also been increasing. Therefore, finding a low-cost material that can be used in MBR water treatment is a hot topic that should be paid attention to at present.

[0003] PE raw materials are low-cost, but they are naturally hydrophobic, so the prepared PE battery separators have strong hydrophobicity and significant cost advantages. Due to its advantages such as small thickness, large porosity, and high mechanical strength, many researchers have applied it to the field of water treatment in recent years. The main applications are as follows: First, it is used as an ultrafiltration membrane for water treatment after hydrophilic modification; second, it is used as a support layer for nanofiltration membranes after hydrophilic modification. However, the application of hydrophilic modified PE battery separators in MBR water treatment has not yet been studied. Summary of the invention

[0004] In view of this, the present invention aims to propose a filtration membrane assembly, a coagulation-coupled polyethylene battery membrane bioreactor and a method of use. The present invention proposes to use a low-cost and hydrophilically modified polyethylene battery membrane for MBR water treatment, establish a coagulation-coupled process to control the development of membrane pollution and make it stable for a long time, and provide a new way to reduce the cost of MBR membrane. To achieve the above purpose, the technical solution of the present invention is implemented as follows:

[0005] A filter membrane assembly, the filter membrane assembly comprising a filter membrane;

[0006] The filter membrane assembly includes a filter membrane; the filter membrane is a polyethylene lithium battery diaphragm;

[0007] The porosity of polyethylene lithium battery separator is 35-45%;

[0008] The contact angle of polyethylene lithium battery separator is 75-85°.

[0009] Furthermore, the filtration membrane assembly also includes a non-woven fabric and a plate frame;

[0010] A water outlet is provided at the upper part of the plate frame, and a filter membrane and non-woven fabric form a composite membrane, which is arranged at the front and rear sides of the plate frame;

[0011] Both the front and rear sides of the plate frame are provided with channels through which liquid can enter.

[0012] Furthermore, the average pore size of the filter membrane is 55-65 nm.

[0013] Further, the width of the plate frame is 12-14 cm, the thickness is 0.5-1.5 cm, and the length is 17-19 cm;

[0014] And / or, the length of the membrane is 14-16 cm, and the width of the membrane is 9-11 cm;

[0015] And / or, the effective areas of the filter membrane and the non-woven fabric are the same, and the filter membrane and the non-woven fabric are both adhered to the plate frame by epoxy resin glue;

[0016] And / or, the effective area of ​​the filter membrane is 280-320 cm 2 .

[0017] A coagulation-coupled polyethylene battery membrane bioreactor, using the above-mentioned filter membrane assembly, comprises a reactor body, a water inlet assembly is arranged on one side of the reactor body, and an aeration assembly is arranged at the bottom of the reactor body;

[0018] The filter membrane assembly is arranged in the middle of the reactor body;

[0019] A water outlet assembly is arranged on the upper part of the filtering membrane assembly, and a drug adding assembly is arranged on the reactor body.

[0020] Furthermore, the water inlet assembly includes a water inlet bucket, a water inlet pipe, and a first peristaltic pump;

[0021] The water inlet bucket is arranged on one side of the reactor body, one end of the water inlet pipe is connected to the water inlet bucket, and the other end of the water inlet pipe is connected to the reactor body through the water inlet;

[0022] The first peristaltic pump is arranged on the water inlet pipe;

[0023] Aeration components include aeration pipes, aeration plates, and aeration pumps;

[0024] The aeration plate is arranged at the bottom of the reactor body, one end of the aeration pipe is connected to the aeration plate, and the other end of the aeration pipe is connected to the aeration pump;

[0025] The aeration plate is provided with a number of evenly distributed aeration holes;

[0026] The aeration holes are opened 45° downward along the surface of the aeration plate, with a hole diameter of 1.5-2.5 mm and a spacing of 8-12 mm;

[0027] The water outlet assembly includes a water outlet pipe, a water outlet bucket, and a second peristaltic pump. One end of the water outlet pipe is connected to the water outlet of the filter membrane assembly, and the other end of the water outlet pipe is connected to the water outlet bucket. The second peristaltic pump is arranged on the water outlet pipe.

[0028] A pressure sensor is provided on the water outlet pipe, and the pressure sensor is electrically connected to the paperless recorder;

[0029] The material of the reactor body is organic glass.

[0030] A method for using a coagulation-coupled polyethylene battery membrane bioreactor, using the above-mentioned coagulation-coupled polyethylene battery membrane bioreactor, comprises the following steps:

[0031] S1: Construction of a coagulation-coupled polyethylene battery membrane bioreactor;

[0032] S2: Conduct membrane fouling filtration experiment on coagulation-coupled polyethylene battery membrane bioreactor to determine the optimal dosage of coagulant in membrane fouling filtration experiment;

[0033] S3: After the membrane fouling filtration experiment, the coagulation-coupled polyethylene battery diaphragm bioreactor with and without coagulant addition was subjected to multi-cycle movement, as well as the control bioreactor with and without coagulant addition. The feasibility and stability of the coagulation-coupled polyethylene battery diaphragm bioreactor with coagulant addition was evaluated by comparing the total membrane filtration resistance.

[0034] Furthermore, in step S1, building a coagulation-coupled polyethylene battery membrane bioreactor includes building a filter membrane assembly, placing the filter membrane assembly into the reactor body; connecting a water inlet pipe to a water inlet at the bottom of the reactor body, installing an aeration pump on the aeration pipe, connecting a water outlet pipe to a water outlet above the membrane assembly, connecting the water outlet pipe to a water outlet bucket, and installing a pressure sensor on the water outlet pipe of the water outlet bucket;

[0035] The construction of the filter membrane assembly includes forming a composite membrane with the filter membrane and the non-woven fabric through epoxy resin glue, and bonding the composite membrane to the front and back sides of the plate frame.

[0036] Furthermore, step S2 also includes determining the optimal dosage of the coagulant after multiple coagulant dosage tests, and taking the optimal dosage of the coagulant as the dosage value under long-term operation conditions;

[0037] The coagulant dosage test includes pumping the coagulant solution into the sludge mixture through a dosing pump, aerating and mixing thoroughly, and then starting the membrane fouling filtration test;

[0038] A membrane fouling filtration experiment was carried out in a coagulation-coupled polyethylene battery membrane bioreactor; the membrane fouling filtration experiment was operated in a constant flux, continuous water inlet, and intermittent water outlet mode. When the flux decayed, the speed of the first peristaltic pump was increased until the filtration experiment was completed.

[0039] Further, in step S3, the feasibility and stability of coagulation coupling are evaluated by comparing the total filtration resistance of the membrane, including:

[0040] If the total membrane filtration resistance of the coagulation-coupled polyethylene battery membrane bioreactor with the addition of coagulant is less than the total membrane filtration resistance of the coagulation-coupled polyethylene battery membrane bioreactor without the addition of coagulant;

[0041] And the total membrane filtration resistance of the coagulation-coupled polyethylene battery membrane bioreactor with the addition of coagulant is less than the total membrane filtration resistance of the control bioreactor with the addition of coagulant;

[0042] Moreover, the total membrane filtration resistance of the coagulation-coupled polyethylene battery membrane bioreactor with the addition of coagulant is less than the total membrane filtration resistance of the control bioreactor without the addition of coagulant;

[0043] The coagulation-coupled polyethylene battery membrane bioreactor with coagulant addition can operate stably for a long time, which is feasible.

[0044] The difference between the control bioreactor with added coagulant and the coagulation-coupled polyethylene battery membrane bioreactor is that the filter membrane of the reactor is a hollow fiber membrane, and the rest of the structures are the same.

[0045] The calculation formula of total membrane filtration resistance is as follows:

[0046] ;

[0047] The ΔP is the transmembrane pressure difference on both sides of the membrane (Pa);

[0048] The μ is the dynamic viscosity of water (Pa∙s). At 20°C, μ=1.01×10 -3 Pa∙s;

[0049] The J is the permeation flux during membrane filtration (m / s);

[0050] The R t is the total filtration resistance of the membrane (m -1 ).

[0051] Furthermore, R t The resistance is composed of the following parts:

[0052] ;

[0053] The R m is the intrinsic resistance of the membrane (m -1 ), determined by the flux of pure water filtered through a new membrane;

[0054] The R r is the hydraulic reversible resistance (m -1 ), determined by physically cleaning the membrane module;

[0055] The R ir is the irreversible hydraulic resistance (m -1 ), determined by chemical cleaning of membrane modules;

[0056] The R f is the irreversible resistance (m -1 ), by R t -R m -R r -R ir Sure.

[0057] Compared with the prior art, the filtration membrane assembly, coagulation-coupled polyethylene battery membrane bioreactor and use method described in the present invention have the following advantages:

[0058] 1. The membrane used in the traditional membrane bioreactor is generally a high-cost PVDF hollow fiber membrane, while the present invention uses a low-cost polyethylene battery separator.

[0059] 2. The present application enables the polyethylene battery membrane bioreactor to operate stably for a long time at a normal flux after a simple coagulation coupling process. The addition of coagulant does not significantly increase the cost, which reflects the feasibility and applicability of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] 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 used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0061] Figure 1 This is a schematic diagram of the surface morphology of the polyethylene battery separator of the present invention;

[0062] Figure 2 A schematic diagram of a polyethylene battery separator assembly according to an embodiment;

[0063] Figure 3 This is a schematic diagram of a membrane bioreactor according to an embodiment of the present invention;

[0064] Figure 4 It is a schematic diagram of the development and change of the transmembrane pressure difference (TMP) of the PE-MCBR with the addition of coagulant and the PE-MBR without the addition of coagulant over time according to the embodiment of the present invention;

[0065] Figure 5 It is a schematic diagram of the development and change of TMP over time of 3 cycles of PE-MCBR and PVDF-MCBR with added coagulant and PVDF-MBR without added coagulant according to the embodiment of the present invention.

[0066] Description of reference numerals:

[0067] 1. Water inlet bucket; 2. Water inlet pipe; 3. First peristaltic pump; 4. Aeration hole; 5. Reactor body; 6. Aeration pipe; 7. Aeration pump; 8. Water inlet; 9. Sampling port; 10. Filter membrane assembly; 11. Liquid level; 12. Dosing pump; 13. Dosing tube; 14. Pressure sensor; 15. Paperless recorder; 16. Second peristaltic pump; 17. Water outlet pipe; 18. Water outlet bucket; 19. Filter membrane; 20. Non-woven fabric; 21. Plate frame; 22. Water outlet. DETAILED DESCRIPTION

[0068] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0069] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0070] Glossary:

[0071] MBR stands for Membrane bioreactors;

[0072] PVDF is polyvinylidene fluoride;

[0073] PE is polyethylene;

[0074] PE-MCBR is a filtration membrane module using a hydrophilically modified PE battery diaphragm membrane and adding a coagulant;

[0075] PE-MBR is a filtration membrane module that uses a hydrophilically modified PE battery diaphragm membrane and does not add coagulant;

[0076] PVDF-MCBR is a filtration membrane module using PVDF hollow fiber membrane and adding coagulant;

[0077] PVDF-MBR is a filtration membrane module that uses PVDF hollow fiber membranes and does not require the addition of coagulants.

[0078] Example 1

[0079] The filter membrane assembly 10 includes a filter membrane 19; the filter membrane assembly 10 includes a filter membrane 19; the filter membrane 19 is a polyethylene lithium battery separator; the porosity of the polyethylene lithium battery separator is 35-45%; the contact angle of the polyethylene lithium battery separator is 75-85°.

[0080] The filter membrane assembly 10 also includes a non-woven fabric 20 and a plate frame 21; a water outlet 22 is provided at the upper portion of the plate frame 21, the filter membrane 19 and the non-woven fabric 20 form a composite membrane, and the composite membrane is arranged on the front and rear sides of the plate frame 21; both sides of the plate frame 21 are provided with channels for liquid to enter.

[0081] The average pore size of the filter membrane 19 is 55-65 nm.

[0082] The width of the plate frame 21 is 12-14 cm, the thickness is 0.5-1.5 cm, and the length is 17-19 cm;

[0083] The length of the membrane is 14-16 cm, and the width of the membrane is 9-11 cm;

[0084] The effective areas of the filter membrane 19 and the non-woven fabric 20 are the same. The filter membrane 19 and the non-woven fabric 20 are both attached to the plate frame 21 by epoxy resin adhesive. The effective area of ​​the filter membrane 19 is 280-320 cm 2 .

[0085] A coagulation-coupled polyethylene battery diaphragm bioreactor uses the above-mentioned filter membrane assembly 10, including a reactor body 5, one side of the reactor body 5 is provided with a water inlet assembly, and the bottom of the reactor body 5 is provided with an aeration assembly; the filter membrane assembly 10 is arranged in the middle of the reactor body 5; the upper part of the filter membrane assembly 10 is provided with a water outlet assembly, and the reactor body 5 is provided with a dosing assembly.

[0086] The water inlet assembly includes a water inlet bucket 1, a water inlet pipe 2, and a first peristaltic pump 3; the water inlet bucket 1 is arranged on one side of the reactor body 5, one end of the water inlet pipe 2 is connected to the water inlet bucket 1, and the other end of the water inlet pipe 2 is connected to the reactor body 5 through the water inlet 8; the first peristaltic pump 3 is arranged on the water inlet pipe 2; the aeration assembly includes an aeration pipe 6, an aeration plate, and an aeration pump 7; the aeration plate is arranged at the bottom of the reactor body 5, one end of the aeration pipe 6 is connected to the aeration plate, and the other end of the aeration pipe 6 is connected to the aeration pump 7; the aeration plate is provided with a plurality of evenly distributed aeration holes 4; the aeration holes 4 are opened 45° downward along the surface of the aeration plate, the aperture is 1.5-2.5 mm, and the spacing is 8-12 mm;

[0087] The water outlet component includes a water outlet pipe 17, a water outlet bucket 18, and a second peristaltic pump 16. One end of the water outlet pipe 17 is connected to the water outlet 22 of the filter membrane assembly 10, and the other end of the water outlet pipe 17 is connected to the water outlet bucket 18. The second peristaltic pump 16 is arranged on the water outlet pipe 17; a pressure sensor 14 is provided on the water outlet pipe 17, and the pressure sensor 14 is electrically connected to the paperless recorder 15; the material of the reactor body 5 is plexiglass.

[0088] A sampling port 9 is provided on one side of the reactor body 5 . The position of the sampling port 9 corresponds to the position of the filtration membrane assembly 10 . The liquid level 11 is set above the position of the filtration membrane assembly 10 .

[0089] The dosing assembly includes a dosing pump 12 and a dosing pipe 13 . One end of the dosing pipe 13 is connected to a drug source, and the other end of the dosing pipe 13 extends into the reactor body. The dosing pump 12 is arranged on the dosing pipe 13 .

[0090] A coagulation-coupled polyethylene battery membrane bioreactor comprises the following steps:

[0091] Preparation of polyethylene battery diaphragm assembly (filtration membrane assembly 10): non-woven fabric 20 is used as an inner lining and is attached to the plate frame 21 with epoxy resin adhesive, and then the hydrophilic modified PE battery diaphragm is attached to the non-woven fabric 20 with epoxy resin adhesive and dried for more than 24 hours. The effective membrane area is 300 cm 2 , the effective area of ​​the hollow fiber membrane module is the same.

[0092] Construction of the reactor: connect the water inlet pipe, the water outlet pipe 17, the first peristaltic pump 3, the second peristaltic pump 16, the pressure sensor 14, and the paperless recorder 15 of the reactor in sequence, connect the aeration pump 7 to the gas flow meter to set the aeration volume, and then connect it to the aeration device at the bottom of the reactor, and the reactor construction is completed.

[0093] Influent ratio: The influent used in this embodiment is artificially synthesized simulated domestic sewage, and the specific ingredients are shown in Table 1.

[0094] Table 1 Ingredients of simulated domestic sewage

[0095]

[0096] Acquisition and domestication of activated sludge: The activated sludge taken from the MBR aerobic tank of the sewage treatment plant is put into the reactor for domestication and put into use after the effluent indicators such as chemical oxygen demand are normal.

[0097] Setting of operating conditions: The operating conditions set in this embodiment are determined according to the "Membrane Bioreactor Urban Wastewater Treatment Process Design Code T / CECS 152-2017" and the "Environmental Protection Product Technical Requirements Membrane Bioreactor HJ2527-2012", and the specific operating conditions are shown in Table 2 below.

[0098] Table 2 MBR operating conditions

[0099]

[0100] Determination of coagulant and selected amount: The coagulant selected in this embodiment is polyaluminium chloride (PAC). The coagulant is added to the sludge mixture in the reactor. Before determining the dosage, a batch test is carried out to measure indicators such as effluent COD (oxygen demand), sludge specific resistance, sludge average particle size, and sludge surface Zeta potential. Finally, it is determined that when the dosage is 500 mg / L, the properties of the sludge mixture can be improved to the greatest extent, and this is used as the dosage value under long-term operation conditions.

[0101] Membrane cleaning plan: After the membrane assembly is taken out of the reactor, it is first flushed with clean water for physical cleaning, placed in a clean water tank and soaked in 1 wt% oxalic acid for 3 h, and then cleaned with 1000 mg / L sodium hypochlorite + 100 mg / L ethylenediaminetetraethylene glycol for 3 h.

[0102] Comparative Example: In order to better evaluate the fouling development rate of the hydrophilically modified PE battery diaphragm, the PE-MCBR with coagulant added was compared with the PE-MBR without coagulant added under the same conditions. Figure 4 As shown in Table 3, under the same conditions, the pollution period of PE-MCBR is 21 days longer than that of PE-MBR, which preliminarily shows that adding coagulant is feasible to slow down the development rate of PE-MBR membrane pollution. After the membrane pollution filtration experiment, the membrane was cleaned and the distribution of each resistance was calculated. The calculation results are shown in Table 3.

[0103] R t is the total filtration resistance of the membrane Calculated, μ is 1.01×10 -3 Pa∙s. The data are shown in Table 3. After calculation, the PE-MBR without adding coagulant is 39.60%.

[0104] The ΔP is the transmembrane pressure difference on both sides of the membrane (Pa);

[0105] The μ is the dynamic viscosity of water (Pa∙s). At 20°C, μ=1.01×10 -3 Pa∙s;

[0106] The J is the permeation flux during membrane filtration (m / s);

[0107] The R t is the total filtration resistance of the membrane (m -1 ).

[0108] R t The resistance is composed of the following parts:

[0109] ;

[0110] The R m is the intrinsic resistance of the membrane (m -1 ), determined by the flux of pure water filtered through a new membrane;

[0111] The R r is the hydraulic reversible resistance (m -1 ), determined by physically cleaning the membrane module;

[0112] The R ir is the irreversible hydraulic resistance (m -1 ), determined by chemical cleaning of membrane modules;

[0113] The R f is the irreversible resistance (m -1 ), by R t -R m -R r -R ir Sure.

[0114] The hydraulic reversible resistance of PE-MBR without coagulant and PE-MCBR with coagulant was 39.60% and 52.85% respectively, and the hydraulic irreversible resistance was 44.27% and 32.24% respectively. The hydraulic irreversible resistance of PE-MBR was the largest, and the hydraulic reversible resistance of PE-MCBR was the largest. This shows that the addition of coagulant makes the contaminated PE membrane easier to be physically and chemically cleaned.

[0115] Table 3 Membrane resistance ratio

[0116]

[0117] The coagulation PE-MCBR was compared with the non-coagulation PVDF-MBR and the coagulation PVDF-MCBR for three cycles of membrane fouling operation. After each fouling, the membrane was cleaned and placed in the MBR to evaluate the feasibility and applicability of the PE-MCBR.

[0118] After each filtration experiment, the PE membrane or PVDF hollow fiber membrane was removed from the reactor, and the reactor that reached 50 kPa was put back into other membrane components and operated synchronously under the same conditions until the last reactor that reached 50 kPa. The purpose of doing this was to ensure that each cycle of the three reactors was consistent and better compared. At the same time, the reactor was drained of mud, on the one hand to discharge the residual PAC, and on the other hand to control the sludge concentration at 8000 mg / L, followed by three days of acclimatization. After cleaning, the membrane component was put back into the reactor, PAC was added again, and the three reactors were operated simultaneously. The three cycles were repeated in this way. The membrane pollution time of each cycle is shown in Table 4. Each pollution cycle of PE-MCBR is significantly longer than that of PVDF-MCBR and PVDF-MBR, and the first and second cycles are at least 5 days longer than PVDF-MCBR and PVDF-MBR, respectively.

[0119] This shows that compared with PVDF hollow fiber membrane, the addition of coagulant is more advantageous in slowing down the development of PE membrane pollution, which illustrates the feasibility and applicability of coagulation PE-MCBR.

[0120] Table 4 Membrane fouling time of each MBR three-cycle

[0121]

[0122] The present invention provides a coagulation-coupled polyethylene battery membrane bioreactor. The hydrophilically modified polyethylene battery membrane is first used in the MBR water treatment field, and its membrane pollution development behavior is studied. By comparing with the commercially available polyvinylidene fluoride hollow fiber membrane, its sewage treatment effect and the speed of transmembrane pressure difference development are evaluated. The coagulation coupling process is combined to control the membrane pollution development rate and achieve multi-cycle stable operation, which can effectively solve the current problem of high cost of MBR membranes and provide a new way to reduce the cost of MBR membranes.

[0123] 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 coagulation-coupled polyethylene battery membrane bioreactor, characterized in that: It comprises a reactor body, one side of the reactor body is provided with a water inlet assembly, and the bottom of the reactor body is provided with an aeration assembly; The filter membrane assembly is arranged in the middle of the reactor body; A water outlet assembly is provided on the upper part of the filtration membrane assembly, and a drug adding assembly is provided on the reactor body; The filter membrane assembly includes a filter membrane; The filter membrane is a polyethylene lithium battery separator; The porosity of polyethylene lithium battery separator is 35-45%; The contact angle of polyethylene lithium battery separator is 75-85°; The filter membrane assembly also includes a non-woven fabric and a plate frame; A water outlet is provided at the upper part of the plate frame, and a filter membrane and non-woven fabric form a composite membrane, which is arranged at the front and rear sides of the plate frame; Both the front and rear sides of the plate frame are provided with channels that allow liquid to enter; The average pore size of the filter membrane is 55-65nm; A method for using a coagulation-coupled polyethylene battery diaphragm bioreactor comprises the following steps: S1: Construction of a coagulation-coupled polyethylene battery membrane bioreactor; S2: Conduct membrane fouling filtration experiment on coagulation-coupled polyethylene battery membrane bioreactor to determine the optimal dosage of coagulant in membrane fouling filtration experiment; S3: After the membrane fouling filtration experiment, the coagulation-coupled polyethylene battery membrane bioreactor with and without coagulant addition was subjected to multi-cycle movement, and the control bioreactor with and without coagulant addition was subjected to multi-cycle movement. The feasibility and stability of the coagulation-coupled polyethylene battery membrane bioreactor with coagulant addition was evaluated by comparing the total membrane filtration resistance; In step S3, the feasibility and stability of coagulation coupling are evaluated by comparing the total membrane filtration resistance, including that if the total membrane filtration resistance of the coagulation-coupled polyethylene battery membrane bioreactor with the addition of coagulant is less than the total membrane filtration resistance of the coagulation-coupled polyethylene battery membrane bioreactor without the addition of coagulant, then the coagulation-coupled polyethylene battery membrane bioreactor with the addition of coagulant can operate stably for a long time and is feasible; And the total membrane filtration resistance of the coagulation-coupled polyethylene battery membrane bioreactor with the addition of coagulant is less than the total membrane filtration resistance of the control bioreactor with the addition of coagulant; And the total membrane filtration resistance of the coagulation-coupled polyethylene battery membrane bioreactor with coagulant added is less than the total membrane filtration resistance of the control bioreactor without coagulant added, so the coagulation-coupled polyethylene battery membrane bioreactor with coagulant added can operate stably for a long time and is feasible; The difference between the control bioreactor with added coagulant and the coagulation-coupled polyethylene battery membrane bioreactor is that the filter membrane of the reactor is a hollow fiber membrane, and the rest of the structures are the same.

2. A coagulation-coupled polyethylene battery membrane bioreactor according to claim 1, characterized in that: The width of the board frame is 12-14cm, the thickness is 0.5-1.5cm, and the length is 17-19cm; And / or, the length of the filter membrane is 14-16 cm, and the width of the filter membrane is 9-11 cm; And / or, the effective areas of the filter membrane and the non-woven fabric are the same, and the filter membrane and the non-woven fabric are both adhered to the plate frame by epoxy resin glue; And / or, the effective area of ​​the filter membrane is 280-320 cm 2 .

3. A coagulation-coupled polyethylene battery membrane bioreactor according to claim 1, characterized in that: The water inlet assembly includes a water inlet bucket, a water inlet pipe, and a first peristaltic pump; The water inlet bucket is arranged on one side of the reactor body, one end of the water inlet pipe is connected to the water inlet bucket, and the other end of the water inlet pipe is connected to the reactor body through the water inlet; The first peristaltic pump is arranged on the water inlet pipe; Aeration components include aeration pipes, aeration plates, and aeration pumps; The aeration plate is arranged at the bottom of the reactor body, one end of the aeration pipe is connected to the aeration plate, and the other end of the aeration pipe is connected to the aeration pump; The aeration plate is provided with a number of evenly distributed aeration holes; The aeration holes are opened 45° downward along the surface of the aeration plate, with a hole diameter of 1.5-2.5mm and a spacing of 8-12mm; The water outlet assembly includes a water outlet pipe, a water outlet bucket, and a second peristaltic pump. One end of the water outlet pipe is connected to the water outlet of the filter membrane assembly, and the other end of the water outlet pipe is connected to the water outlet bucket. The second peristaltic pump is arranged on the water outlet pipe. A pressure sensor is provided on the water outlet pipe, and the pressure sensor is electrically connected to the paperless recorder; The material of the reactor body is organic glass.

4. A coagulation-coupled polyethylene battery membrane bioreactor according to claim 1, characterized in that: In step S1, building a coagulation-coupled polyethylene battery membrane bioreactor includes building a filter membrane assembly, placing the filter membrane assembly into the reactor body; connecting a water inlet pipe to a water inlet at the bottom of the reactor body, installing an aeration pump on the aeration pipe, connecting a water outlet pipe to a water outlet above the membrane assembly, connecting the water outlet pipe to a water outlet bucket, and installing a pressure sensor on the water outlet pipe of the water outlet bucket; The construction of the filter membrane assembly includes forming a composite membrane with the filter membrane and the non-woven fabric through epoxy resin glue, and bonding the composite membrane to the front and back sides of the plate frame.

5. A coagulation-coupled polyethylene battery membrane bioreactor according to claim 4, characterized in that: Step S2 also includes determining the optimal dosage of the coagulant after multiple coagulant dosage tests, and taking the optimal dosage of the coagulant as the dosage value under long-term operation conditions; The coagulant dosage test includes pumping the coagulant solution into the sludge mixture through a dosing pump, aerating and mixing thoroughly, and then starting the membrane fouling filtration test; A membrane fouling filtration experiment was carried out in a coagulation-coupled polyethylene battery membrane bioreactor; the membrane fouling filtration experiment was operated in a constant flux, continuous water inlet, and intermittent water outlet mode. When the flux decayed, the speed of the first peristaltic pump was increased until the filtration experiment was completed.

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