An MBR membrane pollution control system

Abstract

The present invention discloses an MBR membrane pollution control system, comprising an MBR membrane system and an MBR membrane pollution dynamic control unit. The MBR membrane system comprises an inlet regulating tank, an inlet pump, an MBR reaction tank, an MBR membrane module and a water production pump connected in sequence. The inlet regulating tank is provided with an inlet COD online monitor; the MBR reaction tank is provided with a reaction tank level gauge, a sludge concentration meter, a supernatant online COD monitor, and a supernatant online NH3-N monitor. The MBR membrane pollution dynamic control unit comprises a reaction endpoint control unit and a pollution load dynamic control unit. The pollution load dynamic control unit is combined with the reaction endpoint control unit, and controls the pollution load of the reaction tank to be relatively constant by adjusting the reaction tank liquid level before periodic water inflow and the inlet reaction tank liquid level increment. The contact concentration and contact time of system pollutants with the MBR membrane system are controlled by adjusting the water volume rather than adjusting the reaction time, thereby delaying MBR membrane pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane water treatment, in particular to an MBR membrane pollution control system. Background Art

[0002] Sewage, especially decentralized sewage, often has the characteristics of large fluctuations in water quality and quantity. This places higher demands on the stability and economy of the sewage treatment system. The continuous flow membrane bioreactor (CMBR) can respond to the impact of high load and high flow inflow by increasing the sludge concentration and improving the operating flux. However, under low load or low flow inflow conditions, the water production performance of the continuous flow CMBR system is difficult to exert, and the problem of high operating energy consumption is prominent. The sequencing batch membrane bioreactor (SMBR) can respond to the low load or low flow inflow characteristics by adjusting the inflow-reaction stage time and other measures. It can serve as an effective supplement to the CMBR, but at the same time there is the problem that the MBR membrane is easily contaminated.

[0003] Therefore, how to prevent MBR membrane pollution and effectively play the advantages of SMBR is of great significance to this field. Summary of the Invention

[0004] To achieve the above object, the present invention provides an MBR membrane pollution control system.

[0005] The technical solution adopted in the present invention is:

[0006] A MBR membrane pollution control system includes an MBR membrane system and an MBR membrane pollution dynamic control unit. The MBR membrane system includes an inlet regulating tank, an MBR reaction tank, and an MBR membrane module. The inlet regulating tank and the MBR reaction tank are connected to an inlet pump via an inlet pipeline. A regulating tank level gauge is provided in the inlet regulating tank, and an inlet flow meter and an inlet online COD monitor are provided on the inlet pipeline. The MBR reaction tank is provided with a reaction tank level gauge, a sludge concentration meter, a reaction tank dissolved oxygen meter, a supernatant online COD monitor, a supernatant online NH3-N monitor, an MBR membrane module, and a biochemical aerator. The biochemical aerator is connected to a biochemical aeration fan. The MBR membrane module is connected to a membrane scrubbing aeration fan via a gas flow meter. A water production pipeline of the MBR membrane module is provided with a water production pump, an air compressor, a water production flow meter, a pressure regulating valve, a pressure relief valve, a water production online COD monitor, and a water production pressure transmitter. The pressure regulating valve is connected to an outlet pipeline of the air compressor.

[0007] The MBR membrane pollution dynamic control unit includes a reaction endpoint control unit and a pollution load dynamic control unit;

[0008] The reaction endpoint control unit includes a reaction endpoint data acquisition module and a reaction endpoint controller. The reaction endpoint data acquisition module includes a supernatant online COD monitor and a supernatant online NH3-N monitor. The reaction endpoint controller performs logical judgment based on the COD value and NH3-N value input by the reaction endpoint data acquisition module, and feeds back to the pollution load dynamic control unit with the reaction tank reaction time compensation Δt;

[0009] The pollution load dynamic control unit includes a pollution load dynamic data acquisition module, a pollution load dynamic controller and a pollution load dynamic control object module; the pollution load dynamic data acquisition module includes an inlet water online COD monitor, a supernatant liquid online COD monitor, a reaction tank level meter and a sludge concentration meter, and the pollution load dynamic control object module includes an inlet water pump and a production water pump; the pollution load dynamic controller controls the operation of the inlet water pump and the production water pump based on the reaction tank reaction time compensation △t fed back by the reaction endpoint control unit, as well as the inlet water online COD value, supernatant liquid online COD value, reaction tank level and reaction tank sludge concentration collected by the pollution load dynamic data acquisition module.

[0010] Furthermore, the principle of logical judgment of the reaction endpoint controller is as follows: when COD and NH3-N satisfy equations (1) and (2), the reaction endpoint controller uses the reaction time compensation of the reaction pool △t=0h to feed back to the pollution load dynamic control unit; when equations (1) and (2) are not satisfied, the reaction endpoint controller calculates the reaction time compensation of the reaction pool △t according to equations (3) and (4). COD and △t NH3-N ; and use the reaction time compensation of the reaction pool △t=max{△t COD , △t NH3-N}, feedback to the pollution load dynamic control unit;

[0011]

[0012] (COD)1 and (NH3-N)1 are the COD value and NH3-N value of the supernatant in the reaction tank detected by the reaction endpoint data acquisition module before the start of the aeration reaction stage;

[0013] (COD)2 and (NH3-N)2 are the COD value and NH3-N value of the supernatant of the reaction tank detected by the reaction endpoint data acquisition module when the reaction time of the aeration reaction stage reaches t0-1 according to the designed aeration reaction stage reaction time t0.

[0014] Furthermore, the pollution load dynamic control unit controls the operation of the water inlet pump and the water production pump according to equations (5), (6) and (7);

[0015]

[0016] Where:

[0017] k is the allowable deviation, ranging from 0.9 to 1.1;

[0018] C d Design the influent COD concentration for the reaction tank, mg / L;

[0019] C0 is the COD concentration of the supernatant in the reaction tank before the cycle water inflow, mg / L;

[0020] C t COD concentration of the supernatant in the periodic influent reaction tank, mg / L;

[0021] M a is the actual sludge concentration in the reaction tank, g / L;

[0022] M d Design sludge concentration for the reaction tank, g / L;

[0023] M0 is the sludge concentration in the reaction tank before the cycle water inflow, g / L;

[0024] t a is the actual reaction time of the reaction cell, h;

[0025] △t is the reaction time compensation of the reaction cell, h;

[0026] t d Design reaction time for the reaction cell, h;

[0027] H t is the liquid level increment of the inlet reaction tank, m;

[0028] H0 is the target liquid level in the drainage stage of the previous cycle, m;

[0029] H max is the designed maximum liquid level of the reaction tank, m;

[0030] H min is the minimum liquid level of the designed reaction tank, m;

[0031] Assign values to H0 in sequence, and 01 =H min , H 02 =H min +0.05, H 03 =H min +0.1, ...H 0n =H min +(n-1)*0.05 is substituted into formula (5) and formula (6) to obtain H t1 , H t2 ,...H tn In H 0n +Htn ≤H max Under the boundary conditions, H tn The maximum value H tn-max , and the corresponding H 0n-min ;

[0032] H 0n-min As the target liquid level of the drainage stage of the previous cycle, it is linked with the water production pump. When the liquid level of the reaction tank drops to H 0n-min When the water production pump is stopped;

[0033] H tn-max As the liquid level increment of the reaction tank in the water inlet stage of this cycle, it is linked with the water inlet pump. When the liquid level of the reaction tank rises to H 0n-min +H tn-max When the water inlet pump is stopped.

[0034] Furthermore, it also includes a membrane wire internal pressure control unit; the membrane wire internal pressure control unit includes a membrane wire internal pressure acquisition module, a membrane wire internal pressure dynamic controller and a membrane wire internal pressure control object module; the membrane wire internal pressure acquisition module includes a reaction tank level gauge and a water production pressure transmitter, and the membrane wire internal pressure control object module includes a pressure regulating valve and a pressure relief valve;

[0035] During the water inlet stage, the membrane internal pressure dynamic controller calculates the MBR membrane internal control pressure P1 according to formula (8), and adjusts the opening of the pressure regulating valve according to the pressure deviation P1-P between P1 and the membrane internal pressure P, so that the membrane internal pressure P is always equal to the P1 value;

[0036] During the stirring stage, the membrane wire internal pressure dynamic controller first calculates the MBR membrane wire internal control pressure P1 according to formula (8), and adjusts the opening of the pressure regulating valve according to the pressure deviation P1-P, so that the membrane wire internal pressure P is equal to the P1 value; when the set intermittent period is reached, the membrane wire internal pressure dynamic controller calculates the MBR membrane wire internal maximum target pressure P2 according to formula (9), and adjusts the opening of the pressure regulating valve according to the pressure deviation P2-P between P2 and the membrane wire internal pressure P, so that the membrane wire internal pressure P is equal to the P2 value; after a certain period of time, the membrane wire internal pressure dynamic controller calculates the MBR membrane wire internal control pressure P1 according to formula (8), and adjusts the opening of the pressure relief valve according to the pressure deviation P1-P, so that the membrane wire internal pressure P is equal to the P1 value;

[0037]

[0038] Where:

[0039] P1 is the internal control pressure of the MBR membrane fibers during the water inlet stage, kPa;

[0040] H is the liquid level of the reaction tank, m;

[0041] H min is the minimum liquid level of the designed reaction tank, m;

[0042] P min For H min Corresponding water production pressure, kPa;

[0043] P b is the bubble point pressure of the MBR membrane, kPa;

[0044] P α As a safety margin, take 5~10kPa;

[0045]

[0046] Where:

[0047] P2 is the maximum target pressure inside the MBR membrane, kPa;

[0048] H is the liquid level of the reaction tank, m;

[0049] H min is the minimum liquid level of the designed reaction tank, m;

[0050] P min For H min Corresponding water production pressure, kPa;

[0051] P b is the bubble point pressure of the MBR membrane, kPa;

[0052] P β To compensate for the margin, take 3~5kPa.

[0053] Furthermore, during the stirring stage, the intermittent period is 10 to 30 minutes and the duration is 10 to 30 seconds.

[0054] Furthermore, it also includes a drainage dynamic control unit, which includes a water production dynamic control subunit;

[0055] The water production dynamic control subunit includes a water production dynamic control acquisition module, a water production dynamic controller and a water production dynamic control object module. The water production dynamic control acquisition module includes a reaction tank level meter and a water production flow meter. The water production dynamic control object module includes a water production pump.

[0056] In the drainage stage, the water production dynamic controller controls the reaction tank liquid level H and water production flow Q input by the water production dynamic control acquisition module. L , the target water production flow Q1 is calculated by formula (10), and according to the water production flow Q L Flow rate deviation Q from target water production flow rate Q1 1- Q LAdjust the working frequency of the water production pump to make the water production flow rate Q L Equal to Q1; when the reaction tank liquid level H is equal to H calculated by the pollution load dynamic control unit 0n-min When , the water production pump is stopped and the drainage stage ends;

[0057]

[0058] Where:

[0059] Q1 is the target water production flow rate, L / h;

[0060] K is the correlation coefficient, ranging from 0.001 to 0.005, L 2 mg -1 ·m -2 ·h -1 ;

[0061] A is the membrane area of the membrane module, m 2 ;

[0062] M d is the design sludge concentration, mg / L;

[0063] H d Design liquid level for the reaction tank, m;

[0064] H is the liquid level of the reaction tank, m;

[0065] C is the correlation constant, and its value range is 30-40, L / h.

[0066] Furthermore, the water production dynamic controller intermittently calculates the water production flow deviation Q1-Q L , the intermittent calculation period is 3 to 5 minutes.

[0067] Furthermore, the drainage dynamic control unit also includes a membrane scrubbing aeration dynamic control subunit;

[0068] It includes a membrane scrubbing aeration dynamic control acquisition module, a membrane scrubbing aeration dynamic controller and a membrane scrubbing aeration dynamic control object module. The membrane scrubbing aeration dynamic control acquisition module includes a reaction tank level meter and a gas flow meter. The membrane scrubbing aeration dynamic control object module includes a membrane scrubbing aeration fan.

[0069] In the drainage stage, the membrane scrubbing aeration dynamic controller controls the membrane scrubbing air volume Q input by the scrubbing aeration dynamic control acquisition module. A and the reaction tank level H, the target membrane scrubbing aeration air volume Q2 is calculated by equations (11), (12) and (13), and the target membrane scrubbing aeration air volume Q2 is calculated based on the membrane scrubbing air volume Q A Flow deviation Q2-Q AAdjust the operating frequency of the membrane scrubbing aeration fan so that the membrane scrubbing air volume Q A Equal to Q2; when the reaction tank liquid level H is equal to H calculated by the pollution load dynamic control unit 0n-min When the membrane scrubbing aeration fan is stopped, the drainage stage ends;

[0070]

[0071] Where:

[0072] Q2 is the target membrane scrubbing aeration air volume, m 3 / h;

[0073] Q d Design membrane scrubbing aeration air volume, m 3 / h;

[0074] H d Design liquid level for the reaction tank, m;

[0075] H is the liquid level in the reaction tank, m.

[0076] Beneficial effects of the present invention:

[0077] 1. The reaction endpoint control unit is used to control membrane fouling during the aeration reaction stage. By detecting the COD and NH3-N concentrations of the supernatant, it prevents the supernatant pollutants from entering the drainage stage before they are completely degraded, thereby causing the supernatant pollutants to accumulate on the membrane surface.

[0078] 2. The pollution load dynamic control unit is combined with the reaction endpoint control unit to control the pollution load of the reaction tank to be relatively constant by adjusting the liquid level of the reaction tank before the water inflow and the liquid level increment of the water inflow reaction tank. By adjusting the water volume instead of adjusting the reaction time, the contact concentration and contact time between the system pollutants and the MBR membrane system are controlled, thereby delaying the pollution of the MBR membrane.

[0079] During the water inlet phase, contaminants are easily deposited on the membrane surface due to the lack of aeration. The membrane filament internal pressure control unit injects pressure into the membrane filaments, creating a pressure differential between the inside and outside of the membrane filaments. This prevents contaminants from diffusing into the membrane filaments during the water inlet phase, thereby controlling membrane fouling. Furthermore, during the agitation phase, the filaments are periodically shaken by regulating the internal pressure fluctuations, effectively preventing the adsorption and deposition of contaminants from outside the membrane filaments, thereby reducing the risk of membrane fouling.

[0080] 4. During the drainage stage, the liquid level in the reaction tank continues to drop and the sludge concentration in the reaction tank continues to rise. The water production dynamic control subunit can effectively avoid excessive concentration of the reaction tank sludge on the membrane surface by reducing the target water production flow rate, thereby reducing the risk of membrane pollution; the membrane scrubbing aeration dynamic control subunit can effectively avoid excessive concentration of the reaction tank sludge on the membrane surface by increasing the target membrane scrubbing aeration air volume in steps, thereby reducing the risk of membrane pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 This is a schematic structural diagram of the MBR membrane system of Example 1.

[0082] Figure 2 This is a schematic structural diagram of the MBR membrane pollution control system of Example 2. DETAILED DESCRIPTION

[0083] In order to make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and a preferred embodiment.

[0084] Example 1

[0085] See Figure 1 , this embodiment provides an MBR membrane system, including an inlet unit, an MBR reaction unit and an outlet unit.

[0086] The water inlet unit includes an inlet regulating tank 10, a regulating tank level gauge 11, an inlet pipeline 12, an inlet pump 13, an inlet flow meter 14, and an inlet COD monitor 15. The regulating tank level gauge 11 is located in the inlet regulating tank 10 and measures the liquid level therein. The inlet flow meter 14 is located on the inlet pipeline 12 and measures the inlet flow rate. The inlet COD monitor 15 is located on the inlet pipeline 12 and measures the inlet COD value.

[0087] The MBR reaction unit includes an MBR reaction tank 20, a reaction tank level gauge 21, a sludge concentration meter 22, a reaction tank dissolved oxygen meter 23, an online supernatant COD monitor 24, an online supernatant NH3-N monitor 28, an MBR membrane module 25, a biochemical aerator 26, and a biochemical aeration fan 27. The inlet regulating tank 10 and the MBR reaction tank 20 are connected via an inlet pipe 12. The reaction tank level gauge 21, sludge concentration meter 22, reaction tank dissolved oxygen meter 23, online supernatant COD monitor 24, and online supernatant NH3-N monitor 28 are installed in the reaction tank 20 and are used to measure the reaction tank 20 liquid level, sludge concentration, dissolved oxygen, supernatant COD value, and supernatant NH3-N value, respectively. A submersible agitator and a biochemical aerator 26 are installed in the MBR reaction tank 20. The biochemical aerator 26 is connected to the biochemical aeration fan 27 via an aeration pipe. The MBR membrane module 25 is disposed in the MBR reaction tank 20 .

[0088] The water outlet unit includes a water production pipeline 31, a water production pump 32, a water production flowmeter 33, an air compressor 34, a pressure regulating valve 35, a pressure relief valve 36, an online water production COD monitor 37, a water production pressure transmitter 38, a membrane scrubbing aeration fan 310, and a gas flowmeter 311. The water production outlet of the MBR membrane module 25 is connected to the water production pump 32 via the water production pipeline 31. The water production pipeline 31 is equipped with the following components: a water production pressure transmitter 38, a pressure regulating valve 35, a pressure relief valve 36, a water production pump 32, a water production flowmeter 33, an online water production COD monitor 37, and a water production flowmeter 33. The outlet of the air compressor 34 is connected to the water production pipeline 31 via a pressure regulating valve 35, which supplies compressed air to the production pipeline. The pressure relief valve 36 is used to relieve pressure in the production pipeline. The online water production COD monitor 37 measures the COD value of the produced water. The water production pressure transmitter 38 measures the water production pressure. The membrane scrubbing aeration blower 310 is connected to the MBR membrane module 25 via a membrane scrubbing aeration pipeline, and is used to provide membrane scrubbing aeration for the MBR membrane module 25. A gas flow meter 311 is provided on the membrane scrubbing aeration pipeline, and is used to measure the gas flow in the pipeline.

[0089] Example 2

[0090] This embodiment provides an MBR membrane pollution control system for Example 1, including a pollution load dynamic control unit, a membrane filament internal pressure control unit, a reaction endpoint control unit, and a drainage dynamic control unit.

[0091] The reaction endpoint control unit and the pollution load dynamic control unit constitute the MBR membrane pollution dynamic control unit. The reaction endpoint control unit feeds back the reaction tank reaction time compensation △t to the pollution load dynamic control unit; the pollution load dynamic control unit controls the operation of the inlet pump and the production water pump based on the reaction tank reaction time compensation △t fed back by the reaction endpoint control unit, as well as the inlet online COD value, supernatant online COD value, reaction tank liquid level and reaction tank sludge concentration.

[0092] The reaction endpoint control unit includes a reaction endpoint data acquisition module and a reaction endpoint controller. The reaction endpoint data acquisition module includes a supernatant online COD monitor 24 and a supernatant online NH3-N monitor 28. The working principle of the reaction endpoint control unit is:

[0093] (1) After the stirring stage ends and before the aeration reaction stage begins, the supernatant online COD monitor 24 and the supernatant online NH3-N monitor 28 are sampled to detect the COD value and NH3-N value of the supernatant, and the supernatant COD and supernatant NH3-N values at the beginning of the aeration reaction stage are obtained, which are recorded as (COD)1 and (NH3-N)1, respectively;

[0094] (2) According to the designed aeration reaction stage reaction time t0, when the aeration reaction stage reaction time reaches t0-1, the supernatant online COD monitor 24 and the supernatant online NH3-N monitor 28 are sampled again to detect the COD value and NH3-N value of the supernatant, and the supernatant COD and supernatant NH3-N values at the end of the aeration reaction stage are obtained, which are recorded as (COD)2 and (NH3-N)2 respectively;

[0095] (3) The reaction endpoint controller makes a judgment based on the input values of the supernatant online COD monitor 24 and the supernatant online NH3-N monitor 28. When (COD)2 and (NH3-N)2 satisfy equations 1 and 2, it is determined that the aeration reaction stage is over and the reaction endpoint has been reached. The controller then compensates the reaction time of the reaction tank with Δt=0h and feeds back to the pollution load dynamic control unit.

[0096]

[0097] (4) When (COD)2 and (NH3-N)2 do not satisfy Equation 1 or Equation 2, it is determined that the aeration reaction stage has not ended and the reaction endpoint has not been reached. The reaction time compensation △t of the reaction tank is calculated according to Equation 3 and Equation 4 respectively. COD and △t NH3-N ;

[0098]

[0099] And the reaction time compensation of the reaction pool is △t=max{△t COD , △t NH3-N}, and feed back to the pollution load dynamic control unit.

[0100] The pollution load dynamic control unit includes a pollution load dynamic data acquisition module, a pollution load dynamic controller, and a pollution load dynamic control object module. The pollution load dynamic data acquisition module includes an influent online COD monitor 15, a supernatant online COD monitor 24, a reaction tank level meter 21, and a sludge concentration meter 22. The pollution load dynamic control object module includes an influent pump 13 and a produced water pump 32. The working principle of the pollution load dynamic control unit is as follows:

[0101] The pollution load dynamic controller controls the operation of the inlet pump 13 and the production water pump 32 according to Formulas 5, 6 and 7 based on the reaction time compensation △t of the reaction tank fed back by the reaction endpoint control unit, and the inlet online COD value, supernatant online COD value, reaction tank liquid level and reaction tank sludge concentration collected by the pollution load dynamic data acquisition module.

[0102]

[0103] Where:

[0104] k is the allowable deviation, ranging from 0.9 to 1.1;

[0105] C d The COD concentration of the influent designed for the reaction tank, mg / L; design value;

[0106] C0 is the COD concentration of the supernatant in the reaction tank before the periodic water inflow, mg / L; it is measured by the online COD monitor 24 for the supernatant in the reaction tank;

[0107] C t COD concentration of the supernatant of the periodic influent reaction tank, mg / L; measured by the online COD monitor 24 for the supernatant of the reaction tank;

[0108] M a is the actual sludge concentration in the reaction tank, g / L; measured by the reaction tank sludge concentration meter 22;

[0109] M d Design sludge concentration for the reaction tank, g / L; design value;

[0110] M0 is the sludge concentration in the reaction tank before the cycle water inflow, g / L; measured by the reaction tank sludge concentration meter 22;

[0111] t a is the actual reaction time of the reaction tank, h; take the design value;

[0112] △t is the reaction time compensation of the reaction cell, h; it is fed back by the reaction endpoint control unit;

[0113] t d Design reaction time for the reaction tank, h; design value;

[0114] H t is the liquid level increment of the inlet reaction tank, m;

[0115] H0 is the target liquid level in the drainage stage of the previous cycle, m;

[0116] H max is the highest liquid level of the designed reaction tank, m; design value;

[0117] H min is the minimum liquid level of the designed reaction tank, m; design value.

[0118] Assign values to H0 in sequence, and 01 =H min , H 02 =H min +0.05, H 03 =H min +0.1, ...H 0n =H min +(n-1)*0.05 is substituted into Equation 5 and Equation 6 to obtain H t1, H t2 ,...H tn In H 0n +H tn ≤H max Under the boundary conditions, H tn The maximum value H tn-max , and the corresponding H 0n-min .

[0119] H 0n-min As the target liquid level of the drainage stage of the previous cycle, it is linked with the water production pump 32. When the liquid level of the reaction tank drops to H 0n-mi At n, the water production pump 32 is stopped.

[0120] H tn-max As the liquid level increment of the reaction tank in the water inlet stage of this cycle, it is linked with the water inlet pump 13. When the liquid level of the reaction tank rises to H 0n-min +H tn-max When , stop the water inlet pump 13.

[0121] Calculation example:

[0122] The allowable deviation k is set to 1.0, and the designed influent COD concentration of the reaction tank is C d The COD concentration of the supernatant in the reaction tank before the periodic water inflow is 200 mg / L. The COD concentration of the supernatant in the reaction tank before the periodic water inflow is C0. t is 250 mg / L, the actual sludge concentration in the reaction tank is M a is 6g / L, and the designed sludge concentration of the reaction tank is M d is 4g / L, the sludge concentration M0 of the reaction tank before the cycle water inflow is 8g / L, and the actual reaction time of the reaction tank is t a is 4h, the reaction time compensation △t of the reaction pool is 0h, and the reaction time of the reaction pool is designed to be t d For 4h, the maximum liquid level of the reaction tank is designed to be H max The lowest liquid level of the designed reaction tank is H min is 2m.

[0123] Assign values to H0 in sequence, and 01 =H min , H 02 =H min +0.05, H 03 =H min +0.1, ...H 0n =H min +(n-1)*0.05 into Equation 1 and Equation 2 to obtain H t1 , H t2 ,...H tn In H 0n +H tn ≤H maxUnder the boundary conditions, we can obtain H tn The maximum value H tn-max , and the corresponding H 0n-min .

[0124] Take H 01 =2m, H 01 Substituting into Equation 5 and Equation 6, we form the following system of equations:

[0125]

[0126] Solve for H t1 =2.2m.

[0127] Take H in turn 02 =H min +0.05, H 03 =H min +0.1, ...H 0n =H min +(n-1)*0.05 into Equation 1 and Equation 2 to obtain H t2 ,...H tn， The series of solutions are shown in Table 1 below:

[0128] Table 1 H0 and H t Series Solution

[0129] <![CDATA[H0]]> <![CDATA[H t ]]> <![CDATA[H0+H t ]]> 2.00 2.20 4.20 2.05 2.23 4.28 2.10 2.26 4.36 2.15 2.29 4.44 2.20 2.32 4.52 2.25 2.35 4.60 2.30 2.38 4.68 2.35 2.41 4.76 2.40 2.44 4.84 2.45 2.47 4.92 2.50 2.50 5.00 2.55 2.53 5.08

[0130] When H0 is 2.5m, H t 2.5m, H0+H t 5.0m, in line with H 0n +H tn ≤H max The boundary conditions are as follows: H0 is determined to be the liquid level of the reaction tank before the periodic water inflow is 2.5m, H t The liquid level increment for the water inlet reaction tank is 2.5m.

[0131] The membrane internal pressure control unit includes a membrane internal pressure acquisition module, a membrane internal pressure dynamic controller, and a membrane internal pressure control object module; the membrane internal pressure acquisition module includes a reaction tank level gauge 21 and a produced water pressure transmitter 38, and the membrane internal pressure control object module includes a pressure regulating valve 35 and a pressure relief valve 36; the working principle of the membrane internal pressure control unit is as follows:

[0132] (1) During the water inlet stage, the liquid level in the reaction tank continues to rise, and the external pressure of the membrane wire continues to rise. The reaction tank level gauge 21 and the water production pressure transmitter 38 transmit the reaction tank liquid level H and the water production pipe pressure P data to the membrane wire internal pressure dynamic controller respectively. The membrane wire internal pressure dynamic controller calculates the MBR membrane wire internal control pressure P1 according to formula 8, and adjusts the opening of the pressure regulating valve 35 according to the pressure deviation P1-P between P1 and the membrane wire internal pressure P, so that the membrane wire internal pressure P is always equal to the P1 value, thereby effectively preventing the external pollutants of the membrane wire from continuously entering the membrane wire under the action of the internal and external pressure difference, and forming membrane pollution on the membrane wire surface.

[0133]

[0134] Where:

[0135] P1 is the internal control pressure of the MBR membrane fibers during the water inlet stage, kPa;

[0136] H is the liquid level of the reaction tank, m; measured by the reaction tank level gauge 21;

[0137] H min is the lowest liquid level of the designed reaction tank, m; design value;

[0138] P min For H min The corresponding produced water pressure, kPa, is measured by the produced water pressure transmitter 38;

[0139] P b is the MBR membrane bubble point pressure, kPa; design value;

[0140] P α As a safety margin, take 5 to 10 kPa.

[0141] (2) During the stirring stage, the membrane wire internal pressure dynamic controller first calculates the MBR membrane wire internal control pressure P1 through formula 8, and adjusts the opening of the pressure regulating valve 35 according to the pressure deviation P1-P, so that the membrane wire internal pressure P is equal to the P1 value; when the set intermittent period is reached, the membrane wire internal pressure dynamic controller calculates the MBR membrane wire internal maximum target pressure P2 through formula 9, and adjusts the opening of the pressure regulating valve 35 according to the pressure deviation P2-P, so that the membrane wire internal pressure P is equal to the P2 value; after a certain period of time, the membrane wire internal pressure dynamic controller calculates the MBR membrane wire internal control pressure P1 through formula 8, and adjusts the opening of the pressure relief valve 36 according to the pressure deviation P1-P, so that the membrane wire internal pressure P is equal to the P1 value.

[0142] The periodic fluctuation of the internal pressure of the membrane filament can cause the membrane filament to vibrate periodically, effectively preventing the adsorption and deposition of external pollutants on the surface of the membrane filament, and reducing the risk of membrane contamination.

[0143]

[0144] Where:

[0145] P2 is the maximum target pressure inside the MBR membrane, kPa;

[0146] H is the liquid level of the reaction tank, m; measured by the reaction tank level gauge 21;

[0147] H min is the lowest liquid level of the designed reaction tank, m; design value;

[0148] P min For H min The corresponding produced water pressure, kPa, is measured by the produced water pressure transmitter 38;

[0149] P b is the MBR membrane bubble point pressure, kPa; design value;

[0150] P β To compensate for the margin, take 3~5kPa.

[0151] Preferably, during the stirring stage, the intermittent period is 30 minutes and the duration is 10 seconds.

[0152] The drainage dynamic control unit includes a water production dynamic control subunit and a membrane scrubbing aeration dynamic control subunit.

[0153] The water production dynamic control subunit includes a water production dynamic control acquisition module, a water production dynamic controller and a water production dynamic control object module. The water production dynamic control acquisition module includes a reaction tank level meter 21 and a water production flow meter 33 , and the water production dynamic control object module includes a water production pump 32 .

[0154] The working principle of the water production dynamic control subunit is: in the drainage stage, the reaction tank level meter 21 and the water production flow meter 33 respectively measure the reaction tank level H and the water production flow Q L The data is transmitted to the water production dynamic controller. The water production dynamic controller calculates the target water production flow rate Q1 according to formula 10, and adjusts the water production flow rate Q L Flow rate deviation Q1-Q from the target water production flow rate Q1 L Adjust the working frequency of the water production pump 32 so that the water production flow rate Q L Equal to Q1. When the reaction tank liquid level H is equal to H calculated by the pollution load dynamic control unit 0n-min When , the water production pump 32 is stopped and the drainage stage ends.

[0155]

[0156] Where:

[0157] Q1 is the target water production flow rate, L / h;

[0158] K is the correlation coefficient, ranging from 0.001 to 0.005, L 2 mg -1 ·m -2 ·h -1 ;

[0159] A is the membrane area of the membrane module, m 2 ; Design value;

[0160] M d is the design sludge concentration, mg / L; design value;

[0161] H d is the design liquid level of the reaction tank, m; design value;

[0162] H is the liquid level of the reaction tank, m; measured by the reaction tank level gauge 21;

[0163] C is the correlation constant, ranging from 30 to 40, L / h.

[0164] Preferably, the water production dynamic controller intermittently calculates the water production flow deviation to avoid frequent adjustment of the water production pump frequency.

[0165] Preferably, the intermittent calculation period is 3 to 5 minutes.

[0166] The membrane scrubbing aeration dynamic control subunit includes a membrane scrubbing aeration dynamic control acquisition module, a membrane scrubbing aeration dynamic controller and a membrane scrubbing aeration dynamic control object module. The membrane scrubbing aeration dynamic control acquisition module includes a reaction tank level meter 21 and a gas flow meter 311. The membrane scrubbing aeration dynamic control object module includes a membrane scrubbing aeration fan 310.

[0167] The working principle of the membrane scrubbing aeration dynamic control subunit is: in the drainage stage, the reaction tank level meter 21 and the gas flow meter 311 respectively measure the reaction tank level H and the gas flow Q A The data is transmitted to the membrane scrubbing aeration dynamic controller. The membrane scrubbing aeration dynamic controller calculates the target membrane scrubbing aeration air volume Q2 through equations 11, 12, and 13, and adjusts the target membrane scrubbing aeration air volume Q2 according to the gas flow rate Q A Flow deviation Q2-Q A Adjust the operating frequency of the membrane scrubbing aeration fan 310 so that the membrane scrubbing air volume Q A Equal to Q2. When the reaction tank liquid level H is equal to H calculated by the pollution load dynamic control unit 0n-min When the membrane scrubbing aeration fan is stopped, the drainage stage ends.

[0168]

[0169] Where:

[0170] Q2 is the target membrane scrubbing aeration air volume, m 3 / h;

[0171] Q d Design membrane scrubbing aeration air volume, m 3 / h; design value;

[0172] H d is the design liquid level of the reaction tank, m; design value;

[0173] H is the liquid level of the reaction tank, m; it is measured by the reaction tank level meter 21.

[0174] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also within the scope of protection of the present invention.

Claims

1. An MBR membrane pollution control system, comprising an MBR membrane system and an MBR membrane pollution dynamic control unit, characterized in that: The MBR membrane system comprises an inlet regulating tank (10), an MBR reaction tank (20) and an MBR membrane module (25). The inlet regulating tank (10) and the MBR reaction tank (20) are connected via an inlet pipe (12) and an inlet pump (13). A regulating tank level gauge (11) is provided in the inlet regulating tank (10), and an inlet flow meter (14) and an inlet online COD monitor (15) are provided on the inlet pipe (12). The MBR reaction tank (20) is provided with a reaction tank level gauge (21), a sludge concentration meter (22), a reaction tank dissolved oxygen meter (23), a supernatant online COD monitor (24), and a supernatant online COD monitor (25). An NH3-N monitor (28), an MBR membrane module (25) and a biochemical aerator (26), the biochemical aerator (26) is connected to a biochemical aeration fan (27), the MBR membrane module (25) is connected to a membrane scrubbing aeration fan (310) via a gas flow meter (311), a water production pump (32), a water production flow meter (33), an air compressor (34), a pressure regulating valve (35), a pressure relief valve (36), a water production online COD monitor (37) and a water production pressure transmitter (38) are provided on the water production pipeline (31) of the MBR membrane module (25); the pressure regulating valve (35) is connected to the outlet pipeline of the air compressor (34); The MBR membrane pollution dynamic control unit includes a reaction endpoint control unit and a pollution load dynamic control unit; The reaction endpoint control unit includes a reaction endpoint data acquisition module and a reaction endpoint controller. The reaction endpoint data acquisition module includes a supernatant online COD monitor (24) and a supernatant online NH3-N monitor (28). The reaction endpoint controller performs logical judgment based on the COD value and NH3-N value input by the reaction endpoint data acquisition module, and feeds back to the pollution load dynamic control unit with the reaction tank reaction time compensation Δt; The pollution load dynamic control unit includes a pollution load dynamic data acquisition module, a pollution load dynamic controller and a pollution load dynamic control object module; the pollution load dynamic data acquisition module includes an influent online COD monitor (15), a supernatant online COD monitor (24), a reaction tank level meter (21) and a sludge concentration meter (22); the pollution load dynamic control object module includes an influent pump (13) and a production water pump (32); the pollution load dynamic controller controls the operation of the influent pump (13) and the production water pump (32) based on the reaction tank reaction time compensation Δt fed back by the reaction endpoint control unit, and the influent online COD value, supernatant online COD value, reaction tank level and reaction tank sludge concentration collected by the pollution load dynamic data acquisition module; The principle of logical judgment of the reaction endpoint controller is: When COD and NH3-N satisfy equations (1) and (2), the reaction endpoint controller uses the reaction time compensation Δt=0h to feed back to the pollution load dynamic control unit; when they do not satisfy equations (1) and (2), the reaction endpoint controller calculates the reaction time compensation Δt according to equations (3) and (4). COD and △t NH3-N ; and use the reaction time compensation of the reaction pool △t=max{△t COD , △t NH3-N }, feedback to the pollution load dynamic control unit; (COD)1 and (NH3-N)1 are the COD value and NH3-N value of the supernatant in the reaction tank detected by the reaction endpoint data acquisition module before the start of the aeration reaction stage; (COD)2 and (NH3-N)2 are the COD value and NH3-N value of the supernatant in the reaction tank detected by the reaction endpoint data acquisition module when the reaction time of the aeration reaction stage reaches t0-1 according to the designed aeration reaction stage reaction time t0; The pollution load dynamic control unit controls the operation of the water inlet pump (13) and the water production pump (32) according to equations (5), (6) and (7); Where: k is the allowable deviation, ranging from 0.9 to 1.1; C d Design the influent COD concentration for the reaction tank, mg / L; C0 is the COD concentration of the supernatant in the reaction tank before the cycle water inflow, mg / L; C t COD concentration of the supernatant in the periodic influent reaction tank, mg / L; M a is the actual sludge concentration in the reaction tank, g / L; M d Design sludge concentration for the reaction tank, g / L; M0 is the sludge concentration in the reaction tank before the cycle water inflow, g / L; t a is the actual reaction time of the reaction cell, h; △t is the reaction time compensation of the reaction cell, h; t d Design reaction time for the reaction cell, h; H t is the liquid level increment of the inlet reaction tank, m; H0 is the target liquid level in the drainage stage of the previous cycle, m; H max is the designed maximum liquid level of the reaction tank, m; H min is the minimum liquid level of the designed reaction tank, m; Assign values to H0 in sequence, and 01 =H min , H 02 =H min +0.05, H 03 =H min +0.1, ...H 0n =H min +(n-1)*0.05 is substituted into formula (5) and formula (6) to obtain H t1 , H t2 ,...H tn ; in H 0n +H tn ≤H max Under the boundary conditions, H tn The maximum value H tn-max , and the corresponding H 0n-min ; H 0n-min As the target liquid level of the drainage stage of the previous cycle, it is linked with the water production pump (32). When the liquid level of the reaction tank drops to H 0n-min When , the water production pump (32) is stopped; H tn-max As the liquid level increment of the reaction tank in the water inlet stage of this cycle, it is linked with the water inlet pump (13). When the liquid level of the reaction tank rises to H 0n-min +H tn-max When , stop the water inlet pump (13).

2. An MBR membrane pollution control system according to claim 1, characterized in that: It also includes a membrane filament internal pressure control unit; the membrane filament internal pressure control unit includes a membrane filament internal pressure acquisition module, a membrane filament internal pressure dynamic controller and a membrane filament internal pressure control object module; the membrane filament internal pressure acquisition module includes a reaction tank level meter (21) and a produced water pressure transmitter (38), and the membrane filament internal pressure control object module includes a pressure regulating valve (35) and a pressure relief valve (36); During the water inlet stage, the membrane internal pressure dynamic controller calculates the MBR membrane internal control pressure P1 according to formula (8), and adjusts the opening of the pressure regulating valve (35) according to the pressure deviation P1-P between P1 and the membrane internal pressure P, so that the membrane internal pressure P is always equal to the P1 value; During the stirring stage, the membrane wire internal pressure dynamic controller first calculates the MBR membrane wire internal control pressure P1 according to formula (8), and adjusts the opening of the pressure regulating valve (35) according to the pressure deviation P1-P, so that the membrane wire internal pressure P is equal to the P1 value; when the set intermittent period is reached, the membrane wire internal pressure dynamic controller calculates the MBR membrane wire internal maximum target pressure P2 according to formula (9), and adjusts the opening of the pressure regulating valve (35) according to the pressure deviation P2-P between P2 and the membrane wire internal pressure P, so that the membrane wire internal pressure P is equal to the P2 value; after a certain period of time, the membrane wire internal pressure dynamic controller calculates the MBR membrane wire internal control pressure P1 according to formula (8), and adjusts the opening of the pressure relief valve (36) according to the pressure deviation P1-P, so that the membrane wire internal pressure P is equal to the P1 value; Where: P1 is the internal control pressure of the MBR membrane fibers during the water inlet stage, kPa; H is the liquid level of the reaction tank, m; H min is the minimum liquid level of the designed reaction tank, m; P min For H min Corresponding water production pressure, kPa; P b is the bubble point pressure of the MBR membrane, kPa; P α As a safety margin, take 5~10kPa; Where: P2 is the maximum target pressure inside the MBR membrane, kPa; H is the liquid level of the reaction tank, m; H min is the minimum liquid level of the designed reaction tank, m; P min For H min Corresponding water production pressure, kPa; P b is the bubble point pressure of the MBR membrane, kPa; P β To compensate for the margin, take 3~5kPa.

3. An MBR membrane pollution control system according to claim 2, characterized in that: During the stirring stage, the intermittent period is 10 to 30 minutes and the duration is 10 to 30 seconds.

4. The MBR membrane pollution control system according to claim 1, characterized in that: It also includes a drainage dynamic control unit, which includes a water production dynamic control subunit; The water production dynamic control subunit includes a water production dynamic control acquisition module, a water production dynamic controller and a water production dynamic control object module, wherein the water production dynamic control acquisition module includes a reaction tank level meter (21) and a water production flow meter (33), and the water production dynamic control object module includes a water production pump (32); In the drainage stage, the water production dynamic controller controls the reaction tank liquid level H and water production flow Q input by the water production dynamic control acquisition module. L , the target water production flow Q1 is calculated by formula (10), and according to the water production flow Q L Flow rate deviation Q1-Q from the target water production flow rate Q1 L Adjust the working frequency of the water production pump (32) so that the water production flow rate Q L Equal to Q1; when the reaction tank liquid level H is equal to H calculated by the pollution load dynamic control unit 0n-min When , the water production pump (32) is stopped and the drainage phase ends; Where: Q1 is the target water production flow rate, L / h; K is the correlation coefficient, ranging from 0.001 to 0.005, L 2 mg -1 ·m -2 ·h -1 ; A is the membrane area of the membrane module, m 2 ; M d is the design sludge concentration, mg / L; H d Design liquid level for the reaction tank, m; H is the liquid level of the reaction tank, m; C is the correlation constant, and its value range is 30-40, L / h.

5. An MBR membrane pollution control system according to claim 4, characterized in that: The water production dynamic controller intermittently calculates the water production flow deviation Q1-Q L , the intermittent calculation period is 3 to 5 minutes.

6. An MBR membrane pollution control system according to claim 5, characterized in that: The drainage dynamic control unit also includes a membrane scrubbing aeration dynamic control subunit; The system comprises a membrane scrubbing aeration dynamic control acquisition module, a membrane scrubbing aeration dynamic controller and a membrane scrubbing aeration dynamic control object module, wherein the membrane scrubbing aeration dynamic control acquisition module comprises a reaction tank level meter (21) and a gas flow meter (311), and the membrane scrubbing aeration dynamic control object module comprises a membrane scrubbing aeration fan (310); In the drainage stage, the membrane scrubbing aeration dynamic controller controls the membrane scrubbing air volume Q input by the scrubbing aeration dynamic control acquisition module. A and the reaction tank level H, the target membrane scrubbing aeration air volume Q2 is calculated by equations (11), (12) and (13), and the target membrane scrubbing aeration air volume Q2 is calculated based on the membrane scrubbing aeration air volume Q A Flow deviation Q2-Q A Adjust the operating frequency of the membrane scrubbing aeration fan (310) so that the membrane scrubbing air volume Q A Equal to Q2; when the reaction tank liquid level H is equal to H calculated by the pollution load dynamic control unit 0n-min When the membrane scrubbing aeration fan (310) is stopped, the drainage stage ends; Where: Q2 is the target membrane scrubbing aeration air volume, m 3 / h; Q d Design membrane scrubbing aeration air volume, m 3 / h; H d Design liquid level for the reaction tank, m; H is the liquid level in the reaction tank, m.

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