Control method for dynamically regulating and controlling photocatalytic efficiency and effective growth of biological membrane
By dynamically controlling the photocatalytic efficiency and biofilm growth, the contact problem between photocatalytic materials and biofilms was solved, achieving efficient synergy between photocatalytic reaction and biofilm, thus improving the efficiency and stability of wastewater treatment. In particular, in MABR modified membrane fibers, the ratio of biofilm-covered area to photocatalytic material exposed area was controlled, promoting the simultaneous removal of recalcitrant organic matter and nitrogen.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-19
- Publication Date
- 2026-04-21
AI Technical Summary
Overlapping or lack of substantial contact between photocatalytic materials and biofilms reduces photon absorption and utilization efficiency, decreases photocatalytic performance, and makes it impossible to effectively control the ratio of biofilm-covered areas to exposed photocatalytic materials. This leads to impaired mass transfer and biofilm inhibition, making it difficult to achieve efficient removal of recalcitrant organic matter and nitrogen.
By dynamically regulating photocatalytic efficiency and biofilm growth, the ratio of biofilm-covered area to exposed photocatalytic material area is controlled. MABR-modified membrane fibers are used, the biofilm coverage growth rate is set and graded, and parameters such as circulation flow ratio, gas supply flow rate, scrubbing flow rate, scrubbing frequency, and light intensity are adjusted to achieve efficient synergy between photocatalytic reaction and microbial film growth on the membrane fiber surface.
It improves the efficiency of photocatalytic reaction, promotes the stable growth of biofilm, enhances the simultaneous removal of recalcitrant organic matter and nitrogen, and achieves more efficient and stable wastewater treatment.
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Figure CN121894790A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of wastewater treatment technology, and in particular to a method for dynamically regulating photocatalytic efficiency and effective biofilm growth. Background Technology
[0002] Currently, photocatalytic materials and biofilms often overlap or lack substantial contact, leading to a series of problems: reduced photocatalytic material absorption and utilization efficiency; inability to utilize oxygen transferred by MABR-modified membrane fibers to induce reactive oxygen species (ROS) generation, resulting in decreased photocatalytic efficiency; and unstable biofilm formation and activity. The inability to effectively control the ratio of biofilm-covered to photocatalytically exposed areas on the MABR-modified membrane fiber surface hinders mass transfer and causes biofilm inhibition. These problems prevent photocatalytic products from adequately nourishing the biofilm, and the biofilm itself struggles to effectively absorb photocatalytic degradation products, severely restricting photocatalytic reaction efficiency, efficient growth of microbial films on the MABR-modified membrane fiber surface, and the achievement of the goal of simultaneous and efficient removal of recalcitrant organic matter and nitrogen. Therefore, when photocatalytic oxidation is coupled in situ with MABR, there is no effective method for deep synergistic control, and there is a lack of effective regulation of the reaction interface and process. Summary of the Invention
[0003] In view of the above-mentioned prior art, and to solve at least one of the above-mentioned technical problems, this application proposes a method for dynamically regulating photocatalytic efficiency and effective biofilm growth. By controlling the ratio of the biofilm-covered area to the exposed area of the photocatalytic material, a highly efficient synergistic effect between photocatalytic reaction and microbial film growth on the membrane filament surface is achieved, thereby achieving efficient and stable simultaneous removal of recalcitrant organic matter and nitrogen.
[0004] This application provides a method for dynamically regulating photocatalytic efficiency and effective biofilm growth, comprising the following steps: Select MABR-modified membrane fibers and determine the total amount to be used; The test included the quality of the incoming water and the concentration of ROS generated in the MABR modified membrane fibers under pure water conditions. The control parameters for the biofilm attachment and growth stage in the MABR modified membrane filaments were identified, including the biofilm coverage growth rate. Based on the biofilm coverage growth rate, the biofilm was divided into 5 levels, 4 levels, 3 levels, 2 levels, and 1 levels. When the biofilm appears on the surface of the MABR-modified membrane filament and the coverage growth rate is ≤4, the MABR-modified membrane filament enters the normal operation stage; and is then regulated sequentially according to the following steps (a)-(i): (a) During normal operation, the growth rate R of the biofilm on the surface of the MABR modified membrane filaments is set. 3’ ; Evaluate the graded range of the biomembrane in the MABR-modified membrane fibers; (b) Set the circulation flow ratio R 4’ ; (c) Maintain gas supply pressure P air’ The constant value remains unchanged; (d) Set the gas supply flow rate Q air’ ; (e) Set the scrubbing flow rate Q scrub’ ; (f) Set the cleaning frequency f ’ ; (g) Set the duration t of a single scrubbing session ’ ; (h) Set the light intensity P ’ .
[0005] In some embodiments, the test parameters for the incoming water quality include COD. Cr TN, NH4 + -N, NO2 - -N and NO3 - -N.
[0006] In some embodiments, the ROS of the MABR-modified membrane fibers include ·OH, 1 O2, ·O2-, H2O2; their corresponding concentrations in the reactor under pure water conditions are: , , , The corresponding concentration in the reactor under the incoming water quality environment is: , , , .
[0007] In some embodiments, the regulating parameters for the biofilm attachment and growth stage in the MABR-modified membrane fibers also include the internal circulation flow ratio R4 and the gas supply flow rate Q. air ; Scrub flow rate Q scrub ; wiping frequency f; single wiping duration t; light intensity P; air supply pressure P air And temperature T.
[0008] In some embodiments, during the biofilm attachment growth stage of the MABR modified membrane filaments, the growth rate R3 of the biofilm is calculated using equation (2).
[0009] Where SPi: area of the exposed photocatalytic material region, m2; SBi: area of the biofilm growth region, m2; n is the number of MABR modified membrane fibers used for testing; Calculate the internal circulation flow ratio R4 using equation (3);
[0010] The gas supply pressure P air Maintain a constant value; The gas supply flow rate Q is calculated using equation (4). air ;
[0011] Where Q is the influent flow rate, m 3 / h; The percentage of oxygen in the air is 0.2095. The value range is 0.2 to 0.4; The photogenerated hole reaction constant is 1.58. : Hydroxyl radical reaction constant; 2.39 at pH 7; 2.74 at pH < 7; 1.97 at pH > 7; The reaction constant for superoxide radicals is 0.94. The singlet oxygen reaction constant has a value of 0.65. The reaction constant for hydrogen peroxide is 0.87 at pH 7; 1.72 at pH < 7; and 0.69 at pH > 7. The concentration of ·OH in pure water, mg / L; The concentration of OH in the incoming water under environmental conditions, in mg / L; In a pure water environment 1 O2 concentration, mg / L; Incoming water quality environment 1 O2 concentration, mg / L; In a pure water reaction system, Concentration, mg / L; the stated Incoming water quality environment Concentration, mg / L; the stated The concentration of H2O2 in the pure water reaction system is mg / L; The concentration of H2O2 in the incoming water is in mg / L. The water quality environment that needs to be removed Concentration, mg / L; Initial water quality under the current conditions Concentration, mg / L; The scrubbing flow rate Q is calculated using equation (5). scrub ;
[0012] Where S MABR The total surface area of the MABR-modified membrane fibers is given in m. 2 S TANK The bottom area of the reaction tank is m. 2 β is the redundancy coefficient, with a value ranging from 0.2 to 0.4. The wiping frequency f is calculated using equation (6);
[0013] The light intensity P is calculated using equation (7);
[0014] 0 P: Default photon density, mW / cm² 2 The value ranges from 100 to 500; The duration of a single scrubbing session, t, is 0. The temperature T is room temperature.
[0015] In some embodiments, in the initial stage, 1 / R3 in equation (2) is 0; in equation (3), C is the inner loop constant with a value of 10; in equation (4) The value is 0.4; in equation (5), β is 0.2; in equation (7) 0 P < 200 mW / cm 2 .
[0016] In some embodiments, the growth rate R of the biofilm is calculated using equation (2). 3’ ; The current internal circulation flow ratio R is calculated using equation (3). 4’ ; The gas supply pressure P air’ Maintain a constant value; Preliminary determination , , , The gas supply flow rate Q is calculated using the above formula (4). air’ In the above formula (4) The value range is less than 0.4; The scrubbing flow rate Q is calculated using the above formula (5). scrub’ ; The wiping frequency f is calculated using the above formula (6). ’ ; The light intensity P is calculated using the above formula (7). ’ ;in 0 P > 400 mW / cm 2 .
[0017] According to the R 3’ For levels 1, 2, 3, and 4, the duration t of a single scrubbing session is... ’ The corresponding values are 25, 15, 10, and 5, respectively.
[0018] In some embodiments, the R 3’ The surface of the MABR-modified membrane fibers was photographed using a microscope or industrial camera to determine the area of the exposed photocatalytic material and the area of the biofilm growth region.
[0019] In some embodiments, the photocatalytic material loading rate R1 on the surface of the MABR modified membrane fiber is ≥0.8; and the coverage of the photocatalytic material on the surface of the MABR modified membrane fiber is 0.2 < R2 ≤ 0.8.
[0020] In some embodiments, R2 is scanned using EDS energy dispersive spectroscopy to measure the distribution area of characteristic elements of the photocatalytic material and calculate it according to equation (1):
[0021] Where S Ci Area of the region where the photocatalytic material is distributed, in meters. 2 S Mi : The area of the cut MABR modified membrane fibers, in m 2 n: The number of MABR-modified membrane fibers used in the test.
[0022] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0023] The above or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which: Figure 1 A flowchart illustrating a method for dynamically regulating photocatalytic efficiency and effective biofilm growth according to an embodiment of this application. Detailed Implementation
[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present application, not all of them, and are not intended to limit the scope of the disclosure of the present application. Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion regarding the concepts disclosed in the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort should fall within the scope of protection of the present application.
[0025] The accompanying drawings show structural schematic diagrams according to embodiments disclosed in this application. These drawings are not drawn to scale, and some details have been enlarged and may have been omitted for clarity. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.
[0026] The following is a reference to the appendix. Figure 1 The embodiments described herein are illustrated. Specifically, this application provides a method for dynamically regulating photocatalytic efficiency and effective biofilm growth, comprising the following steps: S1: Select MABR modified membrane fibers and determine the total amount to be used; S2: Test the quality of incoming water and test the ROS concentration generated by MABR modified membrane fibers in a pure water environment; S3: Confirm the regulatory parameters for the biofilm attachment and growth stage in MABR modified membrane fibers; these include the biofilm coverage growth rate; based on the biofilm coverage growth rate, the biofilm is divided into 5 levels, 4 levels, 3 levels, 2 levels, and 1 levels. S4: When a biofilm appears on the surface of the MABR modified membrane filaments and the coverage growth rate is ≤4, the MABR modified membrane filaments enter the normal operation stage; and are adjusted sequentially according to the following steps (a)-(i): (a) During normal operation, the growth rate R of the biofilm on the surface of the MABR modified membrane filaments is set. 3’ ; Evaluate the graded range of the biomembrane in which the MABR-modified membrane fibers are located; (b) Set the circulation flow ratio R 4’ ; (c) Maintain gas supply pressure P air’ The constant value remains unchanged; (d) Set the gas supply flow rate Q air’ ; (e) Set the scrubbing flow rate Q scrub’ ; (f) Set the cleaning frequency f ’ ; (g) Set the duration t of a single scrubbing session ’ ; (h) Set the light intensity P ’ .
[0027] In S1, MABR-modified membrane fibers are selected, meaning the chosen MABR-modified membrane fibers have a photocatalytic material loading rate (R1) ≥ 0.8 on their surface and a photocatalytic material coverage rate (0.2 < R2 ≤ 0.8) on the MABR-modified membrane fiber surface. The photocatalytic material loading rate (R1) on the MABR-modified membrane fiber surface is related to the synthesis method (and must be provided by the manufacturer). To ensure the effectiveness of the loading method, the stability of the photocatalytic material loading, and its stability in subsequent use, MABR-modified membrane fibers with R1 ≥ 0.8 should be selected. Meanwhile, the photocatalytic material coverage rate (R2) on the MABR-modified membrane fiber surface is related to the synthesis process. This can be provided by the manufacturer or evaluated using Table 1.
[0028] Table 1 R2 Grading Evaluation Table
[0029] Methods for evaluating coverage R² R2 uses EDS energy dispersive spectroscopy to scan the MABR modified membrane fibers, counts the distribution area of characteristic elements of the photocatalytic material, and calculates it according to equation (1).
[0030]
[0031] In the formula: where S Ci Area of the region where the photocatalytic material is distributed, in meters. 2 S Mi : The area of the cut MABR modified membrane fibers, in m 2 n: The number of MABR modified membrane fibers used in the test.
[0032] S2 tests the incoming water quality, and the test parameters for the incoming water quality include COD. Cr TN, NH4 + -N, NO2 - -N and NO3 - -N; then the ROS formation concentration of all MABR modified membrane fibers was tested under pure water conditions. The ROS formation concentration included ·OH, 1 The concentrations of ROS such as O2, ·O2-, and H2O2 were tested and recorded in the reactor under pure water conditions. , , , The corresponding concentration in the reactor under the incoming water quality environment is: , , , .
[0033] in 1 The quantitative method for O2 is as follows: singlet oxygen is determined using furfuryl alcohol (FFA) (50 μM, 8 h irradiation). 1 O2. The concentration of FFA was analyzed using an Agilent Technologies 1260 Infinity II liquid chromatography system (high performance liquid chromatography, HPLC). This system was equipped with an Agilent-Philomon Venusil MP C18 (4.6 mm × 250 mm × 5 mm) reversed-phase column. Water samples were tested after filtration through a 0.22 μm filter membrane. Specific testing methods for FFA are detailed in Table 2. The concentration was determined by linear regression of ln[FFA]. t / [FFA] t=0 Determine the pseudo-first-order decay rate constant k of the probe compound FFA. FFA By dividing the observed FFA consumption rate by the FFA and... 1 The second-order reaction rate of O2 is used to calculate singlet oxygen. 1 O2] ss The steady-state concentration is detailed in the following formula S1:
[0034] In the formula: It is the first-order rate constant of the FFA. Is FFA and 1 The second-order rate constant of the O2 reaction (k = 1.2 × 10⁻⁶) 8 M -1 s -1 ).
[0035] Table 2 Liquid phase detection parameters for FFA
[0036] The quantitative method for ·OH involves determining the ·OH concentration using terephthalic acid (TA, 3 mM, dissolved in 10 mM NaOH solution) as a probe. Since TA reacts with ·OH to form the strongly fluorescent product 2-hydroxyterephthalic acid (2-HTA), a fluorescence spectrophotometer (E) is used to measure the ·OH concentration. x = 312 nm, E mThe fluorescence intensity was detected at 350-600 nm. A standard curve was first constructed with a series of different concentrations of 2-HTA from 0.1 μM to 0.2 μM. Then, based on the fact that the capture efficiency of TA for ·OH is about 80%, the concentration of ·OH was estimated by the reaction formula S2 (molar ratio of ·OH, TA and 2-HTA 1:1:1).
[0037]
[0038] (3)·O2 - Quantitative method: 0.1 mM nitroblue tetrazolium (NBT) was used to identify the ·O2 produced in the sample. - Photoinduced O2 - NBT can be reduced to form insoluble purple formazan (S3) in a molar ratio of 1:4. Absorbance was measured at a series of NBT concentrations of 0.002, 0.004, 0.006, 0.008, 0.01, and 0.02 mM to plot a standard curve. Subsequently, the decrease in NBT concentration at 260 nm was monitored using a UV-Vis spectrophotometer to quantitatively analyze O2. - Yield.
[0039]
[0040] (4) Quantitative method for H2O2: The concentration of H2O2 was determined by spectrophotometry. A specific volume of sample dilution containing H2O2 (c[H2O2] < 0.25 mg) was accurately measured and placed in a 50 mL volumetric flask. 5.00 mL of methyl red and 1.00 mL of Fe were added sequentially. 3+ The solution and 0.50 mL of 1 mol / L HCl (pH = 2) were added at 40°C. o The reaction was carried out at a constant temperature for 60 min, followed by dilution with water to a final volume. Using distilled water as a reference, the absorbance A was measured at 520 nm using a 1 cm cuvette. A blank H₂O₂ test was also performed simultaneously (absorbance recorded as A₀). The H₂O₂ concentration was calculated based on ΔA (ΔA = A₀ - A). Absorbances were also measured at H₂O₂ concentrations of 0.02, 0.04, 0.06, 0.08, and 0.1 mM to plot a standard curve.
[0041] S3 identifies the regulatory parameters for the biofilm attachment and growth stage in MABR-modified membrane fibers; these include the biofilm coverage growth rate; the biofilm coverage growth rate is sequentially increased to classify it into 5 levels, 4 levels, 3 levels, 2 levels, and 1 level; in some embodiments, the regulatory parameters for the biofilm attachment and growth stage in MABR-modified membrane fibers also include the internal circulation flow rate ratio R4 and the gas supply flow rate Q. air ; Scrub flow rate Q scrub; wiping frequency f; single wiping duration t; light intensity P; air supply pressure P air And temperature T. The parameter setting ideas for the biofilm attachment and growth stage in MABR modified membrane fibers are as follows: (a) R3 setting: In this embodiment, the biofilm coverage growth rate R3 (whether the biofilm is attached to the surface of the MABR modified membrane fiber or covers the photocatalytic material) is evaluated and assessed by R3 classification according to Table 3.
[0042] Table 3 R3 Grading Evaluation Table
[0043] In other words, based on the increasing coverage growth rate of the biofilm, it is divided into five levels: level 5, level 4, level 3, level 2, and level 1, as shown in Table 3. to Level 5; to Level 4; to Level 3; to Level 2; 0 to Level 1.
[0044] The growth rate R3 evaluation method uses a microscope or industrial camera to photograph the surface of the MABR modified membrane fibers to count the area of the exposed photocatalytic material region and the area of the biofilm growth region. The microscope can be a handheld digital microscope; the industrial camera can be a high-definition industrial camera. In this embodiment, the growth rate R3 of the biofilm is calculated using formula (2).
[0045] Where SPi: area of the exposed photocatalytic material region, m2; SBi: area of the biofilm growth region, m2; n is the number of MABR modified membrane fibers used for testing; at the beginning of the experiment, the pure MABR modified membrane fibers have not yet attached to the biofilm, so R3 can be considered to be close to +∞, that is, 1 / R3 in formula (2) takes the value of 0.
[0046] (b) Setting R4: Calculate the internal circulation flow ratio R4 in the reaction system using equation (3);
[0047] Gas supply pressure P air Maintain a constant value; at the beginning of the experiment, since R3 approaches +∞, this means that R4 is equal to the constant C, where C in equation (3) is the inner circulation constant with a value of 10.
[0048] (c)P airSetting: Maintain a constant value, where P is the constant value. ai This is related to the inherent properties of MABR modified membrane fibers. The manufacturer provides the normal operating pressure, and the experimental process remains constant without adjustment.
[0049] (d)Q air Setting: Calculate the gas supply flow rate Q using equation (4) air ;
[0050] Where Q is the influent flow rate, m 3 / h; The percentage of oxygen in the air is 0.2095. The value range is 0.2 to 0.4; The photogenerated hole reaction constant is 1.58. : Hydroxyl radical reaction constant; 2.39 at pH 7; 2.74 at pH < 7; 1.97 at pH > 7; The reaction constant for superoxide radicals is 0.94. The singlet oxygen reaction constant has a value of 0.65. The reaction constant for hydrogen peroxide is 0.87 when pH is 7; 1.72 when pH < 7; and 0.69 when pH > 7. The concentration of ·OH in pure water, in mg / L; The concentration of OH in the incoming water is in mg / L. In a pure water environment 1 O2 concentration, mg / L; Incoming water quality environment 1 O2 concentration, mg / L; In a pure water reaction system, Concentration, mg / L; Incoming water quality environment Concentration, mg / L; The concentration of H2O2 in the pure water reaction system is in mg / L. The concentration of H2O2 in the incoming water is in mg / L. The water quality environment that needs to be removed Concentration, mg / L; Initial water quality under the current conditions Concentration, mg / L. Specifically, at the beginning of the experiment, 1 / R³ approaches 0. A value of 0.4 is recommended to ensure an adequate oxygen supply.
[0051] (e)Qscrub Setting: Calculate the scrubbing flow rate Q using equation (5) scrub ;
[0052] Where S MABR The total surface area of the MABR-modified membrane fibers is m. 2 S TANK The bottom area of the reaction tank is m. 2 β is the redundancy coefficient, with a value ranging from 0.2 to 0.4. In particular, at the beginning of the experiment, 1 / R3 approaches 0, so β is 0.2 and no excessive wiping is required.
[0053] (f) Setting f: Calculate the wiping frequency f using equation (6);
[0054] Specifically, at the beginning of the experiment, 1 / R3 is close to 0, and the frequency of wiping is low to ensure the film adhesion effect.
[0055] (g) Setting the duration t of a single wipe: The duration of a single wipe is set according to Table 4. For the initial stage of the experiment, the duration t of a single wipe is 0. Table 4. Single Washing Duration Lookup Table
[0056] (h) Setting the light intensity P, and calculating the light intensity P using equation (7);
[0057] 0 P: Default photon density, mW / cm² 2 The value ranges from 100 to 500; specifically, at the beginning of the experiment, 1 / R³ approaches 0, which means P equals 0 P. 0 The recommended value for P is <200 mW / cm². 2 It is not advisable to use excessively high light intensity at this stage; priority should be given to ensuring the rapid and stable growth of the biofilm.
[0058] (i) Temperature T setting: Temperature T is room temperature and does not require adjustment.
[0059] When a biofilm appears on the surface of the MABR-modified membrane filaments and the coverage growth rate is ≤4, the MABR-modified membrane filaments enter the normal operation stage. When a biofilm is observed on the surface of the membrane filaments with the naked eye, and when R3 is ≤8 / 2, the MABR-modified membrane filaments can enter the normal operation stage for regulation. In this embodiment, the regulation is carried out sequentially according to the following steps (a)-(i): However, it should be noted that the following steps are a gradual, multiple-adjustment, and step-by-step process.
[0060] (a) During normal operation, the growth rate R of the biofilm on the surface of the MABR modified membrane filaments is set. 3’ Calculate the growth rate R according to Equation 2 above. 3’ Numerical value, R 3’ The surface of the MABR-modified membrane fibers was photographed using a microscope or industrial camera to determine the area of the exposed photocatalytic material and the area of the biofilm growth region. This stage assesses the hierarchical range of the biofilm in the MABR-modified membrane fibers, providing support for subsequent parameter control.
[0061] (b) Set the circulation flow ratio R 4’ Calculate the internal circulation ratio R4 based on Equation 3 above.
[0062] (c) Maintain gas supply pressure P air’ The constant value remains unchanged.
[0063] (d) Set the gas supply flow rate Q air’ Preliminary determination , , , Then, calculate the gas supply flow rate Q according to Equation 4 above. air Numerical values. Specifically, during normal operation, It is recommended to set the value to <0.4 to reduce the probability of excessive oxygen supply and promote the occurrence of reactions such as Anammox.
[0064] (e) Set the scrubbing flow rate Q scrub’ Calculate the scrubbing flow rate Q according to Equation 5 above. scrub Numerical value.
[0065] (f) Set the cleaning frequency f ’ The frequency of wiping, f, is calculated according to Equation 6 above. ’ The value.
[0066] (g) Set the duration t of a single scrubbing session ’ According to Table 4, the duration of a single scrubbing cycle is set. Specifically, if the biofilm grows rapidly and extensively covers the photocatalytic material, the duration can be appropriately increased. ’ .
[0067] (h) Set the light intensity P ’ The light intensity P value is calculated according to Equation 7 above. Specifically, during normal operation... 0 P is recommended to be greater than 400 mW / cm². 2 A certain intensity of light is required to promote the synergistic growth of biofilm and photocatalytic reaction, and to selectively screen for light-tolerant bacterial communities.
[0068] (i) T setting: room temperature is sufficient, no adjustment is required.
[0069] To further explain this application, relevant embodiments will be provided below as examples: The experimental water used is quinolone wastewater produced by a pharmaceutical company, and its water quality characteristics are: COD... Cr The concentrations of ≤ 400 mg / L, BOD5 ≤ 10 mg / L, TN ≤ 80 mg / L, TP ≤ 5 mg / L, and B / C ≈ 0.02 indicate that the wastewater has almost no biodegradability.
[0070] (2) Basic conditions The equipment includes a reaction vessel with internal membrane bundles, as detailed in "A Wastewater Treatment Device with MABR Coupled Photocatalytic Oxidation". The membrane bundle fibers should be pre-modified. The modified MABR fibers consist of MABR fibers and a photocatalytic coating coupled to at least a portion of the surface of the MABR fibers. The photocatalytic coating also has a channel structure corresponding to the gas outlet channels of the MABR fibers. The photocatalytic coating includes a coupling agent and a photocatalytic material. The particle size of the photocatalytic material is less than 1 µm, and g-C3N4 can be used. Based on the total mass of the modified MABR fibers (100%), the MABR fiber content is 30-48%, the photocatalytic material content is 40-60%, and the coupling agent content is 4-10%. The coupling agent is selected from at least one of PVDF, silica gel, and PVA sol. Membrane fibers meeting the requirements are selected according to the definitions of R1 and R2, ensuring that the total surface area of the membrane fibers within the reaction system is 528 m². 2 The design influent COD load is 150 g / m³. 2 ·d, Influent BOD5 load: 3.75 g / m³ 2 ·d, Influent TN load 30 g / m 2 ·d, Influent TP load: 1.88 g / m³ 2 •d. The light source uses a xenon lamp to simulate sunlight, with a wavelength range of 320 nm to 780 nm.
[0071] Based on the above experimental conditions, two control methods were adopted to treat quinolone wastewater: one with constant process parameters and the other with dynamic adjustment (based on the above method). These included the constant control method and the dynamic adjustment control method described in this application.
[0072] In the constant control mode: the internal circulation flow ratio (R4) is 12.5; the gas supply flow rate (Q) is... air ) is 20 m 3 / h; scrubbing flow rate (Q scrub ) is 200 m 3 / h; wiping frequency 24 times / day; single wiping duration (t) 30 min; initial light intensity ( 0P) is 500 mW / cm 2 Gas supply pressure (P) air =250 mbar; Experimental temperature (T) was room temperature (20) o C).
[0073] In the dynamic control method: relying on R3 as an important performance indicator, the internal circulation flow ratio (R4) is dynamically adjusted through corresponding formula calculations and indicator tables; the gas supply flow rate (Q) is... air ); Scrubbing flow rate (Q) scrub ); wiping frequency (f); duration of a single wiping session (t); light intensity (P). Specifically, light intensity during the biofilm growth stage ( 0 P) is 200 mW / cm 2 Light intensity during normal operation ( 0 P) is 500 mW / cm 2 Gas supply pressure (P) air =250 mbar; Experimental temperature (T) was room temperature (20) o C).
[0074] The removal effects of the two control methods on pollutants are shown in Table 5.
[0075] Table 5 Comparison of the operating effects of different control methods
[0076] As can be seen from the data in Table 5, the calculation method and control strategy of this invention can promote the formation of a more stable and efficient biofilm on the surface of the membrane fibers, reduce the possibility of conflict between biofilm growth and photocatalytic materials, enhance the synergistic effect of biological reaction and photocatalytic reaction, and thus achieve better and more stable effluent water quality.
[0077] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0079] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.
Claims
1. A method for dynamically regulating photocatalytic efficiency and effective biofilm growth, characterized in that, Includes the following steps: Select MABR-modified membrane fibers and determine the total amount to be used; The test included the quality of the incoming water and the concentration of ROS generated in the MABR modified membrane fibers under pure water conditions. The control parameters for the biofilm attachment and growth stage in the MABR modified membrane filaments were identified, including the biofilm coverage growth rate. The biofilm coverage growth rate was then sequentially increased to classify the biofilm into 5, 4, 3, 2, and 1 levels. When the biofilm appears on the surface of the MABR-modified membrane filament and the coverage growth rate is ≤4, the MABR-modified membrane filament enters the normal operation stage; and is then regulated sequentially according to the following steps (a)-(i): (a) During normal operation, the growth rate R of the biofilm on the surface of the MABR modified membrane filaments is set. 3’ ; Evaluate the graded range of the biomembrane in the MABR-modified membrane fibers; (b) Set the circulation flow ratio R 4’ ; (c) Maintain gas supply pressure P air’ The constant value remains unchanged; (d) Set the gas supply flow rate Q air’ ; (e) Set the scrubbing flow rate Q scrub’ ; (f) Set the cleaning frequency f ’ ; (g) Set the duration t of a single scrubbing session ’ ; (h) Set the light intensity P ’ .
2. The control method according to claim 1, characterized in that, The test parameters for the incoming water quality include COD. Cr TN, NH4 + -N, NO2 - -N and NO3 - -N.
3. The control method according to claim 2, characterized in that, The ROS of the MABR-modified membrane fibers include ·OH, 1 O2, ·O2-, H2O2; their corresponding concentrations in the reactor under pure water conditions are: , , , The corresponding concentration in the reactor under the incoming water quality environment is: , , , .
4. The control method according to claim 3, characterized in that, The control parameters for the biofilm attachment and growth stage in the MABR-modified membrane fibers also include the internal circulation flow ratio R4 and the gas supply flow rate Q. air ; Scrubbing flow rate Q scrub ; wiping frequency f; single wiping duration t; light intensity P; air supply pressure P air And temperature T.
5. The control method according to claim 4, characterized in that, During the biofilm attachment and growth stage of the MABR modified membrane filaments, the growth rate R3 of the biofilm is calculated using equation (2). Where SPi: area of the exposed photocatalytic material region, m2; SBi: Area of the biofilm growth region, m2; n is the number of MABR-modified membrane fibers used for testing; Calculate the internal circulation flow ratio R4 using equation (3); The gas supply pressure P air Maintain a constant value; The gas supply flow rate Q is calculated using equation (4). air ; Where Q is the influent flow rate, m 3 / h; The percentage of oxygen in the air is 0.2095. The value range is 0.2 to 0.4; The photogenerated hole reaction constant is 1.
58. : Hydroxyl radical reaction constant; 2.39 at pH 7; 2.74 at pH < 7; 1.97 at pH > 7; The reaction constant for superoxide radicals is 0.
94. The singlet oxygen reaction constant has a value of 0.
65. The reaction constant for hydrogen peroxide is 0.87 at pH 7; 1.72 at pH < 7; and 0.69 at pH > 7. The concentration of ·OH in pure water, mg / L; The concentration of ·OH in the incoming water under environmental conditions, in mg / L; In a pure water environment 1 O2 concentration, mg / L; Incoming water quality environment 1 O2 concentration, mg / L; In a pure water reaction system, Concentration, mg / L; the stated Incoming water quality environment Concentration, mg / L; the stated The concentration of H2O2 in the pure water reaction system is mg / L; The concentration of H2O2 in the incoming water is in mg / L. The water quality environment that needs to be removed Concentration, mg / L; Initial water quality under the current conditions Concentration, mg / L; The scrubbing flow rate Q is calculated using equation (5). scrub ; Where S MABR The total surface area of the MABR-modified membrane fibers is given in m. 2 ; S TANK The bottom area of the reaction tank is m. 2 β is the redundancy coefficient, with a value ranging from 0.2 to 0.
4. The wiping frequency f is calculated using equation (6); The light intensity P is calculated using equation (7); 0 P: Default photon density, mW / cm² 2 The value ranges from 100 to 500; The duration of a single scrubbing session, t, is 0. The temperature T is room temperature.
6. The control method according to claim 5, characterized in that, In the initial stage, 1 / R3 in equation (2) is 0; in equation (3), C is the inner circulation constant with a value of 10; in equation (4) The value is 0.4; in equation (5), β is 0.2; in equation (7) 0 P < 200 mW / cm 2 .
7. The control method according to claim 5, characterized in that, The growth rate R of the biofilm is calculated using equation (2). 3’ ; The current internal circulation flow ratio R is calculated using equation (3). 4’ ; The gas supply pressure P air’ Maintain a constant value; Preliminary determination , , , The gas supply flow rate Q is calculated using the above formula (4). air’ In the above formula (4) The value range is less than 0.4; The scrubbing flow rate Q is calculated using the above formula (5). scrub’ ; The wiping frequency f is calculated using the above formula (6). ’ ; The light intensity P is calculated using the above formula (7). ’ ;in 0 P > 400 mW / cm 2 . According to the R 3’ For levels 1, 2, 3, and 4, the duration t of a single scrubbing session is... ’ The corresponding values are 25, 15, 10, and 5, respectively.
8. The control method according to claim 6, characterized in that, The R 3’ The surface of the MABR-modified membrane fibers was photographed using a microscope or industrial camera to determine the area of the exposed photocatalytic material and the area of the biofilm growth region.
9. The control method according to any one of claims 1-8, characterized in that, The photocatalytic material loading rate R1 on the surface of the MABR modified membrane fiber is ≥0.8; at the same time, the coverage of the photocatalytic material on the surface of the MABR modified membrane fiber is 0.2<R2≤0.
8.
10. The control method according to claim 9, characterized in that, The R2 was scanned using EDS energy dispersive spectroscopy to analyze the MABR-modified membrane fibers, and the distribution area of the characteristic elements of the photocatalytic material was statistically analyzed and calculated according to equation (1): Where S Ci Area of the region where the photocatalytic material is distributed, in meters. 2 S Mi : The area of the cut MABR modified membrane fibers, in m 2 n: The number of MABR-modified membrane fibers used in the test.