CN114455697A - A method for controlling fouling of MBR membranes based on microbial quorum sensing quenching - Google Patents

Abstract

The invention discloses a method for controlling MBR membrane fouling based on microbial quorum sensing quenching. In the M9 medium with only one carbon source, after culturing in a 150rpm shaker for 5-7 days at 30°C, S3: wash the GCL enriched bacteria or activated sludge with 50mmol/L pH=7.0 TRIS buffered saline solution, Add 100uL of pure water to an equal volume of 400nmol/L AHL as a blank control. After boiling the activated sludge for 10min, adjust OD600=1.0, incubate the mixture in a shaker at 30°C and 120rpm, and take out a portion regularly. The mixed solution is placed in a 99° C. water bath for 10 minutes to inactivate the bacteria, at which point the pollution control of the MBR membrane can be completed. , which reduced the adhered cells and secreted polysaccharides in the biofilm on the membrane surface, which proved that with the increase of sludge residence time, the biological pollution in MBR was lighter.

Description

A method for controlling fouling of MBR membranes based on microbial quorum sensing quenching

technical field

The invention relates to the field of pollution control of MBR membranes, in particular to a method for controlling pollution of MBR membranes based on microbial quorum sensing quenching.

Background technique

The process of membrane bioreactor has experienced traces from maturity to popularization, but the problem of membrane fouling has been difficult to solve and hinders the development of this technology. In the field of microbial research, the concept of microbial quorum sensing is almost the same as that of membrane bioreactor technology. It was proposed at the same time and experienced rapid development at the same time. Microbial quorum sensing means that bacteria sense the density of bacteria by secreting signal molecules and detecting their concentration, which in turn triggers a series of group behaviors. Previously, research on quorum sensing mainly focused on microorganisms. In recent years, some reports on quorum sensing in water treatment processes have appeared one after another, and some studies have achieved good membrane fouling control effects by inhibiting microbial quorum sensing in MBR, which provides a new idea for membrane fouling control. The research on quorum sensing and its quenching in membrane bioreactors is still in the exploratory stage. Quorum sensing quenching measures are too complicated and their stability needs to be strengthened. In addition, the effect of membrane fouling control measures based on quorum sensing quenching on the decontamination efficiency of MBR has not been carefully investigated.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a method for controlling the fouling of MBR membranes based on microbial quorum sensing quenching, which can effectively solve the problems in the background art.

To achieve the above object, the technical scheme adopted in the present invention is:

A method for controlling fouling of MBR membranes based on microbial quorum sensing quenching, comprising the following operation steps:

S1: Preparation materials: hollow fiber membrane, domestic sewage, activated sludge, M9 medium, Tris buffered saline solution, phosphate buffered saline solution;

S2: Use MBR reactor for reaction: When using, it is necessary to ensure that the temperature is about 20-26 °C, and the domestic sewage filtered by 1mm screen is added to the high-level water tank every day, and the raw water in the high-level water tank enters each constant water level The water tank is redistributed to the reactor, and then the peristaltic pump sucks the water, and the pressure transmitter is connected between the membrane module and the suction peristaltic pump, and the transmembrane pressure difference data in each MBR is accurately measured and collected. Collect and process the pressure transmitter signal and transmit it to the computer to record the data. The data collection frequency is 1 minute/time. After the membrane module in the MBR is completely polluted, when the transmembrane pressure difference is >70kPa, take it out, and first use tap water to clean the membrane surface. The pollutants are washed down, and then soaked in a chemical cleaning solution containing 0.01molL of NaOH and 200ppm of sodium hypochlorite for 1-2h, and can be reused after chemical cleaning;

S3: Inoculate activated sludge at 1% v/v into 20 mL of M9 medium with GCL as a single carbon source, and culture it in a shaker at 150 rpm at 30°C for 5-7 days. It was transferred to a new M9 medium with GCL as a single carbon source, the medium was 20 mL, and the cultivation was continued. After three transfer cultivations, the enrichment was completed, and the obtained bacteria were stored in a 4°C refrigerator;

S4: Wash the GCL-enriched bacteria or activated sludge with 50mmol/L Tris buffered saline solution with pH=7.0. The specifications of the centrifuge cleaning machine are 7000rpm, 10min, centrifuge at 4°C, discard the supernatant, and then add TRIS Wash with buffer salt twice, then adjust the concentration of bacterial solution to absorbance at 600nm to 1.0 with TRIS buffer salt, dilute 1g/L AHL stock solution to 400nmol/L with TRIS buffer salt, and add 100uL to a 1.5mL centrifuge tube The above bacterial liquid and an equal volume of 400nmol/L AHL solution were prepared in several copies for continuous sampling in subsequent degradation experiments, and 100uL of pure water was added to an equal volume of 400nmol/L AHL as a blank control. After boiling for 10min, adjust OD600=1.0, incubate the mixture in a shaker at 30°C and 120rpm, and periodically take out a portion of the mixture and place it in a 99°C water bath for 10min to inactivate bacteria. Use a 0.45um filter to remove bacteria. After filtration, the samples were stored at 4°C, and the contamination control of the MBR membrane could be completed at this time.

Preferably, the hollow fiber membrane used in the experiment is made of polytetrafluoroethylene, the pore size is 0.01um, the outer diameter of the membrane filament is 1.85mm, and the length of a single membrane filament is 60cm. After the application is finished, before use, filter out the particulate matter in the sewage with a 1mm sieve, and then add 255mg/L NaHCO ₃ to the water to adjust the alkalinity.

Preferably, when the M9 medium is prepared, 5×M9 salt is prepared first, and 92.39g of Na ₂ HPO ₄ -12H ₂ O, 15g of KH ₂ PO ₄ , 2.5g of NaCl and 5.0g of NH ₄ Cl are dissolved Dissolve it in 800mL of distilled water, fully dissolve it to 1000mL, adjust its pH to 7.4 with a pre-prepared NaOH solution, sterilize it at 121°C for 20min, and store it at room temperature. Take about 700mL of sterilized water and add 200mL Prepared and sterilized 5×M9 salt, add 2mL of sterilized 1molL MgSO ₄ solution, add 2mL GCL, add 100uL of sterilized 1mol/LCaCl ₂ , if the solution is still hot when CaCl ₂ is added, precipitation will occur , then shake vigorously until the precipitate dissolves, dilute to 1000mL with sterilized distilled water, and store at room temperature until use.

Preferably, when the Tris buffered salt solution is prepared, 6.05g of Tris and 8.76g of NaCl are dissolved in 800mL of deionized water, adjusted to pH 7.0 with 1molL of HCl solution, and dissolved in 1L at 121°C for 20min After sterilization, store at room temperature for use.

Preferably, when the phosphate buffered saline solution is configured, 10x phosphate buffered saline solution stock solution is first prepared, and 80 g of NaCl, 2 g of KCl, 35.8 g of Na ₂ HPO ₄ -12H ₂ O, 2.4 g of KH ₂ PO ₄ Dissolve in 800mL of water, fully dissolve and dilute to 1000mL, adjust pH to 7.4, and store at room temperature.

Compared with the prior art, the present invention has the following beneficial effects:

In the present invention, by adding NaHCO ₃ , the alkalinity in the domestic sewage can be adjusted, because the ammonia nitrogen concentration in the domestic sewage is relatively high, it is avoided that the digestion in the MBR will consume the alkalinity excessively, so that the pH in the reactor is reduced, and then the After the reaction, the cells adhering to the biofilm on the membrane surface and the secreted polysaccharides are reduced, which proves that with the increase of the sludge residence time, the biological pollution in the MBR is lighter, and then encounters the sludge in the sludge. The long-chain signal molecules secreted by quorum-sensing bacteria are more likely to be degraded by quorum-sensing rough sterilization, and the concentration of long-chain chains in the reactor will be higher until they are completely degraded. Under this method, sludge has better degradation performance of signal molecules And the concentration of signal molecules in the reactor is correspondingly lower.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The present invention relates to a kind of MBR membrane fouling control method based on microbial quorum sensing quenching, comprising the following steps:

S1: Preparation materials: central fiber membrane, domestic sewage, activated sludge, M9 medium, Tris buffered saline solution, phosphate buffered saline solution, the hollow fiber membrane used in the experiment is made of polyvinylidene fluoride with a pore size of 0.01um , the outer diameter of the membrane wire is 1.85mm, and the length of a single membrane wire is 60cm. It should be used within two days after the domestic sewage is taken. Before use, use a 1mm sieve to filter out the particles in the sewage, and then add 255mg/ L of NaHCO ₃ to adjust the alkalinity, first prepare 5×M9 salt when M9 medium is prepared, mix 92.39g of Na ₂ HPO ₄ -12H ₂ O, 15g of KH ₂ PO ₄ , 2.5g of NaCl and 5.0g of NH ₄ Cl, dissolved in 800 mL of distilled water, fully dissolved and then adjusted to 1000 mL, adjusted to pH 7.4 with a pre-prepared NaOH solution, sterilized at 121 °C for 20 min, and stored at room temperature, take about 700 mL of sterilized Bacteria water, add 200mL prepared and sterilized 5xM9 salt, add 2mL sterilized 1molL MgSO ₄ solution, add 2mL GCL, add 100uL sterilized 1mol/LCaCl ₂ , if CaCl ₂ is added, the solution is still hot Precipitation will appear, then shake vigorously until the precipitation dissolves, dilute to 1000mL with sterilized distilled water, and store it at room temperature until use. When preparing the TRIS buffered saline solution, mix 6.05g of tris-hydroxymethylaminomethane and 8.76g of tris. Dissolve gNaCl in 800 mL of deionized water, adjust its pH to 7.0 with 1 molL of HCl solution, dissolve in 1 L, sterilize at 121 °C for 20 min, and store it at room temperature for use. When configuring phosphate buffered saline solution, first configure 10x Phosphate buffered saline solution stock solution, dissolve 80g of NaCl, 2g of KCI, 35.8g of Na ₂ HPO ₄ -12H ₂ O, and 2.4g of KH ₂ PO ₄ in 800 mL of water, fully dissolve and set the volume to 1000 mL, and adjust the pH To 7.4, store at room temperature.

S2: Use MBR reactor for reaction: When using, it is necessary to ensure that the temperature is about 20-26 degrees, and the domestic sewage filtered by 1mm screen is added to the high-level water tank every day, and the raw water in the high-level water tank enters each constant water level The water tank is redistributed to the reactor, and then the peristaltic pump sucks the water, and the pressure transmitter is connected between the membrane module and the suction peristaltic pump, and the transmembrane pressure difference data in each MBR is accurately measured and collected. Collect and process the pressure transmitter signal and transmit it to the computer to record the data. The data collection frequency is 1 minute/time. After the membrane module in the MBR is completely polluted, when the transmembrane pressure difference is >70kPa, take it out, and first use tap water to clean the membrane surface. The pollutants are washed down, and then soaked in a chemical cleaning solution containing 0.01molL of NaOH and 200ppm of sodium hypochlorite for 1-2h, and can be reused after chemical cleaning.

S3: Inoculate activated sludge at 1% v/v into 20 mL of M9 medium with GCL as a single carbon source, and culture it in a shaker at 150 rpm at 30°C for 5-7 days. It was transferred to a new M9 medium with GCL as a single carbon source, the medium was 20 mL, and the cultivation was continued. After three transfer cultivations, the enrichment was completed, and the obtained bacteria were stored in a 4°C refrigerator.

S4: Wash the GCL enriched bacteria or activated sludge with 50mmol/L pH=7.0 TRIS buffered saline solution, the specifications of the centrifuge cleaning machine are 7000rpm, 10min, centrifuge at 4°C, discard the supernatant, and then add Tris buffer Wash twice with salt, then adjust the concentration of the bacterial solution to 1.0 at 600nm with Tris buffer, dilute 1g/L AHL stock solution to 400nmolL with TRIS buffer, and add more than 100uL of bacterial solution to a 1.5mL centrifuge tube and an equal volume of 400nmol/L AHL solution, repeat the preparation of several copies for continuous sampling in subsequent degradation experiments, add 100uL of pure water to an equal volume of 400nmol/L AHL as a blank control, and boil the activated sludge for 10min. , adjust OD600=1.0, cultivate the mixture in a shaker at 30°C and 120rpm, take out a portion of the mixture regularly and place it in a 99°C water bath for 10 minutes to inactivate bacteria, and filter out the bacteria with a 0.45um filter. The samples were stored at 4°C, at which point the contamination control of the MBR membrane was completed.

The present invention can adjust the alkalinity in the domestic sewage by adding NaHCO ₃ , because the ammonia nitrogen concentration in the domestic sewage is relatively high, it is avoided that the digestion in the MBR will consume the alkalinity excessively, so that the pH in the reactor is lowered, and then the reaction is carried out. After that, the cells adhered to the biofilm on the membrane surface and the secreted polysaccharide substances were reduced, which proved that with the increase of the sludge residence time, the biological pollution in the MBR was lighter, and then encountered the quorum sensing in the sludge. The long-chain signal molecules secreted by bacteria are more likely to be degraded by quorum sensing rough sterilization, and the concentration of long chains in the reactor will be higher until they are completely degraded. The concentration of signal molecules in the device is correspondingly lower.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, and substitutions can be made in these embodiments without departing from the principle and spirit of the invention and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (5)

1. a MBR membrane fouling control method based on microbial quorum sensing quenching, is characterized in that: comprise the following operation steps: S1: Preparation materials: hollow fiber membrane, domestic sewage, activated sludge, M9 medium, Tris buffered saline solution, phosphate buffered saline solution; S2: Use MBR reactor for reaction: When using, it is necessary to ensure that the temperature is about 20-26 degrees, and the domestic sewage filtered by 1mm screen is added to the high-level water tank every day, and the raw water in the high-level water tank enters each constant water level The water tank is redistributed to the reactor, and then the peristaltic pump sucks the water, and the pressure transmitter is connected between the membrane module and the suction peristaltic pump, and the transmembrane pressure difference data in each MBR is accurately measured and collected. Collect and process the pressure transmitter signal and transmit it to the computer to record the data. The data collection frequency is 1 minute/time. After the membrane module in the MBR is completely polluted, when the transmembrane pressure difference is >70kPa, take it out, and first use tap water to clean the membrane surface. The pollutants are washed down, and then soaked in a chemical cleaning solution containing 0.01mol/L NaOH and 200ppm sodium hypochlorite for 1-2 hours, and can be reused after chemical cleaning; S3: Inoculate activated sludge at 1% v/v into 20 mL of M9 medium with GCL as a single carbon source, and culture it in a shaker at 150 rpm at 30°C for 5-7 days. It was transferred to a new M9 medium with GCL as a single carbon source, the medium was 20 mL, and the cultivation was continued. After three transfer cultivations, the enrichment was completed, and the obtained bacteria were stored in a 4°C refrigerator; S4: Wash the GCL-enriched bacteria or activated sludge with 50mmol/L Tris buffered saline solution with pH=7.0. The specifications of the centrifuge cleaning machine are 7000rpm, 10min, centrifuge at 4°C, discard the supernatant, and then add TRIS Wash with buffer salt twice, then adjust the concentration of bacterial solution to absorbance at 600nm to 1.0 with TRIS buffer salt, dilute 1g/L AHL stock solution to 400nmol/L with TRIS buffer salt, and add 100uL to a 1.5mL centrifuge tube The above bacterial liquid and an equal volume of 400nmol/L AHL solution were prepared in several copies for continuous sampling in subsequent degradation experiments, and 100uL of pure water was added to an equal volume of 400nmol/L AHL as a blank control. After boiling for 10min, adjust OD600=1.0, incubate the mixture in a shaker at 30°C and 120rpm, and periodically take out a portion of the mixture and place it in a 99°C water bath for 10min to inactivate bacteria. Use a 0.45um filter to remove bacteria. After filtration, the samples were stored at 4°C, and the contamination control of the MBR membrane could be completed at this time. 2. a kind of MBR membrane pollution control method based on microbial quorum sensing quenching according to claim 1 is characterized in that: the hollow fiber membrane adopted in the experiment is made of polytetrafluoroethylene, and the aperture is 0.01um , the outer diameter of the membrane wire is 1.85mm, and the length of a single membrane wire is 60cm. The domestic sewage should be used within two days after the water is taken. Before use, use a 1mm sieve to filter out the particulate matter in the sewage, and then add it to the water. 255 mg/L of NaHCO ₃ to adjust alkalinity. 3. a kind of MBR membrane pollution control method based on microbial quorum sensing quenching according to claim 1, is characterized in that: when described M9 medium is configured, first prepare 5 × M9 salts, and 92.39g of Na ₂ HPO ₄ -12H ₂ O, 15 g of KH ₂ PO ₄ , 2.5 g of NaCl and 5.0 g of NH ₄ Cl, dissolved in 800 mL of distilled water, fully dissolved and then adjusted to 1000 mL, and adjusted to pH with a pre-prepared NaOH solution To 7.4, after sterilization at 121℃ for 20min, store at room temperature, take about 700mL of sterilized water, add 200mL of prepared and sterilized 5×M9 salt, add 2mL of sterilized 1mol/L MgSO ₄ solution, Add 2mL of GCL, add 100uL of sterilized 1mol/LCaCl ₂ , if the solution is still hot when CaCl ₂ is added, precipitation will occur, then shake vigorously until the precipitation dissolves, dilute to 1000mL with sterilized distilled water, Store at room temperature until use. 4. a kind of MBR membrane fouling control method based on microbial quorum sensing quenching according to claim 1, is characterized in that: 6.05g Tris and 8.76gNaCl are dissolved in 6.05g Tris and 8.76g NaCl when described Tris buffered salt solution configuration Adjust the pH to 7.0 with 1 mol/L HCl solution in 800 mL of deionized water, dissolve in 1 L, sterilize at 121 °C for 20 min, and store at room temperature for use. 5. a kind of MBR membrane fouling control method based on microbial quorum sensing quenching according to claim 1, is characterized in that: when the described phosphate buffered saline solution is configured, first configure the phosphate buffered saline solution of 10× the phosphate buffered saline solution stock solution, the 80g NaCl, 2 g of KCI, 35.8 g of Na ₂ HPO ₄ ·12H ₂ O, and 2.4 g of KH ₂ PO ₄ were dissolved in 800 mL of water, fully dissolved and settled to 1000 mL, adjusted to pH 7.4, and stored at room temperature.