Method for immobilizing microorganisms on surface of MABR membrane

Abstract

The invention relates to a method for immobilizing microorganisms on the surface of an MABR membrane, and relates to the technical field of MABR sewage treatment.The method comprises the steps that microorganism suspension liquid and a sodium alginate solution are sequentially prepared, MABR membrane filaments are cleaned, the MABR membrane is placed in a container containing the sodium alginate solution, sodium alginate microorganism suspension liquid is prepared, the MABR membrane filaments are evenly wrapped with the sodium alginate microorganism suspension liquid, and then the MABR membrane is immobilized on the surface of the MABR membrane. And co-culturing and internally fixing, and cleaning residual liquid after fixing, so as to obtain the complete fixed MABR microbial film. According to the invention, the microorganisms are immobilized on the surface of the MABR membrane silk by using sodium alginate, so that the method has the advantages of being green, ecological and non-toxic, improving the degradation efficiency of the microorganisms on pollutants, improving the stability of an MABR biological membrane and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of MABR sewage treatment, and in particular relates to a method for fixing microorganisms on the surface of a MABR membrane. Background Art

[0002] MABR is a new type of bioreactor technology, which is widely used in wastewater treatment and gas resource recovery. It combines membrane separation and biological reaction process, using permeable membrane to separate organic matter and microorganisms in wastewater, while promoting the degradation activity of microorganisms through gas oxygen supply. Immobilizing microorganisms on the surface of MABR membrane can improve oxygen transfer and wastewater degradation efficiency.

[0003] Sodium alginate is a seaweed extract and the main polysaccharide component in deep-sea brown algae. It is highly biocompatible and degradable. It appears as a viscous gel in water and can form a porous structure to provide support for microbial attachment.

[0004] In traditional wastewater biological treatment processes, microorganisms usually grow in a suspended state in water and are therefore easily lost from the reactor. Also, due to the small density difference between them and water, it becomes difficult or complicated to recover microorganisms from the outflowing water for reuse. Therefore, sodium alginate immobilization technology is used to fix the microorganisms on the outer surface of the MABR membrane through certain technical means, which is beneficial to increase the number of microorganisms in the bioreactor and improve the system's processing capacity and adaptability. It is a wastewater biological treatment technology with high efficiency, low consumption, and simple operation and management. Summary of the invention

[0005] In view of the problems in the prior art, the present invention provides a method for fixing microorganisms on the surface of a MABR membrane, so that the biofilm on the MABR membrane fibers is more solid, so as to better resist the shedding of the biofilm caused by changes in water quality.

[0006] The present invention is achieved by the following technology, a method for fixing microorganisms on the surface of MABR membrane, characterized in that the method comprises the following steps: (1) preparation of microbial suspension: adding 1g of domestic sludge to 200mL of LB culture medium to increase the microbial content of the sludge itself, centrifuging the bacterial liquid at 6000 rpm and 4°C for 5 minutes, and washing with phosphate buffer solution to prepare a microbial suspension; (2) preparation of sodium alginate solution: adding sodium alginate to ultrapure water and stirring evenly to prepare a sodium alginate solution; (3) preparation of MABR membrane surface: soaking the MABR membrane in pure water, thoroughly cleaning to remove dirt and impurities on the surface, and then placing the MABR membrane in a container containing sodium alginate solution to ensure that the entire membrane surface is completely immersed in the solution; (4) addition of microorganisms: slowly and evenly adding the sodium alginate solution to the pre-cultured microbial suspension to prepare sodium alginate Microbial suspension: evenly wrap the MABR membrane fibers with sodium alginate microbial suspension and place them in an incubator for fusion; (5) Microbial fixation: take out the MABR membrane fibers and immerse them in a 2% CaCl2 saturated boric acid solution and place them in a 4°C incubator for fixation for 48 hours; (6) MABR membrane fiber cleaning: take out the MABR membrane fibers with fixed microorganisms from the 2% CaCl2 saturated boric acid solution and gently clean and rinse them with ultrapure water to remove the unfixed microorganisms and sodium alginate residual liquid, thereby obtaining a complete fixed MABR microbial membrane.

[0007] In some embodiments of the present invention, the LB medium contains: 10 g / L peptone, 5 g / L yeast extract powder, and 10 g / L sodium chloride, and the culture conditions are shaking at 120-150 rpm, a temperature of 25-30° C., and a culture time of 24 hours.

[0008] In some embodiments of the present invention, the concentration of the microbial suspension is 1.0 at OD600 nm.

[0009] In some embodiments of the present invention, the domestic sludge is taken from the residual activated sludge in the biochemical pool of a sewage treatment plant.

[0010] In some embodiments of the present invention, the sodium alginate solution is prepared by heating sodium alginate and dissolving it in water, and the sodium alginate solution is evenly mixed with the treated domestic sludge to make the final concentration of sodium alginate be 2% to 4%.

[0011] In some embodiments of the present invention, the incubator temperature is 20°C-35°C, and the fusion time is 24h-48h.

[0012] In some embodiments of the present invention, the amount of microbial suspension added to prepare sodium alginate microbial suspension is 10% to 30%.

[0013] In some embodiments of the present invention, during the fusion process, gentle stirring or weak bubbles are provided to maintain the dynamic conditions of the solution, which helps to evenly distribute the microorganisms on the surface of the MABR membrane and promotes the binding with sodium alginate.

[0014] In some embodiments of the present invention, the method is used in MABR process wastewater treatment.

[0015] The method of fixing microorganisms on the surface of MABR membranes of the present invention is to use the immobilization technology of sodium alginate to fix and grow microorganisms on the outer surface of MABR membrane fibers, thereby improving the stability of MABR biofilms and the degradation ability of MABR biofilms to pollutants. The use method of the present invention has the advantages of being green, ecological and non-toxic, improving the degradation efficiency of microorganisms to pollutants, and improving the stability of MABR biofilms. DETAILED DESCRIPTION

[0016] The concept and the technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments, so as to fully understand the purpose and effects of the present invention.

[0017] Embodiment 1: 1 g of domestic sludge was added to 200 mL of LB medium (10 g / L peptone, 5 g / L yeast extract, 10 g / L sodium chloride) to increase the microbial content of the sludge itself. The bacterial liquid was centrifuged at 6000 rpm and 4 °C for 5 min and washed with phosphate buffer solution to prepare a microbial suspension. The final concentration of the microbial suspension was OD600 nm 1.0. The sodium alginate solution was prepared by heating sodium alginate and dissolving it in water to make the final concentration of the sodium alginate solution 2%. The sodium alginate solution was mixed evenly with the treated domestic sludge. The MABR membrane was soaked in pure water and thoroughly cleaned to remove dirt and impurities on the surface. The MABR membrane was then placed in a container containing the sodium alginate solution to ensure that the entire membrane surface was completely immersed in the solution. Slowly and evenly add 10% pre-cultured microbial suspension to the sodium alginate solution to prepare the sodium alginate microbial suspension, place the MABR membrane fibers uniformly wrapped with the sodium alginate microbial suspension in an incubator at a temperature of 20℃-35℃ for fusion for 24h-48h, gently stir or provide weak bubbles to maintain the dynamic conditions of the solution, which helps to evenly distribute the microorganisms on the membrane surface and promote the combination with sodium alginate. After taking out the MABR membrane fibers, soak them in a 2% CaCl2 saturated boric acid solution and place them in a 4℃ incubator for fixation for 48h. After fixation, take out the MABR membrane fibers with fixed microorganisms from the 2% CaCl2 saturated boric acid solution, and gently wash and rinse with ultrapure water to remove the unfixed microorganisms and sodium alginate residual liquid, thereby obtaining a complete MABR microbial membrane A.

[0018] Embodiment 2: The operation steps are the same as those in Example 1, except that 1) the final concentration of the sodium alginate solution is 3%, and 2) 20% of the pre-cultured microbial suspension is slowly and evenly added to the sodium alginate solution to prepare a sodium alginate microbial suspension.

[0019] According to the above steps, a complete MABR microbial membrane B different from that in Example 1 was obtained.

[0020] Example 3 The operation steps are the same as those of Example 1 and Example 2, except that 1) the final concentration of the sodium alginate solution is 4%, and 2) 30% of the pre-cultured microbial suspension is slowly and evenly added to the sodium alginate solution to prepare a sodium alginate microbial suspension.

[0021] According to the above steps, a complete MABR microbial membrane C different from Example 1 and Example 2 was obtained.

[0022] The MABR microbial membrane obtained above was used to conduct a comparative analysis of pollutant removal tests under the same water quality conditions, and the following conclusions were obtained: (1) The removal efficiency of pollutants by MABR microbial membrane A obtained in Example 1 is relatively lower than that of the other two; (2) The MABR microbial membrane B obtained in Example 2 has the best stability and the highest pollutant removal efficiency; (3) The MABR microbial membrane C obtained in Example 3 has the best thickness and the shortest biofilm acclimatization period for pollutant removal.

[0023] In the above embodiment, using sodium alginate to fix microorganisms on the surface of MABR membrane has the following advantages: 1. Sodium alginate is a natural material with high biocompatibility and no toxic effect on the growth and attachment of microbial cells; 2. Immobilized microorganisms can form a stable biological attachment layer, improving the degradation efficiency and resistance of microorganisms; 3. Immobilization technology can also reduce the movement and loss of microorganisms and improve the overall stability of the system.

[0024] The capabilities described in the above embodiments are only part of the embodiments of the present invention. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work all belong to the scope of protection of the present invention.

Claims

1. A method for fixing microorganisms on the surface of a MABR membrane, characterized in that: The method comprises the following steps: (1) Preparation of microbial suspension: 1 g of domestic sludge was added to 200 mL of LB medium to increase the microbial content of the sludge itself. The bacterial liquid was centrifuged at 6000 rpm and 4°C for 5 min and washed with phosphate buffer solution to prepare a microbial suspension. (2) Preparation of sodium alginate solution: Add sodium alginate into ultrapure water and stir evenly to prepare a sodium alginate solution; (3) Preparation of MABR membrane surface: Soak the MABR membrane in pure water and thoroughly clean it to remove dirt and impurities on the surface. Then place the MABR membrane in a container containing sodium alginate solution to ensure that the entire membrane surface is completely immersed in the solution. (4) Adding microorganisms: Slowly and evenly add the pre-cultured microbial suspension to the sodium alginate solution to prepare a sodium alginate microbial suspension, evenly wrap the MABR membrane fibers with the sodium alginate microbial suspension, and place them together in an incubator for fusion; (5) Microbial fixation: After taking out the MABR membrane fibers, soak them in a 2% CaCl2 saturated boric acid solution and place them in a 4°C incubator for 48 hours; (6) MABR membrane fiber cleaning: The MABR membrane fibers with fixed microorganisms were removed from the 2% CaCl2 saturated boric acid solution and gently cleaned and rinsed with ultrapure water to remove the unfixed microorganisms and sodium alginate residual liquid, thereby obtaining a complete fixed MABR microbial membrane.

2. The method for immobilizing microorganisms on the surface of a MABR membrane according to claim 1, characterized in that: The LB medium contains: 10 g / L peptone, 5 g / L yeast extract powder, and 10 g / L sodium chloride. The culture conditions are: shaking at 120-150 rpm, temperature at 25-30° C., and culture time of 24 hours.

3. The method for immobilizing microorganisms on the surface of a MABR membrane according to claim 1, characterized in that: The concentration of the microbial suspension was 1.0 at OD600 nm.

4. The method for immobilizing microorganisms on the surface of a MABR membrane according to claim 1, characterized in that: The domestic sludge is taken from the residual activated sludge in the biochemical pool of the sewage treatment plant.

5. The method for immobilizing microorganisms on the surface of a MABR membrane according to claim 1, characterized in that: The sodium alginate solution is prepared by heating sodium alginate and dissolving it in water, and uniformly mixing the sodium alginate solution with the treated domestic sludge to make the final concentration of the sodium alginate be 2% to 4%.

6. The method for immobilizing microorganisms on the surface of a MABR membrane according to claim 1, characterized in that: The incubator temperature is 20°C-35°C, and the fusion time is 24h-48h.

7. The method for immobilizing microorganisms on the surface of a MABR membrane according to claim 1, characterized in that: The amount of microbial suspension added in the preparation of sodium alginate microbial suspension is 10% to 30%.

8. The method for immobilizing microorganisms on the surface of a MABR membrane according to claim 1, characterized in that: During the fusion process, gentle stirring or providing weak bubbles to maintain the dynamic conditions of the solution helps to evenly distribute the microorganisms on the surface of the MABR membrane and promotes the combination with sodium alginate.