Preparation method of aerobic bacillus immobilized carrier and application of aerobic bacillus immobilized carrier in black and odorous water body

Abstract

The invention discloses a preparation method of an aerobic bacillus immobilization carrier and application of the aerobic bacillus immobilization carrier in black and odorous water, the immobilization carrier is a light brick with a porous structure inside, the surface of the light brick is provided with positive charges and hydrophilic groups, and the volume weight of the light brick is smaller than that of water. The interior of the immobilized carrier is of a porous structure, the immobilized carrier is good in adsorbability, a sufficient growth environment can be provided for microorganisms, biofilm formation, growth and reproduction of the microorganisms are facilitated, hydrophilic groups and positive charge donors are subsequently added to modify the light bricks, and the adhesion and activity of the microorganisms can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a preparation method of an aerobic bacillus immobilized carrier and application of the same in black and smelly water bodies. Background Art

[0002] At present, the phenomenon of direct discharge of industrial wastewater and domestic sewage without treatment still exists, which will not only lead to the deterioration of water quality in urban rivers and the appearance of black and smelly phenomena, but also easily aggravate the excessive reproduction of algae, which will have adverse effects on the safety and stability of the water ecosystem. In the process of ecological management of rivers, although the method of directly releasing microorganisms is simple and easy, it often faces challenges such as the bacteria are easily lost with the water flow and difficult to play a long-term role. Therefore, it is particularly important to find a technical means to effectively fix microorganisms. Although the traditionally used microbial immobilization carriers have solved the above problems to a certain extent, they still have shortcomings such as high cost and low efficiency. In view of this, it is necessary to improve the traditional microbial immobilization carriers. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing an aerobic Bacillus immobilized carrier and its application in black and smelly water bodies. The interior of the immobilized carrier has a porous structure and good adsorption properties, which can provide a sufficient growth environment for microorganisms, which is conducive to the formation of microbial biofilms, growth and reproduction. The subsequent addition of hydrophilic groups and positive charge donors to modify the lightweight bricks can improve the adhesion and activity of the microorganisms.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: The invention discloses an aerobic bacillus immobilization carrier, wherein the immobilization carrier is a light brick with a porous structure inside, the surface of the light brick has positive charge and hydrophilic groups, and the bulk density of the light brick is less than the bulk density of water.

[0005] A method for preparing an aerobic Bacillus immobilized carrier comprises the following specific steps: S1. Preparation of lightweight bricks: crushing and sieving the raw materials, adding water, a foaming agent, a positive charge donor and a dispersant, grinding and adding a plasticizer to form porous lightweight bricks; S2. Lightweight brick modification: soaking the lightweight brick in a mixed solution of a surface modifier and distilled water to obtain a modified lightweight brick carrier; S3, preparing a bacterial agent: inoculating aerobic Bacillus into LB medium, shaking and culturing to obtain seed solution, inoculating the seed solution into a fermentation tank of fermentation medium for expansion culture, and obtaining aerobic Bacillus bacterial solution; S4. Forming an immobilized carrier: loading the aerobic Bacillus bacterial liquid onto a modified lightweight brick carrier to obtain an immobilized carrier.

[0006] Preferably, in the aforementioned step S1, the preparation of lightweight bricks specifically includes the following steps: (1) crushing and sieving the raw materials, adding water, foaming agent, positive charge donor and dispersant, and grinding; (2) adding a plasticizer to the ground slurry and drying the slurry to obtain a spherical embryo; (3) The spherical embryo is subjected to high-temperature sintering and annealing to form porous lightweight bricks.

[0007] Preferably, in the aforementioned step (1), the added amounts of the components are: 40-50 wt% of water, 1.5 wt% of foaming agent, 0.4-0.6 wt% of dispersant, and 4-6 wt% of positive charge donor; the raw materials are construction waste or minerals; the foaming agent is ground potassium feldspar; the positive charge donor is one or a combination of polyquaternary ammonium salt or sulfate ore; and the dispersant is sodium silicate.

[0008] Preferably, in the aforementioned step (2), the plasticizer is carboxymethyl cellulose, the addition amount is 0.08-0.2 wt%, and the diameter of the spherical embryo is 9-11 cm.

[0009] Preferably, in the aforementioned step (3), the specific steps of high temperature sintering and annealing are: (3.1) Initial heating stage: the temperature is gradually raised to 450 °C, and the inside of the brick begins to foam; (3.2) Pre-burning stage: raise the temperature to 450~750℃ and maintain it for 30~60 min; (3.3) Rapid heating stage: When the temperature exceeds 750 °C, the heating rate is accelerated to 9-11 °C / h; (3.4) High temperature firing stage: The temperature is raised to 1000~1200℃ for firing. The oxides in the brick material begin to melt and the internal pores gradually become larger. The firing time is 150~170 min. (3.5) Cooling and insulation stage: After firing, the temperature is lowered and kept at 700-750 °C for 20-40 min to obtain foamed bricks; (3.6) Annealing: The foamed bricks are transferred into an annealing chamber and cooled to room temperature to obtain a modified lightweight brick carrier.

[0010] Preferably, in the aforementioned step S2, the surface modifier is 3-aminopropyltriethoxysilane, the mass ratio of the surface modifier to distilled water is 1:2, the pH of the mixed solution is 8-9, and the soaking time of the lightweight brick is 20-40 min.

[0011] Preferably, in the aforementioned step S3, the Bacillus is selected from one of Bacillus subtilis, Bacillus velez or Bacillus cereus.

[0012] Preferably, in the aforementioned step S3, the seed solution is inoculated into the fermentation tank at a volume ratio of 1%, and the concentration is cultured to 10 9 CFU / mL.

[0013] Application of aerobic Bacillus immobilized carrier in degradation of ammonia nitrogen and total phosphorus in black and smelly water bodies.

[0014] The advantages of the present invention are as follows: the present invention adopts lightweight bricks as carrier materials, which are inexpensive, easy to obtain, have a smaller bulk density than water, have a porous structure inside, good adsorption, and stable physical and chemical properties. It can provide a sufficient growth environment for microorganisms, which is conducive to the biofilm formation, growth and reproduction of microorganisms; positive charges are introduced into the lightweight brick carrier, and electrostatic attraction is used to enable aerobic Bacillus to be adsorbed on the carrier, thereby increasing the load capacity of the carrier; the lightweight brick is modified so that its surface has hydrophilic groups, which can form homologous affinity with the hydrophilic surface of the biofilm produced by bacteria; the prepared immobilized carrier can effectively degrade ammonia nitrogen and total phosphorus in black and odorous water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the immobilized carrier in Example 4 of the present invention.

[0016] The meanings of the reference numerals in the figure: 1. river channel, 2. biological rope, 3. suspended ball, 4. immobilized carrier. DETAILED DESCRIPTION

[0017] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Example 1: A method for preparing an aerobic Bacillus immobilized carrier, comprising the following specific steps: S1. Preparation of lightweight bricks: Step 1: crush construction waste or mineral raw materials, add water, foaming agent, positive charge donor and dispersant to the sieved materials, and grind them by ball milling or the like; wherein water is 40-50 wt%, dispersant is 0.4-0.6 wt%, positive charge donor is 4-6 wt%, and the foaming agent is potassium feldspar powder, which is about 1.5 wt%; the dispersant is sodium silicate, and the positive charge donor is polyquaternary ammonium salt.

[0019] Step 2: Add a plasticizer to the ground slurry and dry it, and make a spherical embryo through a mold and a cutting device, wherein the amount of the plasticizer added is 0.08-0.2 wt%, the plasticizer is carboxymethyl cellulose, and the size of the spherical embryo is 10 cm in diameter.

[0020] Step 3: Initial heating stage: The temperature is gradually raised to below 450°C to promote the evaporation of water and the generation of gas by the foaming agent, so that the inside of the brick begins to foam. As the temperature rises, the water content in the adhesive decreases and the polymer system gradually solidifies.

[0021] Pre-firing stage: Raising the temperature to 450~750℃ and maintaining it for 30~60 minutes will help to completely decompose organic matter, improve the quality of the brick, eliminate black blocks, and prevent cracks caused by changes in the crystal form of silica.

[0022] Rapid heating stage: When the temperature exceeds 750 °C, the heating rate is accelerated to promote gas discharge and enhance the porosity effect.

[0023] High-temperature firing stage: The temperature is raised to 1000~1200℃ for firing. The oxides in the brick blank begin to melt and the internal pores gradually become larger. At 900℃, the organic matter is basically decomposed. After high-temperature sintering, the pores are reduced or disappeared, and the particles are in contact, which improves the density of the brick body. Fire at 1000~1200℃ for 160 minutes to remove pores and achieve the highest density. At the same time, avoid long-term firing that affects the quality of the brick body and achieve energy saving.

[0024] Cooling and insulation stage: After firing, lower the temperature and keep it at 700~750℃ for 30 minutes to obtain high-quality foam bricks. Too long insulation time will cause the volume density to decrease first and then increase, so the insulation time needs to be moderate.

[0025] Annealing stage: The foamed bricks that have undergone the high-temperature sintering step are transferred to the annealing chamber, where they are cooled to room temperature.

[0026] S2. Lightweight brick modification: The lightweight brick is immersed in a mixed solution of a surface modifier and distilled water, wherein the surface modifier is 3-aminopropyltriethoxysilane, the pH value of the mixed solution of the surface modifier and distilled water is 8-9, and the lightweight brick is immersed for 20-40 min to obtain a modified lightweight brick carrier.

[0027] S3, preparation of bacterial agent: Bacillus subtilis was inoculated into 100 mL LB medium and cultured in a shaker at 30 °C and 180 rpm for 24 h to obtain seed solution. The seed solution was then inoculated into a fermentation medium in a fermenter at a volume ratio of 1% for expansion culture. The culture was continued until 10 9 CFU / mL concentration.

[0028] The components of LB medium are: 5 g yeast extract, 10 g peptone, 5 g NaCl and 1 L water, and the culture conditions are: temperature 35 °C, time 24 h, pH 6-8. The components of fermentation medium are: glucose 15-20 g / L, soybean meal 15-20 g / L, yeast extract 4-8 g / L, mannitol 5-8 g / L, potassium dihydrogen phosphate 1-2 g / L and magnesium sulfate 0.5-1 g / L, and the culture conditions are: temperature 35 °C, time 36 h, pH 6-8.

[0029] S4. Forming an immobilized carrier: loading the aerobic Bacillus bacterial liquid onto the modified lightweight brick carrier, and completing the fixation after forming the biofilm for 4 days to obtain an immobilized carrier.

[0030] Example 2: Treatment effect of immobilized carrier on black and odorous water Prepare 1L of water sample, in which the initial concentrations of ammonia nitrogen and total phosphorus are set to 15 mg / L and 3 mg / L respectively, add a carrier with a film attached to it into the container, and after incubation at 30 ℃ for 48 h, measure the concentrations of ammonia nitrogen and total phosphorus in the water sample.

[0031] The results showed that after 48 hours, the concentrations of ammonia nitrogen and total phosphorus in the water sample were 2.24 mg / L and 1.33 mg / L, respectively, and the degradation rates were 85.1% and 55.6%, respectively. It can be seen that the immobilized microbial carrier has excellent treatment effects on ammonia nitrogen and TP.

[0032] Example 3: Treatment effect of immobilized carrier on actual black and odorous water The carrier was prepared according to the method of Example 1, and the bacterial agent used was Bacillus Velez. The water source to be treated was a black and smelly river in a rural area. The laboratory simulated aeration treatment of the biochemical system with a treatment capacity of 20 L was placed at the bottom. Some black and smelly sludge was placed at the bottom, and 5 carriers were added. The aeration treatment made the dissolved oxygen above 2 mg / L, the pH of the water sample was maintained at 7-8, the initial concentrations of ammonia nitrogen and total phosphorus were 12.45 mg / L and 2.57 mg / L, respectively. The water was inlet and outlet once a day, and 1 L of water was inlet and outlet each time. The concentrations of ammonia nitrogen and total phosphorus in the effluent were detected by sampling.

[0033] The results showed that the degradation rates of ammonia nitrogen and total phosphorus were 79.6% and 54.7% respectively, and the effluent quality met the effluent requirements for black and odorous water bodies.

[0034] Example 4: Practical application of immobilized carrier Prepare the carriers according to the method of Example 1, place three carriers in the suspended ball filler, connect the suspended balls with biological ropes, and fix them on both sides of the river. The main material of the suspended ball filler is polypropylene, and the outer part is a hollow fishnet sphere, such as Figure 1 shown.

[0035] Example 5: Immobilized carrier immersion experiment A section of a black and smelly river was selected for the test. The carrier suspension balls were prepared according to the methods of Example 1 and Example 4. The biological rope with the suspended ball carrier was fixed in the river. The rope was taken out every 24 hours to record the material morphology and sustained release.

[0036] By observing the morphology of the material, it can be seen that when the material is placed in water for 10 days, the carrier has no obvious softening, is still in a solid state and has no obvious change in size. After 1 month, the carrier is reduced in size and slightly damaged, indicating that the aerobic Bacillus carrier has good stability.

[0037] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. An aerobic Bacillus immobilized carrier, characterized in that: The immobilized carrier is a light brick with a porous structure inside. The surface of the light brick has positive charges and hydrophilic groups, and the bulk density of the light brick is less than that of water.

2. The method for preparing an aerobic Bacillus immobilized carrier according to claim 1, characterized in that: The specific steps include: S1. Preparation of lightweight bricks: crushing and sieving the raw materials, adding water, a foaming agent, a positive charge donor and a dispersant, grinding and adding a plasticizer to form porous lightweight bricks; S2. Lightweight brick modification: soaking the lightweight brick in a mixed solution of a surface modifier and distilled water to obtain a modified lightweight brick carrier; S3, preparing a bacterial agent: inoculating aerobic Bacillus into LB medium, shaking and culturing to obtain seed solution, inoculating the seed solution into a fermentation tank of fermentation medium for expansion culture, and obtaining aerobic Bacillus bacterial solution; S4. Forming an immobilized carrier: loading the aerobic Bacillus bacterial liquid onto a modified lightweight brick carrier to obtain an immobilized carrier.

3. The method for preparing an aerobic Bacillus immobilized carrier according to claim 2, characterized in that: In the step S1, the preparation of lightweight bricks includes the following specific steps: (1) crushing and sieving the raw materials, adding water, foaming agent, positive charge donor and dispersant, and grinding; (2) adding a plasticizer to the ground slurry and drying the slurry to obtain a spherical embryo; (3) The spherical embryo is subjected to high-temperature sintering and annealing to form porous lightweight bricks.

4. The method for preparing an aerobic Bacillus immobilized carrier according to claim 3, characterized in that: In the step (1), the added amounts of the components are: 40-50 wt% of water, 1.5 wt% of a foaming agent, 0.4-0.6 wt% of a dispersant, and 4-6 wt% of a positive charge donor; the raw materials are construction waste or minerals; the foaming agent is ground potassium feldspar; the positive charge donor is one or a combination of polyquaternary ammonium salt or sulfate ore; and the dispersant is sodium silicate.

5. The method for preparing an aerobic Bacillus immobilized carrier according to claim 3, characterized in that: In the step (2), the plasticizer is carboxymethyl cellulose, the addition amount is 0.08-0.2 wt%, and the diameter of the spherical embryo is 9-11 cm.

6. The method for preparing an aerobic Bacillus immobilized carrier according to claim 3, characterized in that: In the step (3), the specific steps of high temperature sintering and annealing are: (3.1) Initial heating stage: the temperature is gradually raised to 450 °C, and the inside of the brick begins to foam; (3.2) Pre-burning stage: raise the temperature to 450~750℃ and maintain it for 30~60 min; (3.3) Rapid heating stage: When the temperature exceeds 750 °C, the heating rate is accelerated to 9-11 °C / h; (3.4) High temperature firing stage: The temperature is raised to 1000~1200℃ for firing. The oxides in the brick material begin to melt and the internal pores gradually become larger. The firing time is 150~170 min. (3.5) Cooling and insulation stage: After firing, the temperature is lowered and kept at 700-750 °C for 20-40 min to obtain foamed bricks; (3.6) Annealing and molding: The foamed bricks are transferred to the annealing chamber and cooled to room temperature to obtain the modified lightweight brick carrier.

7. The method for preparing an aerobic Bacillus immobilized carrier according to claim 2, characterized in that: In the step S2, the surface modifier is 3-aminopropyltriethoxysilane, the mass ratio of the surface modifier to distilled water is 1:2, the pH of the mixed solution is 8-9, and the soaking time of the lightweight brick is 20-40 min.

8. The method for preparing an aerobic Bacillus immobilized carrier according to claim 2, characterized in that: In the step S3, the Bacillus is selected from one of Bacillus subtilis, Bacillus velez or Bacillus cereus.

9. The method for preparing an aerobic Bacillus immobilized carrier according to claim 2, characterized in that: In step S3, the seed solution is inoculated into the fermentation tank at a volume ratio of 1%, and the concentration is cultured to 10 9 CFU / mL.

10. Use of the aerobic Bacillus immobilized carrier according to claim 1 in degrading ammonia nitrogen and total phosphorus in black and smelly water.

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