Method for combined treatment of heavy metal sewage by microorganisms

Abstract

The invention discloses a method for combined treatment of heavy metal sewage by microorganisms, heavy metal sewage is treated by a microorganism-containing treatment agent, the microorganism-containing treatment agent comprises a microbial preparation and an adsorbent, and the microbial preparation is a bdellovibrio bacteriovorus agent; the adsorbent is bentonite-based adsorption particles; by adopting the method disclosed by the invention, heavy metal ions in the sewage can be well removed, and the heavy metal pollution degree of the sewage is reduced; the treatment time is obviously shortened, and the sewage treatment efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly relates to a method for jointly treating heavy metal sewage by microorganisms. Background Art

[0002] Sewage contains various harmful chemical substances such as heavy metals, organic pollutants, bacteria, and suspended solids. If directly discharged without treatment, it will have a serious impact on the water body ecosystem. Biological treatment technology has been widely used in the field of sewage treatment due to its advantages such as high cost-effectiveness and environmental friendliness. Among them, Bdellovibrio bacteriovorus is smaller than bacteria and can pass through a bacterial filter. It has a similar effect to phages, but it is not a virus. It is indeed a type of bacteria that can "eat" bacteria and is a type of Gram-negative bacteria that parasitizes other bacteria and can cause their lysis. This bacterium can remove genera such as Salmonella, Shigella, Proteus, Pseudomonas, Escherichia, Erwinia, and Vibrio in water within a short time, eliminate pathogenic bacteria, and control or reduce the pollution of environmental water sources by pathogenic bacteria. Since Bdellovibrio bacteriovorus can lyse a variety of bacteria and has a special lifestyle and ecological advantages, it is considered one of the biological factors for natural purification and has been developed and applied as a strain of a new type of microecological preparation in the field of microecological research. Summary of the Invention

[0003] In view of this, the present invention provides a method for jointly treating heavy metal sewage by microorganisms. The heavy metal sewage is treated with a microbial treatment agent. The microbial treatment agent includes a microbial preparation and an adsorbent. The microbial preparation is a Bdellovibrio bacteriovorus agent; the adsorbent is a bentonite-based adsorption particle. The treatment steps include:

[0004] (1) Inoculate the Bdellovibrio bacteriovorus bacterial suspension and the Escherichia coli bacterial suspension onto an LB medium, culture at 32 ± 2 °C for 50 - 100 h. After culturing, pick a single colony and immerse it in sterile water, centrifuge, and then inoculate it into an agar medium for continuous subculture for 3 - 5 generations for activation. When plaques appear, pick the plaques into sterile water, centrifuge and separate, and use a bacterial filter to remove Escherichia coli from the supernatant to obtain a Bdellovibrio bacteriovorus agent;

[0005] (2) Prepare an aqueous solution of sodium carbonate and an aqueous solution of fulvic acid; add bentonite to the aqueous solution of sodium carbonate under stirring, and after adding the material, heat it in a water bath to 60 ± 5 °C, keep stirring for more than 30 min. After stirring, perform solid-liquid separation, wash the solid phase with deionized water for more than 3 times, and dry it to obtain a pretreated powder; add the pretreated powder to the aqueous solution of fulvic acid, and after adding the material, stir for more than 30 min. Then, add cetyltrimethylammonium bromide to the solution under stirring, and after adding the material, continue stirring for more than 5 h. Then, perform solid-liquid separation, wash the solid phase with deionized water for more than 3 times, and dry it to obtain fulvic acid-modified particles;

[0006] (3) Add the modified fulvic acid particles to deionized water, stir for more than 20 min under ultrasonic environment to obtain a suspension; stir the suspension, and then add glyphosate to the suspension under stirring state. After the feeding is completed, adjust the pH of the suspension to 10 - 11 with sodium hydroxide solution, and then stir for more than 8 h; after the stirring ends, perform solid-liquid separation, wash the solid phase with deionized water for more than 3 times, and dry it to obtain bentonite-based adsorption particles.

[0007] (4) Add the Bdellovibrio agent to the sewage, heat it to 35 ± 3 °C and keep stirring for more than 20 min, then add the bentonite-based adsorption particles under stirring state. After the feeding is completed, continue to stir at a constant temperature of 35 ± 3 °C for 1 - 2 h to complete the heavy metal sewage treatment.

[0008] Further, in the step (1), in the LB medium, the mass percentage of peptone is 0.5%, the mass percentage of yeast extract is 0.15%, the mass percentage of sodium chloride is 0.25%, the mass percentage of agar is 0.4%, and the rest is sterile distilled water.

[0009] Further, in the step (2), in the aqueous solution of sodium carbonate, the concentration of sodium carbonate is 2 - 3 g / 100 mL, and the solvent is water; in the aqueous solution of fulvic acid, the concentration of fulvic acid is 0.8 - 1.4 g / 100 mL, and the solvent is water; the mass ratio of adding bentonite to the aqueous solution of sodium carbonate is bentonite:aqueous solution of sodium carbonate = 1:50 - 100; the mass ratio of adding the pretreated powder to the aqueous solution of fulvic acid is pretreated powder:aqueous solution of fulvic acid = 1:100; the mass ratio of adding cetyltrimethylammonium bromide to the mass of the added pretreated powder is cetyltrimethylammonium bromide:pretreated powder = 3 - 4:1.

[0010] Further, in the step (3), the mass ratio of adding the modified fulvic acid particles to deionized water is modified fulvic acid particles:deionized water = 1:1000; the mass ratio of adding glyphosate to the mass of the added modified fulvic acid particles is glyphosate:modified fulvic acid particles = 1 - 2:1.

[0011] Further, in the step (3), the concentration of the solute in the sodium hydroxide solution is 1.5 - 2 mol / L, and the solvent is water.

[0012] Further, in the step (4), the mass ratio of adding the Bdellovibrio agent and the bentonite-based adsorption particles to the volume of the sewage is Bdellovibrio agent:bentonite-based adsorption particles:sewage = 2 - 2.5 g:0.2 - 0.3 g:500 mL.

[0013] The beneficial effects of the present invention are as follows: By using the method of the present invention, heavy metal ions in sewage can be better removed, reducing the heavy metal pollution degree of sewage; and the treatment time is significantly shortened, improving the sewage treatment efficiency. By introducing a microbial agent into the traditional adsorbent treatment process, the present invention can significantly improve the removal rate of heavy metals. This is mainly because a large number of bacteria and other microorganisms are inevitably contained in sewage, and traditional adsorbents cannot effectively prevent the adhesion of bacteria on the surface of the adsorbent. Therefore, a large number of adsorption sites on the surface of traditional adsorbents are often covered by bacteria or other microorganisms, resulting in poor adsorption effect on heavy metals. The present invention introduces a Bdellovibrio agent with bactericidal function, significantly reducing the adsorption of bacteria and other microorganisms on the surface of the adsorbent, thereby improving the adsorption and removal effect of the adsorbent on heavy metal ions. In addition, the present invention improves and optimizes the preparation method of the traditional bentonite-based adsorbent, introduces fulvic acid groups on the surface of bentonite, and at the same time modifies it by grafting with glyphosate, improving the adsorption and chelation of the adsorbent on heavy metal ions, which macroscopically shows the improvement of the removal rate of heavy metal ions in sewage. Detailed implementation mode

[0014] The following further illustrates the present invention in conjunction with embodiments.

[0015] Embodiment 1

[0016] A method for jointly treating heavy metal sewage by microorganisms, using a microbial treatment agent containing to treat heavy metal sewage. The microbial treatment agent containing includes a microbial agent and an adsorbent, wherein the microbial agent is a Bdellovibrio agent; the adsorbent is a bentonite-based adsorption particle; the treatment steps include:

[0017] (1) Inoculate the Bdellovibrio bacterium suspension and Escherichia coli bacterium suspension onto an LB medium. In the LB medium, the mass percentage of peptone is 0.5%, the mass percentage of yeast extract is 0.15%, the mass percentage of sodium chloride is 0.25%, the mass percentage of agar is 0.4%, and the rest is sterile distilled water; culture at 32 ± 2 °C for 80 h. After culture, pick a single colony and immerse it in sterile water, centrifuge, and then inoculate it into an agar medium for continuous passage 4 times for activation. Plaques appear. In the agar medium, the mass percentage of beef extract is 0.3%, the mass percentage of peptone is 1%, the mass percentage of sodium chloride is 0.5%, the mass percentage of agar is 2%, and the rest is sterile distilled water; pick the plaque into sterile water, centrifuge and separate, and take the supernatant to remove Escherichia coli with a bacterial filter to obtain a Bdellovibrio agent;

[0018] (2) Prepare an aqueous solution of sodium carbonate. In the aqueous solution of sodium carbonate, the concentration of sodium carbonate is 2 g / 100 mL, and the solvent is water; prepare an aqueous solution of fulvic acid. In the aqueous solution of fulvic acid, the concentration of fulvic acid is 0.8 g / 100 mL, and the solvent is water; add bentonite to the aqueous solution of sodium carbonate under stirring. The mass ratio of bentonite to the aqueous solution of sodium carbonate added to the aqueous solution of sodium carbonate is bentonite: aqueous solution of sodium carbonate = 1:50; after the addition is completed, heat in a water bath to 60 °C, keep stirring for 30 min, after the stirring is completed, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry at 60 °C for 3 h to obtain a pretreated powder; add the pretreated powder to the aqueous solution of fulvic acid. The mass ratio of the pretreated powder to the aqueous solution of fulvic acid added to the aqueous solution of fulvic acid is pretreated powder: aqueous solution of fulvic acid = 1:100; after the addition is completed, stir for 30 min, and then add cetyltrimethylammonium bromide to the solution under stirring. The mass ratio of the added cetyltrimethylammonium bromide to the mass of the added pretreated powder is cetyltrimethylammonium bromide: pretreated powder = 3:1; after the addition is completed, continue to stir for 5 h, then perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry at 60 °C for 3 h to obtain fulvic acid-modified particles;

[0019] (3) Add the fulvic acid-modified particles to deionized water. The mass ratio of the fulvic acid-modified particles to deionized water added to deionized water is fulvic acid-modified particles: deionized water = 1:1000; stir in an ultrasonic environment for 20 min to obtain a suspension; stir the suspension, and then add glyphosate to the suspension under stirring. The mass ratio of the added glyphosate to the mass of the added fulvic acid-modified particles is glyphosate: fulvic acid-modified particles = 1:1; after the addition is completed, adjust the pH of the suspension to 10 with a sodium hydroxide solution, and then stir for 8 h; the concentration of the solute in the sodium hydroxide solution is 1.5 mol / L, and the solvent is water; after the stirring is ended, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry at 60 °C for 3 h to obtain bentonite-based adsorption particles;

[0020] (4) Add the Bdellovibrio agent to the test sewage (copper ion concentration is 150 mg / L, pH is 5), heat to 35 ± 3 °C and keep stirring for 20 min, and then add the bentonite-based adsorption particles under stirring. After the addition is completed, continue to stir at a constant temperature of 35 ± 3 °C for 1 h to complete the treatment of heavy metal sewage; the mass ratio of the added Bdellovibrio agent, bentonite-based adsorption particles to the volume of the sewage is Bdellovibrio agent: bentonite-based adsorption particles: sewage = 2 g: 0.2 g: 500 mL.

[0021] Example 2

[0022] A method for treating heavy metal sewage by microbial combination uses a microbial treatment agent to treat heavy metal sewage. The microbial treatment agent includes a microbial preparation and an adsorbent. The microbial preparation is a Bdellovibrio agent, and the adsorbent is a bentonite-based adsorption particle. The treatment steps include:

[0023] (1) Inoculate the Bdellovibrio bacterium suspension and the Escherichia coli bacterium suspension onto an LB medium. In the LB medium, the mass percentage of peptone is 0.5%, the mass percentage of yeast extract is 0.15%, the mass percentage of sodium chloride is 0.25%, the mass percentage of agar is 0.4%, and the rest is sterile distilled water. Cultivate at 32 ± 2 °C for 80 h. After cultivation, pick a single colony and immerse it in sterile water, centrifuge, and then inoculate it into an agar medium for continuous passage 4 times for activation. Plaques appear. In the agar medium, the mass percentage of beef extract is 0.3%, the mass percentage of peptone is 1%, the mass percentage of sodium chloride is 0.5%, the mass percentage of agar is 2%, and the rest is sterile distilled water. Pick the plaque into sterile water, centrifuge and separate, and use a bacterial filter to remove Escherichia coli from the supernatant to obtain a Bdellovibrio agent.

[0024] (2) Prepare an aqueous solution of sodium carbonate. In the aqueous solution of sodium carbonate, the concentration of sodium carbonate is 2 g / 100 mL, and the solvent is water. Prepare an aqueous solution of fulvic acid. In the aqueous solution of fulvic acid, the concentration of fulvic acid is 1 g / 100 mL, and the solvent is water. Add bentonite to the aqueous solution of sodium carbonate under stirring. The mass ratio of bentonite to the aqueous solution of sodium carbonate is bentonite: aqueous solution of sodium carbonate = 1:50. After adding the materials, heat in a water bath to 60 °C, keep warm and stir for 30 min. After stirring, perform solid-liquid separation. Wash the solid phase with deionized water 3 times and dry at 60 °C for 3 h to obtain a pretreated powder. Add the pretreated powder to the aqueous solution of fulvic acid. The mass ratio of the pretreated powder to the aqueous solution of fulvic acid is pretreated powder: aqueous solution of fulvic acid = 1:100. After adding the materials, stir for 30 min, and then add cetyltrimethylammonium bromide to the solution under stirring. The mass ratio of the added cetyltrimethylammonium bromide to the added pretreated powder is cetyltrimethylammonium bromide: pretreated powder = 3:1. After adding the materials, continue to stir for 5 h, and then perform solid-liquid separation. Wash the solid phase with deionized water 3 times and dry at 60 °C for 3 h to obtain fulvic acid-modified particles.

[0025] (3) Add the modified fulvic acid particles to deionized water. The mass ratio of the modified fulvic acid particles to deionized water is modified fulvic acid particles: deionized water = 1:1000. Stir for 20 min under ultrasonic conditions to obtain a suspension. Stir the suspension, and then add glyphosine to the suspension under stirring. The mass ratio of the added glyphosine to the mass of the added modified fulvic acid particles is glyphosine: modified fulvic acid particles = 1:1. After the addition is completed, adjust the pH of the suspension to 10 with sodium hydroxide solution, and then stir for 8 h. The concentration of the solute in the sodium hydroxide solution is 1.5 mol / L, and the solvent is water. After the stirring is completed, perform solid-liquid separation. Wash the solid phase with deionized water 3 times and dry it at 60 °C for 3 h to obtain bentonite-based adsorption particles.

[0026] (4) Add the Bdellovibrio agent to the test sewage (copper ion concentration is 150 mg / L, pH is 5), heat to 35 ± 3 °C and keep stirring for 20 min. Then add the bentonite-based adsorption particles under stirring. After the addition is completed, continue to stir at a constant temperature of 35 ± 3 °C for 1 h to complete the heavy metal sewage treatment. The mass ratio of the added Bdellovibrio agent, bentonite-based adsorption particles to the volume of the sewage is Bdellovibrio agent: bentonite-based adsorption particles: sewage = 2.2 g: 0.2 g: 500 mL.

[0027] Example 3

[0028] A method for treating heavy metal sewage by microorganism combination uses a microorganism-containing treatment agent to treat heavy metal sewage. The microorganism-containing treatment agent includes a microbial agent and an adsorbent. The microbial agent is a Bdellovibrio agent; the adsorbent is a bentonite-based adsorption particle. The treatment steps include:

[0029] (1) Inoculate the Bdellovibrio bacterium suspension and Escherichia coli bacterium suspension onto an LB medium. In the LB medium, the mass percentage of peptone is 0.5%, the mass percentage of yeast extract is 0.15%, the mass percentage of sodium chloride is 0.25%, the mass percentage of agar is 0.4%, and the rest is sterile distilled water. Cultivate at 32 ± 2 °C for 80 h. After cultivation, pick a single colony and immerse it in sterile water, centrifuge, and then inoculate it into an agar medium for continuous passage 4 times for activation. Plaques appear. In the agar medium, the mass percentage of beef extract is 0.3%, the mass percentage of peptone is 1%, the mass percentage of sodium chloride is 0.5%, the mass percentage of agar is 2%, and the rest is sterile distilled water. Pick the plaque into sterile water, centrifuge and separate, and take the supernatant to remove Escherichia coli with a bacterial filter to obtain the Bdellovibrio agent.

[0030] (2) Prepare an aqueous solution of sodium carbonate. In the aqueous solution of sodium carbonate, the concentration of sodium carbonate is 3 g / 100 mL and the solvent is water. Prepare an aqueous solution of fulvic acid. In the aqueous solution of fulvic acid, the concentration of fulvic acid is 1.2 g / 100 mL and the solvent is water. Add bentonite to the aqueous solution of sodium carbonate under stirring. The mass ratio of bentonite to the aqueous solution of sodium carbonate added to the aqueous solution of sodium carbonate is bentonite: aqueous solution of sodium carbonate = 1:50. After the feeding is completed, heat in a water bath to 60 °C, keep stirring for 30 min, separate the solid and liquid after stirring is completed, wash the solid with deionized water 3 times, and dry at 60 °C for 3 h to obtain a pretreated powder. Add the pretreated powder to the aqueous solution of fulvic acid. The mass ratio of the pretreated powder to the aqueous solution of fulvic acid added to the aqueous solution of fulvic acid is pretreated powder: aqueous solution of fulvic acid = 1:100. After the feeding is completed, stir for 30 min, and then add cetyltrimethylammonium bromide to the solution under stirring. The mass ratio of the added cetyltrimethylammonium bromide to the mass of the added pretreated powder is cetyltrimethylammonium bromide: pretreated powder = 4:1. After the feeding is completed, continue stirring for 5 h, then separate the solid and liquid, wash the solid with deionized water 3 times, and dry at 60 °C for 3 h to obtain fulvic acid-modified particles;

[0031] (3) Add the fulvic acid-modified particles to deionized water. The mass ratio of the fulvic acid-modified particles to deionized water added to deionized water is fulvic acid-modified particles: deionized water = 1:1000. Stir in an ultrasonic environment for 20 min to obtain a suspension. Stir the suspension, and then add glyphosine to the suspension under stirring. The mass ratio of the added glyphosine to the mass of the added fulvic acid-modified particles is glyphosine: fulvic acid-modified particles = 2:1. After the feeding is completed, adjust the pH of the suspension to 10 with a sodium hydroxide solution, and then stir for 8 h. The concentration of the solute in the sodium hydroxide solution is 1.5 mol / L and the solvent is water. After stirring is completed, separate the solid and liquid, wash the solid with deionized water 3 times, and dry at 60 °C for 3 h to obtain bentonite-based adsorption particles;

[0032] (4) Add the Bdellovibrio agent to the test sewage (copper ion concentration is 150 mg / L, pH is 5), heat to 35 ± 3 °C and keep stirring for 20 min, and then add the bentonite-based adsorption particles under stirring. After the feeding is completed, continue stirring at 35 ± 3 °C for 1 h to complete the heavy metal sewage treatment. The mass ratio of the added Bdellovibrio agent, bentonite-based adsorption particles to the volume of the sewage is Bdellovibrio agent: bentonite-based adsorption particles: sewage = 2.4 g: 0.3 g: 500 mL.

[0033] Example 4

[0034] A method for treating heavy metal sewage by microbial combination uses a microbial treatment agent to treat heavy metal sewage. The microbial treatment agent includes a microbial preparation and an adsorbent. The microbial preparation is a Bdellovibrio agent, and the adsorbent is a bentonite-based adsorption particle. The treatment steps include:

[0035] (1) Inoculate the Bdellovibrio bacterium suspension and the Escherichia coli bacterium suspension onto an LB medium. In the LB medium, the mass percentage of peptone is 0.5%, the mass percentage of yeast extract is 0.15%, the mass percentage of sodium chloride is 0.25%, the mass percentage of agar is 0.4%, and the rest is sterile distilled water. Cultivate at 32 ± 2 °C for 80 h. After cultivation, pick a single colony and immerse it in sterile water, centrifuge, and then inoculate it into an agar medium for continuous passage 4 times for activation. Plaques appear. In the agar medium, the mass percentage of beef extract is 0.3%, the mass percentage of peptone is 1%, the mass percentage of sodium chloride is 0.5%, the mass percentage of agar is 2%, and the rest is sterile distilled water. Pick the plaque into sterile water, centrifuge and separate, and use a bacterial filter to remove Escherichia coli from the supernatant to obtain a Bdellovibrio agent.

[0036] (2) Prepare an aqueous solution of sodium carbonate. In the aqueous solution of sodium carbonate, the concentration of sodium carbonate is 3 g / 100 mL, and the solvent is water. Prepare an aqueous solution of fulvic acid. In the aqueous solution of fulvic acid, the concentration of fulvic acid is 1.4 g / 100 mL, and the solvent is water. Add bentonite to the aqueous solution of sodium carbonate under stirring. The mass ratio of bentonite to the aqueous solution of sodium carbonate is bentonite: aqueous solution of sodium carbonate = 1:50. After adding the materials, heat in a water bath to 60 °C, keep warm and stir for 30 min. After stirring, perform solid-liquid separation. Wash the solid phase with deionized water 3 times and dry at 60 °C for 3 h to obtain a pretreated powder. Add the pretreated powder to the aqueous solution of fulvic acid. The mass ratio of the pretreated powder to the aqueous solution of fulvic acid is pretreated powder: aqueous solution of fulvic acid = 1:100. After adding the materials, stir for 30 min, and then add cetyltrimethylammonium bromide to the solution under stirring. The mass ratio of the added cetyltrimethylammonium bromide to the added pretreated powder is cetyltrimethylammonium bromide: pretreated powder = 4:1. After adding the materials, continue to stir for 5 h, and then perform solid-liquid separation. Wash the solid phase with deionized water 3 times and dry at 60 °C for 3 h to obtain fulvic acid-modified particles.

[0037] (3) Add the modified fulvic acid particles into deionized water, and the mass ratio of the modified fulvic acid particles to deionized water is modified fulvic acid particles: deionized water = 1:1000; stir for 20 min under ultrasonic environment to obtain a suspension; stir the suspension, and then add glyphosine to the suspension under stirring. The mass ratio of the added glyphosine to the mass of the modified fulvic acid particles is glyphosine: modified fulvic acid particles = 2:1; after the feeding is completed, adjust the pH of the suspension to 10 with sodium hydroxide solution, and then stir for 8 h; the concentration of the solute in the sodium hydroxide solution is 1.5 mol / L, and the solvent is water; after the stirring is completed, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry it at 60 °C for 3 h to obtain bentonite-based adsorption particles;

[0038] (4) Add the Bdellovibrio agent into the test sewage (copper ion concentration is 150 mg / L, pH is 5), heat it to 35 ± 3 °C and keep stirring for 20 min, then add the bentonite-based adsorption particles under stirring. After the feeding is completed, continue to stir at a constant temperature of 35 ± 3 °C for 1 h to complete the heavy metal sewage treatment; the mass ratio of the added Bdellovibrio agent, bentonite-based adsorption particles to the volume of the sewage is Bdellovibrio agent: bentonite-based adsorption particles: sewage = 2.5 g: 0.3 g: 500 mL.

[0039] Comparative Example 1

[0040] A method for jointly treating heavy metal sewage by microorganisms uses a microbial treatment agent to treat heavy metal sewage. The microbial treatment agent includes a microbial preparation and an adsorbent. The microbial preparation is a Bdellovibrio agent; the adsorbent is a bentonite-based adsorption particle; the treatment steps include:

[0041] (1) Inoculate the Bdellovibrio bacterium suspension and Escherichia coli bacterium suspension onto the LB medium. In the LB medium, the mass percentage of peptone is 0.5%, the mass percentage of yeast extract is 0.15%, the mass percentage of sodium chloride is 0.25%, the mass percentage of agar is 0.4%, and the rest is sterile distilled water; culture at 32 ± 2 °C for 80 h. After culturing, pick a single colony and immerse it in sterile water, centrifuge, and then inoculate it into the agar medium for continuous passage 4 times for activation. A plaque appears. In the agar medium, the mass percentage of beef extract is 0.3%, the mass percentage of peptone is 1%, the mass percentage of sodium chloride is 0.5%, the mass percentage of agar is 2%, and the rest is sterile distilled water; pick the plaque into sterile water, centrifuge and separate, take the supernatant and remove Escherichia coli with a bacterial filter to obtain the Bdellovibrio agent;

[0042] (2) Prepare an aqueous solution of sodium carbonate. In the aqueous solution of sodium carbonate, the concentration of sodium carbonate is 2 g / 100 mL, and the solvent is water. Add bentonite to the aqueous solution of sodium carbonate under stirring. The mass ratio of bentonite to the aqueous solution of sodium carbonate added to the aqueous solution of sodium carbonate is bentonite: aqueous solution of sodium carbonate = 1:50. After the feeding is completed, heat it in a water bath to 60 °C, keep stirring for 30 min. After the stirring is completed, perform solid-liquid separation. Wash the solid phase with deionized water 3 times, and dry it at 60 °C for 3 h to obtain the pretreated powder. Add the pretreated powder to deionized water. The mass ratio of the pretreated powder to deionized water added to deionized water is pretreated powder: deionized water = 1:100. After the feeding is completed, stir for 30 min, and then add cetyltrimethylammonium bromide to the solution under stirring. The mass ratio of the added cetyltrimethylammonium bromide to the mass of the added pretreated powder is cetyltrimethylammonium bromide: pretreated powder = 3:1. After the feeding is completed, continue to stir for 5 h, and then perform solid-liquid separation. Wash the solid phase with deionized water 3 times, and dry it at 60 °C for 3 h to obtain the post-treated particles of this comparative example;

[0043] (3) Add the post-treated particles to deionized water. The mass ratio of the post-treated particles to deionized water added to deionized water is post-treated particles: deionized water = 1:1000. Stir for 20 min under an ultrasonic environment to obtain a suspension. Stir the suspension, and then add glyphosate to the suspension under stirring. The mass ratio of the added glyphosate to the added mass of the post-treated particles is glyphosate: post-treated particles = 1:1. After the feeding is completed, adjust the pH of the suspension to 10 with a sodium hydroxide solution, and then stir for 8 h. The concentration of the solute in the sodium hydroxide solution is 1.5 mol / L, and the solvent is water. After the stirring is completed, perform solid-liquid separation. Wash the solid phase with deionized water 3 times, and dry it at 60 °C for 3 h to obtain bentonite-based adsorption particles;

[0044] (4) Add the Bdellovibrio agent to the test sewage (copper ion concentration is 150 mg / L, pH is 5), heat it to 35 ± 3 °C, keep stirring for 20 min, and then add the bentonite-based adsorption particles under stirring. After the feeding is completed, continue to stir at a constant temperature of 35 ± 3 °C for 1 h to complete the treatment of heavy metal sewage. The mass ratio of the added Bdellovibrio agent, bentonite-based adsorption particles to the volume of the sewage is Bdellovibrio agent: bentonite-based adsorption particles: sewage = 2.2 g: 0.2 g: 500 mL.

[0045] Comparative Example 2

[0046] A method for jointly treating heavy metal sewage by microorganisms uses a microbial treatment agent to treat heavy metal sewage. The microbial treatment agent includes a microbial preparation and an adsorbent. The microbial preparation is a Bdellovibrio agent; the adsorbent is bentonite-based adsorption particles. The treatment steps include:

[0047] (1) Inoculate the Bdellovibrio bacteriovorus suspension and Escherichia coli suspension onto LB medium. In the LB medium, the mass percentage of peptone is 0.5%, the mass percentage of yeast extract is 0.15%, the mass percentage of sodium chloride is 0.25%, the mass percentage of agar is 0.4%, and the rest is sterile distilled water. Incubate at 32 ± 2 °C for 80 h. After incubation, pick a single colony and immerse it in sterile water, centrifuge, and then inoculate it into agar medium for continuous subculture for 4 generations for activation. Plaques appear. In the agar medium, the mass percentage of beef extract is 0.3%, the mass percentage of peptone is 1%, the mass percentage of sodium chloride is 0.5%, the mass percentage of agar is 2%, and the rest is sterile distilled water. Pick the plaque into sterile water, centrifuge and separate, take the supernatant and remove Escherichia coli with a bacterial filter to obtain the Bdellovibrio bacteriovorus agent;

[0048] (2) Prepare an aqueous solution of sodium carbonate. In the aqueous solution of sodium carbonate, the concentration of sodium carbonate is 2 g / 100 mL and the solvent is water. Prepare an aqueous solution of fulvic acid. In the aqueous solution of fulvic acid, the concentration of fulvic acid is 1 g / 100 mL and the solvent is water. Add bentonite to the aqueous solution of sodium carbonate under stirring. The mass ratio of bentonite to the aqueous solution of sodium carbonate added to the aqueous solution of sodium carbonate is bentonite: aqueous solution of sodium carbonate = 1:50. After adding the materials, heat in a water bath to 60 °C and keep stirring for 30 min. After stirring, perform solid-liquid separation. Wash the solid phase with deionized water 3 times and dry at 60 °C for 3 h to obtain the pretreated powder. Add the pretreated powder to the aqueous solution of fulvic acid. The mass ratio of the pretreated powder to the aqueous solution of fulvic acid added to the aqueous solution of fulvic acid is pretreated powder: aqueous solution of fulvic acid = 1:100. After adding the materials, stir for 30 min, and then add cetyltrimethylammonium bromide to the solution under stirring. The mass ratio of the added cetyltrimethylammonium bromide to the mass of the added pretreated powder is cetyltrimethylammonium bromide: pretreated powder = 3:1. After adding the materials, continue stirring for 5 h, and then perform solid-liquid separation. Wash the solid phase with deionized water 3 times and dry at 60 °C for 3 h to obtain the bentonite-based adsorption particles of this comparative example;

[0049] (3) Add the Bdellovibrio bacteriovorus agent to the test sewage (copper ion concentration is 150 mg / L, pH is 5), heat to 35 ± 3 °C and keep stirring for 20 min, and then add the bentonite-based adsorption particles under stirring. After adding the materials, continue stirring at a constant temperature of 35 ± 3 °C for 1 h to complete the treatment of heavy metal sewage. The mass ratio of the added Bdellovibrio bacteriovorus agent, bentonite-based adsorption particles to the volume of the sewage is Bdellovibrio bacteriovorus agent: bentonite-based adsorption particles: sewage = 2.2 g: 0.2 g: 500 mL.

[0050] Blank control group

[0051] A method for treating heavy metal sewage, which uses bentonite-based adsorption particles to treat heavy metal sewage. The treatment steps include:

[0052] (1) Prepare an aqueous solution of sodium carbonate. In the aqueous solution of sodium carbonate, the concentration of sodium carbonate is 2 g / 100 mL, and the solvent is water; prepare an aqueous solution of humic acid. In the aqueous solution of humic acid, the concentration of humic acid is 1 g / 100 mL, and the solvent is water; add bentonite to the aqueous solution of sodium carbonate under stirring. The mass ratio of bentonite to the aqueous solution of sodium carbonate is bentonite: aqueous solution of sodium carbonate = 1:50; after the addition is completed, heat in a water bath to 60 °C, keep stirring for 30 min, after stirring is completed, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry at 60 °C for 3 h to obtain a pretreated powder; add the pretreated powder to the aqueous solution of humic acid. The mass ratio of the pretreated powder to the aqueous solution of humic acid is pretreated powder: aqueous solution of humic acid = 1:100; after the addition is completed, stir for 30 min, and then add cetyltrimethylammonium bromide to the solution under stirring. The mass ratio of the added cetyltrimethylammonium bromide to the added pretreated powder is cetyltrimethylammonium bromide: pretreated powder = 3:1; after the addition is completed, continue stirring for 5 h, then perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry at 60 °C for 3 h to obtain humic acid-modified particles;

[0053] (2) Add the humic acid-modified particles to deionized water. The mass ratio of the humic acid-modified particles to deionized water is humic acid-modified particles: deionized water = 1:1000; stir in an ultrasonic environment for 20 min to obtain a suspension; stir the suspension, and then add diglycolic acid to the suspension under stirring. The mass ratio of the added diglycolic acid to the added mass of the humic acid-modified particles is diglycolic acid: humic acid-modified particles = 1:1; after the addition is completed, adjust the pH of the suspension to 10 with a sodium hydroxide solution, and then stir for 8 h; the concentration of the solute in the sodium hydroxide solution is 1.5 mol / L, and the solvent is water; after stirring is completed, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry at 60 °C for 3 h to obtain bentonite-based adsorption particles;

[0054] (3) Add the bentonite-based adsorption particles to the test sewage (copper ion concentration is 150 mg / L, pH is 5), heat to 35 ± 3 °C, keep stirring for 1 hour and 20 min to complete the treatment of heavy metal sewage; the mass ratio of the added bentonite-based adsorption particles to the volume of the sewage is bentonite-based adsorption particles: sewage = 0.2 g: 500 mL.

[0055] Example 5

[0056] After testing the copper ion removal rates after the sewage treatment of the above-mentioned examples and comparative examples, the results are shown in Table 1. The removal rate = (copper ion concentration before treatment - copper ion concentration after treatment) / copper ion concentration before treatment × 100%.

[0057] As can be seen from Table 1, the method of the present invention can effectively remove heavy metal ions in sewage and reduce the heavy metal pollution degree of sewage; moreover, the treatment time is significantly shortened, improving the sewage treatment efficiency. By comparing Example 2 with each comparative example, it can be seen that by introducing a microbial agent into the traditional adsorbent treatment process, the removal rate of heavy metals can be significantly improved. This is mainly because a large number of bacteria and other microorganisms are inevitably contained in the sewage, and the traditional adsorbent cannot effectively prevent the adhesion of bacteria on the surface of the adsorbent. Therefore, a large number of adsorption sites on the surface of the traditional adsorbent are often covered by bacteria or other microorganisms, resulting in poor adsorption effect of heavy metals. The present invention introduces a Bdellovibrio agent with bactericidal function, which significantly reduces the adsorption of bacteria and other microorganisms on the surface of the adsorbent, thereby improving the adsorption and removal effect of the adsorbent on heavy metal ions. In addition, the present invention improves and optimizes the preparation method of the traditional bentonite-based adsorbent, introduces fulvic acid groups on the surface of bentonite, and simultaneously grafts and modifies with glyphosate, improving the adsorption and chelation of the adsorbent on heavy metal ions, which macroscopically shows the improvement of the removal rate of heavy metal ions in sewage.

[0058] Table 1

[0059] Experimental group Removal rate of copper ions Example 1 94.6％ Example 2 95.5％ Example 3 96.1％ Example 4 96.3％ Comparative example 1 87.0％ Comparative example 2 81.9％ Blank control group 72.4％

[0060] The above has introduced the technical solution provided by the present invention in detail. For those of ordinary skill in the art, according to the idea of the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for treating heavy metal wastewater by microbial combination, characterized in that: The heavy metal wastewater is treated by using a microbial treatment agent, wherein the microbial treatment agent comprises a microbial preparation and an adsorbent, wherein the microbial preparation is a Bdellovibrio agent; the adsorbent is bentonite-based adsorption particles; the treatment steps include: (1) Inoculating a Bdellovibrio suspension and an Escherichia coli suspension onto an LB medium, culturing at 32±2°C for 50-100 hours, picking a single plaque after culturing and immersing it in sterile water, centrifuging it, and then inoculating it into an agar medium for continuous passage for 3-5 generations for activation, until plaques appear, picking the plaques into sterile water, centrifuging them, taking the supernatant and removing the Escherichia coli with a bacterial filter, and obtaining a Bdellovibrio agent; (2) preparing an aqueous solution of sodium carbonate and an aqueous solution of fulvic acid; adding bentonite to the aqueous solution of sodium carbonate under stirring, heating in a water bath to 60±5° C. after the addition is completed, and stirring at this temperature for more than 30 minutes, separating the solid and liquid after the stirring is completed, washing the solid phase with deionized water for more than 3 times, and drying to obtain a pretreated powder; adding the pretreated powder to the aqueous solution of fulvic acid, stirring for more than 30 minutes after the addition is completed, and then adding hexadecyltrimethylammonium bromide to the solution under stirring, continuing to stir for more than 5 hours after the addition is completed, and then separating the solid and liquid, washing the solid phase with deionized water for more than 3 times, and drying to obtain fulvic acid modified particles; (3) adding the fulvic acid modified particles to deionized water, stirring for more than 20 minutes under an ultrasonic environment to obtain a suspension; stirring the suspension, and then adding dimethylaminophosphine to the suspension under stirring, and after the addition is completed, adjusting the pH of the suspension to 10-11 with a sodium hydroxide solution, and then stirring for more than 8 hours; after the stirring is completed, the solid-liquid separation is carried out, the solid phase is washed with deionized water for more than 3 times, and dried to obtain bentonite-based adsorption particles; (4) Add the Bdellovibrio agent to the sewage, heat it to 35±3°C and stir it for more than 20 minutes, then add the bentonite-based adsorption particles under stirring, and continue stirring at 35±3°C for 1 to 2 hours after the addition is completed to complete the heavy metal sewage treatment.

2. The method for treating heavy metal wastewater by microbial combination according to claim 1, characterized in that: In the step (1), in the LB medium, the mass percentage of peptone is 0.5%, the mass percentage of yeast extract is 0.15%, the mass percentage of sodium chloride is 0.25%, the mass percentage of agar is 0.4%, and the rest is sterile distilled water.

3. The method for treating heavy metal wastewater by microbial combination according to claim 1, characterized in that: In the step (2), the concentration of sodium carbonate in the aqueous solution is 2-3 g / 100 mL, and the solvent is water; the concentration of fulvic acid in the aqueous solution is 0.8-1.4 g / 100 mL, and the solvent is water; the mass ratio of bentonite added to the aqueous solution of sodium carbonate is bentonite: aqueous solution of sodium carbonate = 1:50-100; the mass ratio of pretreated powder added to the aqueous solution of fulvic acid is pretreated powder: aqueous solution of fulvic acid = 1:100; the mass ratio of the added mass of hexadecyltrimethylammonium bromide to the added mass of the pretreated powder is hexadecyltrimethylammonium bromide: pretreated powder = 3-4:

1.

4. The method for treating heavy metal wastewater by microbial combination according to claim 1, characterized in that: In the step (3), the mass ratio of the fulvic acid modified particles added to the deionized water is fulvic acid modified particles: deionized water = 1:1000; the mass ratio of the added glyphosate to the fulvic acid modified particles is glyphosate: fulvic acid modified particles = 1-2:

1.

5. The method for treating heavy metal wastewater by microbial combination according to claim 1, characterized in that: In the step (3), the concentration of the solute in the sodium hydroxide solution is 1.5-2 mol / L, and the solvent is water.

6. The method for treating heavy metal wastewater by microbial combination according to claim 1, characterized in that: In the step (4), the volume ratio of the added mass of the Bdellovibrio agent and bentonite-based adsorption particles to the sewage is Bdellovibrio agent: bentonite-based adsorption particles: sewage = 2-2.5 g: 0.2-0.3 g: 500 mL.