CN114289497A - Chemical-microorganism step-by-step repair process for treating Cr (VI) in chromium slag storage yard - Google Patents
Chemical-microorganism step-by-step repair process for treating Cr (VI) in chromium slag storage yard Download PDFInfo
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Abstract
The invention provides a chemical-microbial step-by-step repair process for treating Cr (VI) in a chromium slag stockyard. In the embodiment of the invention, the concentration of Cr (VI) in the chromium slag is reduced by using a chemical agent (FeS solution), so that the concentration of Cr (VI) in the chromium slag is reduced to a value that functional microorganisms can survive or adapt to the chromium slag, and the chromium slag is treated as a first step; then, adding nutrient solution inoculated with functional microorganisms into the chromium slag stockyard repair system, and solidifying Cr (VI) in the chromium slag along with the growth and metabolism of the functional microorganisms to be treated as a second step. According to the embodiment of the invention, the concentration of Cr (VI) in the slag sample is rapidly reduced through wet detoxification in the first step, and then Cr (VI) with relatively low concentration is solidified through a microbial remediation process in the second step, so that the aim of sustainable remediation is fulfilled, and the method can be applied to remediation of chromium-polluted sites with high Cr (VI) concentration.
Description
Technical Field
The invention relates to the technical field of heavy metal restoration. In particular to a chemical-microorganism step-by-step repair process for treating Cr (VI) in a chromium slag stockyard.
Background
The historical chromium slag stockyard left in China has the problems of large quantity, high Cr (VI) concentration and wide pollution area, and the traditional method cannot thoroughly treat chromium pollution.
The traditional chromium pollution treatment methods mainly comprise two methods: one processing method is as follows: replacing or covering non-polluted soil by engineering measures so as to dilute the concentration of Cr (VI); the other treatment method comprises the following steps: cr (vi) is reduced by adding chemicals. But the first treatment method has the defects of shortage of foreign soil resources, high treatment cost, incomplete pollutant treatment and the like; in the second treatment method, the chromium pollutants after chemical treatment are easy to re-dissolve, so that secondary pollution is caused. In addition, the traditional chromium pollution treatment method needs the intervention of large-scale equipment and the repeated addition of various medicaments, so that the ecological damage is serious.
In recent years, the development of the microbial remediation technology provides a new idea for the solidification of Cr (VI) in chromium slag, the technology utilizes the adsorption, reduction and mineralization of functional microorganisms to solidify Cr (VI) in chromium slag, which is considered as one of the most ideal remediation technologies, but because the microorganisms are organic life bodies and the growth and metabolism of the microorganisms are limited by the excessively high Cr (VI) concentration in the chromium slag, the microbial technology is suitable for chromium slag with relatively low Cr (VI) concentration. Because the concentration of Cr (VI) in the existing chromium slag stockyard in China is relatively high, the chromium slag stockyard needs longer adaptation time and has limited microbial activity even can not survive after being treated by only microorganisms.
Therefore, a technical scheme for rapidly reducing Cr (VI) in a chromium slag storage site with high Cr (VI) concentration is needed.
Disclosure of Invention
The invention aims to provide a chemical-microorganism step-by-step repair process for treating Cr (VI) in a chromium slag storage yard, which is used for rapidly reducing Cr (VI) in the chromium slag storage yard with high Cr (VI) concentration and combining the action of functional microorganisms to carry out sustainable bioremediation so as to solve the problems of incomplete treatment and Cr (VI) redissolution in the traditional process.
In order to achieve the purpose, the invention designs the following scheme:
the process utilizes chemical agents to rapidly reduce Cr (VI) in the chromium slag, thereby reducing the Cr (VI) concentration in the chromium slag to the concentration which can be adapted by functional microorganisms, and finally realizes the purpose that the chromium slag stockpiling field with high Cr (VI) concentration can be continuously repaired by combining with a microorganism repairing process.
In a first aspect, the present invention provides three microorganisms having cr (vi) solidifying ability, comprising: the preservation number is: CCTCC NO: m2018672 Bacillus megaterium GRINML5, with the collection number: CCTCC NO: pseudomonas of M2018674 (Pseudomonas sp. grinml7), and accession no: CCTCC NO: oligotrophomonas of M2018676 (Stenotrophomonas sp.
In a second aspect, the invention provides a chemical-microbial step-by-step repair process for treating cr (vi) in a chromium slag stockyard, the process comprising:
step 1: rapidly preparing a FeS solution with the concentration of 1-3%, adding the FeS solution into chromium slag with high Cr (VI) concentration, and performing wet detoxification on the chromium slag to reduce the Cr (VI) concentration of the chromium slag to below 1000 mg/L;
step 2: acclimatizing and culturing in an expanded manner one or more of the microorganisms having cr (vi) solidifying ability according to claim 1 to obtain functional microorganisms;
and step 3: preparing a nutrient solution required by the functional microorganisms, and inoculating the functional microorganisms into the nutrient solution in the form of bacterial sludge;
and 4, step 4: and (3) adding nutrient solution inoculated with functional microorganisms into the detoxified chromium slag in the step (1) to obtain a chromium slag stockpiling field repairing system.
Optionally, the process further comprises:
and 5: monitoring the concentration of Cr (VI) in the percolate of the chromium slag stockyard repair system and the concentration change of the functional microorganisms, and adjusting the concentration of the functional microorganisms.
Optionally, the process further comprises:
collecting a sample from the chromium slag of a chromium slag storage yard, carrying out air drying on the sample to obtain an air-dried sample, measuring the Cr (VI) concentration of the air-dried sample, and taking the Cr (VI) concentration as the Cr (VI) concentration of the chromium slag storage yard, wherein the air-drying temperature is lower than 65 ℃.
Optionally, the step 1 further includes:
calculating a theoretical value of FeS solution required for reducing the Cr (VI) concentration in the chromium slag to 1000mg/L according to the Cr (VI) concentration of the chromium slag;
adding the FeS solution into chromium slag with high Cr (VI) concentration, comprising:
adding FeS solution which is larger than the theoretical value into the chromium slag.
Optionally, the step 2 includes:
gradually adding potassium dichromate in LB culture medium to provide Cr (VI) concentration, and acclimating one or more of the microorganisms having Cr (VI) solidifying ability until the Cr (VI) concentration is increased to 1000 mg/L; obtaining domesticated microorganisms;
performing amplification culture on the acclimatized microorganism in LB culture medium with Cr (VI) concentration of 1000mg/L to obtain OD concentration600Up to 0.4 functional microorganisms.
Optionally, in the acclimation process and the amplification culture process, the temperature of the LB medium is 25-35 ℃, and the pH value is 7-9.
Optionally, the amount of the microorganism inoculated into the nutrient solution during acclimation and during the expansion culture is 10% to 18% per time of the transfer.
Optionally, in the step 3, the inoculation amount of the functional microorganisms inoculated into the nutrient solution is 10-18%.
Optionally, the step 5 includes: monitoring the concentration of Cr (VI) and the concentration change of microorganisms in leachate of the chromium slag stockyard repair system in real time, and adjusting the concentration of the functional microorganisms to ensure that the concentration OD of the functional microorganisms6000.4 to 1.5.
In the embodiment of the invention, a wet detoxification method is firstly utilized to carry out chemical repair on a chromium slag storage yard with high Cr (VI) concentration to obtain a chromium slag storage yard repair system with lower Cr (VI) concentration, and functional microorganisms are inoculated into the chromium slag storage yard repair system to carry out microbial repair.
In the embodiment of the invention, aiming at the chromium slag storage yard with high Cr (VI) concentration, the Cr (VI) concentration of the chromium slag storage yard is reduced through chemical-microorganism step-by-step repair, so that microorganisms can quickly adapt to the environmental Cr (VI) concentration in the subsequent microorganism repair process, the survival rate of the microorganisms is improved, and the microorganism repair is continuously carried out after the chemical repair, so that the cost of chemical agents can be saved, the sustainable repair can be realized, the problem of're-dissolution' of Cr (VI) in the chromium slag is avoided, and the overall repair effect is optimized.
Drawings
FIG. 1 is a schematic flow chart of a chemical-microbial stepwise repair process for treating Cr (VI) in a chromium slag storage yard according to an embodiment of the present invention;
FIG. 2 is an analysis chart of the experimental results of the solidification ability verification experiment of functional microorganism Cr (VI) in example 1 of the present invention;
FIG. 3 is a design chart of a chemical-microbial stepwise remediation process bench test in example 2 of the present invention;
FIG. 4 is a diagram showing the analysis of the Cr (VI) removal rate in the chemical-microbial step-by-step repair process in example 2.
Detailed Description
In an embodiment of the present invention, three microorganisms having cr (vi) solidifying ability are provided, including: the preservation number is: CCTCC NO: m2018672 Bacillus megaterium GRINML5, with the collection number: CCTCC NO: pseudomonas of M2018674 (Pseudomonas sp. grinml7), and accession no: CCTCC NO: oligotrophomonas of M2018676 (Stenotrophomonas sp.
In the embodiment of the invention, the provided microorganism is separated from a chromium slag storage yard in Qinghai province, the Cr (VI) concentration in the chromium slag storage yard is higher, after long-term natural domestication, functional strains capable of solidifying Cr (VI) are bred, after identification, the strains are named as Bacillus megaterium sp.GRINML5, Pseudomonas sp.GRINML7 and oligotrophomonas sp.GRINML9, the three microorganisms are all preserved, the preservation unit is China national type culture collection, and the addresses are as follows: wuhan university, the preservation date is: 2018, 10 and 15.
In an embodiment of the present invention, there is also provided a chemical-microbial step-by-step repair process for treating cr (vi) in a chromium slag storage yard by using one or more of the above three microbes, as shown in fig. 1, the process includes:
step 1: quickly preparing a FeS solution with the concentration of 1-3%, adding the FeS solution into the chromium slag with high Cr (VI) concentration, and carrying out wet detoxification on the chromium slag to reduce the Cr (VI) concentration of the chromium slag to below 1000 mg/L.
In the embodiment of the present invention, in order to prevent the ferrous ions from being oxidized into ferric ions in the air, it is necessary to prepare the FeS solution quickly.
After the preparation of the FeS solution is completed, the FeS solution can be added into the chromium slag to perform wet detoxification on the chromium slag and reduce the concentration of Cr (VI) in the chromium slag, so that microorganisms can quickly adapt to the concentration of Cr (VI) in the chromium slag in the subsequent microorganism curing process, and the survival rate of the microorganisms and the repair efficiency of the microorganisms are improved.
In the embodiment of the invention, the concentration of Cr (VI) in the chromium slag after wet detoxification can be determined by technical personnel according to actual conditions, and specifically can be determined according to the adaptability of microorganisms and Cr (VI) in a chromium slag storage yard. For example: the concentration of Cr (VI) which can be adapted by the domesticated microorganism is 1000mg/L, and the concentration of Cr (VI) in the chromium residue after wet detoxification can be below 1000 mg/L.
In the embodiment of the invention, in the wet detoxification process, the required amount of the FeS solution can be determined by the concentration of Cr (VI) in the chromium slag before and after wet detoxification.
In the embodiment of the present invention, before performing wet detoxification, the method may further include the following steps:
s1: collecting a sample from the chromium slag of a chromium slag storage yard, carrying out air drying on the sample to obtain an air-dried sample, and measuring the Cr (VI) concentration of the air-dried sample as the Cr (VI) concentration of the chromium slag storage yard.
Wherein, in order to avoid influencing the concentration of Cr (VI) in the original slag sample in the air drying process, the air drying temperature is set to be lower than 65 ℃.
S2: and calculating the theoretical value of the FeS solution required for reducing the Cr (VI) concentration in the chromium slag to 1000mg/L according to the Cr (VI) concentration of the chromium slag.
In the embodiment of the invention, after the Cr (VI) concentration in the chromium slag is determined, the theoretical value of the FeS solution required for reducing the Cr (VI) concentration of the chromium slag to 1000mg/L can be calculated according to the redox reaction.
In the embodiment of the invention, considering that ferrous ions in the FeS solution are easily oxidized, the FeS solution with a value larger than the theoretical value needs to be added into the chromium slag in the practical application process.
Therefore, in the embodiment of the invention, the FeS solution larger than the theoretical value can be added into the chromium slag according to the calculated theoretical value.
Step 2: acclimatizing one or more of the microorganisms having Cr (VI) solidifying ability, and culturing in an expanded manner to obtain functional microorganisms.
In the embodiment of the present invention, one or more of the three microorganisms may be selected to perform microbial remediation of cr (vi) in the chromium slag storage yard.
In the embodiment of the invention, when a plurality of microorganisms are simultaneously selected for microbial remediation, the plurality of microorganisms can be mixed and then domesticated and expanded to obtain the mixed functional microorganisms. Or domesticating and expanding culturing of multiple microorganisms, and mixing to obtain functional microorganism.
In the embodiment of the invention, the functional microorganisms can be domesticated by utilizing the microorganism culture medium containing Cr (VI), so that the domesticated functional microorganisms can quickly adapt to the Cr (VI) concentration in the chromium slag, and the repair efficiency is improved.
In the embodiment of the present invention, the culture medium of the microorganism may be a commonly used culture medium of the microorganism, such as: LB medium.
Specifically, in the embodiment of the present invention, step 2 may include:
gradually adding potassium dichromate in LB culture medium to provide Cr (VI) concentration, and acclimating one or more of the microorganisms having Cr (VI) solidifying ability until the Cr (VI) concentration is increased to 1000 mg/L; obtaining the domesticated microorganism.
Performing amplification culture on the acclimatized microorganism in LB culture medium with Cr (VI) concentration of 1000mg/L to obtain OD concentration600Up to 0.4 functional microorganisms.
In the embodiment of the invention, domestication and culture of the microorganism with Cr (VI) solidifying capability is realized by adding potassium dichromate into an LB culture medium step by step.
Specifically, the acclimatization process may include: setting the Cr (VI) concentration of the LB culture medium with the first gradient to be 100mg/L, gradually increasing the Cr (VI) concentration in the domestication process, setting the Cr (VI) concentration of the LB culture medium with the nth gradient to be 1000mg/L, gradually culturing and transferring the microorganisms in a plurality of LB culture media with the Cr (VI) concentrations gradually increasing, and finally domesticating to obtain the functional microorganisms capable of adapting to the Cr (VI) concentration of 1000 mg/L.
The gradient of the Cr (VI) concentration gradually increased can be determined according to the actual situation, and for example, the gradient can be 100mg/L or 50 mg/L.
Wherein, in the acclimatization process of each gradient, the concentration OD of the microorganism is obtained600And after reaching 0.2, transferring to the next gradient for further domestication culture, wherein the inoculation amount of each transfer is consistent and is 10-18% of the nutrient solution of the next gradient.
Specifically, the process of scale-up culture may include: performing multiple times of amplification culture on the domesticated microorganism in LB culture medium with Cr (VI) concentration of 1000mg/L for more than 6 times until OD concentration is obtained600Up to 0.4 functional microorganisms.
Wherein, in the process of the enlarged culture, the inoculation amount of each transfer is consistent and is 10 to 18 percent of the nutrient solution in the next culture stage.
In the embodiment of the invention, in the domestication process and the amplification culture process, the temperature of the LB culture medium is 25-35 ℃, and the pH value is 7-9.
And step 3: preparing a nutrient solution required by the functional microorganisms, and inoculating the functional microorganisms into the nutrient solution in the form of bacterial sludge. Wherein the inoculation amount of the functional microorganism inoculated into the nutrient solution is 10-18%.
In the embodiment of the invention, during the acclimation process and the amplification culture process of the microorganisms and the application process of the functional microorganisms, the inoculation is carried out in the form of bacterial sludge every time the inoculation is carried out.
Inoculating in the form of bacterial sludge, specifically comprising the steps of carrying out centrifugal treatment on the seed culture liquid, removing supernatant liquid after the centrifugation is finished to obtain bacterial sludge, and inoculating the bacterial sludge into a culture medium in the next culture stage.
And 4, step 4: and (3) adding nutrient solution inoculated with functional microorganisms into the detoxified chromium slag in the step (1) to obtain a chromium slag stockpiling field repairing system.
In the embodiment of the invention, after wet detoxification is completed in the step 1, the chromium slag storage yard repair system with the Cr (VI) concentration of below 1000mg/L is obtained. Then, the domesticated and expanded functional microorganism and the nutrient solution can be inoculated into the chromium residue storage yard repairing system for biological repairing.
In the embodiment of the invention, a wet detoxification method is firstly utilized to carry out chemical repair on a chromium slag storage yard with high Cr (VI) concentration to obtain a chromium slag storage yard repair system with lower Cr (VI) concentration, and functional microorganisms are inoculated into the chromium slag storage yard repair system to carry out microbial repair.
In the embodiment of the invention, aiming at the chromium slag storage yard with high Cr (VI) concentration, the Cr (VI) concentration of the chromium slag storage yard is reduced through chemical-microorganism step-by-step repair, so that microorganisms can quickly adapt to the environmental Cr (VI) concentration in the subsequent microorganism repair process, the survival rate of the microorganisms is improved, and the microorganism repair is continuously carried out after the chemical repair, so that the cost of chemical agents can be saved, the sustainable repair can be realized, the problem of're-dissolution' of Cr (VI) in the chromium slag is avoided, and the overall repair effect is optimized.
In an alternative embodiment, the repair process further comprises:
and 5: monitoring the concentration of Cr (VI) in the percolate of the chromium slag stockyard repair system and the concentration change of the functional microorganisms, and adjusting the concentration of the functional microorganisms.
Specifically, the monitoring process in step 5 includes:
monitoring the concentration of Cr (VI) and the concentration change of microorganisms in leachate of the chromium slag stockyard repair system in real time, and adjusting the concentration of the functional microorganisms to ensure that the concentration OD of the functional microorganisms6000.4 to 1.5.
In the embodiment of the invention, the chromium slag stockyard repair system can be continuously monitored, and the microbial concentration is adjusted to always keep OD6000.4 to 1.5. The aim of continuously repairing the chromium slag stockyard is fulfilled.
The invention is further illustrated by the following specific examples:
example 1, cr (vi) solidification ability verification experiment of functional microorganism:
rejuvenating the three microorganism vacuum-frozen powder, inoculating in LB culture medium, performing enrichment culture at 30 deg.C and 120rpm in shaking table, and performing enrichment culture when the concentration OD of functional microorganism is600When 0.4 was reached, inoculation was performed. The functional microorganisms were inoculated into 10 culture systems with Cr (VI) initial concentration of 100mg/L to 1000mg/L and gradient of 100mg/L in equal amounts, respectively, as repair groups, and 10 control groups (not inoculated with functional microorganisms) were set, respectively.
After 28 days of culture, the concentrations of Cr (VI) in each culture system and in the control group were measured, and the concentration of functional microorganisms in each culture system was measured.
Analysis of all data gave figure 2.
OD of microorganism in each culture system from FIG. 2600The change in value indicates that the acclimated microorganism can survive in an environment with an initial concentration of Cr (VI) of 100mg/L to 1000mg/L, but the Cr (VI) removal capacity of the acclimated microorganism decreases with the increase of the initial concentration.
Wherein, in a culture system with the concentration of Cr (VI) of 100 mg/L-400 mg/L, the removal rates of the functional microorganisms to Cr (VI) respectively reach 90.05 percent, 88.30 percent, 78.45 percent and 72.45 percent, and the OD thereof is600The values were reduced to 1.28,0.98,0.86 and 0.80, respectively. When the initial concentration of Cr (VI) in the culture system continues to increase, the removal rate and OD of Cr (VI)600The value decreases accordingly. In the culture system with the initial Cr (VI) concentration of 600mg/L, the removal rate of Cr (VI) is only 55.00 percent; in the culture medium system with initial Cr (VI) concentrations of 700mg/L,800mg/L,900mg/L and 1000mg/L, the removal rates of Cr (VI) are respectively reduced to 45.01%, 42.10%, 24.45% and 22.61%; and OD in the culture system600The values were also reduced to 0.30,0.23,0.21 and 0.11.
Wherein, compared with the repairing group inoculated with the microorganism, the removal rate of Cr (VI) in the control group (without inoculated microorganism) is about 5 percent within 28 days. These results indicate that the domesticated functional microorganism has a certain removal effect on Cr (VI) and has a higher tolerance capacity (1000mg/L can still survive) on Cr (VI).
Example 2. chemical-microbiological step-by-step repair procedure bench for the treatment of cr (vi) in a chromium slag stockyard:
test field: qinghai certain chromium slag stockpiling field
The forming process of the chromium slag storage field comprises the following steps: production of chromium salt (mainly comprising Na) in the nineties of the last century2Cr2O7And K2Cr2O7) A large amount of chromium-containing waste is generated in the process, and the waste is disorderly stockpiled and discharged to form a huge chromium slag stockpiling site. Under the action of oxygen and oxidizing microorganisms in an open environment, Cr (VI) in the chromium slag is continuously dissolved out and diffused to the surrounding environment. The detection of samples collected in 2008 shows that Cr (VI) of the chromium slag stockpiling site reaches more than 6000mg/L, and the surface of the site presents a large amountThe chromium salt is precipitated. In 2010, the chromium slag stockyard is subjected to harmless treatment, and standard treatment is realized in a short period by adding a large amount of chemical agents. However, the re-sampling detection after several years shows that the Cr (VI) in the chromium slag stockpiling field is re-dissolved, and the concentration of the Cr (VI) is as high as 1200 mg/L.
Therefore, the site has the problems that the Cr (VI) concentration is relatively high, the treatment method of chemical agents is incomplete, the re-dissolution is easy to occur, the chromium slag stockyard cannot be continuously and effectively repaired, and the like.
Sample collection and pretreatment:
sampling is carried out on certain chromium slag stockpiling site in Qinghai, a site with relatively high pollutant concentration is collected, the collected samples are fully mixed and naturally dried, the drying temperature is lower than 65 ℃, and the treated samples are uniformly loaded into an experimental column, as shown in figure 2.
Microorganism domestication and enlarged culture:
gradually adding potassium dichromate in an LB culture medium to provide Cr (VI) concentration, mixing and rejuvenating freeze-dried bacterial powder of three microorganisms with Cr (VI) solidifying capacity, and performing domestication, wherein the Cr (VI) concentration of the LB culture medium with a first gradient is set to be 100mg/L, and the Cr (VI) concentration is gradually increased by taking 100mg/L as a gradient in the domestication process until the Cr (VI) concentration is increased to 1000 mg/L; obtaining the domesticated microorganism. During acclimation of each gradient, when the microorganism concentration OD600And after reaching 0.2, switching to the next gradient to continue domestication culture, wherein the inoculation amount of each switching is consistent and is 15 percent of the nutrient solution of the next gradient.
Performing multiple amplification culture on the acclimatized microorganism in LB culture medium with Cr (VI) concentration of 1000mg/L for 6 times until OD concentration is obtained600Up to 0.4 functional microorganisms.
Design of column experiment for chemical-microbial stepwise repair:
1) different experimental treatment groups were designed to include a control group (C) without reducing agent and microorganism, a chemical remediation group (R1) with only chemical agent added, a microorganism remediation group (R2) inoculated with only complex-function microorganism, and a chemical-microorganism combined remediation group (R1+ R2) with 3% chemical agent added and then inoculated with complex-function microorganism, respectively, and the experimental design is shown in fig. 3.
2) For an experimental group, a FeS solution is rapidly prepared and added into a treatment system, the addition amount of the FeS solution needs to be higher than a theoretical value required by the Cr (VI) concentration in the chromium slag reduced by the FeS solution to 1000mg/L, the Cr (VI) concentration of the leaching solution is monitored in real time after a chemical agent is added, and the FeS solution is stopped being added until the Cr (VI) concentration of the leaching solution is lower than 1000 mg/L.
3) Adding equal volume of solution into each test column every week, wherein the solution added in the control group is deionized water solution; the chemical repairing group is 3% FeS solution; the microorganism repairing group is a compound functional microorganism liquid; the experimental group is that 3% FeS solution is added in the early stage until the concentration of Cr (VI) in the percolate is 1000mg/L, and then the compound microorganism bacterium solution is inoculated.
4) Sampling is carried out every week between the liquid addition to each experimental column, and the concentration and OD of Cr (VI) in the percolate are detected600And is used for analyzing the removal rate and the microorganism concentration of Cr (VI) in each experimental column.
Fig. 4 shows the change of cr (vi) removal rate in each experimental column during the column experiment of the chemical-microbial stepwise remediation, and it can be seen from fig. 4 that the cr (vi) concentration can be rapidly reduced and the cr (vi) removal rate is continuously increased by adding the FeS solution to the chemical remediation group and the experimental group for wet detoxification, compared with the microbial remediation group inoculated with only microorganisms. However, in the chemical repair group, after 30 days, the removal rate of Cr (VI) begins to decrease, and the phenomenon of "re-dissolution" of Cr (VI) occurs in the chemical repair group.
Compared with the experimental group, the microorganism repairing group has lower Cr (VI) removal rate, which shows that the Cr (VI) concentration is reduced by using a chemical repairing method, and then the functional microorganism is inoculated, so that the functional microorganism can adapt to the environment as soon as possible, and the repairing efficiency of the functional microorganism is improved.
The removal rate of Cr (VI) can be continuously improved after the functional microorganisms are inoculated in the experimental group, and can reach more than 80% in 70 days, which shows that the microorganisms can continuously solidify Cr (VI) in the experimental group.
Claims (10)
1. A microorganism having cr (vi) solidifying ability, comprising: the preservation number is: CCTCC NO: m2018672 Bacillus megaterium GRINML5, with the collection number: CCTCC NO: pseudomonas of M2018674 (Pseudomonas sp. grinml7), and accession no: CCTCC NO: oligotrophomonas of M2018676 (Stenotrophomonas sp.
2. A chemical-microbial step-by-step remediation process for treating cr (vi) in a chromium slag stockyard, the process comprising:
step 1: rapidly preparing a FeS solution with the concentration of 1-3%, adding the FeS solution into chromium slag with high Cr (VI) concentration, and performing wet detoxification on the chromium slag to reduce the Cr (VI) concentration of the chromium slag to below 1000 mg/L;
step 2: acclimatizing and culturing in an expanded manner one or more of the microorganisms having cr (vi) solidifying ability according to claim 1 to obtain functional microorganisms;
and step 3: preparing a nutrient solution required by the functional microorganisms, and inoculating the functional microorganisms into the nutrient solution in the form of bacterial sludge;
and 4, step 4: preparing a nutrient solution required by the functional microorganisms, and inoculating the functional microorganisms into the nutrient solution in the form of bacterial sludge.
3. The chemical-microbial step-repair process for the treatment of cr (vi) in a chromium slag stockyard according to claim 2, further comprising:
and 5: monitoring the concentration of Cr (VI) in the percolate of the chromium slag stockyard repair system and the concentration change of the functional microorganisms, and adjusting the concentration of the functional microorganisms.
4. The chemical-microbial step-repair process for the treatment of Cr (VI) in a chromium slag stockyard according to claim 2 or 3, wherein before step 1, the process further comprises:
collecting a sample from the chromium slag of a chromium slag storage yard, carrying out air drying on the sample to obtain an air-dried sample, measuring the Cr (VI) concentration of the air-dried sample, and taking the Cr (VI) concentration as the Cr (VI) concentration of the chromium slag storage yard, wherein the air-drying temperature is lower than 65 ℃.
5. The chemical-microbial step-repair process for the treatment of Cr (VI) in a chromium slag stockyard according to claim 4, wherein the step 1 further comprises:
calculating a theoretical value of FeS solution required for reducing the Cr (VI) concentration in the chromium slag to 1000mg/L according to the Cr (VI) concentration of the chromium slag;
adding the FeS solution into chromium slag with high Cr (VI) concentration, comprising:
adding FeS solution which is larger than the theoretical value into the chromium slag.
6. The chemical-microbial step-by-step remediation process for treating cr (vi) in a chromium slag stockyard according to claim 2 or 3, wherein said step 2 comprises:
gradually adding potassium dichromate in LB culture medium to provide Cr (VI) concentration, and acclimating one or more of the microorganisms with Cr (VI) solidifying ability until the Cr (VI) concentration is increased to 1000mg/L to obtain acclimated microorganisms;
the domesticated microorganism is expanded and cultured in LB culture medium with Cr (VI) concentration of 1000mg/L to obtain the functional microorganism with OD600 of 0.4.
7. The chemical-microbial stepwise remediation process of claim 6, wherein the temperature of the LB medium during said acclimation process and during the expansion culture process is 25-35 ℃ and the pH value is 7-9.
8. The chemical-microbial step-by-step remediation process for treating Cr (VI) in a chromium slag stockyard according to claim 6,
in the acclimation process and the expansion culture process, the inoculation amount of the microorganism inoculated into the nutrient solution is 10-18% each time the transfer is carried out.
9. The chemical-microbial step-by-step repair process for treating Cr (VI) in a chromium slag stockyard according to claim 2 or 3, wherein in the step 3, the inoculation amount of the functional microbes inoculated to the nutrient solution is 10-18%.
10. The chemical-microbial step-by-step remediation process for treating Cr (VI) in a chromium slag stockyard as claimed in claim 2 or 3, wherein said step 5 comprises: monitoring the concentration of Cr (VI) and the concentration change of microorganisms in leachate of the chromium slag stockyard repair system in real time, and adjusting the concentration of the functional microorganisms to ensure that the concentration OD of the functional microorganisms6000.4 to 1.5.
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| DE19514577A1 (en) * | 1995-04-20 | 1996-11-07 | Franz Dietrich Oeste | Immobilisation of harmful substances in substrates |
| CN1962096A (en) * | 2005-11-10 | 2007-05-16 | 中国科学院过程工程研究所 | Chromium slag processing method for chemical-biological coupling reduction of hexavalent chrome |
| CN111375631A (en) * | 2018-12-27 | 2020-07-07 | 有研工程技术研究院有限公司 | Pseudomonas and microorganism in-situ solidification method for restoring chromium-contaminated soil by using same |
| CN112553100A (en) * | 2019-09-26 | 2021-03-26 | 有研工程技术研究院有限公司 | Composite microbial agent and method for soil fertility improvement and ecological restoration of heavy metal-containing field by using same |
| CN113122463A (en) * | 2019-12-31 | 2021-07-16 | 有研资源环境技术研究院(北京)有限公司 | Bacillus megaterium and method for restoring chromium-contaminated soil by using same |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| DE19514577A1 (en) * | 1995-04-20 | 1996-11-07 | Franz Dietrich Oeste | Immobilisation of harmful substances in substrates |
| CN1962096A (en) * | 2005-11-10 | 2007-05-16 | 中国科学院过程工程研究所 | Chromium slag processing method for chemical-biological coupling reduction of hexavalent chrome |
| CN111375631A (en) * | 2018-12-27 | 2020-07-07 | 有研工程技术研究院有限公司 | Pseudomonas and microorganism in-situ solidification method for restoring chromium-contaminated soil by using same |
| CN112553100A (en) * | 2019-09-26 | 2021-03-26 | 有研工程技术研究院有限公司 | Composite microbial agent and method for soil fertility improvement and ecological restoration of heavy metal-containing field by using same |
| CN113122463A (en) * | 2019-12-31 | 2021-07-16 | 有研资源环境技术研究院(北京)有限公司 | Bacillus megaterium and method for restoring chromium-contaminated soil by using same |
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