A bioremediation composition for remediating contaminated groundwater, a remediation agent, and a preparation method and application thereof

Abstract

The present application belongs to the technical field of groundwater pollution remediation, and particularly relates to a biological remediation composition for remediation of contaminated groundwater, a remediation agent, and a preparation method and application thereof. The biological remediation composition for remediation of contaminated groundwater comprises a composite bacterial flora, a slow-release carrier material, a nutrient slow-release agent, a surfactant, and a stabilizer; the composite bacterial flora is composed of the following bacterial strains: Bacillus subtilis, Pseudomonas putida, Desulfovibrio and Serratia marcescens. The biological remediation composition provided by the present application has high remediation efficiency and improves the removal rate of diesel oil, chlorophenol, and sulfadimethoxine.

Description

Technical Field

[0001] This invention belongs to the field of groundwater pollution remediation technology, specifically relating to a bioremediation composition, remediation agent, preparation method and application for remediating polluted groundwater. Background Technology

[0002] Various ex-situ and in-situ methods have been used to treat, remediate, and clean up contaminated soil. Ex-situ methods typically involve the permanent transfer of contaminated soil to a safe landfill, incineration, indirect thermal treatment, ventilation, and venting. Transferring contaminated soil to landfills is no longer an attractive option due to the high costs of excavation, transportation, and cleanup, as well as potential residual liability. Incineration and indirect thermal treatment can be carried out either on-site or off-site, but in either case, they involve excavating, unloading, and treating essentially all of the contaminated soil, as well as a large amount of soil adjacent to the contaminated soil. The soil must then be transported to a treatment facility, or a treatment unit must be installed on-site. Other sophisticated and expensive technologies that have been adopted include the use of multi-step unit operations to excavate and treat the contaminated soil to separate and recover the soil from the contaminant.

[0003] Other existing cleanup methods and technologies include the "extraction and treatment" approach, in which contaminated groundwater is pumped to the surface for chemical purification or purification by passing the groundwater through a bioreactor and then reinjecting it into the groundwater. This approach is typically implemented over a long period, usually one to ten years or longer. Common remediation treatments for groundwater contaminated with chlorinated hydrocarbons include pumping water from wells or aquifers, evaporating the contaminants in a stripping tower, and returning the purified water to the land. A related type of environmental remediation is the "excavation and towing" approach, in which contaminated soil is removed and then treated or landfilled. The biggest problem with using extraction and treatment systems is that they become increasingly inefficient over time, leading to stable residual concentrations. When this occurs, the system is called "flat-lined" and yields little benefit. Furthermore, channeling often occurs, resulting in significant amounts of contaminants remaining, and recontamination frequently occurs after the pumps are shut down.

[0004] Bioremediation, as an environmentally friendly remediation technology, utilizes the metabolic processes of microorganisms to transform pollutants into harmless substances, offering advantages such as low cost, no secondary pollution, and minimal environmental disturbance. However, existing bioremediation technologies still face some challenges in practical applications: low survival rates of microorganisms in complex underground environments, degradation efficiency significantly influenced by environmental factors, and long remediation cycles.

[0005] For example, patent CN111704226A discloses a process for remediating petroleum organic polluted groundwater, including measuring the TPH content in the polluted groundwater as a mg / L and the total amount of polluted groundwater as bm. 3 Rhamnollipid was prepared into a solution and injected into the contaminated groundwater as remediation agent A. Sodium persulfate was prepared into a solution and used as remediation agent B. Citric acid and ferrous sulfate were chelated to form CA-Fe. 2+ An activator is used as remediation agent C, and remediation agents B and C are injected into the contaminated groundwater. Simultaneously, calcium peroxide is prepared as a solution and injected into the contaminated groundwater as remediation agent D. This invention also discloses a petroleum organic pollutant groundwater remediation system and the application of rhamnolipids in the removal of TPH from organic pollutant groundwater. This invention utilizes the biosurfactant rhamnolipids to synergistically enhance the remediation effect with the remediation agents, achieving highly efficient removal of organic pollutants. The provided method has strong oxidizing power, controllable agent dosage, low remediation cost, and minimal environmental impact.

[0006] For example, a study titled "Pilot-scale Study on In-situ Anaerobic Enhanced Bioremediation of Chlorinated Hydrocarbon-Contaminated Groundwater," published in the journal *Environmental Engineering*, investigated in-situ anaerobic enhanced bioremediation of chlorinated hydrocarbon-contaminated groundwater in a bedrock fissure zone at a depth of 40m, using a typical chlorinated hydrocarbon-contaminated site as the research object. The pilot-scale study employed a self-developed anaerobic dehalogenating bacteria agent, BS-1. By injecting appropriate carbon sources and nutrient additives, a suitable underground environment for the growth of anaerobic dehalogenating bacteria was effectively regulated. Pressurized nitrogen injection was used to promote the effective diffusion of the agent in low-permeability bedrock fissures. Groundwater was continuously monitored for 399 days to evaluate the pilot-scale results. The pilot-scale results show that: (1) it solves the problem of limited agent transport in low-permeability bedrock fissure areas; (2) it achieves rapid regulation and long-term maintenance of groundwater environmental indicators, creating ideal growth conditions for anaerobic dehalogenation bacteria for more than a year, and promoting the biodegradation of chlorinated hydrocarbon pollutants; (3) the slow-release carbon source emulsified oil can provide a stable and lasting carbon source and electron donor for anaerobic dehalogenation bacteria in groundwater, effectively reducing the frequency of carbon source injection during bioremediation and saving operating costs; (4) it enables efficient and thorough degradation of various chlorinated hydrocarbon pollutants such as vinyl chloride, cis-1,2-dichloroethylene, trichloroethylene, and chloroform in groundwater, with a removal rate as high as 95%, and reaching the Class IV groundwater standard in some periods. The successful application of this bacterial agent in contaminated sites provides an economical, feasible, and efficient solution for the remediation of chlorinated hydrocarbon-contaminated groundwater in China, and has broad engineering application prospects.

[0007] Therefore, developing a highly efficient, stable, and adaptable bioremediation composition to improve the survival rate and degradation efficiency of microorganisms in the underground environment is of great significance for solving the problem of groundwater pollution. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the present invention provides a bioremediation composition, remediation agent, preparation method and application for remediating polluted groundwater.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides: a bioremediation composition for remediating contaminated groundwater, comprising: a complex microbial community, a slow-release carrier material, a nutrient slow-release agent, a surfactant, and a stabilizer; wherein the complex microbial community is composed of the following strains: Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans, and Cytomegalovirus.

[0011] Furthermore, the sustained-release carrier material is selected from one or more of bentonite, perlite, diatomaceous earth, sodium alginate, chitosan, and gelatin.

[0012] More preferably, the sustained-release carrier material is composed of perlite and chitosan in a mass ratio of 1:0.2-0.5.

[0013] More preferably, the mass ratio of perlite to chitosan in the sustained-release carrier material is 1:0.3.

[0014] Furthermore, the nutrient slow-release agent is selected from one or more of glucose, vitamin B2, sodium lactate, and β-cyclodextrin.

[0015] More preferably, the nutrient slow-release agent is β-cyclodextrin and sodium lactate, with a mass ratio of 1:(0.5-1.5), and more preferably 1:1.

[0016] Furthermore, the mass ratio of the sustained-release carrier material to the nutrient sustained-release agent is (25-40):(5-15).

[0017] Furthermore, the surfactant is selected from at least one of rhamnolipid, sophorolipid, and tea saponin.

[0018] Preferably, the surfactant is rhamnolipid.

[0019] Furthermore, the stabilizer is selected from at least one of sodium carboxymethyl cellulose and xanthan gum.

[0020] Preferably, the stabilizer is sodium carboxymethyl cellulose.

[0021] Furthermore, the mass ratio of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans and Bacillus fibrillosa is (1-2):1:(1-3):1.

[0022] More preferably, the mass ratio of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans, and Cytomegalovirus in the composite microbial community is 1.5:1:2:1.

[0023] Furthermore, the bioremediation composition for remediating contaminated groundwater comprises, by weight, the following components: 10-30 parts of complex microbial flora, 25-40 parts of slow-release carrier material, 5-15 parts of nutrient slow-release agent, 2-3 parts of surfactant, and 2-3 parts of stabilizer.

[0024] Preferably, the bioremediation composition comprises, by weight, the following components: 20 parts of complex microbial flora, 30 parts of sustained-release carrier material, 10 parts of nutrient sustained-release agent, 3 parts of surfactant, and 2 parts of stabilizer.

[0025] Secondly, the present invention also provides a method for preparing the above-mentioned biorepair composition, comprising the following steps: mixing the raw materials according to the specified ratio.

[0026] Thirdly, the present invention also provides: a repair agent comprising the above-described biological repair composition.

[0027] Fourthly, the present invention also provides the application of the above-mentioned bioremediation composition in the remediation of contaminated groundwater.

[0028] The present invention has the following beneficial effects: This invention achieves high removal rates and rapid removal speeds for diesel fuel, sulfadimethylpyrimidine, and chlorophenol, primarily due to the synergistic effect of its components. (1) Bacillus subtilis, Pseudomonas putida, Vibrio desulfurization and Bacillus fibrillosa in the compound microbial community are compounded in a specific ratio to form an aerobic-facultative-anaerobic synergistic degradation system, which can efficiently degrade diesel hydrocarbons, chlorophenols and sulfonamides, which are difficult pollutants to degrade.

[0029] (2) Surfactants can reduce interfacial tension, solubilize hydrophobic pollutants, and significantly improve the bioavailability and degradation rate of pollutants; composite slow-release carriers can provide stable attachment sites for microorganisms and protect the bacterial cells, thereby improving the retention and tolerance of the bacterial community in groundwater; nutrient slow-release agents can provide carbon sources and nutrients in a stable manner for a long time, maintaining the continuous activity of the bacterial community; stabilizers can improve the dispersibility and stability of the system, further improving the overall remediation efficiency, thereby achieving rapid and efficient removal of diesel, chlorophenol and sulfadiazine. Detailed Implementation

[0030] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0031] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0032] The Bacillus subtilis used in this invention has CAS number 68038-70-0.

[0033] The *Pseudomonas putida* used in this invention is ATCC 47054.

[0034] The desulfurization Vibrio used in this invention is ATCC 29577.

[0035] The *Syntheticotropha* strain used in this invention is ATCC 43964.

[0036] The Rhodopseudomonas palustris used in this invention is ATCC 33872.

[0037] The chlorophenol used in this invention is 4-chlorophenol (4-CP), CAS number 106-48-9.

[0038] I. Examples and Comparative Examples Example 1: A bioremediation composition for remediating contaminated groundwater It is composed of the following raw materials: The mixture contains 20 parts of a complex microbial community, 30 parts of a slow-release carrier material, 10 parts of a nutrient slow-release agent, 3 parts of a surfactant, and 2 parts of a stabilizer. The complex microbial community consists of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans, and Pseudomonas fibrinolyticus in a mass ratio of 1.5:1:2:1. The slow-release carrier material consists of perlite and chitosan in a mass ratio of 1:0.3. The nutrient slow-release agent consists of β-cyclodextrin and sodium lactate in a mass ratio of 1:1. The surfactant is rhamnolipid. The stabilizer is sodium carboxymethyl cellulose.

[0039] The single-cell concentrations of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans, and Cytomegalovirus were 1 × 10⁻⁶. 9 CFU·mL -1 .

[0040] Example 2: A bioremediation composition for remediating contaminated groundwater It is composed of the following raw materials: The mixture contains 10 parts of a complex microbial community, 25 parts of a slow-release carrier material, 5 parts of a nutrient slow-release agent, 3 parts of a surfactant, and 2 parts of a stabilizer. The complex microbial community consists of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans, and Cytomegalovirus in a mass ratio of 2:1:3:1. The slow-release carrier material consists of diatomaceous earth and sodium alginate in a mass ratio of 1:0.5. The nutrient slow-release agent consists of β-cyclodextrin and sodium lactate in a mass ratio of 1:0.5. The surfactant is tea saponin. The stabilizer is sodium carboxymethyl cellulose.

[0041] The single-cell concentrations of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans, and Cytomegalovirus were 1 × 10⁻⁶. 9 CFU·mL -1 .

[0042] Example 3: A bioremediation composition for remediating contaminated groundwater It is composed of the following raw materials: The mixture contains 30 parts of a complex microbial community, 40 parts of a slow-release carrier material, 15 parts of a nutrient slow-release agent, 2 parts of a surfactant, and 3 parts of a stabilizer. The complex microbial community consists of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans, and Pseudomonas fibrinolyticus in a mass ratio of 1:1:1:1. The slow-release carrier material consists of bentonite and gelatin in a mass ratio of 1:0.2. The nutrient slow-release agent consists of β-cyclodextrin and glucose in a mass ratio of 1:1.5. The surfactant is rhamnolipid. The stabilizer is xanthan gum.

[0043] The single-cell concentrations of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans, and Cytomegalovirus were 1 × 10⁻⁶. 9 CFU·mL -1 .

[0044] Comparative Example 1 The difference from Example 1 is that an equal amount of *Pseudomonas putida* in the complex microbiota is replaced with an equal amount of *Syntheticotropha*, and the rest is the same as in Example 1.

[0045] Comparative Example 2 The difference from Example 1 is that Rhodopseudomonas pulmonae is replaced with Rhodopseudomonas palustris, otherwise it is the same as Example 1.

[0046] Comparative Example 3 The difference from Example 1 is that the mass ratio of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans and Bacillus fibrillosa is 0.5:2:2:1.5, while the rest is the same as in Example 1.

[0047] Comparative Example 4 The difference from Example 1 is that the ratio of sustained-release carrier material to nutrient sustained-release agent is different.

[0048] The compound microbial community consists of 20 parts, the sustained-release carrier material consists of 20 parts, the nutrient sustained-release agent consists of 20 parts, the surfactant consists of 3 parts and the stabilizer consists of 2 parts, and the rest are the same as in Example 1.

[0049] Comparative Example 5 The difference from Example 1 is that the ratio of surfactant to stabilizer is different.

[0050] The compound microbial community consists of 20 parts, the sustained-release carrier material consists of 30 parts, the nutrient sustained-release agent consists of 10 parts, the surfactant consists of 1 part and the stabilizer consists of 4 parts, and the rest are the same as in Example 1.

[0051] Comparative Example 6 The difference from Example 1 is that the surfactant is sodium dodecyl sulfonate, while the rest is the same as in Example 1.

[0052] Preparation methods of Examples 1-3 and Comparative Examples 1-6: The raw materials are mixed according to the specified ratio to obtain the final product.

[0053] II. Detection Examples (1) Prepare a polluted aqueous solution containing: 5 mg / L chlorophenol (4-CP), 1000 mg / L diesel and 10 mg / L sulfadiazine, with distilled water as the solvent.

[0054] (2) The experiment was divided into Example 1-3 groups, Comparative Examples 1-6 groups, and commercial reagent (Bio-Feng). ® The oil removal group was divided into three parallel tests.

[0055] According to 5g composite composition / 1m 3 The dosage of distilled water was adjusted by adding the corresponding groups of polluted aqueous solutions to the groups of Examples 1-3, Comparative Examples 1-6, and commercial reagents. The reaction was carried out under the conditions of 150 rpm, 20-25°C, dissolved oxygen (0.5 mg / L), and pH = 7.

[0056] (3) The removal rate was detected by taking water samples from the experimental group at 1d, 2d, 4d and 7d of the reaction.

[0057] Diesel fuel testing: The testing shall be conducted in accordance with the testing method of HJ 894-2017.

[0058] Detection of sulfadimethylpyrimidine: Refer to the detection method in DB50 / T 1367-2023.

[0059] Chlorophenol detection: The detection method shall be followed according to HJ 744-2015.

[0060] Removal rate = (Total content of substance - Residual content of substance) / Total content of substance 100%.

[0061] Diesel removal rate is shown in Table 1, sulfadimethylpyrimidine removal rate is shown in Table 2, and chlorophenol removal rate is shown in Table 3.

[0062] Table 1 (Unit: %)

[0063] Table 2 (Unit: %)

[0064] Table 3 (Unit: %)

[0065] Examples 1-3 of this invention show high removal rates and faster removal speeds for diesel fuel, sulfadimethylpyrimidine, and chlorophenol.

[0066] The types of compound microbial communities, the dosage relationship of compound microbial communities, the ratio of slow-release carrier material and nutrient slow-release agent, the ratio of surfactant and stabilizer, and the types of surfactants were changed in Comparative Examples 1-6. The removal rates of diesel oil, sulfadiazine and chlorophenol were low and the removal speed was slow.

[0067] Regarding the chlorophenol removal rate, a 6g example 1 / 1m test was conducted. 3 In the distilled water dosage experiment, the chlorophenol removal rate reached 99.6% after 7 days. The technical effects of Examples 1-2 were equivalent to those of Example 1. Comparative Examples 1-6 and commercial reagents, even when calculated at 6g composite composition / 1m... 3 Even with the dosage of distilled water, the chlorophenol removal rate is still less than 80%.

[0068] Examples 1-3 of this invention comply with the relevant provisions of the "HJ / T415-2008 Environmental Safety Evaluation Guidelines for Microbial Agents for Environmental Protection".

[0069] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A bioremediation composition for remediating contaminated groundwater, characterized in that, include: Complex microbial communities, sustained-release carrier materials, sustained-release nutrient agents, surfactants, and stabilizers; The aforementioned complex microbial community consists of the following strains: Bacillus subtilis, Pseudomonas putida, Desulfovibrio, and Pseudomonas fibrinolyticus; The sustained-release carrier material is selected from at least one of bentonite, perlite, diatomaceous earth, sodium alginate, chitosan, and gelatin; The nutrient slow-release agent is selected from at least one of glucose, vitamin B2, sodium lactate, and β-cyclodextrin.

2. The bioremediation composition according to claim 1, characterized in that, The mass ratio of the sustained-release carrier material to the nutrient sustained-release agent is (25-40):(5-15).

3. The bioremediation composition according to claim 1, characterized in that, The surfactant is selected from at least one of rhamnolipin, sophorolipid, and tea saponin.

4. The bioremediation composition according to claim 1, characterized in that, The stabilizer is selected from at least one of sodium carboxymethyl cellulose and xanthan gum.

5. The bioremediation composition according to claim 1, characterized in that, The mass ratio of the surfactant to the stabilizer is (2-3):(2-3).

6. The bioremediation composition according to any one of claims 1-5, characterized in that, The mass ratio of Bacillus subtilis, Pseudomonas putida, Vibrio desulfurans and Bacillus fibrillosa is (1-2):1:(1-3):

1.

7. The bioremediation composition according to any one of claims 1-5, characterized in that, The bioremediation composition for remediating contaminated groundwater comprises, by weight, the following components: 10-30 parts of complex microbial flora, 25-40 parts of slow-release carrier material, 5-15 parts of nutrient slow-release agent, 2-3 parts of surfactant, and 2-3 parts of stabilizer.

8. A method for preparing the bioremediation composition according to any one of claims 1-7, characterized in that, Includes the following steps: The compound microbial community, slow-release carrier material, nutrient slow-release agent, surfactant and stabilizer are mixed evenly to obtain the product.

9. A repair agent, characterized in that, Includes the biorepair composition according to any one of claims 1-7.

10. The use of the bioremediation composition according to any one of claims 1-7 in the remediation of contaminated groundwater.

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