A synergistic treatment of LNAPL-contaminated groundwater with a promoter, a method of preparation and a method of use

Abstract

The application discloses a kind of synergistic treatment LNAPL contaminated groundwater accelerant, preparation method and application method, include lipophilic solubilizer 35-65%, permeation desorption agent 20-50% and dispersion drag-reducing agent 5-25% by mass percentage.The accelerant provided by the application is by compounding different kinds of organic active agent, and the repair effect is improved by exerting respective advantages, and the lipophilic solubilizer containing long carbon chain nonionic hydrophobic group is matched with LNAPL petroleum hydrocarbon molecule reasonably, so that LNAPL is more easily driven away in groundwater, and the flowability of LNAPL in groundwater phase is increased;Permeation desorption agent can accelerate the removal of trapped LNAPL from soil and the mass transfer process of LNAPL from soil surface to water phase;Dispersion drag-reducing agent can accelerate the mixing of accelerant and LNAPL, and form microemulsion phase to enhance the flowability of LNAPL in soil;The three phases of groundwater, LNAPL and soil are more balanced by the joint action of each component, and the extraction of LNAPL is facilitated.

Description

Technical Field

[0001] This invention relates to the field of groundwater remediation technology, specifically to a promoter for the synergistic treatment of LNAPL-contaminated groundwater, its preparation method, and its application method. Background Technology

[0002] With the development of the petroleum industry, oil spills, sudden leaks, and the unreasonable discharge of oily wastewater during the processes of oil extraction, storage, transportation, processing, and petrochemical product production and gathering have led to a large amount of petroleum hydrocarbons entering the groundwater system and spreading over a wide area. Petroleum hydrocarbons contain a variety of toxic substances such as alkanes, cycloalkanes, and aromatics, and have become the most common pollutant in groundwater organic pollution, posing a great threat. Therefore, efficient groundwater oil removal technology has broad application prospects and huge social benefits.

[0003] Current main technologies for treating LNAPL-contaminated groundwater involve vertically isolating the contaminated groundwater and then extracting it for treatment. Firstly, the operating area of ​​a single well is limited; for larger sites with LNAPL-contaminated groundwater, a large number of wells are required, resulting in high efficiency and cost. Secondly, the remediation rate of LNAPL-contaminated groundwater is low and cannot meet treatment requirements. Therefore, providing a high-remediation-rate, high-capacity, and low-cost LNAPL treatment technology to address current groundwater pollution problems is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide an accelerator, preparation method, and application method for the synergistic treatment of LNAPL-contaminated groundwater. This accelerator can enhance the mobility of LNAPL in porous soil media, elute LNAPL adsorbed in the soil, and has good solubilizing and dispersing properties for LNAPL, effectively expanding the treatment range of wells and improving the remediation effect.

[0005] To address the shortcomings of the aforementioned technical problems, the present invention employs the following technical solution: a promoter for the synergistic treatment of LNAPL-contaminated groundwater, comprising, by mass percentage: 35-65% lipophilic solubilizer, 20-50% permeation desorbent, and 5-25% dispersant and drag-reducing agent.

[0006] As a further optimization of the promoter for the synergistic treatment of LNAPL-contaminated groundwater according to the present invention, the lipophilic solubilizer is one or more of hydrogenated castor oil polyoxyethylene ether, fatty amine polyoxyethylene ether, and alkyl polyoxyethylene ether bisquaternary ammonium salt.

[0007] As a further optimization of the promoter for the synergistic treatment of LNAPL-contaminated groundwater according to the present invention, the degree of polymerization of ethylene oxide in the hydrogenated castor oil polyoxyethylene ether and fatty amine polyoxyethylene ether is 1-3, the number of carbon atoms in the fatty amine is 8-18, the number of alkyl carbon atoms in the alkyl polyoxyethylene ether bisquaternary ammonium salt is 12-18, and the degree of polymerization of ethylene oxide is 2-5.

[0008] As a further optimization of the promoter for the synergistic treatment of LNAPL-contaminated groundwater according to the present invention, the permeation desorption agent is one or more of alkyl sulfonates, polyether siloxanes, and fatty alcohol polyoxyethylene ethers.

[0009] As a further optimization of the promoter for the synergistic treatment of LNAPL-contaminated groundwater of the present invention, the alkyl sulfonate has an alkyl group of 10-18, the sulfonate is one of sodium, potassium or calcium, the polyether siloxane has a viscosity of 25℃ / 10-50cps, the fatty alcohol polyoxyethylene ether has a carbon number of 6-16, and the degree of polymerization of ethylene oxide is 2-5.

[0010] As a further optimization of the promoter for the synergistic treatment of LNAPL-contaminated groundwater according to the present invention, the dispersing drag-reducing agent is one or more of dialkyl betaine and long-chain isomeric fatty alcohols.

[0011] As a further optimization of the promoter for the synergistic treatment of LNAPL-contaminated groundwater according to the present invention, the dialkyl betaine has an alkyl carbon number of 3-18 and the fatty alcohol has a carbon number of 10-20.

[0012] As a further optimization of the promoter for the synergistic treatment of LNAPL-contaminated groundwater according to the present invention, the content of the lipophilic solubilizer is 45-55%, the content of the permeation desorbent is 30-40%, and the content of the dispersing drag-reducing agent is 10-20%.

[0013] A method for preparing an accelerator for the synergistic treatment of LNAPL-contaminated groundwater involves adding an oleophilic solubilizer, a permeation desorbent, and a dispersant / drag reducer to a stirring container in a specific ratio and stirring until the mixture is homogeneous to obtain the accelerator.

[0014] The application of a promoter for the synergistic treatment of LNAPL-contaminated groundwater in petroleum hydrocarbon soil pollution involves calculating the total amount of LNAPL pollutants in the groundwater based on the thickness and area of ​​the pollutants, and then injecting a promoter with a mass percentage concentration of 3-12% into the LNAPL.

[0015] As a further optimization of the application of the promoter for the synergistic treatment of LNAPL-contaminated groundwater of the present invention in petroleum hydrocarbon soil pollution, the concentration of the promoter in LNAPL is 5-8% by mass percentage.

[0016] The present invention has the following beneficial effects:

[0017] I. The accelerator provided by this invention is a compound of different types of organic surfactants, which leverage their respective advantages to improve the remediation effect. The lipophilic solubilizer containing long-chain nonionic hydrophobic groups is well matched with LNAPL petroleum hydrocarbon molecules, making LNAPL easier to displace in groundwater and increasing the fluidity of LNAPL in the groundwater phase. The permeation desorbent can accelerate the removal of trapped LNAPL from the soil and the mass transfer process of LNAPL from the soil surface to the water phase. The dispersing drag-reducing agent can accelerate the thorough and uniform mixing of the accelerator and LNAPL to form a microemulsion phase, enhancing the fluidity of LNAPL in the soil. The combined effect of all components makes the three phases of groundwater, LNAPL and soil more balanced, facilitating the extraction of LNAPL and enabling the groundwater pollutant remediation rate to reach more than 90%.

[0018] Second, the invention's accelerator can effectively expand the treatment range. While the LNAPL contaminants in the nearby groundwater are extracted from the working well, causing the liquid level to drop, the organic surfactant component in the accelerator significantly reduces the interfacial tension between LNAPL and soil and groundwater, improving the permeability of LNAPL in the soil. LNAPL mixed with the accelerator at a greater distance can quickly accumulate in the working well through the surrounding soil medium, especially for thinner LNAPL layers, which can increase the working area of ​​the well by more than two times, greatly improving the LNAPL treatment capacity and efficiency.

[0019] Third, the promoter of this invention is an organic active agent with good biodegradability and low toxicity, which does not cause secondary pollution. Due to its good lipophilic, dispersing and penetrating effects, it can wash away petroleum hydrocarbon pollutants in the soil and clean and improve the soil while synergistically treating LNAPL. Furthermore, the promoter can be separated and recycled from the LNAPL extracted from the well, and the promoter remaining in the underground medium can also be used as a carbon source for bioremediation.

[0020] Fourth, the accelerator of this invention can be organically combined with the LNAPL groundwater pollution remediation process, effectively reducing operating costs and improving treatment results. The method provided is highly efficient and stable, and can be widely applied to LNAPL groundwater pollution site remediation projects. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below through three examples. Example 1

[0022] This embodiment provides an accelerator for the synergistic treatment of LNAPL-contaminated groundwater. The accelerator comprises an oleophilic solubilizer, a permeation desorbent, and a dispersant / drag reducer, with a mass ratio of 50:30:20. The oleophilic solubilizer is composed of 50% hydrogenated castor oil polyoxyethylene ether and 50% hexadecyl polyoxyethylene ether bisquaternary ammonium salt. The permeation desorbent is composed of 80% lauryl alcohol polyoxyethylene ether and 20% polyether siloxane (10 cps). The dispersant / drag reducer is composed of 75% didodecyl betaine and 25% isotridecyl alcohol.

[0023] The preparation method of the accelerator in this embodiment is as follows: At room temperature, the above-mentioned components, measured in proportion, are added to a stirring tank and stirred for 20-30 minutes to obtain the accelerator.

[0024] Application of the accelerator in the remediation of LNAPL-contaminated groundwater in this embodiment: At a certain LNAPL-contaminated groundwater site, the treatment area of ​​well 1 had a radius of 3m. After the extraction equipment was in operation, the overall LNAPL extraction rate was 85%. The accelerator prepared in this embodiment was injected at a mass percentage of 6% into the LNAPL-contaminated groundwater within a radius of 8m from the well. After the extraction equipment was in operation, the overall LNAPL extraction rate was 92%. Example 2

[0025] This embodiment provides an accelerator for the synergistic treatment of LNAPL-contaminated groundwater. The accelerator comprises an oleophilic solubilizer, a permeation desorbent, and a dispersant / drag reducer, with a mass ratio of 50:35:15. The oleophilic solubilizer is dodecylamine polyoxyethylene ether, the permeation desorbent is composed of 90% oleyl alcohol polyoxyethylene ether and 10% polyether siloxane (20 cps), and the dispersant / drag reducer is dihexadecyl betaine.

[0026] The preparation method of the accelerator in this embodiment is as follows: at room temperature, the above-mentioned components, measured in proportion, are added to a stirring tank and stirred for 20-30 minutes to obtain the accelerator.

[0027] Application of the accelerator in the remediation of LNAPL-contaminated groundwater in this embodiment: At a certain LNAPL-contaminated groundwater site, the treatment area of ​​the well had a radius of 4m. After the extraction equipment was in operation, the overall LNAPL extraction rate was 80%. The accelerator prepared in this embodiment was injected at a mass percentage of 8% into the LNAPL-contaminated groundwater within a 10m radius of the well. After the extraction equipment was in operation, the overall LNAPL extraction rate was 90%. Example 3

[0028] This embodiment provides an accelerator for the synergistic treatment of LNAPL-contaminated groundwater. The accelerator comprises an oleophilic solubilizer, a permeation desorbent, and a dispersant / drag reducer, with a mass ratio of 55:30:10. The oleophilic solubilizer is composed of 30% hydrogenated castor oil polyoxyethylene ether, 40% dodecylamine polyoxyethylene ether, and 30% dodecyl polyoxyethylene ether bisquaternary ammonium salt. The permeation desorbent is composed of 55% lauryl alcohol polyoxyethylene ether (3), 30% sodium dodecyl sulfonate, and 15% polyether siloxane (10 cps). The dispersant / drag reducer is composed of 80% didodecyl betaine and 20% isotridecyl alcohol.

[0029] The preparation method of the accelerator in this embodiment is as follows: at room temperature, the above-mentioned components, measured in proportion, are added to a stirring tank and stirred for 20-30 minutes to obtain the accelerator.

[0030] Application of the accelerator in the remediation of LNAPL-contaminated groundwater in this embodiment: At a certain LNAPL-contaminated groundwater site, the treatment area of ​​the well had a radius of 3.5m. After the extraction equipment was in operation, the overall LNAPL extraction rate was 82%. When the accelerator prepared in this embodiment was injected at 8% by mass into the LNAPL-contaminated groundwater within a 10m radius of the well, the overall LNAPL extraction rate reached 93% after the extraction equipment was in operation.

[0031] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A promoter for the synergistic treatment of LNAPL-contaminated groundwater, characterized in that: By weight percentage, it includes: 35-65% lipophilic solubilizer, 20-50% penetrant desorbent, and 5-25% dispersant and drag reducer.

2. The accelerator for the synergistic treatment of LNAPL-contaminated groundwater according to claim 1, characterized in that: The lipophilic solubilizer is one or more of hydrogenated castor oil polyoxyethylene ether, fatty amine polyoxyethylene ether, and alkyl polyoxyethylene ether bisquaternary ammonium salt.

3. The accelerator for the synergistic treatment of LNAPL-contaminated groundwater according to claim 2, characterized in that: The degree of polymerization of ethylene oxide in the hydrogenated castor oil polyoxyethylene ether and fatty amine polyoxyethylene ether is 1-3, the number of carbon atoms in the fatty amine is 8-18, the number of alkyl carbon atoms in the alkyl polyoxyethylene ether bisquaternary ammonium salt is 12-18, and the degree of polymerization of ethylene oxide is 2-5.

4. The accelerator for the synergistic treatment of LNAPL-contaminated groundwater according to claim 1, characterized in that: The permeation desorbent is one or more of alkyl sulfonates, polyether siloxanes, and fatty alcohol polyoxyethylene ethers.

5. The accelerator for the synergistic treatment of LNAPL-contaminated groundwater according to claim 4, characterized in that: The alkyl sulfonate has 10-18 alkyl carbons, the sulfonate is one of sodium, potassium or calcium, the polyether siloxane viscosity is 25℃ / 10-50cps, the fatty alcohol polyoxyethylene ether has 6-16 carbons, and the degree of polymerization of ethylene oxide is 2-5.

6. The accelerator for the synergistic treatment of LNAPL-contaminated groundwater according to claim 1, characterized in that: The dispersing drag-reducing agent is one or more of dialkyl betaine and long-chain isomeric fatty alcohols.

7. The promoter for synergistic treatment of LNAPL-contaminated groundwater according to claim 7, characterized in that: The dialkyl betaine has 3-18 alkyl carbons, and the fatty alcohol has 10-20 carbons.

8. The accelerator for the synergistic treatment of LNAPL-contaminated groundwater according to claim 1, characterized in that: The content of the lipophilic solubilizer is 45-55%, the content of the permeation desorbent is 30-40%, and the content of the dispersant drag reducer is 10-20%.

9. A method for preparing an accelerator for the synergistic treatment of LNAPL-contaminated groundwater as described in any one of claims 1-8, characterized in that: The lipophilic solubilizer, penetrant desorbent, and dispersant drag reducer are added to a stirring container in a certain proportion and stirred until they are evenly mixed to obtain the promoter.

10. The application of any one of the promoters for the synergistic treatment of LNAPL-contaminated groundwater as described in claims 1-8 in petroleum hydrocarbon soil pollution, characterized in that: The total amount of LNAPL contaminants is obtained by measuring the thickness and area of ​​the LNAPL in the groundwater, and then an accelerator with a mass percentage concentration of 3-12% is injected into the LNAPL.

11. The application of the promoter for synergistic treatment of LNAPL-contaminated groundwater as described in claim 10 in petroleum hydrocarbon soil pollution, characterized in that: The concentration of the accelerator in LNAPL is 5-8% by mass percentage.