A device for efficiently degrading high-concentration petroleum hydrocarbons in soil

Abstract

The application discloses a kind of high-efficiency degradation device of high concentration petroleum hydrocarbon in soil, including bioreactor, the top of bioreactor is connected with spherical condenser pipe, glass plug and reflux tube;The water outlet of the upper end of condenser pipe is connected with first rubber tube, first rubber tube is connected to faucet;The water outlet of the lower end of condenser pipe is connected with second rubber tube, and second rubber tube is used to facilitate drainage;The upper end of reflux tube is connected to oxygen cylinder by third rubber tube, and the lower end of reflux tube extends to petroleum hydrocarbon contaminated soil in the lower part of bioreactor by fourth rubber tube, and is connected with aeration disc at the bottom of bioreactor;Compared with prior art, the application has the advantages of low cost, simple operation, convenient transportation and high efficiency, the device can keep the water content of petroleum hydrocarbon contaminated soil in bioreactor unchanged, and is simple and easy to operate;And the device can realize water recycling through the condenser pipe above the device.

Description

Technical Field

[0001] This invention belongs to the field of soil pollution remediation, specifically relating to a device for efficiently degrading high concentrations of petroleum hydrocarbons in soil. Background Technology

[0002] With the rapid development of my country's economy, the exploitation and utilization of petroleum resources have increased significantly. At the same time, petroleum pollution is widespread in my country. Statistics show that the area of ​​soil contaminated by organic matter in my country reaches 2 × 10⁻⁶. 7 km 2 Most of the pollution originates from oil. As a complex mixture, oil has teratogenic, carcinogenic, and mutagenic effects, and it also causes serious soil pollution. This manifests itself in two ways: firstly, oil contains large amounts of toxic and harmful substances such as polycyclic aromatic hydrocarbons (PAHs). These substances, once in the soil, accumulate in plants and animals through the food chain and food web, seriously endangering ecological security and human health. Secondly, oil is insoluble in water. When an oil spill occurs, high concentrations of oil adsorb onto the surface of soil particles, blocking the supply of oxygen from the atmosphere to soil microorganisms. This leads to an anaerobic or hypoxic environment in the soil, affecting the community structure of soil microorganisms and causing soil compaction and decreased fertility.

[0003] Over the past few decades, methods for remediating petroleum pollution have received widespread attention, such as thermal treatment, soil flushing, and advanced oxidation processes. While these technologies are time-efficient and effective, they are also expensive, detrimental to environmental remediation, and complex, potentially causing secondary pollution. Microbial remediation is considered a simple, harmless, relatively economical, and eco-friendly sustainable remediation method. Specifically, it utilizes microbial communities capable of degrading pollutants. Under certain environmental conditions, pollutants serve as carbon and energy sources for microbial growth, thereby reducing the activity of toxic pollutants or degrading them into non-toxic substances. However, since microorganisms that degrade petroleum hydrocarbons are aerobic, high concentrations of petroleum can block oxygen supply to the soil, causing clay to form small spheres of varying sizes. This creates an anaerobic or hypoxic environment in the soil, thus affecting the efficiency of petroleum hydrocarbon degradation. Summary of the Invention

[0004] This invention provides a device for efficiently degrading high concentrations of petroleum hydrocarbons in soil, which can solve the problems existing in the prior art: the microorganisms that degrade petroleum hydrocarbons are aerobic microorganisms, and high concentrations of petroleum will block the oxygen supply in the soil, causing the clay to form small balls of different sizes. This will create an anaerobic or hypoxic environment in the soil, thereby affecting the degradation efficiency of petroleum hydrocarbons.

[0005] To solve the above problems, the technical solution provided by the present invention is as follows:

[0006] This invention provides an apparatus for efficiently degrading high concentrations of petroleum hydrocarbons in soil. The apparatus comprises a bioreactor (6), which is a closed reactor used to hold a uniformly mixed mixture of petroleum hydrocarbon-contaminated soil and organic fertilizer. The top of the bioreactor (6) is connected to a spherical condenser tube (1), a glass stopper (3), and a return pipe (4). A first rubber hose is connected to the upper drain outlet (1-1) of the condenser tube (1), which is connected to a faucet. A second rubber hose is connected to the lower drain outlet (1-2) of the condenser tube (1), which facilitates drainage. The upper end of the return pipe (4) is connected to an oxygen cylinder via a third rubber hose, and the lower end of the return pipe (4) extends through a fourth rubber hose into the petroleum hydrocarbon-contaminated soil at the bottom of the bioreactor (6), connecting to an aeration disc (2) at the bottom of the bioreactor (6).

[0007] Before the reaction to degrade high concentrations of petroleum hydrocarbons in the soil, 600-1200g of petroleum hydrocarbon-contaminated soil mixed with organic fertilizer was placed in the bioreactor (6), the moisture content of the mixture was adjusted to 56%, and the mixture was sealed. After the device was connected, the tap was turned on to allow the condenser tube (1) to reflux, and the water flow rate was controlled so that the water discharge rate of the second rubber tube at the lower end drain outlet (1-2) of the condenser tube (1) was 1 drop every 2 seconds. The oxygen cylinder valve was turned on and the gas rate was adjusted to 0.5L / min to form the oxygen experimental group (S1). The oxygen cylinder was replaced with an air cylinder to form the air control group (S2) in the same manner. After the bioreactors in the oxygen experimental group (S1) and the air control group (S2) were ventilated for a period of time, a glowing torch was used to ventilate the mixture. The small paper pieces were tested at the upper opening (1-3) of the condenser tube (1). The glowing paper pieces in the oxygen experimental group (S1) reignited, indicating that the bioreactor (6) in this group was a pure oxygen environment with sufficient oxygen. The glowing paper pieces at the upper opening of the condenser tube in the air experimental group (S2) did not reignite. The remediation experiment lasted for 30 days. During this period, the temperature of the two groups was measured and samples were taken regularly. The pH value, temperature, total number of bacteria, bacterial community structure, and total petroleum hydrocarbon content in the samples were determined. After 30 days, the experimental data of the two groups were compared: the content of petroleum hydrocarbons in the soil of the air control group (S2) did not change much and the degradation rate was relatively slow, while the content of petroleum hydrocarbons in the oxygen experimental group (S1) decreased significantly. Therefore, it can be concluded that pure oxygen conditions can improve the efficiency of microbial degradation of petroleum hydrocarbons in the soil.

[0008] According to an optional embodiment of the present invention, the bioreactor (6) is a glass vessel.

[0009] According to an optional embodiment of the present invention, the organic fertilizer mixture in the bioreactor (6) includes kitchen waste, which serves as a nutrient; the kitchen waste includes food ingredients, eggs and straw powder, and the food ingredients are fully minced using a meat grinder, and the minced food ingredients are fully mixed with a preset amount of eggs and prepared, with the mass ratio of the mixed food ingredients and eggs to the straw powder being 3:1.

[0010] According to an optional embodiment of the present invention, the organic fertilizer mixture in the bioreactor (6) is uniformly mixed with the petroleum hydrocarbon contaminated soil at a dry weight ratio of 1:1.

[0011] Beneficial Effects: This invention provides a highly efficient device for degrading high concentrations of petroleum hydrocarbons in soil, comprising a bioreactor, which is a closed reactor used to hold a uniformly mixed mixture of petroleum hydrocarbon-contaminated soil and organic fertilizer. The top of the bioreactor is connected to a spherical condenser tube, a glass stopper, and a reflux tube. The upper drain of the condenser tube is connected to a first rubber hose, which is connected to a faucet. The lower drain of the condenser tube is connected to a second rubber hose for convenient drainage. The upper end of the reflux tube is connected to an oxygen cylinder via a third rubber hose, and the lower end of the reflux tube extends through a fourth rubber hose into the petroleum hydrocarbon-contaminated soil at the bottom of the bioreactor, connecting to an aeration disc at the bottom of the bioreactor. Compared with existing technologies, this invention has the advantages of low cost, simple operation, convenient transportation, and high experimental efficiency. This device can maintain a constant moisture content in the petroleum hydrocarbon-contaminated soil in the bioreactor and is simple and easy to operate. Furthermore, the device can achieve water recycling through the condenser tube at the top. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments or prior art, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the structure of an apparatus for efficiently degrading high concentrations of petroleum hydrocarbons in soil, provided in an embodiment of this application.

[0014] Figure 2 The diagram shows the changes in petroleum hydrocarbon content before and after two sets of experiments, provided for embodiments of this application. Detailed Implementation

[0015] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0016] like Figure 1 As shown, this embodiment of the invention provides an apparatus for efficiently degrading high concentrations of petroleum hydrocarbons in soil. The apparatus includes a bioreactor 6, which is a closed reactor used to hold a uniformly mixed mixture of petroleum hydrocarbon-contaminated soil and organic fertilizer. In this embodiment, the bioreactor 6 is a glass container.

[0017] The top of the bioreactor 6 is connected to a spherical condenser tube 1, a glass stopper 3, and a return pipe 4; the upper drain outlet 1-1 of the condenser tube 1 is connected to a first rubber tube, which is connected to a faucet; the lower drain outlet 1-2 of the condenser tube 1 is connected to a second rubber tube, which is used for convenient drainage; the upper end of the return pipe 4 is connected to an oxygen cylinder through a third rubber tube, and the lower end of the return pipe 4 extends through a fourth rubber tube into the petroleum hydrocarbon contaminated soil at the bottom of the bioreactor 6, and is connected to the aeration disc 2 at the bottom of the bioreactor 6.

[0018] Among them, such as Figure 1 and Figure 2 As shown, before the reaction to degrade high concentrations of petroleum hydrocarbons in the soil, 600-1200g of petroleum hydrocarbon-contaminated soil, preferably about 900g, was uniformly mixed with organic fertilizer and placed into bioreactor 6. The moisture content of the mixture was adjusted to 56%, and the reactor was sealed. After the device was connected, the water tap was turned on to allow the condenser tube 1 to reflux. The water flow rate was controlled so that the water discharge rate from the second rubber tube at the lower drain outlet 1-2 of the condenser tube 1 was 1 drop every 2 seconds. The oxygen cylinder valve was opened, and the gas rate was adjusted to 0.5L / min as the optimal value to form oxygen experimental group S1. The oxygen cylinder was then replaced. Using an air bottle, an air control group S2 was formed as described above. After a period of time, the bioreactors in both the oxygen experimental group S1 and the air control group S2 were aerated. A glowing piece of paper was then used to test the opening at the top of the condenser tube 1 (points 1-3). In the oxygen experimental group, the glowing paper reignited, indicating that the bioreactor 6 in this group was in a pure oxygen environment with sufficient oxygen. In the air experimental group, the glowing paper at the top of the condenser tube did not reignite. The remediation experiment lasted for 30 days, during which the temperature of both groups was measured periodically and samples were taken to determine the pH value, temperature, total bacterial count, bacterial community structure, and total petroleum hydrocarbon content in the samples. Figure 2As shown, after 30 days, the experimental data of the two groups were compared: the content of petroleum hydrocarbons in the soil of the air control group S2 did not change much and the degradation rate was relatively slow, while the content of petroleum hydrocarbons in the oxygen experimental group S1 decreased significantly. Therefore, it can be concluded that pure oxygen conditions can improve the efficiency of microorganisms in the soil in degrading petroleum hydrocarbons.

[0019] In this embodiment, the organic fertilizer mixture in bioreactor 6 includes kitchen waste, which serves as a nutrient. The kitchen waste includes food ingredients, eggs, and straw powder. The food ingredients are thoroughly minced using a meat grinder, and then thoroughly mixed with a predetermined amount of eggs. The mass ratio of the mixed food ingredients and eggs to the straw powder is 3:1. The organic fertilizer mixture in bioreactor 6 is then uniformly mixed with petroleum hydrocarbon-contaminated soil at a dry weight ratio of 1:1.

[0020] The working principle of this invention is as follows: The process of microbial degradation of petroleum requires suitable environmental conditions, including temperature, pH, oxygen, and nutrients, all of which affect the metabolic activities of microorganisms. To address the issue that after a large-scale leak of high-concentration petroleum hydrocarbon pollutants, the tolerance, species, and quantity of native microorganisms in the environment are greatly reduced. Furthermore, these microorganisms tend to adhere to soil particles, affecting soil permeability and creating an oxygen-deficient environment. This invention addresses this by adding kitchen waste as nutrients to the petroleum hydrocarbon-contaminated soil in a bioreactor, maintaining suitable temperature, pH, and moisture content, and introducing pure oxygen into the bioreactor to accelerate the biodegradation and biotransformation processes of the microorganisms, thereby speeding up the remediation of high-concentration petroleum hydrocarbon-contaminated soil.

[0021] The working procedure of this invention is as follows: (1) Conduct composting experiment. Prepare a certain amount of food ingredients, grind them thoroughly with a meat grinder, and mix them thoroughly with a certain amount of eggs to make kitchen waste. Then, use another clean basin to mix the kitchen waste with straw powder at a mass ratio of 3:1. Turn the kitchen waste and straw powder by hand for about 1 hour to make them fully mixed. Add tap water to make the moisture content of the mixture about 60%. Start aerobic composting and use manual turning to supplement oxygen to the pile. Turn the pile once a day. After three days of aerobic composting, mix the compost material with petroleum hydrocarbon contaminated soil at a dry weight ratio of 1:1 and mix thoroughly. (2) Connect the device: Connect the upper drain of the condenser tube of the device to the first rubber tube, which is connected to the faucet; connect the lower drain of the condenser tube to the second rubber tube, which is used for convenient drainage. Connect the upper end of the specially made bioreactor to the oxygen cylinder with the third rubber tube and the lower end to the aeration plate with the fourth rubber tube. (3) Loading material: The organic fertilizer was prepared with a moisture content of about 60%. After three days of aerobic composting, it was mixed with petroleum hydrocarbon contaminated soil at a dry weight ratio of 1:1. Two portions of the mixture were prepared, each 900g. The moisture content of the mixture was adjusted to 56%. The mixture was placed in the bioreactor and sealed. (4) Turn on the tap to allow the condenser tube to reflux. Control the water flow rate so that the water discharge rate of the lower rubber tube is 1 drop every 2 seconds. Open the valves of the air tank in the air control group and the oxygen tank in the oxygen experimental group respectively. Adjust the gas rate to 0.5L / min. After a period of ventilation, use a glowing piece of paper to test the condenser tubes of the two groups of devices. If the glowing piece of paper above the condenser tube of the oxygen group reignites, it means that the original gas in the device has been completely removed and the device environment is a pure oxygen environment. However, if the glowing piece of paper above the cold wall tube of the air group does not reignite, it indicates that the original gas in the device has been completely removed. (5) The remediation experiment lasted for 30 days, during which temperature was measured and samples were taken regularly to determine the pH value, temperature, total bacterial count, bacterial community structure, and total petroleum hydrocarbon content in the samples. Figure 2 As shown, after 30 days, comparing the experimental data of the two groups, the content of petroleum hydrocarbons in the soil of the air group did not change significantly, indicating a relatively slow degradation rate; while the content of petroleum hydrocarbons in the pure oxygen group decreased significantly. The conclusion can be drawn that pure oxygen conditions can improve the efficiency of microbial degradation of petroleum hydrocarbons in the soil.

[0022] In summary, although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A device for efficiently degrading high concentrations of petroleum hydrocarbons in soil, characterized in that, The system includes a bioreactor (6), which is a closed reactor used to hold a uniformly mixed mixture of petroleum hydrocarbon-contaminated soil and organic fertilizer. The top of the bioreactor (6) is connected to a spherical condenser (1), a glass stopper (3), and a return pipe (4). The upper drain outlet (1-1) of the condenser (1) is connected to a first rubber tube, which is connected to a faucet. The lower drain outlet (1-2) of the condenser (1) is connected to a second rubber tube, which is used for convenient drainage. The upper end of the return pipe (4) is connected to an oxygen cylinder through a third rubber tube, and the lower end of the return pipe (4) extends through a fourth rubber tube into the petroleum hydrocarbon-contaminated soil at the bottom of the bioreactor (6) and is connected to the aeration disc (2) at the bottom of the bioreactor (6). Before the reaction to degrade high concentrations of petroleum hydrocarbons in the soil, 600-1200g of petroleum hydrocarbon-contaminated soil mixed with organic fertilizer was placed in the bioreactor (6), the moisture content of the mixture was adjusted to 56%, and the mixture was sealed. After the device was connected, the tap was turned on to allow the condenser tube (1) to reflux, and the water flow rate was controlled so that the water discharge rate of the second rubber tube at the lower end drain outlet (1-2) of the condenser tube (1) was 1 drop every 2 seconds. The oxygen cylinder valve was turned on and the gas rate was adjusted to 0.5L / min to form the oxygen experimental group (S1). The oxygen cylinder was replaced with an air cylinder to form the air control group (S2) in the same manner. After the bioreactors in the oxygen experimental group (S1) and the air control group (S2) were ventilated for a period of time, a small glowing tip was used to ventilate the oxygen experimental group (S1) and the air control group (S2). The paper was tested at the opening (1-3) at the top of the condenser tube (1). The glowing paper in the oxygen experimental group (S1) reignited, indicating that the bioreactor (6) in this group was in a pure oxygen environment with sufficient oxygen. The glowing paper in the opening at the top of the condenser tube in the air control group (S2) did not reignite. The remediation experiment lasted for 30 days. During this period, the temperature of the two groups was measured and samples were taken regularly. The pH value, temperature, total number of bacteria, bacterial community structure, and total petroleum hydrocarbon content in the samples were determined. After 30 days, the experimental data of the two groups were compared. The content of petroleum hydrocarbons in the soil in the air control group (S2) did not change much and the degradation rate was relatively slow. However, the content of petroleum hydrocarbons in the oxygen experimental group (S1) decreased significantly. Therefore, it can be concluded that pure oxygen conditions can improve the efficiency of microbial degradation of petroleum hydrocarbons in the soil. The organic fertilizer mixture in the bioreactor (6) includes kitchen waste, which serves as a nutrient. The kitchen waste includes food ingredients and straw powder, and the food ingredients are thoroughly minced using a meat grinder, with a mass ratio of food ingredients to straw powder of 3:

1.

2. The device for efficiently degrading high concentrations of petroleum hydrocarbons in soil according to claim 1, characterized in that, The bioreactor (6) is a glass vessel.

3. The device for efficiently degrading high concentrations of petroleum hydrocarbons in soil according to claim 1, characterized in that, The organic fertilizer mixture in the bioreactor (6) is uniformly mixed with the petroleum hydrocarbon contaminated soil at a dry weight ratio of 1:1.

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