KR102545014B1 - Apparatus for remediation of contaminated soil using Modified biopile system and Bio washing device - Google Patents

Abstract

The present invention secures excellent cleaning efficiency for contaminated soil and effectively treats a large amount of contaminated soil by combining the modified biopile treatment device designed by the present applicant with the biological washing device disclosed in Korean Patent Registration No. 1779903 of the present applicant. It relates to a soil restoration device using a modified biopile processing device and a biological washing device that can be used, and the soil restoration device using a modified biopile processing device and a biological washing device according to the present invention is a mixture of culture medium, soil microorganisms and biosurfactants. A rapid stirring tank for mixing the phosphorus washing solution with contaminated soil and rapidly stirring it; A biological washing device for washing crude oil-contaminated soil using a washing liquid; A centrifugal separator that performs centrifugation on the contaminated soil and washing liquid discharged from the biological washing machine to remove scum, and supplies the contaminated soil and washing liquid from which the scum is removed to the modified biopile processing apparatus; A modified bio-pile treatment device for agitating the contaminated soil and washing solution supplied through the centrifugal separator, washing the contaminated soil using a biosurfactant and discharging the treated soil; A flotation tank that separates scum separated from each of the rapid agitation tank, biological washing device, centrifugal separator, and modified biopile processing device into crude oil components and washing liquid by flotation, and supplies the separated washing liquid to the microorganism culture tank. ; A microorganism culture tank for culturing soil microorganisms that produce biosurfactants using a culture medium; and a microbial stabilizing tank for stabilizing a washing liquid, which is a mixture of culture medium, soil microorganisms and biosurfactants, from a microbial culture tank and supplying the washing liquid to a rapid agitation tank.

Description

Apparatus for remediation of contaminated soil using Modified biopile system and Bio washing device}

The present invention relates to a soil restoration device using a modified bio-pile processing device and a bio-washing device, and more particularly, a modified bio-pile processing device designed by the present applicant disclosed in Korea Patent Registration No. 1779903 of the present applicant. It relates to a soil restoration device using a modified biopile treatment device and a biological washing device that can effectively treat a large amount of contaminated soil while ensuring excellent washing efficiency for contaminated soil by combining with.

There are thermal, physicochemical, and biological technologies as methods for restoring soil contaminated with oil such as crude oil.

Thermal technology is a technology that decomposes harmful substances contained in soil through incineration or thermal decomposition by exposing soil to high temperatures. A method of moving to a medium, a method of decomposing by a chemical oxidation/reduction method, a method of separately separating and concentrating through adsorption/precipitation, etc. are included.

Biological treatment technology is a method of promoting biodegradation of organic compounds by activating or optimizing soil microorganisms or adding specially developed microorganisms and optimizing survival conditions, and is an eco-friendly and economical method compared to other technologies. However, the conventional biological treatment technology is difficult to apply directly when the concentration of contamination in soil contaminated with oil exceeds a certain level, and the above-mentioned thermal technology and physicochemical treatment technology are used as pretreatment technology and then applied. can be In particular, in the case of soil contaminated with a high concentration of TPH (Total Petroleum Hydrocarbons) due to crude oil leakage, etc., biological treatment is impossible because growth conditions for microorganisms are not prepared.

The present applicant, through the 'biological washing device and soil restoration device using the same' disclosed in Korean Patent No. 1779903, soil contaminated with recalcitrant organic chemicals such as high concentration TPH (Total Petroleum Hydrocarbons) and PAHs (Polycyclic Aromatic Hydrocarbons) has been shown to be able to effectively restore

The technology disclosed in Korean Patent Registration No. 1779903, in constituting a biological washing device in which contaminated soil is washed by a biosurfactant, dissolves oxygen concentration in the washing liquid in order to induce the continuous growth of soil microorganisms that produce a biosurfactant. It is characterized by presenting a device configuration that increases

The present applicant manufactured a soil restoration device based on the technology disclosed in Korean Patent Registration No. 1779903 and performed soil restoration on soil contaminated with oil (Kuwait crude oil contaminated soil), and Korean Patent No. 1779903 < Experimental Example 4: TPH removal characteristics of crude oil-contaminated soil in Kuwait. In the case of the biological washing device of the soil remediation device manufactured by the present applicant, there was a limit to increasing the throughput of contaminated soil because it had to accommodate 20 to 30 wt% (w / v) of contaminated soil compared to the total volume of the biological washing device.

On the other hand, as one of the biological treatment technologies for contaminated soil, there is a biopile treatment technology. The biopile treatment technology is a method of purifying the contaminated soil by injecting air, nutrients, and microorganisms into the contaminated soil while excavating the contaminated soil and storing it on the ground (see Korean Patent Registration Nos. 552349 and 1147430). However, the biopile treatment technology according to the prior art has a disadvantage in that it is difficult to accurately determine the progress of soil remediation along with the complexity of the method, such as the need to excavate contaminated soil. In addition, biopile treatment technology is a technology that is characterized by low biological treatment efficiency as the process is usually configured alone.

Korean Registered Patent Publication No. 1779903 (Announced on September 19, 2017) Korean Registered Patent Publication No. 552349 (2006. 2. 20. Publication) Korean Registered Patent Publication No. 1147430 (Announced on May 22, 2012)

The present invention has been devised to solve the above problems, and excellent cleaning efficiency for contaminated soil is achieved by combining a modified biopile treatment device designed by the present applicant with a biological washing device disclosed in Korean Patent Registration No. 1779903 of the present applicant. The purpose is to provide a soil restoration device using a modified bio-pile processing device and a bio-washing device that can effectively treat a large amount of contaminated soil along with securing.

In order to achieve the above object, the soil restoration device using the modified biopile processing device and biological washing device according to the present invention receives a culture solution containing soil microorganisms and biosurfactants as a washing solution, mixes the washing solution with contaminated soil, and rapidly A rapid stirring tank for stirring; A biological washing device for washing crude oil-contaminated soil using a washing solution; A modified biopile processing device that receives the contaminated soil subjected to the first-step washing by the biological washing device, stirs the contaminated soil and the washing solution, and performs a second-step washing of the contaminated soil using a biosurfactant and discharges the treated soil; The scum of the rapid agitation tank, the scum and supernatant of the biological washing device, and the scum of the modified biopile treatment device are received and separated by flotation, and the separated liquid components are supplied to the centrifugal separator, and the separated soil components are supplied to the modified biopile. Flotation separation tank for supplying to the treatment device and discarding the separated crude oil components; A centrifugal separator for centrifuging the liquid component separated by the flotation tank, supplying the fine soil to the modified bio-pile processing device, and supplying the separated liquid component again to the microorganism stabilization tank; A microorganism culture tank for culturing soil microorganisms that produce biosurfactants using a culture medium; and a microbial stabilization tank for receiving and stabilizing the washing solution, which is a mixture of the culture solution, soil microorganisms and biosurfactants, from the microbial culture tank and supplying the washing solution to the rapid agitation tank. When it is, the contaminated soil, supernatant and scum are separated by gravity sedimentation, and the separated contaminated soil is supplied to the modified biopile processing device for second-step washing, and the supernatant and scum are moved to the flotation tank.

The modified biopile treatment device includes a reaction tank for accommodating the contaminated soil treated by the biological washing device and providing a space in which the contaminated soil is washed by the contaminated soil agitation-transfer device, and stirring the mixture of the contaminated soil and the washing liquid. It is configured to include a contaminated soil agitation-transfer device for washing the contaminated soil and discharging the washed contaminated soil, that is, the treated soil, to the outside of the reaction tank.

The upper part of the reaction tank is designed to have a smaller cross-sectional area toward the top, and a scum collecting part for collecting scum is provided at the upper end of the reaction tank, and a scum removing device for moving the collected scum to the flotation separator is provided at one side of the scum collecting part.

Contaminated soil agitation-transfer device consists of a transfer screw shaft and an agitation blade, the transfer screw shaft is arranged in a form crossing the reaction tank, and the agitation blade is combined with the transfer screw shaft and rotates together when the transfer screw shaft rotates, and the circumference of the transfer screw shaft It is provided in a spirally wrapped form, and when the transfer screw shaft rotates, the contaminated soil and the washing liquid are stirred by the agitating blade to wash the contaminated soil, and when the transfer screw shaft rotates, a certain amount of contaminated soil is loaded on the transfer screw shaft It moves forward along the transfer screw shaft, and the contaminated soil transported by the transfer screw shaft is introduced into a processing soil chamber provided at one end of the transfer screw shaft, and the processing soil in the processing soil chamber is discharged to the outside through a processing soil discharge port.

An agitation pipe and a washing liquid pipe are provided at the bottom of the contaminated soil agitation-transfer device, the diffusion pipe injects air for soil microorganism growth into the reaction tank, and the washing liquid pipe is provided inside the reaction tank to control moisture in the reaction tank and supply the washing liquid. The washing solution is discharged to the outside of the reaction tank or the washing solution of the microbial culture tank is supplied to the inside of the reaction tank.

The biological washing device includes a reaction chamber providing a space in which crude oil-contaminated soil is washed by a washing liquid containing soil microorganisms and biosurfactants; and an agitation device provided in the reaction chamber to agitate the washing liquid and the crude oil-contaminated soil, wherein the agitation device includes a rotation shaft disposed in a vertical direction of the reaction chamber, and rotation of the rotation shaft at one point of the rotation shaft. It is configured to include a plurality of impellers spaced apart from each other along the direction, and the impeller has an internal space and both ends are open, and the diameter of the middle part of the impeller is smaller than the front opening hole and the rear opening hole of the impeller, so that the impeller The speed of the washing liquid passing through is greater than the speed of the washing liquid inside the reaction chamber, so a decompressed state is generated at the impeller part passing through the washing liquid, and external air under atmospheric pressure is sucked into the impeller in a reduced pressure state, thereby increasing the dissolved oxygen concentration of the washing liquid.

An air inlet is provided at one side of the upper end of the rotating shaft, and an air flow path connected to the air inlet is provided in the rotating shaft, and the impeller is composed of a front opening, a central opening, and a rear opening. Each of the cylinder and the rear hole has an open shape at both ends and has an empty inside, and the front hole, the center hole, and the rear hole are sequentially connected to each other, and the air flow path of the rotating shaft is the impeller. It extends to the central opening of the impeller, and the washing liquid flows into the front opening of the impeller, passes through the center opening, and is discharged through the rear opening. Due to the difference in pressure acting on the part, external air under atmospheric pressure is supplied to the washing liquid under reduced pressure through the central opening through the air inlet and air passage of the rotating shaft.

A culture solution supply tank for supplying a culture solution and a hemoglobin supply device for supplying hemoglobin are provided on one side of the microbial culture tank.

The soil restoration device using the modified biopile treatment device and biological washing device according to the present invention has the following effects.

It is possible to treat a large amount of contaminated soil while securing a certain level of cleaning efficiency for crude oil contaminated soil through a process in which a biological washing device and a modified biopile processing device are linked.

1 is a configuration diagram of a soil restoration device using a modified bio-pile processing device and a biological washing device according to an embodiment of the present invention.
Figure 2 is a configuration diagram of the stirring device of the biological washing device.
3 is a detailed configuration diagram of a modified biopile processing apparatus according to an embodiment of the present invention.
Figure 4 shows the change in TPH of crude oil-contaminated soil in Kuwait according to the process time of the biological washing device.
Figure 5 shows the change in UCM of crude oil-contaminated soil in Kuwait according to the process time of the biological washing device.
Figure 6 shows the change of 16 PAHs of crude oil-contaminated soil in Kuwait according to the process time of the biowashing device.
Figure 7 shows the change of Alkylated PAHs in Kuwait crude oil-contaminated soil according to the process time of the biological washing device.
8 is an experimental result showing changes in TPH, UCM, and Cn Alkane concentrations by a modified biopile processing device.
9 is an experimental result showing the growth change of 16S rRNA gene copy number according to the processing time of the modified biopile processing device.

The present invention proposes a technology related to a soil restoration device capable of treating a large amount of contaminated soil while improving the washing efficiency of contaminated soil.

In order to implement this, the present invention applies a process in which a biological washing device and a modified biopile processing device are linked. The biological cleaning device applied to the present invention uses the biological cleaning device disclosed in Korea Patent Registration No. 1779903 of the present applicant, and the modified biopile processing device is a modified biopile processing device and is linked with the biological cleaning device. newly designed for

As mentioned above in 'Technology Background of the Invention', the biological washing device disclosed in Korean Patent Registration No. 1779903 is actually implemented, and the cleaning efficiency for contaminated soil is excellent, but it is insufficient to treat a large amount of soil contamination. . In order to overcome this, a linkage process between a biological washing device and a modified biopile treatment device is presented, and through the first step washing by the biological washing device and the second step washing by the modified biopile treatment device, not only the cleaning efficiency of the contaminated soil is improved, but also the large quantity of contaminated soil can be treated.

Regarding the modified biopile processing device applied to the present invention, the conventional biopile processing device is a method of expecting biological treatment over time by injecting air, nutrients and microorganisms into the excavated and loaded contaminated soil, The modified biopile treatment device newly designed according to the present invention improves the washing efficiency of the contaminated soil by stirring the contaminated soil and the washing solution in a mixed state, and discharges the washed soil through a soil discharge device. Compared to conventional biopile treatment devices, the scum generated in the soil washing process is separated and discharged through a mechanical configuration, and the water content can be adjusted by discharging the washing liquid or supplying the culture medium if necessary. It can be said that there is a difference.

Hereinafter, a soil restoration device using a modified bio-pile processing device and a biological washing device according to an embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 1, a soil restoration device using a modified biopile processing device and a biological washing device according to an embodiment of the present invention includes a rapid agitation tank 10, a biological washing device 20, and a modified biopile processing device 30. ), a flotation separation tank 40, a centrifugal separator 50, a microbial culture tank 60, and a microbial stabilization tank 70.

The rapid agitation tank 10 rapidly agitates the contaminated soil and the washing liquid, and the stirred contaminated soil and the washing liquid are supplied to the biological washing device 20. Contaminated soil may be sorted through the soil sorter 1 and supplied to the rapid agitation tank 10 by a conveyor belt 2 or the like.

The washing liquid is supplied from the microbial stabilization tank 70, and in the present invention, the washing liquid means a culture medium containing soil microorganisms and biosurfactants. Biosurfactants are produced by soil microorganisms, which grow in culture medium. The culture solution containing these soil microorganisms and biosurfactants, that is, the washing solution is cultured in the microbial culture tank 60 and supplied to the biowashing device 20 via the microbial stabilization tank 70. The microbial culture tank 60 and the microbial stabilization tank 70 will be described later.

As the contaminated soil and the washing liquid are rapidly stirred in the rapid stirring tank 10, the high-viscosity crude oil component is desorbed from the contaminated soil by the biosurfactant of the washing liquid, and the desorbed high-viscosity crude oil component of the rapid stirring tank 10 It moves upward to form a scum. The scum generated in the rapid stirring tank 10 is removed with a scraper and moved to the flotation separation tank 40, and the mixture of contaminated soil and washing liquid in the rapid stirring tank 10 is transferred to the biological washing device 20. are supplied

The biological washing device 20 is a device for dissolving crude oil components adsorbed to contaminated soil through emulsification by a biosurfactant contained in the washing liquid. The detailed configuration of the biological washing device 20 is substantially the same as that of the biological washing device 20 disclosed in Korea Patent Registration No. 1779903 of the present applicant. Therefore, the biological washing device 20 according to the present invention is summarized in the following description.

The biological washing device 20 according to the present invention includes a reaction chamber as shown in FIGS. 1 and 2, and a stirring device composed of a rotating shaft 120 and a plurality of impellers 130 is provided in the reaction chamber. . The reaction chamber 110 provides a space in which the contaminated soil is washed by the biosurfactant, and the stirring device composed of the rotary shaft 120 and a plurality of impellers 130 stirs a mixture of the contaminated soil and the washing liquid.

The rotating shaft 120 is disposed in the vertical direction of the reaction chamber 110, and the plurality of impellers 130 are spaced apart from one point of the rotating shaft 120 at a predetermined angle along the rotational direction of the rotating shaft 120. .

The impeller 130 is a device for contacting and agitating the mixture of the contaminated soil and the washing liquid, and is designed to induce a pressure change of the washing liquid based on Bernoulli's principle. Based on Bernoulli's principle, a pressure change can be induced through a change in fluid velocity. That is, the pressure acting on each point of the washing liquid can be changed by changing the flow velocity of the washing liquid being stirred. In order to induce a pressure change of the washing liquid through a change in the fluid velocity of the washing liquid, the impeller 130 has the following configuration.

The impeller 130 is composed of a front opening cylinder 131, a center opening cylinder 132 and a rear opening cylinder 133.

The front opening 131, the center opening 132, and the rear opening 133 are open at both ends and have a hollow inside, and the front opening 131, the center opening 132 and The rear openings 133 form a sequentially connected form adjacent to each other. In addition, the center opening 132 has a cylindrical shape with a constant diameter, and the front opening 131 and the rear opening 133 provided at both ends of the center opening 132 are center opening 132 It has a form in which the diameter expands as the distance from the connection point with the . In addition, the maximum diameter of the front opening 131 is designed to be larger than the maximum diameter of the rear opening 133. The washing liquid (or the mixture of the washing liquid and contaminated soil) flows into the front opening (131), passes through the central opening (132) and is discharged through the rear opening (133).

According to Bernoulli's principle, as the velocity of a fluid increases, the pressure decreases. Based on this, since the cross-sectional area of the central opening 132 is smaller than that of the front opening 131, the speed of the washing liquid passing through the central opening 132 is greater than the speed of the washing liquid passing through the front opening 131, Accordingly, a pressure reduction phenomenon occurs in the central opening 132 portion. Therefore, it can be said that the washing liquid passing through the impeller 130 due to the rotation of the impeller 130 is placed in a reduced pressure state.

On the other hand, an air passage 122 (corresponding to the dotted line in FIG. 2 ) is provided within the rotational shaft 120, and the air passage 122 within the rotational shaft 120 extends to the central opening 132 of the impeller 130. is extended In addition, an air inlet 121 is provided at one side of an upper end of the rotating shaft 120 , and the air inlet 121 is connected to the air flow path 122 .

Under such a configuration, when the washing liquid achieves a reduced pressure lower than the atmospheric pressure by the rotation of the impeller 130, the air in the atmosphere is sucked through the air inlet 121 and the sucked air passes through the air passage 122 to the impeller 130. ), and is finally supplied to the washing liquid passing through the central opening 132. The reason why air in the atmosphere is supplied to the washing liquid through the central opening 132 of the impeller 130 without a separate power is because of the pressure difference between the washing liquid in a reduced pressure state and atmospheric pressure as described above. At this time, since the pressure acting on the washing liquid passing through the central opening 132 is lower than the atmospheric pressure, the air supplied to the washing liquid expands and disperses in the form of fine bubbles. As the air expands and disperses in the form of fine bubbles and is supplied to the cleaning solution, the dissolved oxygen efficiency is improved and the dissolved oxygen concentration is rapidly increased.

As the dissolved oxygen concentration of the washing liquid increases, the growth of soil microorganisms present in the washing liquid is ensured, and accordingly, biosurfactants are continuously produced by the soil microorganisms. In addition, due to the continuous production of biosurfactants, the cleaning efficiency of contaminated soil by biosurfactants is improved.

A baffle 140 is provided on the inner wall of the reaction chamber 110 to improve the contact efficiency between the washing liquid and the contaminated soil, and a skimmer 140 is provided on the upper side of the reaction chamber 110 to remove floating contaminants such as oil floating to the top of the washing liquid. (skimmer) 150 is provided.

When the first-step cleaning by the biological washing device 20 is completed, contaminated soil, supernatant, and scum are separated through gravity sedimentation, and the separated contaminated soil is supplied to the modified biopile processing device 30 for second-step cleaning, The supernatant and scum are moved to the flotation tank 40.

The modified bio-pile processing device 30 performs a second-step cleaning on contaminated soil for which the first-step washing by the biological washing device 20 has been completed.

As described above, there is a limit to throughput when performing soil restoration with the biological washing device 20 alone. ) in conjunction with a two-step wash by

One of the reasons why the throughput of the biological washing device 20 is limited may be due to the impeller structure designed based on Bernoulli's principle. Through the above-mentioned impeller structure, it is possible to improve the washing efficiency of contaminated soil by inducing the increase in dissolved oxygen concentration and the continuous production of biosurfactant, but in order to maintain the washing efficiency of contaminated soil at a certain level, the biological washing device 20 There is no choice but to limit the amount of contaminated soil that can be accommodated. In addition, as the biological washing device 20 alone constitutes the soil restoration process, the process time in the biological washing device 20 becomes longer for washing the contaminated soil at a certain level or more, which affects the throughput of the contaminated soil.

In order to solve these difficulties, the present invention shortens the process time of the first-step contaminated soil washing by the biological washing device 20, and the contaminated soil treated by the biological washing device 20 is a modified biopile processing device ( 30), a modified biopile processing device 30 having a size capable of accommodating an amount of contaminated soil corresponding to several batches treated by the biological washing device 20 is provided, and the deformation In the biopile treatment device 30, the two-step washing is performed and the treated soil is sequentially discharged, thereby maintaining the washing efficiency of the contaminated soil at a certain level or higher and increasing the throughput of the contaminated soil.

Compared to configuring the process with the biological washing device 20 alone, as the process time of the biological washing device 20 is shortened, the throughput of the biological washing device 20 increases, and the process time of the biological washing device 20 The decrease in washing efficiency in the biological washing device 20 due to this shortening is compensated by the two-step washing in the modified biopile processing device 30.

As shown in FIGS. 1 and 3 , the modified biopile processing device 30 includes a reaction tank 210 and a contaminated soil agitating-transfer device 220. The reaction tank 210 accommodates the contaminated soil treated by the biological washing device 20 and provides a space in which the contaminated soil is washed by the soil agitation-transfer device 220. The volume of the reaction tank 210 is designed to accommodate an amount of contaminated soil corresponding to several batches of the biological washing device 20 . In the process of cleaning the contaminated soil by the contaminated soil agitation-transfer device 220 in the reaction tank 210, scum composed of desorbed crude oil components is generated. In order to effectively remove such scum, the top of the reaction tank 210 is designed to have a smaller cross-sectional area toward the top, and a scum collecting unit 212 is provided on the upper side of the reaction tank 210. The scum moved to the top of the reaction tank 210 is aggregated in the scum collector 212 and moved to the flotation separation tank 40 through the scum removal device 230 provided on one side of the scum collector 212. In addition, an inlet 211 is provided at one side of the upper end of the reaction tank 210, and a mixture of contaminated soil and washing liquid separated by the centrifugal separator 50 flows into the reaction tank 210 through the inlet 211. .

The contaminated soil agitation-transfer device 220 serves to wash the contaminated soil by stirring the mixture of the contaminated soil and the washing liquid and discharge the washed contaminated soil, that is, the treated soil to the outside of the reaction tank 210. Contaminated soil agitation-transport device 220 is composed of a transfer screw shaft 221 and agitation blades 222. The transfer screw shaft 221 is disposed in a form crossing the reaction tank 210, and the stirring blade 222 is coupled with the transfer screw shaft 221 and rotates together when the transfer screw shaft 221 rotates, and the transfer screw shaft ( 221) is provided in a form of spirally wrapping the circumference.

When the transfer screw shaft 221 rotates, the contaminated soil and the washing liquid are stirred by the stirring blade 222, and the contaminated soil is washed by this stirring. As there are soil microorganisms and biosurfactants produced by soil microorganisms in the washing liquid, the contaminated soil is washed by the biosurfactants during the agitation process.

In addition, when the transfer screw shaft 221 rotates, a certain amount of contaminated soil is loaded on the transfer screw shaft 221 and moved forward along the transfer screw shaft 221, and the contaminated soil transferred by the transfer screw shaft 221 It flows into the processing soil chamber 240 provided at one end of the transfer screw shaft 221. A treated soil outlet 250 is provided at one side of the treated soil chamber 240 so that the treated soil processed by the modified biopile processing device 30 is finally discharged.

Meanwhile, a diffuser pipe 260 and a washing liquid pipe 270 are provided at the bottom of the contaminated soil agitation-transfer device 220. Air for the growth of soil microorganisms may be injected into the reaction tank 210 through the diffuser 260, and the washing liquid pipe 270 is used to control moisture in the reaction tank 210 and to supply the washing liquid. It serves to discharge the washing solution to the outside of the reaction tank 210 or supply the washing solution of the microbial culture tank 60 to the inside of the reaction tank 210.

A certain amount of air is injected into the reaction tank 210 of the modified biopile processing device 30 through the diffuser 260 and the washing liquid pipe 270, and the moisture and washing liquid are controlled, and the contaminated soil agitation-transfer device 220 As the washing of the contaminated soil by the proceeds, the second-step washing by the modified biopile processing device 30 also proceeds with the washing of the contaminated soil by the biosurfactant, similar to the first-step washing by the biological washing device 20.

In this way, even if the process time of the biological washing device 20 is set short, as the two-step contaminated soil washing of the biosurfactant method proceeds in the modified biopile processing device 30 having a large volume, the biological washing device 20 ), even if the washing efficiency decreases due to the shortening of the process time, it is possible to compensate for this through the two-step washing in the modified biopile processing device 30.

Next, the flotation tank 40 performs flotation separation on the scum and the supernatant transferred from the rapid stirring tank 10, the biological washing device 20, and the modified biopile processing device 30, respectively, and the flotation separation The crude oil component is discarded and the liquid component is moved to the centrifugal separator (50). In addition, soil components settled at the bottom of the flotation tank are supplied to the modified bio-pile treatment device 30.

Next, the centrifugal separator 50 receives the liquid component from the flotation tank 40 and separates the liquid component into fine soil and liquid component again through centrifugal separation. The separated fine soil is moved to the modified bio-pile treatment device 30, and the liquid component is moved to the microbial stabilization tank 70. The liquid component separated by the centrifugal separator 50 corresponds to the washing liquid component, that is, the culture medium containing the biosurfactant and soil microorganisms. A hydrocyclone may be used as the centrifugal separator 50 .

Finally, the microbial culture tank 60 and the microbial stabilization tank 70 are described as follows.

The microbial culture tank 60 is a device for culturing soil microorganisms, and in the process of culturing soil microorganisms, soil microorganisms produce a biosurfactant, and the biosurfactant produced by the soil microorganisms is washed with soil microorganisms and a culture medium. made and supplied to the microbial stabilization tank (70).

A culture solution supply tank 61 is provided at one side of the microorganism culture tank 60, and a culture solution such as a phosphoric acid solution is supplied to the microorganism culture tank 60 through the culture solution supply tank 61. In addition, a hemoglobin supply device 62 is provided on one side of the microbial culture tank 60, and 0.3 to 0.7 g of hemoglobin per 1 L of the culture medium is injected into the microbial culture tank 60 to promote the growth of soil microorganisms.

On the other hand, it is preferable to apply soil microorganisms extracted from contaminated soil to be treated as soil microorganisms cultured in the microbial culture tank 60. Soil microorganisms present in the contaminated soil to be treated survive in the soil environment contaminated with crude oil and grow using crude oil as a carbon source. When applied, it is effective in the purification of contaminated soil. There are various types of soil microorganisms that grow in soil contaminated with crude oil, depending on the region and environment where the contaminated soil exists. Representative soil microorganisms include Flavobacteriales, Burkholderiales, and Pseudomonadales . Soil microorganisms such as Flavobacteriales, Burkholderiales, and Pseudomonadales grow using crude oil as a carbon source in an environment where crude oil exists, and have the characteristics of producing biosurfactants and releasing them to the outside of cells during the growth process.

The microbial stabilization tank 70 plays a role in receiving a culture solution containing soil microorganisms and biosurfactants from the microbial culture tank 60, stabilizing it, and supplying it to the rapid agitation tank 10. As described above, the culture solution containing soil microorganisms and biosurfactants corresponds to the 'washing liquid', and the microbial stabilization tank 70 supplies the washing solution to the rapid agitation tank 10 .

In the above, the soil restoration device using the modified biopile processing device and the biological washing device according to an embodiment of the present invention has been described. Hereinafter, the present invention will be described in more detail through experimental examples.

<Experimental Example 1: TPU, UCM, 16 PAHs, Alkylated PAHs Removal Characteristics of Kuwait Crude Oil Contaminated Soil>

Kuwait crude oil-contaminated soil was washed with a biological washing machine, and then the changes in TPU, UCM, 16 PAHs, and Alkylated PAHs before and after washing were examined. In Kuwait crude oil-contaminated soil, the initial TPU was 84,198 mg/kg, the initial UCM was 77,784 mg/kg, the initial 16 PAHs were 42 mg/kg, and the initial alkylated PAHs were 3,174 mg/kg. It is a non-degradable material that has lost its properties and can be said to be contaminated soil in a state where direct biological degradation is impossible.

Soil microorganisms were cultured in 1 L of 50 mM phosphate buffer solution in which 0.1 g hemoglobin was dissolved. Then, after supplying the culture solution in which the soil microorganisms were cultured to a biological washing device, 15 kg of crude oil-contaminated soil in Kuwait was washed for 5 days using the culture solution. Subsequently, the contaminated soil was recovered through a centrifugal separator and each of TPU, UCM, 16 PAHs, and alkylated PAHs was measured.

Figure 4 shows the change in TPU of crude oil-contaminated soil in Kuwait according to the process time of the biological washing machine, Figure 5 shows the change in UCM of crude oil-contaminated soil in Kuwait according to the process time of the biological washing machine, and Figure 6 shows the process time of the biological washing machine It shows the change of 16 PAHs in crude oil-contaminated soil in Kuwait according to, and Figure 7 shows the change in Alkylated PAHs in crude oil-contaminated soil in Kuwait according to the process time of the biological washing device. 4 to 7, it can be confirmed that TPU, UCM, 16 PAHs, and Alkylated PAHs are all reduced by more than 90% by washing using a biological washing device for 5 days. In particular, in the case of 16 PAHs and Alkylated PAHs, 1-day It was confirmed that 96% and 93%, respectively, were removed by washing alone. These results can also be confirmed through the growth change of 16S rRNA gene copy number, and there is a slight change during one day of biowashing, but rapid growth after 16 PAHs and alkylated PAHs are removed by more than 90%.

Table 1 below shows values obtained by calculating the first-order reaction rate constants of TPU, UCM, 16 PAHs, and alkylated PAHs, respectively, based on the experimental results of FIGS. 4 to 7.

TPU UCM 16 PAHs Alkylated PAHS reaction rate constant
(1/day) 0.682 0.699 3.238 2.504

<Experimental Example 2: Biodegradation characteristics of modified biopile processing device>

After dissolving 3.5 g of hemoglobin (Hb) in 100 mL of 50 mM Phosphate buffer (pH 7.0) in 350 g of Kuwaiti crude oil-contaminated soil, mixing with the contaminated soil in a modified biological biopile reactor, supplying air at a flow rate of 1 mL/min through an air supply device. Reacted for 1 day. Then, by supplying 50mL Phosphate buffer solution to the microbial culture tank, the crude oil scum desorbed and emulsified from the crude oil-contaminated soil is discharged out of the reaction tank, and then the water in the biological biopile is recovered into the microbial culture tank by reversing rotation using a pump and repeatedly for 3 days. Soil samples were taken at two-week intervals and 1g Hb was additionally added to the microbial culture tank to remove biological decomposition and desorbed crude oil scum. During the initial 3 days, microbial culture solution was supplied at intervals of 1 day to remove crude oil scum detached from the crude oil-contaminated soil, and then air was continuously supplied at a flow rate of 1 mL/min while maintaining the water content in the soil at 12-16% to transform for 8 weeks. Biological biopile treatment was performed.

Referring to FIG. 8, it was confirmed that TPH and UCM were removed by 64.5% and 61.3%, respectively, and the Cn Alkane concentration was reduced by 86.2% after 2 weeks of modified biological biopile treatment. In addition, it can be seen that the TPH, UCM, and Cn Alkane concentrations are all removed by 90% or more after 6 weeks.

In the modified biological biopile process, the primary reaction rate for TPH removal was calculated as 0.067 day ^-1 , and the concentration of microorganisms in the initial crude oil-contaminated soil was 64,769,791 copies after 14 days in 244,926 copy number/g soil based on 16S rRNA gene copy number. It was confirmed that microorganisms were growing about 264 times as number / g soil (see FIG. 9), proving that many crude oil-contaminated soils can be quickly treated when treated in conjunction with a biological cleaning process and a modified biological biopile device.

1: soil sorter 2: conveyor belt
10: rapid stirring tank 20: biological washing device
30: modified biopile processing device 40: flotation separation tank
50: centrifugal separator 60: microbial culture tank
70: microbial stabilization tank
110: reaction chamber
120: rotation shaft 121: air inlet
122: air flow path 123: impeller support shaft
130: impeller 131: front opening
132: central opening 133: rear opening
140: baffle 150: skimmer
210: reaction tank 211: inlet
212: scum collection unit 220: contaminated soil agitation-transfer device
221: transfer screw shaft 222: stirring blade
230: scum removal device 240: treatment soil chamber
250: treated soil outlet 260: diffuser
270: washing liquid piping

Claims (8)

A rapid agitation tank for receiving a culture solution containing soil microorganisms and biosurfactants as a washing solution, mixing the washing solution with contaminated soil and rapidly agitating it;
A biological washing device for washing crude oil-contaminated soil using a washing liquid;
A modified biopile processing device that receives the contaminated soil subjected to the first-step washing by the biological washing device, stirs the contaminated soil and the washing solution, and performs a second-step washing of the contaminated soil using a biosurfactant and discharges the treated soil;
The scum of the rapid agitation tank, the scum and supernatant of the biological washing device, and the scum of the modified biopile treatment device are received and separated by flotation, and the separated liquid components are supplied to the centrifugal separator, and the separated soil components are supplied to the modified biopile. Flotation separation tank for supplying to the treatment device and discarding the separated crude oil components;
A centrifugal separator for centrifuging the liquid component separated by the flotation tank, supplying the fine soil to the modified bio-pile processing device, and supplying the separated liquid component again to the microorganism stabilization tank;
A microorganism culture tank for culturing soil microorganisms that produce biosurfactants using a culture medium; and
A microbial stabilization tank for stabilizing a washing liquid, which is a mixture of culture medium, soil microorganisms and biosurfactants, from a microbial culture tank and supplying the washing liquid to a rapid stirring tank;
When the first stage cleaning is completed by the biological washing device, the contaminated soil, supernatant and scum are separated by gravity sedimentation, and the separated contaminated soil is supplied to the modified biopile treatment device for the second stage cleaning, and the supernatant and scum are floated. moved to the separation tank,
The modified biopile treatment device includes a reaction tank for accommodating the contaminated soil treated by the biological washing device and providing a space in which the contaminated soil is washed by the contaminated soil agitation-transfer device, and stirring the mixture of the contaminated soil and the washing liquid. It is configured to include a contaminated soil agitation-transfer device for washing the contaminated soil and discharging the washed contaminated soil, that is, the treated soil, to the outside of the reaction tank,
The upper part of the reaction tank is designed to have a smaller cross-sectional area toward the top, and a scum collecting part for collecting scum is provided at the upper end of the reaction tank, and a scum removing device for moving the collected scum to the flotation separator is provided at one side of the scum collecting part,
Contaminated soil agitation-transfer device consists of a transfer screw shaft and an agitation blade, the transfer screw shaft is arranged in a form crossing the reaction tank, and the agitation blade is combined with the transfer screw shaft and rotates together when the transfer screw shaft rotates, and the circumference of the transfer screw shaft It is provided in a spirally wrapped form, and when the transfer screw shaft rotates, the contaminated soil and the washing liquid are stirred by the agitating blade to wash the contaminated soil, and when the transfer screw shaft rotates, a certain amount of contaminated soil is loaded on the transfer screw shaft It moves forward along the transfer screw shaft, and the contaminated soil transported by the transfer screw shaft flows into the processing soil chamber provided on one end side of the transfer screw shaft, and the processing soil in the processing soil chamber is discharged to the outside through the processing soil discharge port,
An agitation pipe and a washing liquid pipe are provided at the bottom of the contaminated soil agitation-transfer device, the diffusion pipe injects air for soil microorganism growth into the reaction tank, and the washing liquid pipe is provided inside the reaction tank to control moisture in the reaction tank and supply the washing liquid. Discharging the washing solution to the outside of the reaction tank or supplying the washing solution of the microbial culture tank to the inside of the reaction tank,
The biological washing device includes a reaction chamber providing a space in which crude oil-contaminated soil is washed by a washing liquid containing soil microorganisms and biosurfactants; and an agitation device provided in the reaction chamber to agitate the washing liquid and the crude oil-contaminated soil, wherein the agitation device includes a rotation shaft disposed in a vertical direction of the reaction chamber, and rotation of the rotation shaft at one point of the rotation shaft. It is configured to include a plurality of impellers spaced apart from each other along the direction, and the impeller has an internal space and both ends are open, and the diameter of the middle part of the impeller is smaller than the front opening hole and the rear opening hole of the impeller, so that the impeller The speed of the washing liquid passing through is greater than the speed of the washing liquid inside the reaction chamber, so a decompressed state is generated at the impeller part passing through the washing liquid, and external air under atmospheric pressure is sucked into the impeller in a reduced pressure state, thereby increasing the dissolved oxygen concentration of the washing liquid,
An air inlet is provided at one side of the upper end of the rotating shaft, and an air flow path connected to the air inlet is provided in the rotating shaft, and the impeller is composed of a front opening, a central opening, and a rear opening. Each of the cylinder and the rear hole has an open shape at both ends and has an empty inside, and the front hole, the center hole, and the rear hole are sequentially connected to each other, and the air flow path of the rotating shaft is the impeller. It extends to the central opening of the impeller, and the washing liquid flows into the front opening of the impeller, passes through the center opening, and is discharged through the rear opening. Due to the difference in pressure acting on the part, external air under atmospheric pressure is supplied to the washing liquid under reduced pressure through the central opening through the air inlet and air passage of the rotating shaft,
A culture solution supply tank for supplying a culture solution and a hemoglobin supply device for supplying hemoglobin are provided on one side of the microbial culture tank,
The volume of the reaction tank of the modified biopile treatment device is characterized in that it is designed to accommodate the amount of contaminated soil corresponding to several batches of the biopile treatment device and the soil using the biopile treatment device and biological washing device restoration device.
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