KR101768006B1 - Soil Treatment System Using Nanobubble and Multi-Stage Washing of Inorganic Acid - Google Patents

Abstract

The present invention provides a system for purifying a complex contaminated soil by using nanobubbles and inorganic acid multi-staged cleaning which dissolves oils and separates heavy metals by using nanobubbles, and efficiently removes heavy metals by means of a heavy metal elution through a multi- staged cleaning of an inorganic acid. The system comprises: a plurality of transfer conveyers which supply complex contaminated soil, contaminated by oil contaminants and heavy metals, in a regular quantity; a feeding sorting unit which comprises a contaminated sorter which is placed between the transfer conveyers, sequentially accommodates the contaminated soil, and proceeds a magnetic sorting and a particle size sorting; a first cleaning container which contains the contaminated soil sorted by the feeding sorting unit to clean; a first stage cleaning unit which is connected to and installed in one end of the first cleaning container, and comprises a first bubble generator for injecting nanobubbles to the first cleaning container in order to float and sort the oil contaminants and heavy metals adsorbed in the contaminated soil; a second cleaning container which accommodates the contaminated soil passed through the first stage cleaning unit to clean; a second stage cleaning unit which is connected to and installed in one end of the second cleaning container, and comprises a second bubble generator for injecting nanobubbles to the second cleaning container in order to float and sort the oil contaminants and heavy metals adsorbed in the contaminated soil; and inorganic acid injecting units which are connected to the first cleaning container of the first stage cleaning unit and to the second cleaning container of the second cleaning unit, respectively, and inject inorganic acids to the first cleaning container and the second cleaning container in order to remove heavy metals in the contaminated soil by means of inorganic acid elution.

Description

TECHNICAL FIELD [0001] The present invention relates to a nano-bubble cleaning method and a multi-

The present invention relates to a system for purifying complex soil contaminated with nano bubbles and inorganic acid multi-stage washing, and more particularly, to a system and method for collecting and purifying soil contaminated with oil pollutants and heavy metals, The present invention relates to a system for treating a complex contaminated soil using nanobubbles and inorganic acid multi-stage washing capable of removing heavy metals more efficiently by heavy metal elution through the washing of multi-stages of inorganic acids while progressing desorption of heavy metals.

In Korea, soil pollution is mainly caused by unauthorized landfill or leakage of liquid wastes. In addition, it is caused by the underground diffusion of ground - level objects left in the course of long - term industrial activities. It is caused by various kinds of chemical species rather than species compounds. Typical complex contaminated soils are complex pollution in the form of oil pollutants such as BTEX, diesel, gasoline and heavy metals, and occur in most industrial activity areas.

Methods for recovering contaminated soil can be classified into physical methods such as soil washing, incineration, solidification, stabilization and solvent extraction, and biological methods such as soil cultivation, composting, bio-venting, and plant restoration. Soil flushing is a technique that has recently come into widespread use as a way to quickly and easily restore contaminated soils.

In general, the soil washing method of contaminated soil is a technique of separating the soil particles from the soil particles by weakening the surface tension of the harmful organic pollutants or changing the heavy metal into the liquid phase by using water or a chemical agent. It has the advantage of being able to remove the substance while applying it regardless of the kind of the pollutant.

The in-situ method is divided into the in-situ method and the ex-situ method. The in-situ method removes the contaminated soil from the washing solution injection well, the washing solution discharge well, the washing effluent treatment facility, Soil flushing is a soil flushing method that circulates a cleaning agent in a contaminated soil to be installed on a polluted site to directly clean the contaminated soil. It is difficult to collect the cleaning agent Of course, since there is a disadvantage that there is no mobility, the soil washing method is mainly applied to the Ex-situ method.

Here, the Ex-situ method is used to grasp the distribution of pollutants in the soil and physical / chemical characteristics of the soil, excavate the contaminated soil to the extent to be treated, and then use the appropriate cleaning agent to remove the contaminated soil excavated (Soil Washing), which is a generalized method.

At this time, acid, base, organic acid, and surfactant are widely used as chemical agents applied to the soil washing technique. In the case of acids and bases, the removal efficiency of heavy metals is good, but due to the oxidation of organic substances in the soil after the treatment, additional processes such as fertilization treatment and pH adjustment are required for reuse, which is not environmentally friendly.

In addition, the surfactant has a lower efficiency than the acid and base, and its use is limited because the surfactant itself can act as a contaminant. On the other hand, in the case of organic acid formulations, the removal efficiency of heavy metals from the soil is excellent, and oxalic acid and citric acid are also used as nutrients of microorganisms, except for organic acids which are toxic like NTA or EDTA. .

In the prior art disclosed in relation to the above-mentioned purification treatment of contaminated soil, the Korean Utility Model Registration No. 1103411 (Dec. 30, 2011) discloses a method for recovering the waste activated sludge and washing liquid, A mixing unit for causing the sludge to adsorb and desorb heavy metals in the soil to be cleaned and washing and removing the heavy metal in the soil to be cleaned with the washing liquid; and a mixing unit connected to the mixing unit, A sedimentation part for sedimenting and separating the heavy metals from the soil to be cleaned and the waste activated sludge contained in the cleaning liquid and the separated heavy metal; a neutralizer connected to the sedimentation part and supplied with the cleaning solution from the sedimentation part, And a neutralizing unit for discharging the washing liquid in a neutralized state, Removal of heavy metals in soil is known, which requires less removal cost and removal efficiency while removing metal.

Also, Korean Patent Registration No. 1070706 (Sep. 29, 2011) discloses a purification device for soil contaminated with oil and heavy metals, a reactor for excavating soil contaminated with oil and heavy metals; A steam generator for heating and moisturizing the soil in the reactor; A microorganism incubator configured to operate according to an operation of the valve after operation of the steam generator, the microorganism incubator for inputting a microorganism culture liquid to the reactor; A washing liquid container filled with an acid washing liquid mixed with an organic acid and an inorganic acid therein and injecting the acid washing liquid into the reactor after completion of the operation of the microorganism by the microorganism incubator; A discharge pump for discharging the aqueous solution and the steam generated in the reactor; A water-cooled gas-liquid separator for separating the vapor discharged from the reactor into a liquid and a gas; A gas treatment device for treating the gas separated by the gas-liquid separation device; And a water separator for storing the liquid separated from the gas-liquid separator and separating the oil and water, and a porous distributor for uniformly spraying steam, a microorganism culture liquid, and an acid pickling solution at the top of the reactor And an acid solution circulating device for circulating the pickling solution discharged from the reactor to the upstream part of the reactor. The removal of contaminants due to the microbial injection and the removal of the heavy metals in the soil using the acid solution, A purification device for oil and heavy metal contaminated soil that can be extracted is known.

However, in the above-mentioned prior arts, a chemical is mixed with a cleaning liquid as a means for removing contaminants or heavy metals in contaminated soil, and an oxidizing agent for oxidation treatment of oil pollutants and an organic acid or an inorganic acid for removing heavy metals are used And the use of high concentration of chemicals has caused problems such as soil structure destruction, limited use of purified soil (increased ecotoxicity due to low pH, etc.).

In particular, when the use amount of inorganic acid is relatively lowered in the process of purifying contaminated soil, there is a problem in that it is environmentally advantageous but the purification efficiency is largely deteriorated. When the amount of inorganic acid is increased relatively, it causes serious soil structure destruction .

Korean Registered Patent No. 10-1103411 (December 30, 2011) Korean Registered Patent No. 10-1070706 (September 29, 2011)

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method and apparatus for collecting pollutants and heavy metals in polluted soil collectively by injecting nano bubbles and low concentration inorganic acid into soil contaminated with oil pollutants and heavy metals The present invention provides a system for purifying a complex contaminated soil using nano bubbles and inorganic acid multi-stage washing, which can purify, treat, maintain the use of inorganic acid at a low concentration, and increase the purification efficiency of contaminated soil through multi- It has its purpose.

In addition, the present invention is capable of removing oil pollutants from contaminated soil without using any oxidizing agent and using low concentrations of inorganic acid, thereby enabling eco-friendly soil purification technology capable of removing heavy metals without affecting soil characteristics The present invention provides a system for treating a complex contaminated soil using nano bubbles and inorganic multi-stage washing.

The composite contaminated soil purification system using nano bubbles and inorganic acid multi-stage washing proposed by the present invention comprises a plurality of conveyance conveyors for supplying a soil contaminated with oil pollutants and heavy metals in a complex manner, And a contaminated soil sorter for sequentially performing magnetic force sorting and particle size sorting while sequentially accommodating the contaminated soil sorter; A first washing tank connected to one end of the first washing tank and configured to float the oil pollutant and heavy metal adsorbed on the contaminated soil toward the first washing tank to selectively filter contaminated soil selected from the feeding sorting unit; A first bubble generator for injecting nano bubbles; A second washing tank connected to the one end of the second washing tank and configured to float the oil pollutants and heavy metals adsorbed on the contaminated soil toward the second washing tank A second bubble generator for injecting nano bubbles; The first washing tank and the second washing tank of the first stage washing section and the second washing tank of the second stage washing section, respectively, so that the heavy metals of the contaminated soil can be removed by the dissolution action of the inorganic acid. And an inorganic acid injection part to be injected.

The contaminated soil sorter of the feeding sorting unit includes a magnetic separator for sorting and separating magnetic soil having magnetic force among the contaminated soil and a vibration separator for sorting contaminated soil having a certain particle diameter through the magnetic separator, And the contaminated soil to be introduced into the first washing tank of the step washing unit is selected to have a particle diameter within the range of 0.04 to 2 mm.

The contaminated soil, which is disposed between the first-stage washing unit and the second-stage washing unit, is received from the first-stage washing unit, and the inorganic acid washing water is separated from the contaminated soil. The second washing tank of the second- And a scraper conveyor for supplying soil.

And the inorganic acid washing water separated from the scraper conveyor is regenerated by adding sodium hydroxide (NaOH) so that the inorganic acid can be reused in the first-stage washing section.

The first inorganic acid regeneration unit may include a first reaction tank in which sodium hydroxide (NaOH) is added to the inorganic inorganic acid washing water and stirred, and a second reaction tank in which a coagulating polymer is added to the inorganic acid washing water stirred in the first reaction tank and stirred to form a heavy metal- 1 coagulation tank and a first regeneration settling tank for regenerating heavy metal-hydroxide from washing water containing heavy metal-hydroxide introduced from the first flocculation tank while removing the heavy metal-hydroxide by regeneration with inorganic acid washing water.

And a dehydrating screen for containing the contaminated soil secondarily washed from the second-stage washing section and dehydrating the inorganic acid washing water in the contaminated soil.

And the inorganic acid of the washing water separated from the dewatering screen is regenerated by adding sodium hydroxide (NaOH) to the second-stage washing section so as to be reused.

The second inorganic acid regeneration unit may include a second reaction tank in which sodium hydroxide (NaOH) is added to the internal washing water and stirred, and a second agglomeration unit that agitates the agglomerated polymer in the washing water stirred in the second reaction tank to form heavy metal- And a second regenerating sedimentation tank for regenerating heavy metal-hydroxide from the wash water containing the heavy metal-hydroxide introduced from the second flocculation tank, while regenerating the heavy metal-hydroxide with inorganic acid wash water.

According to the present invention, multi-stage cleaning is applied to the purification treatment of polluted soil contaminated with oil pollutants and heavy metals, so that the use of nanobubbles and low concentration inorganic acids The cleaning efficiency can be improved and an environmentally advantageous cleaning operation can be achieved.

In addition, the system for cleaning contaminated soils using nano bubbles and multi-stage washing of inorganic acids according to the present invention provides excellent oil removal efficiency without using a separate oxidant in the process of purifying contaminated soil, Therefore, it is possible to construct an eco-friendly soil remediation technology by improving the removal efficiency of heavy metals without affecting the soil peculiarity.

In addition, the composite contaminated soil purification system using nano bubbles and inorganic acid multi-stage washing according to the present invention recycles inorganic acid from the washing wastewater used for cleaning contaminated soil, thereby reducing the amount of inorganic acid injected in the washing process, There is an effect.

1 is a block diagram schematically illustrating an embodiment according to the present invention;
Fig. 2 is an overall configuration diagram showing an embodiment according to the present invention; Fig.
3 is a schematic view showing a first stage washing unit according to an embodiment of the present invention.
4 is a view showing a two-stage washing unit according to an embodiment of the present invention.
FIG. 5 is a schematic view showing a first inorganic acid regeneration section according to an embodiment of the present invention. FIG.
6 is a schematic view showing a second inorganic acid regeneration section in an embodiment according to the present invention.

The present invention relates to a method and apparatus for collecting contaminated soil, which comprises a plurality of conveying conveyors for supplying a soil contaminated with oil pollutants and heavy metals in a quantitative manner, and a contaminated soil sorter disposed between the conveying conveyors for sequentially sorting contaminated soil, A feeding selector configured to include a feeder; A first washing tank connected to one end of the first washing tank and configured to float the oil pollutant and heavy metal adsorbed on the contaminated soil toward the first washing tank to selectively filter contaminated soil selected from the feeding sorting unit; A first bubble generator for injecting nano bubbles; A second washing tank connected to the one end of the second washing tank and configured to float the oil pollutants and heavy metals adsorbed on the contaminated soil toward the second washing tank A second bubble generator for injecting nano bubbles; The first washing tank and the second washing tank of the first stage washing section and the second washing tank of the second stage washing section, respectively, so that the heavy metals of the contaminated soil can be removed by the dissolution action of the inorganic acid. And an inorganic acid injecting unit for injecting inorganic nano bubbles and inorganic acid multi-stage washing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, an embodiment of a system for cleaning a composite contaminated soil using nano bubbles and multi-stage washing of inorganic acids according to the present invention includes a feeding sorting unit 10, a first stage washing unit 20, A two-stage washing unit 30, and an inorganic acid injection unit 40.

The feeding sorting unit 10 carries the contaminated soil excavated from the separate excavation equipment toward the first-stage washing unit 20, and performs the function of feeding through the sorting step.

The feeding sorting unit 10 is configured to feed the soil contaminated with oil pollutants and heavy metals toward the first-stage washing unit 20 as a first purification treatment point, And a contaminated soil sorter (13) disposed between the conveying conveyor (11) and sorting contaminated soil.

The contaminated soil sorter 13 sequentially receives the contaminated soil supplied through the conveying conveyor 11 to perform magnetic force sorting and grain size sorting. That is, the contaminated soil sorter 13 includes a magnetic separator 13a disposed between the conveying conveyors 11 for primarily sorting and separating the magnetic soil having magnetic force among the contaminated soil, And a vibration discriminator (13b) for discriminating the contaminated soil conveyed through the conveying conveyor (11) again and sorting the polluted soil with a predetermined particle size.

In the vibration discriminator 13b, the contaminated soil to be supplied to the one-stage washing unit 20 to be introduced is selected within a range of 0.04 to 2 mm in particle size.

The contaminated soil that has passed through the feeding and sorting unit 10 is configured to be able to carry out a multi-stage washing process while sequentially passing through the first-stage washing unit 20 and the second-stage washing unit 30.

The first stage washing unit 20 performs a purification process on the contaminated soil transferred through the sorting process (sorting and sorting of the magnetic force) of the feeding sorting unit 10, but in order to remove oil pollutants and heavy metals in the contaminated soil, Car wash function.

As shown in FIGS. 2 and 3, the first-stage washing unit 20 includes a first washing tank 21 for receiving contaminated soil finally selected through the vibration separator 13b of the feeding and sorting unit 10 And a first bubble generator 23 for injecting nano bubbles toward the first washing tank 21.

The first washing tank (21) is equipped with an agitator which is capable of always stirring to wash the polluted soil while receiving washing water and inorganic acid from the outside together with contaminated soil contained therein, And a pH meter capable of confirming the hydrogen ion concentration in the space.

It is preferable that the concentration of hydrogen ions in the first washing tank 21 is controlled through the pH meter so that the concentration of hydrogen ions can be maintained at a pH of 3 or lower to facilitate the removal of heavy metals according to inorganic acids.

The first bubble generator 23 is connected to one end of the first washing tank 21 and generates nano bubbles to be injected toward the first washing tank 21.

The first bubble generator 23 injects nano bubbles into the first washing tank 21 under a strong pressure so that floating pollutants and heavy metals adsorbed on the contaminated soil can be selected. That is, the nano bubbles in the form of fine bubbles are contacted through the first bubble generator 23 to float the oil contaminants and heavy metals of the contaminated soil, thereby separating the oil contaminants and heavy metals from the contaminated soil.

In the first stage washing unit 20, washing water and inorganic acid in the first washing tank 21 are injected together with the nano bubbles through the first bubble generator 23 to remove oil contaminants and heavy metals from the contaminated soil To operate.

The contaminated soil washed through the first-stage washing unit 20 is separated from the washing water and then transferred to the second-stage washing unit 30. The first-stage washing unit 20 and the second- A scraper conveyor 25 is formed.

The scraper conveyor 25 is disposed between the one-stage washing unit 20 and the two-stage washing unit 30 and supplies the contaminated soil firstly washed from the first-stage washing unit 20 to the waste water (inorganic acid washing water) As shown in Fig.

In the scraper conveyor 25, the contaminated soil supplied from the first-stage washing unit 20 and the inorganic acid washing water are separated from each other, and then supplied through the divided conveyance path, And is supplied to the washing tub 31.

The inorganic acid washing water separated from the contaminated soil in the scraper conveyor (25) constitutes a first inorganic acid regeneration unit (50) for regenerating the inorganic acid so as to be reused.

The first inorganic acid regeneration unit 50 regenerates sodium hydroxide (NaOH) to regenerate inorganic acid washing water so that the inorganic acid used in the first-stage washing unit 20 can be reused in the first-stage washing unit 20 As shown in FIG. 2 and FIG. 5, a first reaction tank 51, a first flocculation tank 53, and a first regeneration tank 55 are provided.

The first reaction tank 51 is composed of a stirring structure in which a reaction solution reservoir (CT) provided for storing sodium hydroxide is connected, sodium hydroxide is injected into the inorganic inorganic acid washing water, and sodium hydroxide is reacted with the inorganic acid washing water. That is, in the first reaction tank 51, the heavy metal-inorganic acid compound contained in the inorganic acid washing water is mixed and reacted with sodium hydroxide.

The first flocculation tank 53 has an agitatable structure in which an agglomerated polymer is introduced into the first reaction tank 51 together with inorganic acid washing water. That is, a polymer storage tank (PT) storing the aggregated polymer is connected to introduce the polymer, and the aggregated polymer is mixed and stirred in the inorganic acid washing water stirred in the first reaction tank (51) to form heavy metal-hydroxide.

The first regenerating sedimentation tank 55 is configured to regenerate heavy metal-hydroxide from the inorganic acid washing water containing the heavy metal-hydroxide introduced from the first flocculating tank 53 while removing it by the inorganic acid washing water.

The first regenerating sedimentation tank 55 precipitates the heavy metal-hydroxide in the inorganic acid washing water to separate the inorganic acid washing water and the heavy metal-hydroxide from each other and feeds the separated water to the sludge storage tank ST for the heavy metal- In the case of the inorganic acid washing water regenerated in the first regeneration settling tank 55, the inorganic acid washing water is supplied to and stored in a separate process water tank WT1 and then stored in the first bubbling generator 23 of the first stage washing unit 20, So that the inorganic acid washing water regenerated toward the vibration discriminating unit 13b of the sorting unit 13 can be supplied.

The two-stage washing unit 30 performs the function of removing pollutants and heavy metals from the contaminated soil by washing the contaminated soil primarily washed through the first-stage washing unit 20 again.

As shown in FIGS. 2 and 4, the two-stage washing unit 30 includes a second washing tank 30, which receives the contaminated soil supplied from the first-stage washing unit 20 through the scraper conveyor 25, A second bubble generator 31 connected to one end of the second washing tank 31 and injecting nano bubbles toward the second washing tank 31 to float and sort the oil pollutants and heavy metals adsorbed on the contaminated soil, (33).

The structures of the second washing tank 31 and the second bubbling generator 33 are the same as those of the first washing tank 21 and the first bubbling generator 23, do.

And a dewatering screen 35 for treating the contaminated soil so as to separate the inorganic acid washing water from the washed soil.

The dewatering screen 35 receives the contaminated soil secondarily washed from the two-stage washing section together with wastewater (inorganic acid washing water), and dehydrates the inorganic acid washing water from the contaminated soil, thereby finally obtaining the treated soil subjected to the purification treatment.

The inorganic acid washing water separated from the contaminated soil in the dewatering screen (35) constitutes a second inorganic acid regeneration unit (60) for regenerating the inorganic acid so as to be reused.

The second inorganic acid regeneration unit 60 regenerates the inorganic acid washing water by adding sodium hydroxide (NaOH) so that the inorganic acid used in the second-stage washing unit 30 can be reused in the second-stage washing unit 30 As shown in FIG. 2 and FIG. 6, a second reaction tank 61, a second flocculation tank 63, and a second regeneration sedimentation tank 65 are provided.

The second reaction vessel (61) has a stirring structure connected to the reaction liquid storage tank (CT) provided for storing sodium hydroxide so that sodium hydroxide is injected into the inorganic inorganic acid washing water and sodium hydroxide is reacted with the inorganic acid washing water . That is, in the second reaction tank (61), the heavy metal-inorganic acid compound contained in the inorganic acid washing water is mixed and reacted with sodium hydroxide.

The second flocculation tank 63 has a stirrer structure in which the flocculation polymer is introduced into the second reaction tank 61 together with inorganic acid washing water. That is, a polymer storage tank (PT) storing the aggregated polymer is connected to feed the aggregated polymer, and the aggregated polymer is mixed and stirred in the inorganic acid washing water stirred in the second reaction tank (61) to form heavy metal-hydroxide.

The second regeneration settling tank 65 is configured to regenerate heavy metal-hydroxide from the inorganic acid washing water containing the heavy metal-hydroxide introduced from the second flocculating tank 63 while removing it by the inorganic acid washing water.

The second regenerating sedimentation tank 65 separates the heavy metal-hydroxide from the inorganic acid washing water to separate the inorganic acid washing water and the heavy metal-hydroxide from each other, and supplies it to the separate sludge storage tank ST for the heavy metal- And the inorganic acid washing water regenerated in the second regeneration settling tank 65 is supplied to and stored in a separate process water tank WT2 and is regenerated toward the second bubble generator 33 of the second washing stage 30 So that inorganic acid washing water can be supplied.

2, inorganic acid is stored in the inorganic acid injecting unit 40, and the inorganic acid is injected into the first washing tank 21 of the first stage washing unit 20 and the second washing tank 21 of the second stage washing unit 30, (31), and the inorganic acid is injected.

The inorganic acid injecting unit 40 injects inorganic acid into the contaminated soil in the first washing tank 21 and the second washing tank 31 to remove the heavy metals in the contaminated soil by the dissolution action of the inorganic acid. In other words, due to the influence of nano bubbles, the oil pollutants on the contaminated soil are decomposed and the heavy metal is desorbed, and the heavy metal is removed by the dissolution action of the inorganic acid.

As the inorganic acid, hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ) nitric acid (HNO ₃ ), phosphoric acid (H ₃ PO ₄ ), ferric chloride (FeCl ₃ ), electrolytic water, hypochlorous acid H ₂ O ₂ ).

The results of the treatment were evaluated by constructing a complex contaminated soil purification system using nano bubbles and inorganic acid multi-stage washing according to the present invention.

[Complex contaminated soil treatment]

(1) Sample preparation of complex contaminated soil

A 10% (v / v) light oil was injected into the soil contaminated with zinc and lead, mixed with 10% (v / v) light oil and kept for 10 days to adsorb to the soil. A total of five samples were prepared.

(2) Nano bubble removal rate (Comparative Example 1)

Table 1 shows the results of the removal of heavy metals after washing the mixed contaminated soil for 1 hour while injecting nano bubbles into the mixed contaminated soil while washing water was added to the prepared composite contaminated soil samples.

(3) Nano bubble + organic acid removal ratio (Comparative Example 2)

The removal rate of heavy metals was measured by washing the mixed contaminated soil with 300mM of organic acid citric acid together with the nano bubbles to the mixed contaminated soil while washing water was added to the prepared contaminated soil samples. The results are shown in Table 1 below.

(4) Nano bubble + inorganic acid removal ratio (Comparative Example 3)

The removal rate of heavy metals was measured after washing the mixed contaminated soil for 1 hour by injecting hydrochloric acid (Hydrochloric) of 300mM together with the nano bubbles toward the mixed contaminated soil while washing water was added to the prepared contaminated soil samples. The results are shown in Table 1 below.

(5) Nano bubble + inorganic acid + multi-stage washing removal rate (Example 1)

The mixed contaminated soil samples were mixed with nano bubbles and mixed with hydrochloric acid (Hydrochloric) of 100mM for 1 hour. Then, the mixed contaminated soil was washed for 1 hour, Was washed again under the same conditions as above, and then the removal rate of heavy metals was measured. The results are shown in Table 1 below.

division Removal rate (%) Comparative Example 1 52.1 Comparative Example 2 64.7 Comparative Example 3 87.7 Example 1 89.1

As shown in Table 1, when the nano bubbles alone were applied, the lowest treatment efficiency (52.1% removal) was shown. As a result, when the organic acid was injected together with the nano bubbles, (64.7% removal), and showed very good treatment efficiency (87.7% removal) when nanobubbles and a large amount of inorganic acid were injected. In addition, nano bubbles and a relatively small amount of inorganic acid were injected, And the highest treatment efficiency (89.1% removal) was observed in one case.

[Regeneration of inorganic acid washing water]

In addition, the inorganic acid injection amount and the removal efficiency were measured (Comparative Example) while the nano bubble and the inorganic acid were injected into the composite contaminated soil. On the other hand, in the washing process of the first contaminated soil, inorganic acid was injected and washed, (NaOH) powder was injected to regenerate inorganic acid washing water, and inorganic acid washing water was applied to a washing process of a mixed contaminated soil, and inorganic acid injection amount and removal efficiency were measured (Examples). The results are shown in Table 2 below.

division Amount of inorganic acid (g) Removal rate (%) Comparative Example 0.06 89.3 Example 0.04 89.7

When the inorganic acid washing water was regenerated from the washing wastewater, the amount of the organic acid was reduced by about 1/3 in the washing process for the contaminated soil, I could confirm.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it is also within the scope of the present invention.

10: Feeding selector 11: Feed conveyor
13: contaminated soil sorter 13a: magnetic force sorter 13b: vibration sorter
20: first stage washing unit 21: first washing tank 23: first bubble generator
25: scraper conveyor 30: second stage washing section
31: second washing tank 33: second bubble generator
35: Dewatering screen 40: Inorganic acid injection part 50: First inorganic acid regeneration part
51: first reaction tank 53: first flocculation tank 55: first regeneration tank
60: Second inorganic acid regeneration unit 61: Second reaction tank 63: Second aggregation tank
65: second regeneration tank WT1, WT2: process tank CT: reaction liquid storage tank
PT: Polymer storage tank ST: Sludge storage tank

Claims (9)

A plurality of conveying conveyors for supplying the soil contaminated with oil pollutants and heavy metals in a complex manner and a contaminated soil sorter disposed between the conveying conveyors for sequentially sorting the contaminated soil, A feeder selection unit configured to feed the feeder; A first washing tank for washing the polluted soil so as to wash the contaminated soil selected from the feeding selector and having a stirrer for washing the contaminated soil and a pH meter for confirming the hydrogen ion concentration, A first bubble generator connected to one end of the first washing tank and configured to inject nano bubbles toward the first washing tank to float the oil pollutant and heavy metal adsorbed on the contaminated soil; A second washing tank including a stirrer for washing the contaminated soil and a pH meter for confirming the hydrogen ion concentration, the washing tank being connected to the one end of the second washing tank, A second bubble generator for injecting nano bubbles toward the second cleaning tank to suspend oil pollutants and heavy metals adsorbed on contaminated soil; The first washing tank and the second washing tank of the first stage washing section and the second washing tank of the second stage washing section, respectively, so that the heavy metals of the contaminated soil can be removed by the dissolution action of the inorganic acid. And an inorganic acid injecting unit to be injected,
The contaminated soil sorter of the feeding sorting unit includes a magnetic separator for sorting and separating magnetic soil having magnetic force among the contaminated soil and a vibration separator for sorting contaminated soil having a certain particle diameter through the magnetic separator, The contaminated soil to be introduced into the first washing tank of the step washing unit is selected to have a particle diameter within the range of 0.04 to 2 mm,
Wherein the contaminated soil is disposed between the first-stage washing unit and the second-stage washing unit, and the contaminated soil first washed from the first-stage washing unit is received, the inorganic acid washing water is separated from the contaminated soil, And a scraper conveyor for supplying the scraper conveyor,
And a first inorganic acid regeneration section for regenerating inorganic acid washing water separated from the scraper conveyor by adding sodium hydroxide (NaOH) so that the inorganic acid can be reused in the first stage washing section, wherein the first inorganic acid regeneration section A first flocculation tank for adding heavy metal-hydroxide to the inorganic acid washing water after stirring the flocculated polymer in the inorganic acid washing water stirred in the first reaction tank; Wherein the inorganic acid washing water recovered in the first regeneration settling tank is supplied to the first bubble generator and the second bubble generator in the first regeneration tank, and the first regenerating tank is regenerated with inorganic acid washing water while precipitating heavy metal-hydroxide from the washing water containing the heavy metal- To the vibration discriminating device of the contaminated soil sorter,
And a dewatering screen for containing the contaminated soil secondly washed from the second-stage washing section, wherein the dehydrating screen dehydrates the inorganic acid washing water in the contaminated soil,
And a second inorganic acid regeneration unit for regenerating the inorganic acid of the washing water separated from the dewatering screen by adding sodium hydroxide (NaOH) so that the inorganic acid can be reused in the second-stage washing unit, wherein the second inorganic acid regeneration unit is configured to regenerate sodium hydroxide A second agglomeration tank in which the agglomerated polymer is charged into the washing water agitated in the second reaction tank and stirred to form a heavy metal-hydroxide; and a second agglomeration tank in which the heavy metal- And a second regenerating sedimentation tank for regenerating the heavy metal-hydroxides from the wash water containing hydroxides by precipitation and regeneration with inorganic acid washing water, wherein the inorganic acid washing water regenerated in the second regeneration settling tank is supplied toward the second bubble generator of the second- Combined Soil Purification System Using Nano Bubble and Multi - Stage Cleaning of Inorganic.
delete delete delete delete delete delete delete The method according to claim 1,
The inorganic acid in the inorganic acid injecting portion may be at least one selected from the group consisting of hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ) nitric acid (HNO ₃ ), phosphoric acid (H ₃ PO ₄ ), ferric chloride (FeCl ₃ ), electrolytic water, (H ₂ O ₂ ), which is used for cleaning contaminated soils.

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