KR100500266B1 - Multi-stage soil washing apparatus for purging complexly contaminated soil - Google Patents

Abstract

The present invention relates to a soil washing apparatus that can obtain the maximum purification efficiency at the minimum cost in treating soil contaminated with oil and heavy metals, and more specifically, an enclosed drum 14 extending in the longitudinal direction. And, a soil feed hopper (21) installed in the upper front of the closed drum, a plurality of high-pressure jet nozzles 22 are provided at regular intervals along the upper center of the inside of the closed drum to spray washing water, A plurality of stirring blades (13) for stirring the soil inside the hermetic drum (13) attached to both sides at regular intervals, and a plurality of installed on the bottom of the hermetic drum so that the stirred washing water and the soil mixture is moved slowly Retention partition 28, formed in the lower part of the front of the closed drum to discharge the washing waste water generated by stirring the washing water and the soil A first washing tank including a washing waste water outlet 26 and a soil outlet 27 formed below the sealed drum rear; And an open drum 16 receiving soil washed by the first washing tank, a rotating shaft 31 attached with a spiral blade 32 capable of moving the soil by rotating inside the open drum, and washed soil. Rotating discharge means 34 installed at the rear of the open drum to discharge the water, a plurality of washing water spray nozzles 37 installed at the top of the rotary discharge means for the final rinsing of the soil to supply and discharge the washing liquid, and Multi-stage soil for complex contaminated soil purification comprising a secondary washing tank consisting of a soil outlet 35 through which the rinsed soil is discharged, and a wastewater outlet 36 installed in front of the open drum for discharge of the waste washing water. It relates to a washing device.

Description

Multi-Stage Soil Washing Apparatus for Purging Complexly Contaminated Soil

Field of invention

The present invention relates to a multi-stage soil washing apparatus for the purification of complex contaminated soil. More specifically, the present invention relates to a first washing tank for desorbing oil compounds from soil by physical agitation and impact of soil contaminated with oil compounds and heavy metals. And it relates to a multi-stage soil washing apparatus having a spiral blade for smooth mixing and stirring of heavy metal eluent and contaminated soil.

Background of the Invention

Soil pollution, once polluted, can cause secondary pollution to the surrounding environment, such as adversely affecting the quality of surface water and groundwater. Therefore, contaminated soil must be purified and restored at the site as soon as possible.

At present, domestic soil pollution is mainly caused by unauthorized landfill or leakage accident of liquid waste, and also by underground spread of ground stocks that have been neglected during long-term industrial activities. The contaminated soils caused by these factors are caused by various chemical species rather than a single compound, and the representative complex pollution occurs in most industrial activities in the form of oil and heavy metals.

In order to clean the contaminated soil, it is divided into two types: soil contaminated with oil compounds and soil contaminated with heavy metals. First, physical, chemical and biological methods are introduced in the case of oil contaminated soil washing.

Physical cleaning methods are mainly known as desorption by high pressure injection of the washing water and washing by mechanical stirring effect. The high pressure injection of the washing water is a method in which the contaminated soil is desorbed by the strong washing water while the contaminated soil passes through the washing water high pressure spraying line by a conveying conveyor using a metal screen mesh belt. On the other hand, the amount of washing water used is high, the soil loss during the washing process is large, and the process size is enormous.

Soil washing method by mechanical agitation is to remove the contaminants from the soil by sufficiently stirring the washing water and contaminated soil in the liquid phase and to move the washing water. The use of washing water is less than the high pressure spraying method and the process size is relatively small. It is slightly lower and requires more washing time. This physical cleaning method has a high cleaning effect by other cleaning methods because the separation of oil compounds from soil depends on the physical friction and the degree of impact, whereas the energy consumption is relatively high and the size of machinery is large. .

Chemical cleaning method is known as a representative additive as a representative method to more easily separate the oil compound from the soil even without strong physical stirring by mixing a chemical additive that can easily dissolve the oil compound of interest in the detergent. The chemical cleaning method is simple in the form of a device, which is advantageous in terms of the mechanical device compared to the physical cleaning method. However, there are known problems such as an increase in the cleaning cost and the post-treatment of chemical additives contained in the washing wastewater. In general, chemical cleaning methods are limited to the purification of small-scale contaminated soils that are difficult to desorb by physical cleaning.

Finally, the biological washing method is a method of mixing contaminated soil and water in the form of slurry to remove contaminants in soil by the decomposition effect of microorganisms while maintaining the nutrients and temperature necessary for the growth and activity of microorganisms. On the other hand, in the case of soil particles having a long treatment period and a large particle size, it is difficult to maintain a slurry state, and thus it is generally applied to the treatment of a small amount of fine contaminated soil which is difficult to desorb.

Therefore, in the case of oil contaminated soil, physical soil washing method is most widely used, and various types of washing apparatuses are introduced accordingly.

In the case of heavy metal contaminated soils, unlike heavy oil contaminated soils, heavy metals present in the soil are fixed by various reaction bonds, so it is difficult to desorb from the soil by general physical effects, and most of them use washing water containing chemical additives. Cleaning method to elute chemically. Therefore, the cleaning methods in this field are introduced in various ways depending on the cleaning performance of the chemical added rather than the device aspect. Separation of heavy metals from soil depends on the elution effect by reaction with these chemicals. Representative chemical eluents include acid and alkali solutions, and EDTA, which can easily form complexes with heavy metals, can be stably present in aqueous solutions. The same chelating agent is used.

In this way, the heavy metal washing method is important because the reaction with the chemical cleaning agent that can easily elute the heavy metal fixed in the soil in the washing liquid phase, the reaction washing liquid and soil heavy metal rather than physical agitation strength to obtain a high desorption effect, such as oil in terms of equipment It is sufficient that the stirring is sufficient to obtain the contact effect required for the liver reaction. In addition, since heavy metals eluted in the liquid phase may be precipitated or adsorbed back into the soil depending on the conditions, recontamination of the soil may occur. Therefore, an apparatus should be devised to minimize re-contact between the eluted heavy metals and the washed soil.

At present, the soil washing apparatus for the purification of contaminated soil is equipped with a system for effectively treating soil contaminated with oil compounds using physical friction means or partially using chemical cleaning agents. The most common type of washing tank uses strong friction force between washing water and soil by high-speed rotation of a rotating stirring shaft with a plurality of stirring blades attached to the washing tank (Republic of Korea Patent Application Publication No. 2000-0019833; Japanese Laid-Open Patent Publication No. 2003-10831), and the situation is merely to change the shape of the stirring rotary shaft.

In the case of a washing apparatus using a chemical aid such as a surfactant as washing water, strong physical agitation is not required, and thus, a mechanical apparatus is usually simpler to obtain only a uniform mixing effect between the washing water and the soil (Korean Patent Publication No. 2003-A). 0005713; US 5,829,691; US 5,637,132).

However, the chemical soil washing apparatuses are equally applicable to the washing of heavy metal contaminated soil as well as the soil contaminated with oil compounds, so that the soil contaminated by heavy metals cannot be effectively washed.

Accordingly, the present inventors have divided the washing step into two steps, and as a result of making diligent efforts to confirm that each oil compound and heavy metals can be effectively treated at each step according to the pollution characteristics, the present invention has been completed.

After all, the main object of the present invention comprises a primary washing tank for desorbing oil compounds from the soil by physical stirring and impact effect and a secondary washing tank configured to effectively separate the heavy metals, the soil contaminated with the oil compound and heavy metals To provide a multi-stage soil washing apparatus that effectively cleans and cleans.

Another object of the present invention is to provide a multi-stage soil washing apparatus that can obtain the maximum purification efficiency at the minimum cost in treating the soil contaminated with oil and heavy metals.

In order to achieve the above object, the present invention provides a sealed drum that is elongated in the longitudinal axis, a soil feed hopper installed at the upper front of the sealed drum, and an upper center of the sealed drum to spray washing water. A plurality of high pressure spray nozzles installed at regular intervals, a plurality of agitator blades for agitating the soil inside the sealed drum are attached to both sides at regular intervals, and the stirred wash water and soil mixture to move slowly A plurality of retention partitions installed on the bottom of the sealed drum, the first waste consisting of a washing waste water outlet formed in the lower front of the sealed drum to discharge the washing waste water generated by stirring the washing water and soil, and a soil outlet formed in the lower portion of the rear behind the closed drum Washing tank; And an open drum receiving the soil washed by the first washing tank, a rotating shaft having a spiral blade attached to the inside of the open drum to move the soil, and a rear of the open drum to discharge the washed soil. Rotating discharge means installed in the, the rinsing liquid supply and discharge for the final rinsing of the soil, the plurality of washing water injection nozzles installed on the upper portion of the rotary discharge means, the soil outlet through which the final rinsed soil, and discharge of the waste washing water In order to provide a multi-stage soil washing apparatus for cleaning the complex contaminated soil, characterized in that it comprises a secondary washing tank consisting of a waste water outlet installed in front of the open drum.

In the present invention, it is preferable that the stirring blade is formed in a hoe shape or a plow shape so as to facilitate stirring and uplifting of the soil.

In addition, in the present invention, a plurality of paddle (paddle) for a smooth mixing and stirring of the soil during the rotation of the secondary washing tank rotating shaft between the screw thread and the screw thread of the spiral blade is a predetermined interval along the circumference of the spiral blade Preferably, the paddle may be provided with a foil-shaped stirring blade or a plow-shaped stirring blade for increasing the effect of stirring and mixing.

In the present invention, the secondary washing tank soil discharge means is a cylindrical wheel (wheel) attached to the outer circumference at a predetermined interval in the metal mesh shape is fixed to the rotating shaft is washed to be introduced from the rear of the washing tank during rotation of the rotating shaft Soil is separated from the water from the bottom of the washing tank can be characterized in that it is configured to be continuously pumped, the second washing tank waste water outlet is a waste water overflow due to the water level difference by placing the ware in the front of the washing tank lower than the height of the washing tank wall It can be characterized in that it is configured to be naturally discharged to the outside.

Multi-stage washing apparatus for the purification of complex contaminated soil according to the present invention constitutes a two-stage washing tank to maximize the physical frictional effect in the first washing tank to quickly desorb oil components from the soil, and includes a heavy metal eluent in the second washing tank. Using the wash water added with a chemical solvent to effectively elute heavy metals from the soil to discharge the purified soil.

That is, the primary washing tank uses the chemical-free washing water to maximize the friction effect between the slurry stir and the collision between the sprayed washing water and the soil particles so that oil contaminants can be quickly desorbed from the soil by physical stirring and collision effects. A closed drum washing tank equipped with a stirring rotating shaft for the second washing tank includes a spiral blade capable of smooth mixing and stirring between heavy metal eluent and contaminated soil to effectively separate heavy metals chemically fixed in soil. It was designed so that the movement of soil and soil in the washing tank was countercurrent to prevent the precipitation and adsorption of the eluted heavy metals on the washed soil surface so that the maximum soil treatment effect could be achieved under the minimum chemical additive injection conditions.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is an overall schematic diagram of a multi-stage soil washing apparatus composed of a first washing tank and a second washing tank according to the present invention. That is, the soil hopper (feed hopper) 21 is installed in the upper portion of the front of the primary washing tank 14 having a closed drum structure by the conveyor 11 in the soil storage tank 10 installed outside the soil. When continuously introduced through, while the stirring blade 13 inside the drum washing tank is advanced by the rotational drive of the first washing tank rotary shaft 23 attached at regular intervals on both sides, the sealed drum in the primary washing water storage tank 12 Stirred mixing with the washing water sprayed through the high-pressure jet nozzle 22 installed at regular intervals along the upper center of the inside and collision friction between the soil particles so that the oil contaminants of the contaminated soil can be quickly desorbed. The waste washing water including the oil contaminants is transferred to the first washing tank septic tank 15 after being discharged and discharged in the opposite direction to the soil.

Soil discharged from the primary washing tank is introduced into the secondary washing tank (16) having an open drum structure and is transported by the rotation of the rotating shaft attached to the spiral blade installed inside the secondary washing tank, and is transferred in the opposite direction to the soil. Desorption of heavy metals from the soil occurs rapidly with sufficient friction stirring with heavy metal eluates. The waste washing liquid is discharged through the second washing tank waste water outlet installed on one side of the washing tank opposite the soil discharge unit, and then flows into the septic tank 17. The final washed soil is discharged by the soil discharge means installed behind the secondary washing tank rotary shaft and then transported to the outside by the belt conveyor 18.

Figure 2 is a detailed view of the first washing tank of the multi-stage soil washing apparatus according to the present invention. The primary washing tank is composed of a closed drum 14 extending in the longitudinal direction, which is capable of preventing the outflow of soil due to strong washing stirring inside and minimizing noise caused by mechanical friction. do.

A soil feed hopper 21 is installed at the upper part of the sealed drum front, and a plurality of high pressure spray nozzles 22 are provided at regular intervals along the upper center of the inside of the sealed drum to spray washing water. The high pressure jet nozzle functions to uniformly spray the washing water introduced into the high pressure condition from the outside at a high pressure in the washing tank.

Inside the hermetic drum, a plurality of stirring blades 13 for soil stirring are installed on both sides with a first washing tank rotating shaft 23 attached at regular intervals. At this time, the stirring blade may be characterized in that it is formed in a hoe shape 24 or a plow shape (25). The stirring blades of the hoe and plow type are strongly scattered in the vertical and centrifugal directions with respect to the longitudinal axis to the upper space above the water surface, as well as the stirring of the washing water and the soil mixture at the bottom of the washing tank along with the soil transfer during rotation of the rotary shaft. As a result, a collision between soil and soil in the upper space and a strong air collision between washing water and soil sprayed from the high-pressure jet nozzle are generated. The angle of the stirring blade can be selected differently depending on the throughput and treatment efficiency, and the soil movement speed, the inclination angle of about 20 degrees is preferred.

A plurality of retention partitions 28 are installed on the bottom of the sealed drum to slowly move the stirred wash water and the soil mixture, and the retention partitions have a plurality of predetermined intervals so that the washing water and the soil are slowly advanced while maintaining a constant height for smooth stirring. Is installed.

A washing waste water outlet 26 is formed at the lower portion of the closed drum front to discharge the washing waste water generated by stirring the washing water and the soil, and a soil outlet 27 is formed at the lower portion of the closed drum rear. That is, the soil goes through the washing process in the primary washing tank and is moved backward in the longitudinal axis direction by the stirring blade attached to the rotating shaft is discharged to the secondary washing tank through the soil outlet 27 in the lower rear of the washing tank.

Figure 3 is a detailed view of the second washing tank of the soil washing apparatus of the present invention. That is, the second washing tank is composed of an open drum 16 which receives the soil washed in the first washing tank.

Inside the open drum is provided with a rotating shaft 31 is attached to the spiral blade 32 that can rotate to move the soil. At this time, the spiral blade is configured to have a constant pitch interval for soil movement.

At the rear of the open drum, a rotary discharge means 34 is installed to discharge the washed soil. The rotary discharge means may be configured to rotate in a watermill type.

A plurality of washing water injection nozzles 37 are installed at the upper portion of the rotary discharge means to achieve a final rinse of the soil supplied and discharged in the washing tank of the washing water.

A soil outlet 35 through which the final rinsed soil is discharged is installed at the rear of the open drum, and a waste water outlet 36 is installed at the front of the open drum to discharge waste wash water. That is, when the contaminated soil flowing into the open drum is advanced to the rear of the washing tank by the rotation of the rotary shaft, the secondary soil is discharged through the soil discharge port 35 by the rotary discharge means 34 installed at one rear of the rotary shaft to which the spiral blade is attached. Drained out of the wash tub. The soil discharge means 34 has a cylindrical wheel (39) having a metal mesh-shaped pin (38) attached to the outer circumference at a fixed interval on the rear of the rotary shaft is fixed to the rotary shaft washing tank at the time of rotating the rotary shaft The washed soil coming in from the rear is separated from the water from the bottom of the washing tank and configured to be continuously pumped up. In addition, the wastewater discharge port 36 is configured to have a weir slightly lower than the height of the wall of the washing tank at the front of the washing tank so that the wastewater is overflowed by the water level and is naturally discharged to the outside.

Between the screw thread and the thread of the spiral blade a plurality of paddles (33) for a smooth mixing and stirring of the soil during the rotation of the secondary washing tank rotary shaft 31 is made at regular intervals along the circumference of the spiral blade It may be installed as. The paddle facilitates continuous elution of heavy metals from the soil by smooth mixing and stirring between the wash water and contaminated soil.

The paddle 33 is provided with a hoe-shaped stirring blade 24 or a plow-shaped stirring blade 25 may increase the effects of stirring and mixing.

Confirmation of Soil Washing Effect

Using a two-step washing process of the present invention, 50 tons of the soil contaminated with 10,000 mg / kg of diesel and 10 mg / kg of lead were introduced and washed at a soil inflow rate of 7 tons per hour. In the case of the first washing tank, pure water was introduced at a rate of 6 tons per hour, and the secondary washing tank was introduced at an acid rate of 1 ton per hour using an acidic solution (pH 2) as a washing solution. Silver stirring 30 rpm, the secondary washing tank was operated at 15 rpm conditions. Diesel concentration of the final washing soil discharged through the secondary washing tank is 1,100mg / kg, lead concentration of 1.5mg / kg showing a high cleaning performance of 89% and 85%, respectively, the multi-stage soil washing apparatus according to the present invention is oil It was confirmed that the effect is excellent in washing not only the compound but also heavy metals.

As described above in detail the specific parts of the present invention, for those of ordinary skill in the art, these specific descriptions are only preferred embodiments, which are not intended to limit the scope of the present invention. Will be obvious. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Multi-stage soil washing apparatus for the purification of complex contaminated soil according to the present invention can effectively remove the complex contaminants continuously while maintaining the optimal operating conditions according to the characteristics of the complex contaminants in one process, washing water and soil, soil It greatly improves the friction effect between soil and soil, and introduces countercurrent movement system of soil and washing water to treat complex contaminated soil economically with higher processing performance than simple device structure. Therefore, the present invention is expected to be a solution for the treatment of complex soils, which currently rely mainly on landfills for complicated treatment procedures and high treatment costs.

1 is an overall schematic diagram of a multi-stage soil washing apparatus of the present invention composed of a first washing tank and a second washing tank.

2 is a detailed view of the first washing tank.

3 is a detailed view of a second washing tank.

<Explanation of symbols for the main parts of the drawings>

10: Soil Reservoir 11: Conveyor

12: primary wash water reservoir 13: stirring blade

14: closed drum 15: primary washing tank septic tank

16: open drum 17: secondary wash tank septic tank

18: belt conveyor 21: soil input hopper

22: high pressure jet nozzle 23: primary washing tank rotating shaft

24: Rhombic stirring blade 25: Plow-shaped stirring blade

26: 1st washing tank wastewater outlet 27: 1st washing tank soil outlet

28: Retention partition 31: Secondary washing tank rotating shaft

32: spiral blade 33: paddle

34: rotary secondary washing tank discharge means 35: secondary washing tank soil outlet

36: secondary washing tank wastewater outlet 37: washing water spray nozzle

38: pin in the form of a metal mesh 39: cylindrical wheel

Claims (6)

A sealed drum 14 that is elongated in the longitudinal axis direction, a soil feed hopper 21 installed at the front of the sealed drum front, and are installed at regular intervals along an upper center of the sealed drum to spray washing water. A plurality of high-pressure jet nozzles 22 and primary washing tank rotating shafts 23 having a plurality of agitating blades 13 for stirring the soil inside the hermetic drum at regular intervals, and agitated washing water and soil A plurality of retention partitions 28 installed on the bottom of the sealed drum to move the mixture slowly, the washing waste water outlet 26 formed in the lower portion in front of the sealed drum to discharge the washing waste water generated by stirring the washing water and the soil, and the closed drum A first washing tank comprising a soil outlet 27 formed at a rear lower portion thereof; And The open drum 16 receives the soil washed in the first washing tank, the rotary shaft 31 is attached to the spiral blade 32 to move the soil by rotating inside the open drum, and the washed soil A metal mesh-shaped pin 38 installed at the rear of the open drum to be discharged is fixed to the rotating shaft with a cylindrical wheel 39 attached to the outer circumference at a predetermined interval so that it flows in from the rear of the washing tank when the rotating shaft is driven. Rotating discharge means 34 configured to continuously separate the washed soil is separated from the water from the bottom of the washing tank and a plurality of washing water installed on the top of the rotary discharge means for the supply of the cleaning liquid and the final rinse of the discharged soil It consists of a spray nozzle (37), a soil outlet (35) through which the final rinsed soil is discharged, and a wastewater outlet (36) installed in front of the open drum for discharging the waste washing water. Multi-stage soil washing apparatus for cleaning the complex contaminated soil, characterized in that comprises a second washing tank. The multi-stage soil washing apparatus according to claim 1, wherein the stirring blade (13) is formed in a hoe shape (24) or a plow shape (25) to facilitate stirring and uplifting of the soil. The paddle 33 of claim 1, wherein a plurality of paddles 33 are provided between the threads and the threads of the spiral blade 32 to allow smooth mixing and stirring of the soil during rotation of the secondary washing tank rotating shaft 31. Multi-stage soil washing apparatus characterized in that it is installed at regular intervals along the circumference of the spiral blade. 4. The multi-stage soil washing apparatus according to claim 3, wherein the paddle 33 is provided with a foil-shaped stirring blade 24 or a plow-shaped stirring blade 25 for increasing the effect of stirring and mixing. . delete The multi-stage soil washing apparatus according to claim 1, wherein the secondary washing tank waste water discharge port 36 is configured such that the waste water is overflowed by the water level difference and is discharged to the outside by placing a weir lower than the height of the washing tank wall. .