KR20090016071A - Extraction system for extracting of soil pore water - Google Patents

Abstract

An apparatus for extracting soil pore water by depths is provided to extract gravitational water or capillary water from a soil unsaturation layer and saturation layer and extract soil pore layer by depths from the ground according to soil tension. An apparatus for extracting soil pore water includes a pore water extracting pressure pump(110) and a soil pore water extracting unit(120). The pore water extracting pressure pump generates pressure and collects extracted soil pore water. The soil pore water extracting unit is connected to the pore water extracting pressure pump and extracts unsaturation layer soil pore water and saturation layer pore water together.

Description

Extraction system for extracting soil pore water by depth {Extraction System for Extracting of Soil Pore Water}

The present invention relates to a device for examining the contamination of soil and groundwater, and more particularly, to a continuous extraction device for extracting soil pore water in unsaturated and saturated bed soil.

Due to the development of the industry, environmental pollution is a serious problem. The spread of pollution based on global media circulation affects air, water quality, soil and groundwater pollution.

Soil pollutants include cadmium, iron, arsenic and nickel, and most of them are harmful to the human body because they are made of heavy metals. Soil pollution and groundwater contamination are becoming more problematic because edible crops based on contaminated soil or drinking groundwater directly affect the human body. Therefore, the spread and behavior of soil pollution must be accurately analyzed and cleaned up quickly.

However, since soil and groundwater contamination is ground based, it is difficult to predict the distribution or behavior of spatial pollution spread. Apparatus and methods should be developed to overcome these difficulties, and the spread of soil contamination of pollutants from hazardous wastes should be predicted.

 Methods for monitoring the spread of pollution and for restoring soil in the context of serious soil pollution are being researched and developed.

In order to measure the soil pollution, the soils should be equipped with depths, but it is difficult to simultaneously collect soils by depths. In addition, the soil alone can not measure the degree of contamination, it must be provided with a pore water penetrated into the void space between the sediment particles. That is, the depth of contamination can be predicted only when the pore water is provided for each depth.

There are two main ways to extract pore water from the collected soil. Gas pressure extraction, which is a method of squeezing the pore water by applying external gas pressure to the sediment, and centrifugal extraction, which separates the pore water by centrifuging the sediment, are performed.

Centrifugal extraction is a method of separating the pore water and the sediment particles by centrifuging the deposit including the pore water. This method has the advantage of minimizing contact with air and having a relatively easy test method, but has a disadvantage in that the volume of pore water obtained by extraction can be limited.

The gas pressure extraction method separates the pore water from the sediment by pushing the pore water in the pores in the sediment to nitrogen gas pressure, which has the advantage of extracting the desired amount of pore water in a large container for extracting the pore water. B. Experimental methods are more complicated and inconvenient than centrifugal methods.

Conventionally, the method of collecting pore water using a device includes a method of extracting soil and rock cross-section samples and using a method of extracting the pore water, and a method of directly extracting pore water by installing a well in groundwater. The method using the above devices is a technique confined to saturated layer soils and can only be used for monitoring groundwater soil contamination. In addition, the difficulty of installing and operating the well is becoming a problem.

There is a method using a soil lysimeter to collect the pore water in the unsaturated layer soil. Soil lammeters can collect pore water in saturated or unsaturated soils. Soil lysimeters are divided into capillary pressure lysimeters and non-tension meter lysimeters. Capillary pressure lysimeters measure tension under tension, and mainly extract gravity water. Nontension gauges measure without tension and can extract capillary water.

However, the prior art device is a method of extracting the pore water separately from the saturated or unsaturated layer, it is difficult to extract the pore water of the soil by depth at the same time.

Accordingly, it is an object of the present invention to provide a device capable of simultaneously extracting the depths of soil pore water by the depth, and simultaneously extracts gravity water and capillary water.

The present invention for achieving the above object is connected to the pore water extraction pressure pump and the pore water extraction pressure pump for generating a pressure, to collect the extracted soil pore water to the ground, and simultaneously the unsaturated layer soil and saturated bed soil pore water Provided is a soil pore water extraction apparatus comprising a soil pore water extraction unit to extract.

Here, the soil pore water extracting apparatus may further include a soil tension sensor for measuring the soil moisture pressure of the soil pore water extraction unit and a soil tension measurement unit for calculating the tension of the soil moisture measured by the soil tension sensor.

Herein, the soil tension sensor may include a soil tension sensor probe for measuring pressures according to depths, and the soil tension sensor probe measures a pressure difference when the soil pore water is extracted to derive a water pressure value. .

Here, the soil tension sensor probe may have at least two probes.

Here, the soil pore water extraction unit may extract the gravity water of the unsaturated layer soil and capillary water of the saturated layer soil at the same time.

Here, the soil pore water extraction unit protects the soil pore water extraction unit, the outer tube is a passage for the soil pore water flows, a porous ceramic cup for introducing the soil pore water in accordance with the depth and the soil pore water according to the depth It may further include a soil pore water extraction pipe that is a passage for collecting to the ground.

Here, the outer tube may further include a first tube having corrosion resistance and impermeable properties, and a second tube preventing corrosion and smoothly introducing the soil pore water.

Here, the first tube may be made of acrylic material, and the second tube may be made of stainless material.

Here, the soil pore water extraction pipe, may have at least two soil pore water extraction pipe according to the depth of the soil.

According to the soil pore water extraction device of the soil pore water by depth in the soil unsaturated layer and the saturated layer as described above, it is possible to simultaneously extract the gravity water or capillary water in the soil unsaturated layer and saturated layer.

In addition, the soil pore water extracting apparatus of the present invention can extract the soil pore water for each depth according to the soil tension from the ground. The soil pore water and soil surface equilibrium and non-equilibrium concentrations can be measured by simultaneously extracting capillary water, which is strong adsorption water, and gravity water, which is weak adsorption water, depending on the strength of soil tension. Pore water collection part is composed of a ceramic of porous medium to facilitate the inflow of soil pore water from the soil, and can predict the diffusion behavior of pollutants by simultaneous extraction of soil pore water by depth.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, it may be named as a first component without departing from the scope of the present invention. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. Hereinafter, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

Example

1 is a block diagram of a soil pore water extracting apparatus according to an embodiment of the present invention, Figure 2 is a perspective view showing a soil pore water extraction unit shown in FIG.

1 to 2, the soil pore water extraction device according to an embodiment of the present invention is a pore water extraction pressure pump 110, soil pore water extraction unit 120, soil tension sensor 130 and soil tension measuring unit 140.

The pore water extraction pressure pump 110 generates a pressure, and collects the extracted soil pore water to the ground, the soil pore water extraction unit 120 is the soil pore water for each depth in the unsaturated layer 152 and saturated layer 154 of the soil Can be extracted at the same time. The soil tension sensor 130 measures the soil moisture pressure of the soil pore water extraction unit 120. In addition, the soil tension measuring unit 140 calculates the soil moisture pressure measured by the soil tension sensor 130 as the tension of the soil moisture. The soil tension sensor 130 and the soil tension measuring unit 140 is not an essential element in the soil pore water extraction device, it may be separated.

The soil pore water extraction unit 120 includes an outer tube 122, a porous ceramic cup 126, and a soil pore water extraction tube 128.

The outer tube 122 protects the soil pore water extraction unit 120 and provides a passage through which the soil pore water is introduced. In addition, the outer tube 122 is composed of a first tube 122A and a second tube 122B. The first tube 122A separates and protects the soil pore water extracting unit 120 from the soil.

Therefore, the first tube 122A is provided to have corrosion resistance and impermeability. Preferably, the first tube 122A is light, has a property of corrosion resistance and impermeability, and is made of an acrylic material that can be easily obtained. In addition, the second tube 122B prevents corrosion and facilitates inflow of soil pore water. Therefore, the second tube 122B is preferably made of a stainless steel material having a void. That is, the soil pore water may flow into the porous ceramic cup 126 of the soil pore water extraction unit 120 through the second tube 122B made of stainless steel having pores.

Porous ceramic cup 126 is composed of a large amount of pores, is used as a container for storing the soil pore water by depth. In addition, it is provided with a void of 3 to 5㎛, it is possible to extract not only soil pore water but also colloidal particulate matter.

The soil pore water extraction tube 128 serves as a movement path of air for the soil pore water extraction unit 120 to be provided in a vacuum state and serves as a channel for collecting the soil pore water introduced into the porous ceramic cup 126 to the ground. The soil pore water extraction pipe 128 is composed of a plurality. Each soil pore water extraction pipe 128 is provided according to the depth of the soil. That is, in order to extract the soil pore water of the unsaturated layer 152 and at the same time to extract the soil pore water of the saturated layer 154, at least two soil pore water extraction tubes 128 should be provided. In addition, if necessary, more soil pore water extraction pipes 128 may be provided to extract and analyze soil pore water at various depths.

 When the pore water extraction pressure pump 110 is operated to extract the soil pore water, a negative pressure (vacuum) state is obtained. Inflow. When the porous ceramic cup 126 is in a vacuum state, the inside of the ceramic cup 126 is in a low pressure state compared to the soil, and the soil pore water is in a high pressure state. Since the water tension of the soil pore water is to be in equilibrium, the high pressure soil pore water is introduced into the low-pressure porous ceramic cup 126. Soil pore water is extracted using this principle (extraction flow 160 of soil pore water is shown in FIG. 1).

When the pore water extraction pressure pump 110 is operated again, as described above, since the ground becomes a high pressure state compared to the soil pore water extraction unit 120, the soil pore water introduced into each porous ceramic cup 126 is extracted from the soil pore water. It can be collected to the ground through the tube (128).

Soil tension sensor 130 may be configured in various ways. That is, any sensor can be used as long as it is a sensor for measuring the pressure of the soil pore water introduced into the porous ceramic cup 126. For example, the soil tension sensor 130 may be composed of long probes 132. The probe 132 may be located inside the porous ceramic cup 126 provided for each depth. The pressure when the soil pore water is extracted varies by depth, and this pressure difference is measured by the probe 132 of the soil tension sensor 130 to derive a water pressure value. In other words, the force of soil pore water is called tension, and it is difficult to measure the force itself. Therefore, the pressure value required when the soil pore water captured by the soil particles is extracted by the pore water extraction pressure pump 110 is measured. If the amount of soil pore water introduced into the porous ceramic cup 126 is high, the water tension is low because the pressure for pulling moisture is required as low, and if the amount of soil pore water inside the porous ceramic cup 126 is low, water is trapped. Since the pressure required for pulling is high, the water tension is measured high.

In addition, the soil tension sensor 130 may take a structure capable of directly connecting the pressure of the soil pore water discharged by connecting tubes having a predetermined thickness to the soil tension sensor 130.

Since the probe 132 of the soil tension sensor 130 is measured in the unsaturated layer 152 or the saturated layer 154, at least two or more rods should be provided, and the measured value is determined by the soil tension measuring unit 140. Moisture tension is calculated.

By using this method, the chemical composition of soil moisture can be measured by changing to a weak pressure or a strong pressure of the pore water extraction pressure pump 110, and can extract gravity water and capillary water contained in the soil for each depth. The soil moisture tension can be calculated.

Experimental Example  One: Soil pore water  Extraction Pressure Experiment

In order to extract the soil pore water adsorbed to the soil particles, the pressure at which the soil pore water can be extracted was measured.

From the soil pore water extraction tube 128 located 30 cm below the soil surface, the pump flow rate was set to 3, 5, 7, 9, 15, 21 mL / min. In order to have an optimum vacuum, the initial 20 minutes were equilibrated, the middle 20 minutes were pressurized extraction, and the latter 20 minutes were measured to maintain equilibrium.

3 is a graph of the extraction time and the water pressure of the soil pore water according to the pump flow rate.

Referring to FIG. 3, when the equilibrium was maintained for 20 minutes, the soil pore water pressure in the extraction using the pump flow rate of 3 mL / min to 21 mL / min was 8 kPa. In the next 20 minutes of pressure extraction, the water pressure of 10 kPa is shown when the pump flow rate is 3 mL / min. When the pump flow rate is 15 mL / min, the water pressure of 30 kPa from which the soil gravity water can be extracted is Indicated. That is, when the pump flow rate is 15mL / min is the minimum pressure to extract the soil pore water present in the soil pore, this pressure can be referred to as the soil moisture tension. In addition, when the pump flow rate was increased to 21 mL / min, the water pressure of 43 kPa was higher than that for extracting a part of capillary water strongly adsorbed to the soil particles. That is, the soil moisture tension from which capillary water can be extracted is 43 kPa.

Gravity water in soil pore water has a chemical composition that is relatively unbalanced with the soil surface. On the other hand, capillary water is strongly bound to soil voids, so it is chemically equilibrated with the soil surface, so the chemical composition of capillary water is closer to equilibrium than gravity water.

Pore water, which is in contact with the soil surface for a long time in the soil, is close to equilibrium. Pore water, such as gravity water, which has a short residence time in soil pore water, is close to equilibrium.

Therefore, in order to extract the soil pore water in equilibrium with the contaminated soil surface, it is necessary to extract the soil pore water in capillary water which is in equilibrium with the soil surface. Soil pore water can be extracted.

Experimental Example  2: Extraction of Metal Contaminants and Organic Contaminants

Soil pore water extracted from capillary water was classified into metal contaminants and organic contaminants to investigate whether the soil pore water was in equilibrium with the soil surface. Using the values derived in Experimental Example 1, a pump flow rate of 21 mL / min or more was given and a water pressure of 40 kPa or more was tested.

Herein, the metal pollutant includes a high concentration of metal and a low concentration of metal. Soil pore water was sampled at 5 minute intervals for 20 minutes from the soil pore water extraction tube 128 located 30 cm below the surface layer. At this time, the contaminated soil used for the extraction of soil pore water was performed in arsenic contaminated soil and oil contaminated soil, respectively.

4a and 4b are graphs of the concentration of metal contaminant extracted according to the extraction time by the soil pore water extraction device.

Referring to Figure 4a, it can be seen that the concentration change with the extraction time of the high concentration metal contaminants. High metal concentrations include arsenic, iron, and zinc, and the high metal concentrations increased during the initial 5 minutes. In addition, iron showed the largest concentration change, and zinc showed the smallest concentration change.

Referring to Figure 4b, it can be seen that the concentration change according to the extraction time of the low concentration metal contaminants. Low concentration metals include cadmium, cobalt, chromium, copper, and nickel. Soil pore water collection showed the largest concentration change during the initial 5 minutes, and the rate of increase gradually decreased over time. Nickel showed the largest change and cadmium did not show any significant change.

Therefore, equilibrium with soil surface of soil pore water containing high and low concentrations of metal pollutants according to extraction time was equilibrated with soil pore water and soil surface for the first 5 minutes. In addition, after 5 minutes, the soil pore water and the surface of the soil had an equilibrium relationship. As time passed, the soil pore water, which is in equilibrium with the surface of the soil, was extracted. This is because it shows a characteristic away from the chemical composition. The high concentration of metal in soil pore water contained a large amount of iron, and the low concentration of metal contained high amounts of nickel.

5 is a graph of the concentration of organic pollutants extracted according to the extraction time by the soil pore water extraction device.

Referring to FIG. 5, the concentration change according to the extraction time of the organic components of naphthalene, phenanthrene, ansrene and pyrene extracted from the soil pore water showed the same tendency as the concentration change of the metal component. That is, high concentrations of organic constituents were observed during the initial 5 minutes, and the concentrations decreased over time, and anthrene was the largest proportion of organic pollutants.

This change in concentration is because the concentration of soil pore water, which is in equilibrium with the surface of the soil, is longer as the extraction time, resulting in the extraction of pore water with non-equilibrium chemical composition, which is far from the chemical composition of the relative equilibrium relationship.

Therefore, from the extraction result of the extraction time according to the extraction time using the soil extracting apparatus of the present invention, the soil pore water of the composition equilibrating with the soil surface was obtained, and after 5 minutes, the soil pore water composition of non-equilibrium relation could be obtained. there was.

Experimental Example  3: Concentration Extraction Test by Depth

Experimental Example 1 using the soil pore water extracting device of the present invention showed the equilibrium of the soil surface and soil pore water when water pressure of 40 kPa or more was used at a pump flow rate of 21 mL / min or more. In addition, the results showing the equilibrium state of the soil surface and soil pore water in the extraction time for the initial 5 minutes from Experimental Example 2.

Based on this, the soil pore water was extracted according to the depth in the optimum state as described above. The equilibrium concentration of pore water was measured at the depths of 30 cm and 60 cm from the soil surface using the soil pore water extraction device. Here, the soil of 30 cm depth represents the unsaturated layer 152 soil, and the 60 cm depth represents the saturated layer 154 soil. In this experimental example, contaminated soils were performed on soil contaminated with arsenic and oil contaminated soils, respectively.

6 is a graph of the concentration of metal contaminants extracted according to the depth by the soil pore water extraction device, Figure 7 is a graph of the concentration of the organic pollutants extracted according to the depth by the soil pore water extraction device.

Moisture movement of the saturated layer 154 includes gravity water in the soil pore water, and is moved in the same manner as water flow in the water system by gravity. In addition, the water movement of the unsaturated layer 152 includes capillary water and moves from the high potential region to the low potential region.

Referring to FIG. 6, due to the property of the soil pollutants of the metal being moved from the soil surface to the low potential region, the metal component was high at a depth of 60 cm.

Referring to FIG. 7, the organic pollutants showed a high concentration at a depth of 30 cm.

Therefore, the heavy metal component was characterized by high solubility and mobility in the saturated layer, and the organic pollutants with hydrophobic properties were more stably present in the surface layer of water and air in the unsaturated layer. This fact is a measure of the soil contamination observed in the general soil, showing that the soil pore water extraction apparatus of the present invention can be effective, in particular, both the unsaturated layer (154) soil and saturated layer (152) soil contamination The fact that the material could be extracted and measured effectively could replace the existing soil groundwater monitoring system.

Although described with reference to the experimental examples above, those skilled in the art will appreciate that various modifications and changes of the present invention can be made without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

1 is a block diagram of a soil pore water extraction apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the soil pore water extraction unit shown in FIG. 1. FIG.

3 is a graph of the extraction time and the water pressure of the soil pore water according to the pump flow rate.

4a and 4b are graphs of the concentrations of the extracted metal contaminants according to the extraction time by the soil pore water extraction apparatus.

5 is a graph of the concentration of organic pollutants extracted according to the extraction time by the soil pore water extraction device.

6 is a graph of the concentration of metal pollutants extracted according to the depth by the soil pore water extraction device.

7 is a graph of the concentration of organic pollutants extracted according to the depth by the soil pore water extraction device.

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

110: pressure pump for pore water extraction 120: soil pore water extraction unit

130: soil tension sensor 140: soil tension measuring unit

122: outer tube 126: porous ceramic cup

138: soil pore water extraction pipe

Claims (9)

A pressure pump for generating a pressure and extracting the pore water to collect the extracted soil pore water into the ground; And Soil pore water extracting device connected to the pore water extraction pressure pump, comprising a soil pore water extraction unit for extracting the unsaturated layer soil and saturated layer soil pore water at the same time. According to claim 1, wherein the soil pore water extracting device, Soil tension sensor for measuring the soil moisture pressure of the soil pore water extraction unit; And Soil pore water extracting device further comprises a soil tension measuring unit for calculating the tension of the soil moisture measured by the soil tension sensor. According to claim 2, wherein the soil tension sensor, And a soil tension sensor probe for measuring pressure according to depths, wherein the soil tension sensor probe measures a pressure difference when the soil pore water is extracted to derive a water pressure value. The method of claim 3, wherein the soil tension sensor probe, Soil pore water extraction apparatus, characterized in that having at least two probes. According to claim 1, wherein the soil pore water extraction unit Soil pore water extraction apparatus, characterized in that for extracting the gravity water of the unsaturated layer soil and capillary water of the saturated layer soil at the same time. According to claim 1, wherein the soil pore water extraction unit, An outer tube protecting the soil pore water extraction unit and serving as a passage through which the soil pore water is introduced; Porous ceramic cup for storing the soil pore water inflow according to the depth; And Soil pore water extraction apparatus further comprises a soil pore water extraction pipe which is a passage for collecting the soil pore water to the ground according to the depth. According to claim 6, wherein the outer tube, A first tube having corrosion resistance and impermeability; And Soil pore water extraction apparatus further comprises a second tube to prevent corrosion and to facilitate the inflow of the soil pore water. The method of claim 7, wherein The first tube is made of an acrylic material, the second tube is soil pore water extraction apparatus, characterized in that made of a stainless material. The soil pore water extraction device according to claim 6, wherein the soil pore water extraction pipe has at least two soil pore water extraction pipes according to the depth of the soil.

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