JP2003154356A - Pumping aeration type apparatus and method for purifying ground water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently collect water from a wide range, to efficiently pump up water from the depths, and to obtain a high water purification capacity. SOLUTION: In a ground water pumping apparatus 1, a casing pipe 2 and a strainer pipe 3 are embedded in the ground, and ground water supplied from a filter layer B into the strainer pipe 3 is discharged forcibly on the ground by a submergible motor pump 7. An inner cylinder pipe 6 is arranged in the strainer pipe 3 to be separated at a prescribed interval from the inner wall of the strainer pipe 3, and a water passage hole is formed at a position lower than the upper end of the strainer pipe 3. A clearance is formed between the strainer pipe 3 and the inner cylinder pipe 6. With the use of the apparatus 1, ground water containing volatile organic compounds is pumped up. The pumped-up water is aerated to obtain treated water and exhaust gas, and the organic compounds contained in the exhaust gas are adsorbed by active carbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pumped aeration groundwater purification device and a pumped aeration groundwater purification method for pumping groundwater polluted by volatile organic compounds and purifying the pumped groundwater.

[0002]

2. Description of the Related Art Conventionally, volatile organic compounds (Volati)
le Organic Compounds; abbreviated as VOCs), for example, the treatment of groundwater contaminated with volatile organochlorine compounds such as trichlorethylene was usually carried out using a packed aeration tower. Specifically, the conventional pumped-up aeration-type groundwater purification method is to introduce polluted groundwater pumped up from a pumping well into a packed aeration tower to perform aeration treatment,
Aeration-treated exhaust gas containing is generated, and the exhaust gas is introduced into the activated carbon adsorption tower. Furthermore, VO is treated with activated carbon.
Cs is adsorbed and purified gas is discharged. Treated water flows out from the bottom.

As a pumping method, for example, the vacuum deep well method could be used. This vacuum deepwell method involves inserting a deepwell pipe, which is a steel pipe connected to a strainer pipe for passing groundwater inside, into the soil, and arranging a shaft-type vacuum pump inside the deepwell pipe to force drainage. This is a construction method for lowering the groundwater level.

[0004]

However, in the above-mentioned vacuum deep well construction method, when the groundwater level falls below the upper end of the strainer pipe, air also flows into the interior together with the groundwater through the strainer pipe. Therefore, the vacuum effect is reduced. Further, as the groundwater level is further lowered, there is a problem that the vacuum effect is lowered and the pumping efficiency is lowered, and it is difficult to pump water from a large depth or collect water from a wide range. Therefore, there was a problem that the groundwater in the deep ground could not be sufficiently purified. In addition, it was inefficient because it was necessary to install many pumping wells because the catchment area was narrowed.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention efficiently collects water from a wider area and pumps water from a greater depth, and has a high groundwater purification capacity. An object of the present invention is to provide a pumped-up aeration type groundwater purification device and a pumped-up aeration type groundwater purification method.

[0006]

In order to solve the above problems, the invention described in claim 1 is, for example, as shown in FIG.
Groundwater pumping device 1, aeration device 21, activated carbon adsorption tower 2
2. The groundwater containing a volatile organic compound is pumped up by the groundwater pumping device, and the pumped groundwater is introduced into the aeration device to perform aeration treatment to obtain treated water and exhaust gas, and the exhaust gas is the activated carbon adsorption tower. A pumping aeration-type groundwater purification device to be introduced into the groundwater pumping device, wherein a casing pipe 2 and a strainer pipe 3 connected to a lower end of the casing pipe are buried in the ground and formed on the outer periphery of the strainer pipe. The groundwater flowing into the strainer pipe from the filter layer B is forcibly discharged to the ground by the pumping means, and is disposed in the strainer pipe at a predetermined distance from the inner wall of the strainer pipe. An inner cylinder pipe 6 having a water passage hole 6a formed at a position lower than the upper end of the pipe is provided, and a gap a is provided between the strainer pipe and the inner cylinder pipe. When the groundwater level is located below the upper end of the strainer pipe and above the water passage hole, the inner cylinder pipe and the casing pipe are prevented so that the air is prevented from entering the inner cylinder pipe. It is a pumped-up aeration type groundwater purification device characterized by being connected.

Therefore, according to the invention of claim 1,
In the gap between the strainer pipe and the inner cylinder pipe, air and groundwater are separated, and while preventing the invasion of air at the portion above the water passage hole of the inner cylinder pipe, the groundwater is taken in from the water passage hole and pumped. It is possible to maintain the vacuum effect. Therefore, water collection from a wider area and pumping from a larger depth are efficiently performed, and as a result, a high groundwater purification capacity can be obtained.

According to a second aspect of the present invention, in the first aspect of the invention, the casing pipe and the strainer pipe connected to the lower end of the casing pipe are embedded in the ground and formed on the outer periphery of the strainer pipe. A groundwater pumping device for forcibly discharging the groundwater flowing into the strainer pipe from a filter layer to the ground by a pumping means, wherein the strainer pipe is arranged at a predetermined distance from the inner wall of the strainer pipe, and the strainer pipe An inner cylinder pipe having a water passage hole formed at a position lower than the upper end of the strainer pipe, a gap is provided between the strainer pipe and the inner cylinder pipe, and the groundwater level is lower than the upper end of the strainer pipe. A groundwater pumping device in which the inner cylinder pipe and the casing pipe are connected to each other so as to prevent air from entering the inner cylinder pipe when positioned above the water passage hole A pumped-up aeration type characterized by pumping groundwater containing a volatile organic compound, aerating the pumped groundwater to obtain treated water and exhaust gas, and adsorbing the volatile organic compound contained in the exhaust gas to activated carbon It is a groundwater purification method.

Therefore, according to the invention of claim 2,
In the gap between the strainer pipe and the inner cylinder pipe, air and groundwater are separated, and while preventing the invasion of air at the portion above the water passage hole of the inner cylinder pipe, the groundwater is taken in from the water passage hole and pumped. It is possible to maintain the vacuum effect. Therefore, water collection from a wider area and pumping from a larger depth are efficiently performed, and as a result, a high groundwater purification capacity can be obtained.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention.

FIG. 1 is a sectional view of the ground showing a pumped-up aeration-type groundwater purification device according to an embodiment of the present invention.
4 is a cross-sectional view of a main part of a groundwater pumping device according to an embodiment of the present invention, FIG. 3 is a side cross-sectional view of a strainer part of the groundwater pumping device according to an embodiment of the present invention, and FIG.
[Fig. 2] is a front view and a bottom view of an inner pipe forming a groundwater pumping device according to an embodiment of the present invention.

As shown in FIG. 1, the pumped-up aeration type groundwater purification apparatus of this embodiment comprises a groundwater pumping apparatus 1, a packed aeration tower 21 as an aeration apparatus, and an activated carbon adsorption tower 22.

The pumped-up aeration type groundwater purification is performed as follows. Contaminated groundwater due to VOCs is pumped up by the groundwater pumping device 1 and injected into the upper part of the packed aeration tower 21 filled with the packing material. On the other hand, air is blown from the lower part of the packed aeration tower 21 by the blower 23, and the air flow is brought into contact with the contaminated groundwater to extract the pollutants in the liquid phase into the gas phase. The treated water that has been aerated is discharged to the soil. The air which has absorbed the pollutants by the aeration process is exhausted from the upper part of the filling aeration tower 21 and introduced into the activated carbon adsorption tower 22. Activated carbon adsorption tower 22
In, VOCs are adsorbed and removed by activated carbon. The gas thus purified is discharged from the activated carbon adsorption tower 22 to the outside. When the adsorption capacity of activated carbon decreases with time, the adsorption capacity can be easily recovered by performing activation.

Instead of the filling aeration tower 21, an air blowing type aeration device or a rotary injection type aeration device may be used. The air blowing method blows air into the contaminated water,
This is a method of contacting gas and liquid on the surface of bubbles. The rotary jet system is a system in which contaminated water is jetted from a rotating sister and agitated with air.

The groundwater pumping device 1 will be described in detail below. The groundwater pumping device 1 includes a casing pipe 2 buried in the ground A, a strainer pipe 3 provided at a lower end of the casing pipe 2, a sand pool pipe 4 provided at a lower end of the strainer pipe 3, and a strainer pipe. 3, an inner cylinder pipe 6 provided inside the casing pipe 2 via a concentric reducer 5, and an underwater pump 7 (pumping pump) provided in the inner space of the inner cylinder pipe 6 for pumping groundwater to the ground. Means) and a drain pipe 8 connected to the submersible pump 7 for draining groundwater pumped up by the submersible pump 7 to the ground. The groundwater pumping device 1 has a casing pipe 2
And the strainer pipe 3 are buried in the ground, and the strainer pipe 3 is formed from the filter layer B formed on the outer periphery of the strainer pipe 3.
The groundwater that has flowed in is forcibly discharged to the ground by pumping means. The inner tube 6 is inside the strainer tube 3,
Is arranged at a predetermined distance from the inner wall of the strainer pipe 3,
A water passage hole 6a is formed at a position lower than the upper end of the strainer pipe 3. A gap a is provided between the strainer pipe 3 and the inner cylindrical pipe 6. When the groundwater level is located below the upper end of the strainer pipe and above the water passage hole 6a, the inner cylinder pipe 7 and the casing pipe 2 are arranged so as to prevent air from entering the inner cylinder pipe 6. It is connected via the concentric reducer 5.

The casing pipe 2 is made of, for example, a steel pipe. The casing tube 1 has, for example, 1 lot = 3.0.
It may be configured by connecting divided bodies (for example, steel pipes) divided for each m. Also, the ground A and the casing pipe 2
A filter layer B filled with gravel or the like is provided between and. The strainer pipe 3 has, for example, a cylindrical outer shape and a steel wire wound around the outer periphery thereof so as to form gaps at predetermined intervals, and allows groundwater to flow into the interior through the gaps. You can do it.
The upper and lower ends of the strainer tube 3 have weld rings 9a and 9b.
It is joined to the concentric reducer 5 and the sand puddle tube 4 via. The concentric reducer 5 is a connecting member for connecting pipes having different diameters, and the diameter of the opening at the upper end is different from the diameter of the opening at the lower end. That is, the casing pipe 2 having a large diameter and the inner cylindrical pipe 6 having a small diameter can be joined.

The inner cylindrical pipe 6 is made of, for example, a water impermeable material such as a steel pipe, and as shown in FIG. 3, a water passage hole 6a into which the ground water flowing from the strainer pipe 3 into its lower end is taken in. There are multiple ... Further, the inner cylindrical tube 6 partitions the space inside the strainer tube 3, and the upper end of the gap a formed by the strainer tube 3 and the inner cylindrical tube 6 is partitioned and shielded by the concentric reducer 5. The lower end of the inner cylindrical pipe 6 is joined to a ring plate 10 provided on the inner wall surface of the weld ring 9b, and the ring plate 10 partitions the gap a between the strainer pipe 3 and the inner cylindrical pipe 6. .

A bottom lid 12 for closing the opening is attached to the lower end of the sand puddle tube 4. The submersible pump 7 has, for example, a pump body and a motor unit integrated with each other, and groundwater flowing into the inner tubular pipe 6 can be drained to the ground via a drainage pipe 8.

The pumping capacity of the submersible pump 7 is a design item, and may be appropriately changed depending on the depth and size of the well, the ground condition of the installation site, and the like.

Next, the operation of pumping the groundwater level by the groundwater pumping device 1 will be described with reference to FIG. For example, when the groundwater level is lower than the upper end of the strainer pipe 3 (Fig. 2
A part of the strainer pipe 3 is located above the groundwater level in the (dashed-dotted line portion).

In this case, the groundwater and the air mixed with the groundwater which have flowed into the clearance a from the ground through the strainer pipe 3 are separated from the water and the air in the clearance a. Water is through hole 6
It will flow into the space in the inner tube 6 through a.
When the submersible pump 7 sucks up the groundwater in the inner tubular pipe 6 in this state, the groundwater level should be further lowered to the position of the water passage holes 6a without mixing the air into the inner tubular pipe 6. Can be done. Therefore, it is possible to efficiently and economically lower the groundwater level, and to pump and purify groundwater at a deeper position.

The amount of water pumped by the submersible pump 7 can be adjusted by, for example, opening and closing a gate valve (not shown) on the ground. As a result, it is possible to prevent the groundwater level near the inner cylinder pipe 6 from being drastically lowered, and the amount of pumped water is adjusted to maintain the groundwater level near the inner cylinder pipe 6 above the water passage hole 6a. As a result, it is possible to efficiently pump water and perform purification treatment while preventing air from being sucked into the inner cylindrical pipe 6.

In this embodiment, a water passage hole 6a is formed in the side portion of the inner cylindrical pipe 6. Since the water passage hole 6a is formed in the side portion of the inner cylindrical pipe 6, when the water surface in the gap a is located in the middle of the water passage hole 6a (hereinafter, referred to as "the water surface in the gap"), the water surface in the gap Depending on the position, the size of the portion of the water passage hole 6a located above the water surface in the gap varies. Water passage hole 6a
Air can pass through the portion above the water surface in the gap. The amount of air per unit time that enters the inner cylindrical pipe 6 varies depending on the size of the portion above the water surface in the gap of the water passage hole 6a through which air can pass. The size of the portion of the water passage hole 6a above the water surface in the gap can be adjusted by the position of the water surface in the gap. The position of the water surface in the gap can be adjusted by the pumping amount (discharge amount) of the pumping pump 7 per unit time. Whether the water surface in the gap has reached the water passage hole 6a can be known from the change in the atmospheric pressure in the casing pipe 2. Because the water surface in the gap is the water passage hole 6a
This is because when air enters the inner tube through the water passage hole 6a and then into the casing tube 2, the atmospheric pressure in the casing tube changes momentarily.

With the above, the following control becomes possible. That is, if it is possible to detect that the water pressure in the casing pipe 2 has changed and the water surface in the gap is approaching the water passage hole 6a, the pumping amount (discharge amount) of the pumping pump 7 per unit time can be detected.
Can be lowered and the size of the portion of the water passage hole 6a above the water surface in the gap can be adjusted to control the amount of air entering the inner tube 6 per unit time. Here, adjusting the size of the portion of the water passage hole 6a above the water surface in the gap also includes raising the water surface in the gap above the water passage hole 6a again. In that case, ventilation is stopped again. By such control, the amount of air entering the inner tube 6 is limited,
A pressure difference between the inside and outside of the pipe can be maintained. Therefore,
Due to the vacuum effect, groundwater can be collected and purified from a wide range.

In the structure in which the water passage hole 6a is not provided in the side portion and the water passage hole 6a is used as the opening portion at the lower end of the pipe, the opening portion is horizontal, so that when the water surface approaches the opening portion, The opening will be fully opened at once, and it will be difficult to limit the amount of invading air depending on the position of the water surface.

When the underground water is forcibly discharged by the submersible pump 7 as described above, the vacuum suction force based on the pressure difference between the inside and outside of the pipe is higher than that of lifting the water in the pipe, that is, pumping the water. It is used to draw groundwater in the surrounding ground toward the pipe. Since the water introduced into the pipe is pumped by the submersible pump 7, the water column to which gravity in the direction opposite to the vacuum suction force is applied is not formed long (high) in the pipe. Therefore, most of the atmospheric pressure difference between the inside and outside of the pipe generates a suction force around the pipe without being balanced with the gravity applied to the water column inside the pipe. In this way, when the underground water in the pipe is pumped by the submersible pump 7, a large amount of ground water in the ground is collected with a strong vacuum suction force per unit time.

[0027]

As described above, according to the present invention, air and groundwater are separated from each other in the gap between the strainer pipe and the inner cylinder pipe, and the invasion of air is prevented from occurring in the portion above the water passage hole of the inner cylinder pipe. While blocking with, the groundwater can be taken in from the water hole and pumped, and the vacuum effect can be maintained. for that reason,
There is an effect that water collection from a wider area and pumping from a larger depth are efficiently performed, and as a result, a high groundwater purification capacity can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the ground showing a pumped aeration-type groundwater purification device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of a groundwater pumping device according to an embodiment of the present invention.

FIG. 3 is a side sectional view of a strainer portion of the groundwater pumping system according to the embodiment of the present invention.

4A and 4B are a front view and a bottom view of an inner pipe forming a groundwater pumping device according to an embodiment of the present invention.

[Explanation of symbols]

1 Groundwater pumping equipment 2 casing tubes 3 strainer tubes 6 inner tube 6a Water passage hole 7 Submersible pump 21 Filling aeration tower 22 Activated carbon adsorption tower

Claims (2)

[Claims] 1. A groundwater pumping device, an aeration device, and an activated carbon adsorption tower. Groundwater containing a volatile organic compound is pumped by the groundwater pumping device, and the pumped groundwater is fed to the aeration device to perform aeration treatment. Then, the treated water and the exhaust gas are obtained, and the pumped-air aeration-type groundwater purification device for introducing the exhaust gas into the activated carbon adsorption tower, wherein the groundwater pumping device is:
A casing pipe and a strainer pipe connected to the lower end of the casing pipe are buried in the ground, and groundwater flowing into the strainer pipe from the filter layer formed on the outer periphery of the strainer pipe is forced to the ground by the pumping means. What is to be discharged, in the strainer pipe, arranged at a predetermined distance from the inner wall of the strainer pipe, comprising an inner cylindrical pipe having a water passage hole formed at a position lower than the upper end of the strainer pipe, A gap is provided between the strainer pipe and the inner cylinder pipe, and when the groundwater level is located below the upper end of the strainer pipe and above the water passage hole, infiltration of air into the inner cylinder pipe A pumped-up aeration-type groundwater purification device, characterized in that the inner cylinder pipe and the casing pipe are connected to each other so as to be prevented. 2. A casing pipe and a strainer pipe connected to the lower end of the casing pipe are buried in the ground, and groundwater flowing into the strainer pipe from a filter layer formed on the outer periphery of the strainer pipe is pumped by a pumping means. A groundwater pumping device forcibly discharging to the ground, wherein the strainer pipe is arranged at a predetermined distance from the inner wall of the strainer pipe, and a water passage hole is formed at a position lower than the upper end of the strainer pipe. If there is a gap between the strainer pipe and the inner pipe, and the groundwater level is below the upper end of the strainer pipe and above the water passage hole, Using a groundwater pumping device in which the inner tubular pipe and the casing pipe are connected so as to prevent air from entering the tubular pipe, pump up groundwater containing a volatile organic compound, and pump it. A pumped-up aeration-type groundwater purification method, which comprises aeration-treating the groundwater that has been raised to obtain treated water and exhaust gas, and adsorbing volatile organic compounds contained in the exhaust gas onto activated carbon.