JP2667541B2 - On-site purification system for polluted groundwater - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an on-site purification system for contaminated groundwater. The US government has the Department of Energy and Eye. EIDuPont de Ne
No. DE-AC09-76SR00001 with mours & Co.) reserves the right to the present invention.

Background of the Invention and Description of the Prior Art Contaminated groundwater poses a serious health problem when used as a source of water for drinking water and growing crops and vegetables. In addition, the cost of collecting and purifying groundwater is expensive.

The most direct way to remove contaminants from groundwater and soil is to dig up contaminated underground material, such as soil, crushed rock sediment, and crushed rock, and pump contaminated water from the underground material to the ground surface. It is done by processing. Drilling and pumping are direct methods of treating contaminated groundwater, but are expensive.

Recently, methods for digging horizontal wells have been developed. Wade D
"Radial Wells and Hazardous Waste Sites" by ickinson, R. Wayne Dickinson and Peter A. Mote describe in detail how to dig horizontal wells and use them for the purification of contaminated groundwater. The possibility of is also described. Wells dug in contaminated areas can be used to drain contaminated groundwater and to inject various treatment materials.

Related U.S. Pat. Nos. 4,593,760 and 4,606,639 describe a method for removing volatile contaminants from the unsaturated upper zone, or "vadose zone," of groundwater. 2 wells dug vertically to the ventilation zone
It has a casing consisting of two parts, an upper non-perforated part and a lower perforated part. Volatile pollutants in the vent zone flow into the perforated casing and are pumped through the non-perforated casing to the surface for treatment.

In the prior art, generally, the system for collecting pollutants is a passive system, not an active system, and not a system that operates in both saturated and ventilated zones,
Has a system that works only in the ventilation zone. Although injecting workpieces for in-situ processing is conventionally considered, the effectiveness of the processing by injection is unknown without substantial post-injection sampling.

No conventional purification method uses a horizontal well to inject a fluid that volatilizes pollutants into a saturated zone and to remove the volatilized pollutants in order to purify contaminated groundwater.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a system and method for purifying contaminated groundwater.

Another object of the present invention is to provide a system and method for removing volatile pollutants from groundwater.

It is another object of the present invention to provide a system and method for on-site treatment of groundwater contaminated by volatile components.

It is another object of the present invention to provide a system and method for limiting the spread of contaminated plumes in groundwater.

As implemented and described herein, in order to achieve the foregoing and other objects in accordance with the objectives of the present invention, the present invention provides two spaced well devices,
That is, it has a fluid injection device and a fluid extraction device. The fluid is preferably a gas, a gas mixture, or a liquid carried by the gas. In the groundwater between the two well devices, there is a portion in which contaminants having an affinity for the gas phase spread like feathers. The injection well device is connected to the injection source and the pump. If an extraction well is provided, the extraction well can diffuse the removed gas to the atmosphere, and can be connected to a treatment device such as an activated carbon filter, an incinerator, and an exhaust gas stack. it can.

A pump injects fluid through the injection well apparatus to volatilize contaminants across the contaminated feathered section. The fluid containing the volatile contaminants then flows into the extraction well equipment,
Then, it is pumped to the processing device by a pump. After the processor separates the contaminants from the fluid, the fluid is circulated to the injection well or vented to the atmosphere. The contaminants are treated in one of a variety of ways to render them harmless or released to the atmosphere in a controlled manner.

In a preferred embodiment, the injection well device is a horizontal well located below the water table and below a contaminated feathered section in a saturated zone. Also, the extraction well device is preferably a horizontal well, but it can also be a series of vertical wells,
This extraction well device is located above the feather down portion of the contaminant in the vent zone. The geology of the area, fluid flow and feather size determine the relative orientation and spacing of the two well devices relative to each other.

The type of fluid and the additional substances carried by the fluid to the feather-shaped part are determined by the type of contamination. When the feathers are large, air is the most economical fluid. Steam can also be used to facilitate evaporation by the addition of thermal energy. Reactants that react with groundwater to form purging gases, such as bicarbonate, can also be used.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate the present invention, and together with the detailed description, explain the principles of the invention.

FIG. 1 is a partially sectional perspective view of an embodiment of the purification system of the present invention.

FIG. 2 is a detailed side sectional view of an embodiment of the purification system of the present invention, showing a horizontal injection well device and an extraction well device.

FIG. 3 is a detailed side sectional view of another embodiment of the purification system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention is an on-site apparatus and method for removing contaminants from groundwater. In a preferred embodiment of the present invention, a horizontal well located in the saturated zone below the feathered portion is used as a means of effectively injecting fluid into the contaminated feathered portion.
The fluid can be a gas carried, for example, air, oxygen, air and oxygen, or a fluid carried by a gas, for example, steam and air, and can be heated to facilitate volatilization of contaminants. .

If the pollutant is the preferred compound for the gas phase, it will rise to the saturated zone due to the volatility of the pollutant. A second well system is used to withdraw and collect the volatile contaminants from the unsaturated zone for further processing.

FIG. 1 shows a partial cross-sectional view of the ground surface 10 and the soil structure beneath, and discloses a preferred embodiment in which the contaminants are volatilized and extracted using two horizontal well devices. The soil structure is the upper aeration zone, namely unsaturated zone A,
It consists of a lower saturated water zone B. These two zones meet at water table 15.

Below the ground surface 10 is a contaminated feather-shaped portion 20. A part of the feather-shaped part 20 is in the ventilation zone A and another part is in the saturation zone B. The entire feather-shaped portion 20 may be located in the ventilation zone A or the saturated zone B.

Below the feather-shaped part 20 of the saturated zone B, there is an injection well device 25, and above the feather-shaped portion 20 of the ventilation zone A, an extraction well device.
There are 30. The injection well device 25 includes a first vertical axis 35, a first horizontal axis 40, and a first pump 45. Extraction well 30
Is a second vertical well shaft 50, a second horizontal shaft 55, and a second pump
The 60 further connects to a treatment device 65 and an exhaust gas chimney 70.

As best shown in FIG. 2, the first and second horizontal axes 4
0,55 each have a casing 75,75 'with a number of openings 80, such as slots or holes. Slots or holes must be sufficiently narrow so that soil particles do not block liquid 85 from moving through traversing casings 75, 75 ', with or without volatile contaminants, It must be large enough and large enough for the 85 to cross freely.

The fluid 85 is pumped by the first pump 45 to the injection well device 25. Fluid 85 flows from first vertical axis 35 to first horizontal axis 40. The fluid 85 then flows from the casing 75 through the hole 80 to the saturated zone B. Fluid 85 then flows into the feather portion 20 of the contaminant, where the volatile contaminants volatilize and the fluid
Conveyed by 85 to the horizontal axis 55 and through the hole 80 the casing
It flows into 75 '.

The fluid 85 carrying the volatile organic pollutants is supplied to the first pump 60
From the second horizontal axis 55 to the second vertical axis 50 of the extraction well apparatus 30
Pumped to Fluid 85 that carries volatile contaminants
At the surface 10, it enters a treatment unit 65 where the fluid 85 is separated from contaminants and discharged from an exhaust gas stack 70.

The feather-shaped part of the saturated zone tends to spread laterally,
A horizontal well is ideal for working over a large part of the feather-shaped part, since it makes the vertical well useless. Such a horizontal well can be installed to match the feathered portion of the contamination.

In the present invention, the first and second horizontal axes 40, 55 need not be circular, oval, or other closed shapes, and the injection device 25 and the withdrawal device 30 need not be identical to each other. It is not necessary to overlap each other in the vertical direction. Its form is
It depends on the size and shape of the feather-shaped part 20, the economics of digging, and the geology of the underground.

For example, emitting multiple "spokes" horizontally from one vertical axis or branching one horizontal axis from one vertical axis would result in feathered contaminants at the boundary. It is most effective when located along.

In order to install the extraction well device 30 at an appropriate position above the feather-shaped portion 20, if the groundwater table 15 is too high, or if a fluid 85 such as gas remains in the ventilation zone A, the extraction well device 30 is used. It can be omitted. To collect the volatile contaminants, the surface 10 may be covered with a fluid impermeable material and the volatile contaminants may be withdrawn from between the impermeable material and the surface 10.

The orientation of the injection well device 25 and the extraction well device 30 with respect to each other is determined by the underground geology and the flow rate of the fluid. Impermeable soils tend to spread the injected fluid more perpendicularly to the line between the lower horizontal axis 40 and the upper horizontal axis 55. As the feather-shaped portion spreads more rapidly, the extraction well device 30 may need to extend over a wider portion than the injection well device 25. In the case of porous soils, vented wells have been shown to affect 200 feet (approximately 60 meters) of affected zone.

It is important that the injection well device 25 comprises a source of fluid that diffuses sufficiently to affect the majority of the feather portion 20 and the extraction well device 30 has the feather portion 20 between the wells In conditions, it is also important to have a contaminant reservoir that collects enough of the volatile contaminants. Furthermore, the lower horizontal axis
The flow of the fluid 85 from 40 to the upper horizontal shaft 55
Of course, it is also important to sufficiently surround most of the adjacent area where the feathered section 20 is expected to spread during operation of the on-site purification system.

This process involves the use of relatively high vapor pressures, low solubility, or both, of volatile organic pollutants, such as trichloroethylene, tetrachloroethylene, gasoline hydrocarbons, benzene, etc., in the gas phase as compared to the liquid phase. Applicable to volatile organic pollutants such as chemicals with affinity.

The fluid carrying the contaminants is withdrawn or the fluid is purified to separate the contaminants from the fluid and treat it. The purified fluid is either released to the atmosphere or recycled to the injection well device 25.

As best shown in FIG. 3, the withdrawal well apparatus may comprise a series of vertical shafts 90, which may be connected by tubing 95 to the pump 100 and the processing unit 65. pump
100, if the fluid 85 is circulated again to the inflow well device 25,
The first and second pumps 45 and 60 of the preferred embodiment described above can be substituted.

The purification treatment by the treatment device 65 can be performed by a known method such as filtration or incineration with activated carbon. Alternatively, the pollutants can be released to the atmosphere in a controlled manner.

The foregoing description of the preferred embodiment of the invention has been presented for the purpose of illustration. Accordingly, it is not intended to limit the invention to that described above, and obviously many modifications are possible in light of the foregoing. The foregoing embodiments were chosen and described to explain the principles of the invention and its practical uses, and those skilled in the art will best utilize the invention in various embodiments. And could be variously modified to suit a particular application. The scope of the invention is defined by the claims.

 ──────────────────────────────────────────────────続 き Continuing the front page (72) Inventor Kabak, Dawn Salama 29801, South Carolina, USA, Cottonwood Drive, Aiken, 1932

Claims (21)

(57) [Claims] Claims: 1. A generally horizontal feather portion, partly or wholly below the water table in an underground saturated zone, containing contaminants that are compatible with the gas phase. A groundwater on-site purification system, comprising: fluid means capable of volatilizing contaminants into a gaseous phase; means for injecting the fluid means below the groundwater surface on one side of the feather-shaped portion; The contaminant is volatilized into the gaseous phase and withdrawn with the fluid by withdrawing the fluid across the feathered portion and spaced from the injection means and opposite the feathered portion. And a fluid withdrawal means so that the groundwater can be discharged. 2. A generally horizontal, feathered portion, partly or wholly below the water table in the underground saturated zone, containing contaminants that are compatible with the gas phase. An on-site purification system for groundwater, comprising: a fluid means capable of volatilizing contaminants into a gaseous phase; and means for injecting the fluid means under the groundwater surface on one side of the feather portion. Injection well means comprising a pump and at least one shaft; spaced apart from said injection well means and positioned opposite said feathered portion, said injection well across said feathered portion. Means for allowing the contaminant to evaporate into the gas phase and withdraw the fluid by withdrawing the fluid from the well means, comprising a pump and at least one shaft. Extraction well Means and; said extraction well means and have been operatively connected, said fluid means and said volatilized processing means and for processing by receiving and groundwater contaminants; site purification system of groundwater consisting. 3. The injection well means further has one vertical axis and at least one horizontal axis,
3. A purification system according to claim 2, wherein one horizontal axis has a casing with a number of openings through which said fluid means passes. 4. A purification system according to claim 3, wherein said at least one horizontal axis of said injection well means is located below said feather-shaped portion. 5. The purification system according to claim 4, wherein said at least one horizontal axis of said injection well means is located in a saturated zone below said feathered portion. 6. The extraction well means further has one vertical axis and at least one horizontal axis.
3. A purification system according to claim 2, wherein one horizontal axis has a casing with a number of openings into which said fluid means and said volatile contaminants can flow. 7. The purification system according to claim 6, wherein said at least one horizontal axis of said withdrawal well means is located in a ventilation zone above said feather-shaped portion. 8. The extraction well means may further comprise at least one
3. A purification system according to claim 2, comprising two vertical axes, said at least one vertical axis comprising a casing with a number of openings through which said fluid means and said volatile contaminants can flow. 9. The purification system according to claim 2, wherein said fluid means is selected from the group consisting of air, oxygen, air and oxygen, and air and water vapor. 10. A purification system according to claim 2, wherein said fluid means is heated before injection. 11. The purification system according to claim 2, wherein the processing means is an incinerator. 12. The purification system according to claim 2, wherein the processing means is an activated carbon filter. 13. The purification system according to claim 2, wherein said processing means is controlled emission to the atmosphere. 14. The purification system according to claim 2, further comprising means for separating said fluid means from said volatile contaminants and recirculating said separated fluid means to said injection well means. 15. A method of purifying groundwater containing volatile contaminants having a feather shape spread underground and having an affinity for a gaseous phase, wherein a fluid capable of volatilizing the contaminants is provided. Injecting into a saturated zone adjacent to the feather portion: withdrawing the fluid across the feather portion to volatilize the contaminant and carry it with the fluid; Pumping the contaminant from the feather portion to a vent zone; collecting the fluid and the contaminant; separating the fluid from the contaminant; treating the contaminant A method for on-site purification of groundwater consisting of: 16. A method for on-site purification of groundwater that contains volatile contaminants that are spread underground in a feather shape and that are compatible with the gas phase, the method comprising: horizontally injecting one side of the feather portion. Installing a well device; and installing a horizontal withdrawal well device on the opposite side of the feather-shaped portion from the horizontal injection well device; and disposing a fluid capable of volatilizing the contaminants with the fluid. Injecting the fluid across the feathered portion to volatilize the contaminants; and extracting the fluid and the contaminants from the extraction well device; Separating the fluid from the volatilized groundwater contaminants; and treating the separated groundwater contaminants. 17. A method according to claim 16, further comprising the step of recirculating said separated fluid to said horizontal injection well device. 18. The purification method according to claim 16, wherein the step of treating the separated volatile contaminants is performed by an incinerator. 19. The purification method according to claim 16, wherein the step of treating the separated volatile contaminants is performed by filtering through activated carbon. 20. The purification method according to claim 16, wherein the step of treating the separated volatile contaminants is performed by controlled emission to the atmosphere. 21. The method of claim 16, further comprising the step of heating said fluid prior to injection.