JP4544399B2 - Soil purification method and system - Google Patents

Description

  The present invention relates to a soil purification method and system, and more particularly, to a soil purification method and system for preventing inflow of contaminants from outside a purification target area of contaminated soil.

  Environmental pollution of soil contaminating groundwater due to the permeation of oil, organochlorine compounds, heavy metals, etc. discharged from factories into the soil has become a serious social problem. As a method for remediating soil that has been confirmed to be contaminated, there is a water injection pumping method in which multiple wells are excavated in the ground of the contaminated soil, water containing the pollutants is pumped, and the treated water is injected into the ground and circulated. .

  A conventional water pumping method is shown in FIG. The ground 1 in FIG. 5 has contaminated soil 2 inside, and has a groundwater level up to the position indicated by 3. A water injection well 4 for injecting water for purification treatment reaching the contaminated soil 2 from the ground to the ground 1 is excavated. A pumping well 5 for digging up pollutant-containing water is excavated at a position spaced apart from the water injection well 4 in the same manner as the water injection well 4 described above. A pumping pump 8 is installed at the bottom of the pumping well 5. The upper ends of the water injection well 4 and the pumping well 5 are connected to the purification device 7 via a pipe 6 on the ground. A water injection pump 9 is installed between the purification device 7 and the water injection well 4. A method for purifying pollutant-containing groundwater with the above configuration is shown below. Contaminant-containing water contaminated by harmful substances in the contaminated soil is pumped by a pump 8 installed at the bottom of the pumping well 5. The pollutant-containing water is treated water after the pollutant is removed by the ground purification device 7. The treated water is returned to the water injection well 4 by the water injection pump 9 and permeates the ground 1. In this way, the contaminated soil can be purified by pumping and purifying the pollutant-containing water and forming a circulation path that circulates and circulates as treated water.

In the case of this water injection method, there is a problem that land subsidence occurs in the surrounding area with the pumping. In order to avoid this problem, for example, a pumping control method disclosed in Patent Document 1 is disclosed as a method of purifying while measuring a groundwater level in a pumping well. According to Patent Document 1, the amount of pumped water is determined by measuring the concentration of contaminants in the pumped water and the groundwater level.
JP 2002-113659 A

  However, according to the conventional water pumping method, the injection well and the pumping well are excavated and arranged in consideration of the flow of groundwater in the purification target area of the contaminated soil. Therefore, in the purification method by pumping up pollutant-containing water and injecting treated water, pollutant-containing water from the unpurified area adjacent to the purification target area may flow into the purification target area along the flow of pumping water. There is a problem that the area to be purified cannot be sufficiently purified.

  Moreover, the pumping control method of the cited document 1 is a pumping control of the purification target area of the contaminated soil, and is not arranged and operated in consideration of the movement of the pollutant between the purification target area and the unpurified area. . Therefore, the problem that the pollutant-containing water flows from the unpurified area to the purification target area and cannot be purified has not been solved.

Therefore, in order to solve the above-described problems of the prior art, an object of the present invention is to prevent the inflow of groundwater containing contaminants from the outside of the purification target and efficiently purify the contaminated soil to be purified.
Another object of the present invention is to efficiently purify contaminated soil to be purified by shielding the inflow of pollutant-containing water to a purification completion region adjacent to the purification target region.

According to the soil purification method of the present invention, the water-conveying means is installed in the center of the purification target area of the contaminated soil, and the water injection means is disposed around it, and the pollutant is injected into the purification target area and flows through the purification target area In the soil purification method in which the contained water is pumped and the treated water purified is circulated and circulated to the purification target area, the groundwater level of the unpurified target area adjacent to the purification target area is measured, and the measurement data based on the control the amount of injected water purifying object region is set higher than the groundwater level of the unpurified area groundwater level of the purification target region near the boundary between the purification target region and the unpurified target area Groundwater is allowed to flow from the purification target area to the unpurified target area .

According to the soil purification system according to the present invention, water injection means for injecting water into the purification target area of the contaminated soil, water pumping means for pumping the water into the purification target area by passing water from the water injection means into the purification target area, and In the soil purification system, comprising the pumping means in the center of the purification target area and the water injection means around it , the purification means for purifying the pollutant-containing water and returning to the water injection means, A water level measuring means for measuring a ground water level between a purification target area and an unpurified area adjacent thereto; and a water injection amount of the water injection means is controlled based on measurement data of the water level measurement means to thereby obtain ground water in the purification target area. position is set higher than the groundwater level of the unpurified area, control flow of groundwater from the purification target region in the vicinity of the boundary between the purification target region and the unpurified target region in the unpurified target area It is characterized by having a means.

  The soil purification method and system according to the above configuration are configured so that the groundwater level in the purification target region is higher than the groundwater level in the unpurified region based on the measurement data of the water level measuring means installed in the purification target region and the adjacent unpurified region. The amount of water injected by the water injection means is controlled. Thereby, water flows from the purification target region to the unpurified region in the vicinity of the boundary between the purification target region and the unpurified region. Accordingly, it is possible to prevent the pollutant-containing water in the unpurified region adjacent to the purification target region from flowing into the purification target region and to efficiently purify the purification target region.

  Further, the amount of water injected in the purification completion region and the pumping amount of the pumping means are controlled so that the groundwater level in the purification completion region is higher than the groundwater level in the purification target region. As a result, water flows from the purification completion region to the purification target region in the vicinity of the boundary between the purification target region and the purification completion region. Therefore, the inflow of pollutant-containing water from the purification target area to the purification completion area is shielded so that the purification target area can be efficiently purified and there is no possibility of recontamination of the purification completion area.

  Hereinafter, a soil purification method and system according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram illustrating a soil purification system according to the present embodiment. FIG. 2 is an arrangement plan view of water injection means and pumping means according to the embodiment.

  As shown in FIG. 1, the ground 1 has contaminated soil 2 to be purified, and 3 indicates the groundwater level. Reference numeral 11 denotes a purification target area of the contaminated soil 2, and 12 denotes an untreated unpurified area that is adjacent to the purification target area and includes contaminated soil in the ground. The soil purification system 10 includes a water injection well 14 serving as a water injection means for injecting water for purification into the ground 1, a pumping well 16 serving as a pumping means for pumping up pollutant-containing water flowing through the contaminated soil, and a groundwater level 3. A water level measuring unit 18 serving as a water level measuring means is installed. Further, on the ground, a purification unit 20 serving as a purification unit for pollutant-containing water and a control unit for controlling the amount of water injected into the water injection well 14 and the amount of water pumped up in the pumping well 16 are installed.

  A plurality of water injection wells 14 are excavated in the purification target region 11 so as to reach the contaminated soil 2 from the ground. A pumping well 16 is installed at a position at an arbitrarily set distance from the water injection well 14. A plurality of pumping wells 16 are excavated so as to reach the contaminated soil 2 from the ground in the same manner as the water injection well 14. As shown in FIG. 2, the arrangement structure of the water injection well 14 and the water pumping well 16 is such that the water pumping well 16 is excavated in the center of the purification target region 11 and the water injection well 14 is excavated so as to surround the pumping well 16.

  The ground side end openings of the water injection well 14 and the pumping well 16 are connected to the purification unit 20 via a pipe 24. The purification unit 20 is arranged in the order of the gas-liquid separation tank 26, the separation water tank 28, the purification device 30, the water injection tank 32, and the water injection pump 34 from the side connected to the pumping well 16. The gas-liquid separation tank 26 has a vacuum pump 36 branched at the side. The vacuum pump 36 is a pump that pumps up pollutant-containing water in the pumping well 16. The pollutant-containing water pumped up in the pumping well 16 by the vacuum pump 36 flows into the gas-liquid separation tank 26 and is gas-liquid separated into air-containing gas and pollutant-containing water. The separated pollutant-containing water flows into the separated water tank 28 and is temporarily stored. Subsequently, the pollutant-containing water flows into the purification device 30 for purification. The treated water from which the pollutants have been removed is reused as the treated water for purification of the contaminated soil 2, and therefore flows into the water injection tank 32 and is temporarily stored. The treated water in the water injection tank 32 is returned to the water injection well 14 by the water injection pump 34 and circulates in the soil purification system 10.

  The water level measurement unit 18 is provided with groundwater level measurement wells 40 a and 40 b on both sides near the boundary between the purification target region 11 and the unpurified region 12. The groundwater level measurement wells 40 a and 40 b are excavated so as to be deeper than the groundwater level 3. Water level sensors 42a and 42b are inserted in the groundwater level measurement wells 40a and 40b along the longitudinal direction. The water level sensors 42a and 42b are connected to the control means via the measuring units 44a and 44b. The water level measuring unit 18 detects the groundwater level of the ground 1 with the water level sensor 42 and sends the data measured by the measuring unit 44 to the control means.

  A control device 46 serving as a control means is connected to the water level measuring unit 18, the water injection pump 34 and the vacuum pump 36. The control device 46 controls the water injection amount of the water injection pump 34 and the pumping amount of the vacuum pump 36 so as to increase or decrease based on the measurement data from the water level measurement unit 18.

  The soil purification system 10 having the above configuration operates as described below. The water stored in the water injection tank 32 of the purification unit 20 is pumped into the water injection well 14 by the water injection pump 34. In the purification target region 11, water penetrates radially around the water injection well 14. The water that flows out from the water injection well 14 flows through the contaminated soil 2 together with harmful substances in the contaminated soil. Water also flows from the water injection well 14 to the unpurified region side 12. The ground water level is measured by the water level measuring unit 18 in the water level measuring wells 40a and 40b installed in the unpurified region 12 and the purification target region 11. The water level sensors 42 a and 42 b installed in the water level measurement wells 40 a and 40 b detect the groundwater level, and the measurement units 44 a and 44 b measure this and send measurement data to the control device 46. The control device 46 is set in advance so that the groundwater level in the purification target region 11 is higher than the groundwater level in the unpurified region 12. The control device 46 compares the measurement data of the unpurified region 12 and the purification target region 11 and increases the amount of water injected into the water injection well 14 to the water injection pump 34 connected to the control device 46 until the water level of the purification target region 11 becomes high. Send a signal. When the amount of water injection from the purification target region 11 to the unpurified region 12 increases, the groundwater level on the purification target region 11 side increases. Therefore, water flows from the purification target region 11 to the unpurified region 12, and the inflow of groundwater containing a contaminant from the purification completion region 12 side to the purification target region 11 side does not occur.

  When the groundwater level in the purification target region 11 shows a measured value higher than the groundwater level in the unpurified region 12, a pumping signal for pollutant-containing water is sent from the control device 46 to the vacuum pump 36, and pumping of the pollutant-containing water is started. Is done. When the pollutant-containing water is pumped, the water injection from the water injection well 14 arranged in the vicinity of the boundary between the unpurified region 12 and the purification target region 11 becomes the flow of the arrow shown in FIG. Can be prevented. The vacuum pump 36 of the purification unit 20 reduces the pressure inside the pumping well 16 and pumps up the pollutant-containing water that has passed through the contaminated soil 2. The contaminated water containing the pumped water is supplied to the gas-liquid separation tank 26. The gas-liquid separation tank 26 gas-liquid separates the mixed solution of gas and pollutant-containing water. The separated pollutant-containing water is stored in the separated water tank 28. The stored pollutant-containing water flows into the purification device 30. The purification device 30 separates and removes organic substances contained in the pollutant-containing water. The treated water after treatment is stored in the water injection tank 32 and reused as treated water for purification of contaminated soil.

  In this way, the pumping well 16 and the water injection well 14 are installed at the center of the purification target region 11, and the groundwater is moved from the purification target region 11 to the unpurified region 12 in the vicinity of the boundary between the purification target region 11 and the seen purification region 12. I made it flow. Therefore, it is possible to prevent the contaminants in the unpurified region 12 from flowing into the purification target region 11, and to efficiently purify the purification target region 11 without being influenced by the periphery of the target region.

  Next, the structure schematic which shows the soil purification system which concerns on 2nd Embodiment of this invention is shown in FIG. FIG. 4 is an arrangement plan view of water injection means and pumping means according to the second embodiment. In FIG. 3, elements having the same reference numerals as those in FIG. 1 have the same functions as those in FIG. As shown in FIG. 3, the purification target area 11 has an adjacent purification completion area 50. The purification completion area 50 is an area where the contaminated soil has already been purified. When the purification process of the purification target area 11 adjacent to the purification completion area 50 is performed, the pollutant-containing water may flow out from the purification target area 11 to the purification completion area 50, and the purification completion area 50 is contaminated.

  Therefore, in order to solve such a problem, water injection means is installed in the vicinity of the boundary between the purification target region 11 and the purification completion region 50 to prevent the inflow of contaminant-containing water. That is, as shown in FIG. 4, in the purification target region 11, a pumping well 16 is drilled in the center of the region, and a water injection well 14 is drilled so as to surround the pumped well 16. Further, in the vicinity of the boundary between the purification target region 11 and the purification completion region 50, the pumping well 16 is disposed on the purification target region 11 side, and the water injection well 14a is disposed on the purification completion region 50 side. The upper end of the water injection well 14a is connected to the water injection pump 34a. The water injection pump 34 a is connected to the control device 46. Water level measurement wells 40c and 40d are excavated near the boundary between the purification target region 11 and the purification completion region 50 so as to be deeper than the groundwater level. Water level sensors 42c and 42d are inserted in the groundwater level measurement wells 40c and 40d along the longitudinal direction. The water level sensors 42c and 42d are connected to the control device 46 via the measuring units 44c and 44d.

  The soil purification system according to the second embodiment configured as described above operates as described below. The water in the water injection tank 32 is pumped to the water injection well 14a installed in the purification completion area 50 by the water injection pump 34a. In the purification completion region 50, water penetrates radially around the water injection well 14a. Further, a pumping signal is sent from the control device 46 to the vacuum pump 36, and pumping of the pollutant-containing water is started. The water in the water injection tank 32 is pumped to the water injection well 14 installed in the purification target region 11 by the water injection pump 34. The ground level is detected by the water level sensors 42c and 42d in the water level measuring wells 40c and 40d installed in the purification target region 11 and the purification completion region 50, and the measurement data measured by the measuring units 44c and 44d is sent to the control device 46. In the control device 46, the groundwater level in the purification completion region 50 is set in advance so as to be higher than the groundwater level in the purification target region 11.

  The control device 46 compares the measurement data in the purification completion region 50 and the purification target region 11 and increases the amount of water injected into the water injection well 14a in the water injection pump 34a connected to the control device 46 until the water level in the purification completion region 50 becomes high. A signal is sent to the vacuum pump 36 to increase the pumping amount of the pumping well 16. Thereby, the water injection from the water injection well 14a arrange | positioned in the vicinity of the boundary of the purification object area | region 11 and the purification completion area | region 50 becomes a flow of the arrow shown in FIG. In the vicinity of the boundary between the purification target region 11 and the purification completion region 50, water flows from the purification completion region 50 to the purification target region 11, and the inflow of contaminant-containing water from the purification target region 11 to the purification completion region 50 is blocked. Can do.

  In this way, the water injection means is installed in the purification completion area 50, and the amount of water injected and the amount of pumped water are controlled so that the groundwater level in the purification completion area 50 becomes high, so that water flows from the purification completion area 50 to the purification target area 11. I made it. Therefore, the inflow of pollutant-containing water from the purification target area 11 to the purification completion area 50 is shielded, so that the purification target area 11 can be efficiently purified and there is no possibility that the purification completion area 50 is recontaminated.

It is a composition schematic diagram showing the soil purification system concerning this embodiment. It is an arrangement top view of the water injection means and pumping means concerning an embodiment. It is a composition schematic diagram showing the soil purification system concerning a 2nd embodiment of the present invention. It is an arrangement top view of the water injection means and pumping means concerning a 2nd embodiment. It is a figure which shows the conventional water injection pumping method.

Explanation of symbols

1 ……… Ground, 2 ……… Contaminated soil, 3 ……… Ground water level, 4 ……… Water injection well, 5 ……… Pump well, 6 ……… Piping, 7 ……… Purification device, 8 …… ... Pumping pump, 9 ......... Water injection pump, 10 ......... Soil purification system, 11 ......... Purified area, 12 ......... Unpurified area, 14 ......... Water injection well, 16 ......... Pump well, 18 ......... Water level measuring unit, 20 ......... Purification unit, 24 ......... Piping, 26 ......... Gas-liquid separation tank, 28 ......... Separated water tank, 30 ......... Purification device, 32 ......... Water injection tank 34 ......... Water injection pump, 36 ......... Vacuum pump, 40 ......... Water level measurement well, 42 ......... Water level sensor, 44 ......... Measurement unit, 50 ......... Purification complete area.

Claims (2)

Water treatment means is installed at the center of the purification target area of the contaminated soil, and water injection means is installed around the water supply means, water is injected into the purification target area, and the pollutant-containing water flowing through the purification target area is pumped and purified. In the soil purification method for circulating and circulating water to the purification target area,
The groundwater level of the unpurified target area adjacent to the purified target area is measured, and based on this measurement data, the amount of water injected into the purified target area is controlled to set the groundwater level of the purified target area to the groundwater of the unpurified area. The soil purification method is characterized in that groundwater flows from the purification target area to the unpurified target area in the vicinity of the boundary between the purification target area and the unpurified target area.   Water injection means for injecting water into the purification target area of the contaminated soil; and water pumping means for pumping water into the purification target area by passing water from the water injection means into the purification target area, and at the center of the purification target area In the soil purification system comprising the pumping means and the water injection means around it, and the purification means for purifying the pollutant-containing water and returning it to the water injection means, the purification target area and the unpurified area adjacent thereto And a water level measuring means for measuring the groundwater level, and controlling the water injection amount of the water injection means based on the measurement data of the water level measuring means, so that the groundwater level in the purification target area is higher than the groundwater level in the unpurified area And a control means for setting and flowing ground water from the purification target area to the unpurified target area in the vicinity of a boundary between the purification target area and the unpurified target area. Stem.

Images