阅读说明：本技术 一种用于地下水污染控制的拦截装置 (Intercepting device for controlling groundwater pollution ) 是由 张峰 王唯实 李莹莹 刘昊 王琛 凃辉 于 2020-06-16 设计创作，主要内容包括：本发明公开了一种用于地下水污染控制的拦截装置,该拦截装置设有一个长条带状的地下沟体；沟体的一侧末端垂直于沟体设有一个纵向的集水集气井；沟体内设有高渗透层,高渗透层的顶部设有密封层,在靠近沟底的高渗透层下部的中间设有一条沿沟体长度方向延伸的集水管,集水管的一端与集水集气井相连通；在集水管的上方靠近密封层的高渗透层上部的中间设有一条沿沟体长度方向延伸的集气管,集气管的一端与集水集气井相连通。本发明提供的用于地下水污染控制的拦截装置,能够快速有效拦截地下水污染羽的迁移并同步修复拦截装置上游目标区域的土壤地下水污染。(The invention discloses an interception device for controlling underground water pollution, which is provided with a strip-shaped underground ditch body; a longitudinal water and gas collecting well is arranged at the tail end of one side of the ditch body and is vertical to the ditch body; a high permeable layer is arranged in the ditch body, a sealing layer is arranged at the top of the high permeable layer, a water collecting pipe extending along the length direction of the ditch body is arranged in the middle of the lower part of the high permeable layer close to the bottom of the ditch, and one end of the water collecting pipe is communicated with the water and gas collecting well; and a gas collecting pipe extending along the length direction of the ditch body is arranged in the middle of the upper part of the high-permeability layer close to the sealing layer above the water collecting pipe, and one end of the gas collecting pipe is communicated with the water collecting and gas collecting well. The intercepting device for controlling the pollution of the underground water can quickly and effectively intercept the migration of the pollution plume of the underground water and synchronously repair the pollution of the soil and the underground water in the target area at the upstream of the intercepting device.)

1. The intercepting device for controlling the pollution of underground water is characterized in that the intercepting device is provided with a strip-shaped underground ditch body; a longitudinal water and gas collecting well is arranged at the tail end of one side of the ditch body and is vertical to the ditch body; a high permeable layer is arranged in the ditch body, a sealing layer is arranged at the top of the high permeable layer, a water collecting pipe extending along the length direction of the ditch body is arranged in the middle of the lower part of the high permeable layer close to the bottom of the ditch, and one end of the water collecting pipe is communicated with the water and gas collecting well; and a gas collecting pipe extending along the length direction of the ditch body is arranged in the middle of the upper part of the high-permeability layer close to the sealing layer above the water collecting pipe, and one end of the gas collecting pipe is communicated with the water collecting and gas collecting well.

2. The intercepting apparatus for groundwater pollution control according to claim 1, wherein the intercepting apparatus is disposed at a downstream side of the groundwater pollution plume perpendicularly to a groundwater flow direction, the cross section of the gutter body is rectangular, the bottom of the gutter body is located below a groundwater level line, the length of the gutter body is 1.1-1.2 times the width of the groundwater pollution plume, and the width of the gutter body is 0.3-1.0 m.

3. An intercepting apparatus for groundwater pollution control as defined in claim 2, wherein the depth of the bottom of the trench is 1m or more greater than the depth of the groundwater pollution plume.

4. An intercepting device for groundwater pollution control according to claim 1, wherein the water collecting pipe and the gas collecting pipe are sieve pipes with a diameter of 100-300 mm, the water collecting pipe is arranged at the bottom of the trench, and the gas collecting pipe is arranged above the water collecting pipe and is higher than the highest operating water level in the trench by 0.5m or more than 0.5 m.

5. An interception device according to claim 4, characterized in that said water and air collection pipes are slotted screen pipe or perforated pipe, and are covered with gauze.

6. An interception device according to claim 5, characterized in that said water and gas collection pipes are both inclined with a slope greater than or equal to 0.5% towards the inside of said collection well.

7. An interception device according to claim 6, characterized in that said water collecting and gas collecting well is sealed at the top, a submersible pump is arranged inside the well for discharging the polluted groundwater or light non-aqueous liquid collected in the well, and a vacuum pump is arranged outside the well for discharging the soil gas collected in the well.

8. An intercepting apparatus for groundwater pollution control as claimed in claim 7, wherein the water collecting and gas collecting well is of a reinforced concrete impermeable structure, the bottom of the well is lower than the bottom of the intercepting apparatus, and the top of the well is provided with an airtight well cover.

9. An interception device according to claim 1, wherein said high permeability layer is filled with high permeability material, and is filled from the bottom of the trench to 0.3m or more than 0.3m above the gas collecting pipe, and is filled with sealing layer to the surface position; the high-permeability material is a quartz sand filter material.

10. An interception device according to claim 9, characterized in that said sealing layer uses a sealing material of bentonite-cement composite material with permeability coefficient less than 1 × 10^-7cm/s, thickness greater than or equal to 0.3 m.

Technical Field

The invention relates to a device used in the field of underground water pollution risk management and control and repair, in particular to an intercepting device used for rapidly controlling underground water pollution.

Background

The groundwater accounts for 1/3 of the total amount of water resources in China, and about 20% of the total water supply amount comes from the groundwater. In recent years, with the aggravation of industrial production activities, the excessive use of pesticides and fertilizers, aging leakage of chemical production and storage facilities and other reasons, the situation of groundwater pollution in China is severe.

The underground water interception ditch is an underground engineering facility for quickly intercepting and collecting polluted underground water, can obviously improve the collection rate of the polluted underground water in a low-permeability stratum during operation, effectively intercepts the migration of pollution plumes of upstream underground water, and is a simple and practical polluted underground water risk management and control and repair technology. The pollution plume of the underground water refers to the space range formed by the movement of pollutants with the underground water. The spatial distribution and the dynamic change of the pollution source are influenced by the input intensity of the pollution source, the motion state of underground water, the attenuation effect of pollutants and the like. Monitoring and identifying of underground water pollution plumes are important basic work of underground pollution remediation and risk management and control.

Compared with other underground water pumping treatment modes, the construction speed of the intercepting ditch is higher, the site universality is better, the efficiency is higher, the hydraulic control effect is more continuous and stable, the cost is generally lower than that of the establishment of an extracting well group system, and the requirement of quickly intercepting and controlling polluted underground water under the condition of sudden pollution can be met.

However, the existing groundwater pollution intercepting ditch is usually only provided with a single-pump type liquid phase extraction system, and the polluted groundwater is passively collected by a single liquid phase extraction mode during operation, although the intercepting effect on groundwater pollution plumes at the upstream of the ditch body is certain, the intercepting efficiency is generally not high. And generally, in order to achieve better groundwater interception efficiency, the design depth of the existing interception ditches is generally deeper so as to increase the hydraulic gradient of the upstream groundwater flowing into the ditches, but the design depth is not beneficial to the control of underground light non-aqueous phase liquid pollution. The gas phase extraction and the liquid phase extraction have certain similarity, but the extraction object is the soil gas in an aeration zone.

Disclosure of Invention

The invention aims to provide an underground intercepting ditch facility for intercepting and repairing underground water pollution, and simultaneously, a liquid phase collection system and a gas phase extraction system are arranged, so that the migration of underground water pollution plumes can be quickly and effectively intercepted, and the soil and underground water pollution in a target area at the upstream of the intercepting ditch can be synchronously repaired.

In order to achieve the aim, the invention provides an interception device for controlling underground water pollution, which is used for extracting and repairing site polluted underground water, wherein the interception device is provided with a strip-shaped underground ditch body; a longitudinal water and gas collecting well is arranged at the tail end of one side of the ditch body and is vertical to the ditch body; a high permeable layer is arranged in the ditch body, a sealing layer is arranged at the top of the high permeable layer, a water collecting pipe extending along the length direction of the ditch body is arranged in the middle of the lower part of the high permeable layer close to the bottom of the ditch, and one end of the water collecting pipe is communicated with the water and gas collecting well; and a gas collecting pipe extending along the length direction of the ditch body is arranged in the middle of the upper part of the high-permeability layer close to the sealing layer above the water collecting pipe, and one end of the gas collecting pipe is communicated with the water collecting and gas collecting well.

The intercepting device for controlling the pollution of the underground water is arranged on the downstream side of the pollution plume of the underground water in a direction perpendicular to the flow direction of the underground water, the section of the ditch body is rectangular, the bottom of the ditch body is positioned below an underground water line, the length of the ditch body is 1.1-1.2 times of the width of the pollution plume of the underground water, and the width of the ditch body is 0.3-1.0 m.

The intercepting device for controlling the pollution of the underground water is characterized in that the depth of the bottom of the ditch body is more than 1m greater than the depth of the pollution plume of the underground water.

The intercepting device for controlling the pollution of the underground water is characterized in that the water collecting pipe and the gas collecting pipe are sieve pipes with the diameters of 100-300 mm, the water collecting pipe is arranged at the bottom of the ditch, and the gas collecting pipe is arranged above the water collecting pipe and is higher than the highest operation water level in the ditch by 0.5m or more than 0.5 m.

The intercepting device for controlling groundwater pollution is characterized in that the water collecting pipe and the gas collecting pipe are both slotted sieve pipes or perforated pipes and are externally coated with gauze.

The intercepting device for controlling the pollution of the underground water is characterized in that the water collecting pipe and the gas collecting pipe are obliquely laid in the direction of the water collecting and gas collecting well at a certain slope, and the slope is greater than or equal to 0.5%.

The intercepting device for controlling the pollution of the underground water is characterized in that the top of the water collecting and gas collecting well is sealed, a submersible pump used for discharging polluted underground water or light non-aqueous phase liquid intercepted and collected in the well is arranged inside the well, and a vacuum pump used for discharging soil gas collected in the well is arranged outside the well.

The intercepting device for controlling the pollution of the underground water is characterized in that the water and gas collecting well is of a reinforced concrete anti-seepage structure, the bottom of the well is lower than the bottom of the intercepting device, and the top of the well is provided with an air-tight well cover.

The intercepting device for controlling groundwater pollution is characterized in that the high-permeability layer is filled with high-permeability materials, the high-permeability materials are filled to a position 0.3m or more than 0.3m above the gas collecting pipe from the bottom of the ditch, and the sealing layer is filled to the ground surface position; the high-permeability material is a quartz sand filter material.

The interception device for controlling groundwater pollution is characterized in that the sealing layer is made of bentonite-cement composite material, and the permeability coefficient of the sealing layer is less than 1 × 10^-7cm/s, thickness greater than or equal to 0.3 m.

The interception device for controlling the pollution of the underground water provided by the invention has the following advantages:

1. under the synergistic effect of the vapor extraction and liquid phase collection systems of the interception devices, underground water pollution plumes can be intercepted rapidly and effectively under the condition of relatively limited depth of the interception devices, and the underground water pollution is prevented from migrating to the downstream.

2. The operation of the gas phase extraction system in the interception device can synchronously repair the possible soil pollution in the aeration zone of the upstream area of the interception device in a soil gas extraction mode, reduce the risk of soil gas invasion possibly caused by upstream groundwater pollution and prevent the problem of secondary pollution possibly generated by large and small breathing waste gas in the water collection and gas collection well.

3. The gas phase extraction equipment and the liquid phase extraction equipment can be operated simultaneously or independently, and the configuration mode is optimized aiming at the underground water pollution condition and the risk management and control purpose, so that the operation is convenient and flexible.

4. The interception device can effectively intercept underground water pollutants of a dissolved phase and has a good effect on interception of non-aqueous phase fluid, particularly light non-aqueous phase fluid pollution.

5. Aiming at shallow groundwater pollution, compared with an extraction well group type groundwater pollution treatment technology, the intercepting device has better economic benefit and simpler design, construction and operation.

Drawings

Fig. 1 is a sectional view of an intercepting apparatus for groundwater pollution control of the present invention.

Fig. 2 is a sectional view of the intercepting apparatus for groundwater pollution control of the present invention.

Wherein, 1, a water collecting pipe; 2. a high permeability layer; 3. a gas collecting pipe; 4. a sealing layer; 5. a water and gas collecting well; 6. a liquid level gauge; 7. a submersible pump; 8. a control system; 9. a vacuum pump.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings.

The invention provides an interception device for controlling underground water pollution, which is provided with a strip-shaped underground ditch body; a longitudinal water and gas collecting well 5 is arranged at the tail end of one side of the ditch body and is vertical to the ditch body; the ditch body is communicated with the water and gas collecting well 5; a high permeability layer 2 is arranged in the ditch body, a sealing layer 4 is arranged at the top of the high permeability layer 2, a water collecting pipe 1 extending along the length direction of the ditch body is arranged in the middle of the lower part of the high permeability layer 2 close to the ditch bottom, and one end of the water collecting pipe 1 is communicated with a water and gas collecting well 5; a gas collecting pipe 3 extending along the length direction of the ditch body is arranged in the middle of the upper part of the position, close to the sealing layer 4, close to the upper end face of the filling layer, above the water collecting pipe 1 in the high-permeability layer 2, and one end of the gas collecting pipe 3 is communicated with a water and gas collecting well 5.

The intercepting device is perpendicular to the flow direction of the underground water and is arranged on the downstream side of the underground water pollution plume, the section of the ditch body is rectangular, the bottom of the ditch body is located a certain distance below an underground water line, the length of the ditch body is 1.1-1.2 times of the width of the underground water pollution plume, the width of the ditch body is 0.3-1.0m, and the intercepting device can be determined according to the actual situation of a site, geological and hydrogeological conditions and a construction mode. The depth of the bottom of the ditch body is more than 1m greater than the depth of the pollution plume of the underground water, or the ditch body directly reaches the position of a top plate of a water-resisting layer covered under a water-bearing layer.

The water collecting pipe 1 and the gas collecting pipe 3 are sieve pipes with the diameter of 100-300 mm, the water collecting pipe 1 is arranged at the bottom of the ditch, and the gas collecting pipe 3 is arranged above the water collecting pipe 1 and is higher than the highest operation water level in the ditch by 0.5m or more than 0.5 m. Preferably, the diameter of the header 1 is larger than the header 3.

The water collecting pipe 1 and the air collecting pipe 3 are both slotted sieve pipes or perforated pipes and are wrapped with gauze. The center of the water collecting pipe 1 and the center of the gas collecting pipe 3 are respectively positioned on the middle point of the width direction of the intercepting device.

The water collecting pipe 1 and the gas collecting pipe 3 are obliquely laid towards the direction of the water collecting and gas collecting well 5 with a certain slope, and the slope is greater than or equal to 0.5%.

The top of the water collecting and gas collecting well 5 is sealed, a submersible pump 7 for discharging polluted underground water or light non-aqueous phase liquid intercepted and collected in the well is arranged inside the well, and a vacuum pump 9 for discharging soil gas collected in the well is arranged outside the well.

The water and gas collecting well 5 is of a reinforced concrete anti-seepage structure, the bottom of the well is slightly lower than the bottom of the intercepting device, and the top of the well is provided with an airtight well cover.

The submersible pump 7 arranged in the water collecting and gas collecting well 5 is connected with the liquid level control system 8, the on-off of the liquid level condition control pump in the well timely discharges the polluted underground water collected in the water collecting pipe 1 and sends the polluted underground water into the external wastewater treatment system, the liquid level in the well is ensured to be lower than the top of the water collecting pipe 1, so that the liquid level in the intercepting device is obviously lower than the surrounding underground water level, an effective hydraulic gradient is formed, the polluted underground water in an upstream target area is promoted to flow into a ditch, and the collection of the polluted underground water and the intercepting effect of pollution feathers are realized.

The vacuum pump 9 is arranged outside the water and gas collecting well 5, an air inlet pipe of the vacuum pump 9 is connected with the upper space of the water and gas collecting well 5, the vacuum in the well is formed by the operation of the vacuum pump 9, soil gas collected in the gas collecting pipe 3 is discharged in time and sent into an external waste gas treatment system, an effective vacuum negative pressure is formed in a high-permeability material filling layer on the upper part of a ditch body of the intercepting device, the actual hydraulic gradient of the upstream polluted underground water flowing into the ditch is improved, the collection of the polluted underground water and the intercepting effect of pollution feathers are realized, and the possible soil pollution in the aeration zone of an upstream target area of the intercepting device is synchronously repaired.

The submersible pump 7 and the vacuum pump 9 can be operated simultaneously or independently when the intercepting device is operated. In the initial stage of operation, under the condition of high pollution load of underground water, the mode of simultaneously operating the submersible pump 7 and the vacuum pump 9 can greatly improve the interception and repair effects on underground water pollution plumes, effectively prevent high-concentration underground water pollutants from migrating towards the downstream direction and quickly reduce the pollution load of upstream underground water. After the pollution load of the upstream underground water is greatly reduced in the later operation period, the operation mode that the submersible pump 7 is switched on and the vacuum pump 9 is switched off is adopted, so that the operation cost can be reduced while the polluted underground water is continuously and effectively intercepted. In addition, in some special occasions where only the risk of soil gas invasion needs to be controlled, the risk of organic steam invasion to the ground surface caused by groundwater pollution can be effectively reduced by adopting an operation mode that the submersible pump 7 switches off the vacuum pump 9.

The ditch is internally and hierarchically paved with filler, the lower part is filled with high-permeability material, and the upper part is filled with sealing material, namely, the high-permeability layer 2 is filled with the high-permeability material, the high-permeability material is filled to a position 0.3m or more than 0.3m above the gas collecting pipe 3 from the bottom of the ditch, and the sealing layer 4 is filled to the ground surface position, the high-permeability material is preferably a quartz sand filter material with a certain grain size distribution, the sealing material adopted by the sealing layer 4 is bentonite-cement composite material, and the permeability coefficient is less than 1 × 10^-7cm/s, thickness greater than or equal to 0.3 m.

The intercepting apparatus for groundwater pollution control provided by the present invention will be further described with reference to the following examples.