CN104692530B - Multistage quasi in-situ groundwater repair device and repair method - Google Patents

Abstract

A multi-stage quasi-in-situ groundwater restoration device, comprising: a water pumping well whose depth reaches the target aquifer; a water pumping pipe inserted in the water pumping well, one end of the water pumping pipe is connected to a water pump arranged at the well head; an aqueduct, It is perpendicular to the water pipe, one end of the water pipe is connected to the water pump, and the other end of the water pipe is respectively connected to two water distribution pipes with water outlets. The water distribution pipe and the water pipe form a triangular water distribution system on the same plane. The water distribution system is placed horizontally in the filling layer, and the soil layer is covered on the filling layer, and plants are planted; the bottom of the filling layer is an anti-seepage layer, and permeable holes are set in the filling layer and the fast seepage area around the pumping well; Water quality monitoring points are set near the permeable holes; water level monitoring points are set in the target aquifer. The invention also discloses a groundwater restoration method using the restoration device.

Description

A multi-stage quasi-in-situ groundwater restoration device and restoration method

technical field

The invention belongs to the technical category of groundwater pollution restoration. It specifically involves a new type of groundwater restoration technology

Background technique

At present, according to different remediation methods, groundwater pollution remediation can be divided into ex-situ remediation and in-situ remediation technologies.

The ectopic restoration technology mainly includes passive collection and extraction treatment (pump and treat, P&T) technology. Ex-situ remediation is a technology that first transfers pollutants to the ground with a collection system or an extraction system, and then treats them. Ex-situ is suitable for polluted sites with a large scope of pollution and deep burial of pollution halos. However, this technical project is expensive and involves groundwater The extraction or refilling will greatly interfere with the restoration area, and the phenomenon of tailing and rebound will be serious.

In-situ repair technology refers to the method of repairing the contaminated objects in situ without moving or transporting the contaminated objects under the condition of basically not destroying the natural environment of the soil and groundwater. In-situ remediation technology is suitable for polluted sites with small groundwater pollution and shallow burial of pollution halos. In-situ remediation technology has low treatment costs, and can also reduce the use of surface treatment facilities, minimizing the exposure of pollutants and disturbance to the environment. However, this technology is not suitable for groundwater polluted sites with deep water level, low flow velocity or high pollutant concentration. At the same time, the construction of in-situ remediation technology and the replacement of filler are difficult, which affects its promotion and application. How to overcome the shortcomings of the two groundwater remediation technologies and develop a groundwater remediation technology with low cost, easy construction and strong applicability is currently a technical problem.

Contents of the invention

The object of the present invention is to provide a multi-level quasi in situ groundwater remediation device MQISGRS (Multi-level quasi in situ groundwater remediation system).

Another object of the present invention is to provide a method for groundwater remediation using the above-mentioned device.

In order to achieve the above object, the multi-level quasi-in-situ groundwater restoration device provided by the present invention includes:

A pumping well, deep to the target aquifer;

A water suction pipe, inserted in the water pumping well, one end of the water suction pipe is connected to a water pump arranged at the well head;

An aqueduct, which is at a perpendicular angle to the suction pipe, one end of the aqueduct is connected to the pump, and the other end of the aqueduct is respectively connected to two water distribution pipes with water outlets, forming a triangular distribution pipe on the same plane as the water distribution pipe and the aqueduct A water system, the water distribution system is horizontally placed in the filling layer, and the soil layer is covered on the filling layer, and plants are planted there;

The bottom and periphery of the packing layer is an anti-seepage layer, and the anti-seepage layer around the pumping well is provided with permeable holes through which the water flow enters the rapid seepage area;

Set up water quality monitoring points near the permeable holes in the fast seepage area;

There are water level monitoring points in the target aquifer.

In the multi-stage quasi-in-situ groundwater restoration device, the water intake point of the pumping pipe is located in the middle of the screen tube of the well screen in the pumping well.

In the multi-stage quasi-in-situ groundwater restoration device, a filter screen is installed at the water intake of the suction pipe.

In the multi-stage quasi-in-situ groundwater remediation device, the filler layer is a filler capable of adsorbing and degrading pollutants in groundwater, such as zeolite or zero-valent iron.

In the multi-stage quasi-in-situ groundwater restoration device, plants with the functions of degrading, absorbing or enriching pollutants in groundwater are planted on the covering soil layer.

In the multi-stage quasi-in-situ groundwater restoration device, the anti-seepage layer is high-density polyethylene.

The method for groundwater restoration provided by the present invention using the above-mentioned multi-stage quasi-in-situ groundwater restoration device:

Start the pump, the groundwater to be repaired enters the aqueduct through the aqueduct, enters the water distribution pipe through the aqueduct, and then enters the packing layer through the water outlet hole of the water distribution pipe, so that the groundwater is evenly distributed in the packing layer, and the groundwater pollutants are absorbed by the packing layer. , After phytoremediation and degradation, the permeable holes around the pumping well will return to the groundwater layer through the fast seepage area. Due to the flow of the groundwater itself, the repaired groundwater will flow downstream, while the unrepaired groundwater will flow into the groundwater layer under the action of the pump. The multi-stage quasi-in-situ groundwater remediation device operates continuously until the groundwater remediation is completed.

In the multi-stage quasi-in-situ groundwater restoration method, the pumping and water distribution are intermittent pumping and water distribution.

In the multi-level quasi-in-situ groundwater restoration method, plants that are beneficial to groundwater pollution restoration are planted in the covering soil layer to enhance the restoration effect.

The advantages of the present invention are:

(1) Low cost. Compared with the groundwater dislocation restoration technology, the present invention has a simple process, no ground facilities are needed, and only a low-power pump needs power, and the construction and operation costs are low;

(2) Easy construction. Compared with in-situ repair technology, it avoids the construction difficulty of deep excavation construction with strong permeable reaction, and has the advantage of easy replacement of filler;

(3) The disturbance of groundwater is small, since the position of groundwater re-seepage coincides with the pumping position, reducing the exposure of pollutants and disturbance to the groundwater environment;

(4) Strong flexibility, according to the characteristics of groundwater pollutants, the medium material of the packing layer can be changed to realize the restoration of different pollutants;

(5) Strong remediation function, the present invention can integrate phytoremediation, adsorption degradation and recharge technology, and strengthen the remediation effect of groundwater pollutants;

(6) Strong adaptability, the present invention is applicable to polluted sites with different buried depths of groundwater, and overcomes the limitation that the permeable reaction wall is only applicable to shallow buried depths of groundwater.

Description of drawings

Fig. 1 is a schematic top view of the groundwater pollution remediation device of the present invention.

Fig. 2 is a sectional view along A-A in Fig. 1 .

Fig. 3 is a sectional view along B-B in Fig. 1 .

Explanation of main component symbols in the attached drawings:

1 Water distribution pipe, 2 Outlet hole, 3 Packing layer, 4 Aqueduct pipe, 5 Suction pipe, 6 Anti-seepage layer, 6' permeable hole, 7 Covering soil layer, 8 Suction pump, 9 Well screen, 10 Water quality monitoring point, 11 Water level monitoring points, 12 fast-seepage zones, and 13 target aquifers.

detailed description

The invention is a multi-stage quasi-in-situ groundwater restoration device integrating phytoremediation, physical restoration, chemical restoration and biological restoration, and optimally combining wetland technology, seepage reaction wall technology and well irrigation technology.

Please refer to the accompanying drawings, the multi-stage quasi-in-situ groundwater restoration device of the present invention is composed of a pumping system, a water distribution system, a restoration filling layer, a soil covering layer, an air duct, restoration plants and a monitoring system. in:

The pumping system includes a pumping well whose well depth reaches the target aquifer 13. The pumping well is inserted with a pumping pipe 5. The water intake point of the pumping pipe 5 is located in the middle of the screen tube of the well screen 9. The filter screen on the well screen 9 is installed At the water intake of the suction pipe 5, the wellhead is provided with a suction pump 8 (as shown in Figure 3).

The water distribution system consists of an aqueduct 4 and two water distribution pipes 1. One end of the aqueduct 1 is connected to a water pump 8, and the water pump 8 is at right angles to the water pipe 5. The other end of the water guide pipe 1 is connected to the water distribution pipe 1 provided with the water outlet hole 2, forming a triangular water distribution system on the same plane (as shown in Figure 1), and placing the water distribution system horizontally in the packing layer 3, and The water distribution system is covered with a certain thickness of soil layer 7 (as shown in Figure 2).

The packing layer 3 is a packing capable of adsorbing and degrading organic pollutants, heavy metals and "tri-nitrogen" and other groundwater pollutants, such as zeolite or zero-valent iron. The periphery and the bottom of the water distribution system are surrounded by an anti-seepage layer 6 formed of high-density polyethylene material, and the anti-seepage layer 6 around the pumping well is provided with a water-permeable hole 6' so that the repaired water can pass through the water-permeable The holes flow into the fast seepage zone 6', and a water quality monitoring point 10 is set near the fast seepage zone 6' and the permeable hole 6'; a water level monitoring point 11 is set in the target aquifer. Plants that can degrade, absorb or enrich pollutants in groundwater can be planted on the covering soil layer.

When the multi-stage quasi-in-situ groundwater remediation device of the present invention is actually installed, it is firstly investigated to fully grasp the characteristics of the stratum structure of the polluted site, determine the level of groundwater pollution, distribution conditions and the amount of water to be repaired, and formulate a plan including the location of pumping water, pumping wells, etc. The well construction scheme of well depth, well construction pipe diameter, water pumping volume, and pumping pipe diameter; determine the water pump model, the pipe diameter of the water distribution pipe in the water distribution system and the diameter of the outlet hole according to the water volume to be repaired and the well depth; The goal of restoration is to determine the composition of the filler in the filler layer and the size and thickness of the filler layer, and to determine the type of restoration plant and the thickness of the covering soil layer according to the characteristics of the pollutants in the groundwater.

During operation, the suction pump 8 is started, and the polluted groundwater enters the aqueduct 4 from the suction pipe 5, enters the water distribution pipe 1 through the aqueduct 4, and then enters the packing layer 3 through the micropores of the water distribution pipe 1, so that the polluted groundwater is evenly distributed. Distributed at one end of the packing layer 3, the polluted groundwater flows into the permeable hole 6' after being fully absorbed and degraded by the packing layer 3, and the repaired groundwater returns to the groundwater layer through the permeable hole 6'. Due to the flow of the groundwater itself, The repaired groundwater flows downstream through the rapid seepage zone 12, and at the same time, the unrepaired groundwater enters the repairing system of the present invention under the action of the pump, and runs continuously in this way to complete the task of repairing groundwater pollution. The device of the present invention adopts intermittent The pumping and water distribution process ensures the stability of the process operation. At the same time, the covering soil layer is planted with plants that are beneficial to the restoration of groundwater pollution, so as to strengthen the good restoration effect of this process.

Claims (9)

1. a kind of multistage quasi- original position subsoil water prosthetic device, including：

One pumped well, well depth is to target water-bearing layer；

One drinking-water pipe, is plugged in pumped well, and one end of drinking-water pipe connects to the suction pump being arranged at well head；

One aqueduct, the perpendicular angle with drinking-water pipe, one end of aqueduct connects suction pump, and the other end of aqueduct connects respectively Offer two water distributors of apopore, formed the water distribution system of triangle at grade by water distributor and aqueduct, This water distribution system is flatly placed in packing layer, and overlying soil on filler, and plants and be implanted with plant；

The bottom of packing layer and periphery are impervious barrier, and the impervious barrier around pumped well is provided with permeable hole, and current pass through permeable Hole enters quick vadose region；

It is provided with Water-quality Monitoring Points near the permeable hole of quick vadose region；

It is provided with water level monitoring point in target water-bearing layer.

2. multistage quasi- original position subsoil water prosthetic device according to claim 1, wherein, the dry point of drinking-water pipe is located at and draws water The screen casing centre position of the well screen in well.

3. multistage quasi- original position subsoil water prosthetic device according to claim 1 and 2, wherein, pacifies at the intake of drinking-water pipe Equipped with drainage screen.

4. multistage quasi- original position subsoil water prosthetic device according to claim 1, wherein, packing layer can be achieved on to underground Water pollutant has the filler of absorption and degradation effect.

5. multistage quasi- original position subsoil water prosthetic device according to claim 1, wherein, overlying soil is planted to subsoil water Middle pollutant have the plant of degraded, absorption or enrichment function.

6. multistage quasi- original position subsoil water prosthetic device according to claim 1, wherein, impervious barrier is high density polyethylene (HDPE).

7. a kind of method carrying out groundwater remediation using quasi- original position subsoil water prosthetic device multistage described in claim 1：

Start suction pump, the subsoil water to be repaired enters aqueduct by drinking-water pipe, enter water distributor through aqueduct, then through water distributor Apopore enter packing layer, so that subsoil water is evenly distributed in packing layer, groundwater pollutant through packing layer absorption and After degraded, returned in Water table by quick vadose region, due to the flowing of itself of subsoil water, the direction of groundwater flow after reparation Downstream, the subsoil water simultaneously do not repaired, in the presence of suction pump, enters multistage quasi- original position subsoil water prosthetic device, continuous operation Until completing the reparation of subsoil water.

8. method according to claim 7, wherein, draws water and water distribution is to be drawn water and water distribution using step.

9. method according to claim 7, wherein, overlying soil plantation is conducive to the plant that underground water pollution is repaired, by force Change repairing effect.