DE9005565U1 - Facility for purifying groundwater - Google Patents

Description

Hermann Frese Am Hang 20

2808 Syke

Cell ₅ 14,05*90

Πδ F 190

Facility for purifying groundwater

The invention relates to a device for cleaning groundwater contaminated with pollutants such as chlorinated hydrocarbons, for example, by means of a roller system that can be lowered into the aquifer.

It is known that the groundwater in the area between the soil, which is the surface of the earth, and the aquifer, which is a layer that is essentially impermeable to groundwater, can be contaminated with pollutants, such as chlorinated hydrocarbons. Such contamination can be found, for example, in areas with old landfills, factories or the like. With such polluted groundwater, there is a risk that the pollutants will enter the deep water, which is so important for drinking water production, over the course of the coming years.

The invention is based on the task of cleaning the groundwater in the area between the field floor and the aquifer floor and thus preventing or reducing the sinking of pollutants into the deep water. This task is solved by a device or a corresponding application with the features defined in claim 1.

236 F 190 14.05.90

In principle, the invention consists in providing a water intake pipe surrounded by a jacket pipe, which is perforated in a lower area for water inlet and in an upper area for water system, that the jacket pipe is perforated on its outer side in order to rewind the sucked water exiting from the intake pipe into the ground, and that an air injector pipe is arranged in the intake pipe, which serves to generate a negative pressure in the intake pipe between the perforated areas, which causes the suction, with an air outlet pipe between

■ ■ - -

see intake pipe and jacket pipe which removes the volatile pollutants separated from the water during the turbulent mixing of water and air and feeds them to a filter. The pipes can each consist of one piece or be made up of several individual pipes and/or filter pipe parts.

Further developments of the invention are described in the subclaims.

To explain the invention in more detail, an exemplary embodiment is described below with reference to the drawing. This shows on the left-hand side the schematic structure of the area of earth between the field floor and the aquifer floor, such that above the aquifer floor up to the water level, i.e. the groundwater level, the aquifer is indicated and between the water level and the field floor the unsaturated zone through which rainwater or the like sinks down to the aquifer. The water in the aquifer can be more or less contaminated with pollutants. In order to remove these pollutants from the groundwater, a water intake pipe 1 is introduced into the soil described so far, the lower end 2 of which reaches into the aquifer floor and forms a sump 3 there in which solids can settle. Above the sump 3, the water intake pipe 1 is perforated and forms through this perforated area ^1J a suction pipe inlet 5 for the water W to be sucked in.

·_· ^# 3 --''··' 236 F 190

11.05.90

The water intake pipe 1 is hermetically sealed at its upper end 6, for example by a flange 7. Above the water level, the water intake pipe 1 is provided with a perforated area 9 to form a suction pipe outlet 8 for the sucked-in water W. The area 10 between the perforated area 9 and the flange 7 is essentially sealed, that is, except for the connection to the perforated area. An air injector pipe 11 is introduced into the water intake pipe 1 through the flange 7, the lower end 12 of which is guided to below the perforated area 9, where it generates an air vacuum through the injected air emerging from the lower pipe end 12 and immediately rising upwards, which sucks in the groundwater through the suction pipe inlet 5. The upwardly striving air-water mixture exits through the perforation 9 in the water intake pipe 1 into a space 13 which is formed between the outside of the water intake pipe 1 and the inner wall of a jacket pipe 14 which concentrically encloses the water intake pipe 1 and is sealed at its upper end except for an air outlet pipe 15. The jacket pipe 14 is sealed at its lower end 16 from the water intake pipe 1 by a sealing ring 17 and is provided with a lateral perforation 18 such that the sucked-in water, after passing through the perforation 9 of the water intake pipe 1, first sinks into the area enclosed by the jacket pipe 11 and then exits laterally into the ground through its perforation 18. The perforation 18 of the casing pipe 14 is arranged so far below the perforation 9 of the water intake pipe 1 that the sucked-in water W shoots through the perforation 9 of the water intake pipe 1 and then hits the closed inner wall of the casing pipe 14. This prevents the sucked-in water W from flushing out the soil behind the perforation 18 of the casing pipe 14. The sucked-in water W thus circulates from the water pipe through the intake pipe inlet 5 into the water intake pipe 1.

: · ··:; · 236 F 19O

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to the water outlet 8 of the pipe 1 and from there through the jacket pipe 1 ¹ J back into the aquifer of the soil.

Depending on the height of the injector pipe outlet 12 in the water intake pipe 1, the water W is sucked in with a greater or lesser negative pressure and therefore shoots upwards with greater or lesser speed. There, the sucked-in water W hits the closed space 10 and is reflected or thrown back from there. The air cushion in the closed space 10 is compressed by the water that is sucked in and impacts the air cushion. Because the water reflected by the air cushion hits the water that is shooting up, the compression of the air cushion is non-uniform. A pulsating or turbulent behavior occurs. Due to this turbulence in conjunction with the water outlet 8 of the intake pipe 1 and the impact of the water W on the inner wall of the jacket pipe 14, the sucked-in water W ₁ is swirled relatively strongly and mixed with the injected air. As a result, the air constantly extracted through the air outlet pipe 15 also contains significant amounts of the pollutants contained in the water W. The vibration of the turbulence in the pipes, which reaches the ground, promotes the separation of the pollutants even from small grain sizes in the soil. The air extracted through the air outlet pipe 15 by means of a pump, a fan or the like is passed over a filter 19. After a certain period of filtering , this filter contains considerable quantities of pollutants, which can then be disposed of in concentrated form.

The entire pipe system 1, 14, 11 can be hidden underground and operated with only the relatively low energy input required for air extraction. After a certain period of operation with groundwater containing pollutants constantly being sucked in and the air constantly being returned to the ground,

; ::.. r. ? · · · · 236 F 190

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Once the water has been purified, no more pollutants settle in the filter 19. The facility can then be shut down or removed and rebuilt and operated at another location. It is also possible to operate a large number of similar facilities simultaneously or alternately over a larger area, for example to completely dispose of the pollutants emerging from a landfill in many places as quickly as possible or to reduce them to a level that is no longer dangerous.

The speed of the water sucked in can be adjusted or changed by moving the injector pipe and thus its lower opening. This allows the amount of water sucked in to be adjusted to a level that can be processed by the device without overfilling. The air can be supplied to the system by compressed air through the injector pipe 11 or by suction through the pipe 15. The filter 19 connected to the outlet of the air suction pipe 15 can be designed as a conventional, known disposable filter.

In a practically tested embodiment of the invention, the water intake pipe 1 had a total length of 18 m, which was installed and assembled together with the casing pipe 14 according to the rules of well construction at the installation site. The casing pipe 14, with a length of 8 m, corresponded approximately to the thickness of the unsaturated zone. The perforation in the casing pipe 14 begins approximately 100 cm above the water level and is dimensioned so long that variations in the water level have no significant influence on the discharge of the water. The perforated area 9 of the water intake pipe 1 begins above the perforation of the casing pipe 14 in order to prevent leaching. The distance between the two perforation areas in the water intake pipe 1 and in the casing pipe 14 is, apart from the leaching effect to be avoided,

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relatively uncritical, since the pumped water only has to find enough space between the pipes 11 and 14 for intake and discharge f . Critical, however, is the distance between the

' ^: Perforation 9 and the injector tube outlet 12, since in a

If the distance is too small, the suction does not work and if the distance is too large, too much water is pumped - At a distance of 1.50 m, the pressure difference is already 1500 mm water column - The correct functioning of the system depends on setting and maintaining the correct pressure difference

The pipes can be made of the usual materials known for pump systems. However, plastics and ^other materials have also proven to be _suitable. The water intake pipe 1 is preferably centered in the casing pipe IH . This is done in the upper area by the flange 7 and in the lower area by the seal 11. The injection pipe 11 is fastened centered in the flange 7. It can be mounted there so that it can be moved longitudinally, with locking means for the set positions being useful, for example a so-called stuffing box.

The filter 19, e.g. an activated carbon filter, can form a structural unit with the air suction unit 20 - As air suction

>. aggregate 3ich has already a

A simple vacuum cleaner has proven to be a viable solution to the problem. Since the system is intended for constant use underground, i.e., depending on the pollution level, also for days and nights, it may be appropriate to house the assembly unit 19, 20 in a soundproof container despite its relatively low noise level.

&bgr; The arrangement described so far is in connection with

the groundwater in the soil. In all application _purposes , water circulation from the deep to the high

*.; richly generated, which enables water circulation throughout the water level where the perforations of the pipes

F190 3 236 05-90 -M 14.

serve both for the inlet and outlet of water and also for retaining sand, gravel or the like. A system with diameters of 250 mm for the jacket pipe 14, 100 mm for the intake pipe 1 and 50 mm for the air injection pipe had favorable conditions for the water circulation as well as for the separation and removal of pollutants from the circulated water. 1·1 - The diameter of the air injection pipe 11 also allows measuring devices to be lowered into the intake pipe during operation, for example to measure the speed of the water shooting up and, if necessary, to use the measured value to automatically adjust the injection pipe 11.

The facility described so far can be delivered as a prefabricated unit, but can also be assembled on site from prefabricated components in order to carry out the described process for cleaning the groundwater. .

Claims (4)

1 4 236 F190
14.05-90 Protection claims -1- Device for cleaning groundwater contaminated with, for example, sludge, substances, characterized in that a water suction pipe (1) and a casing pipe (14) are joined at their upper end to form a structural unit, that the water suction pipe (1) has two separate lateral upper and lower water passage points (5,8) along its length and the casing pipe (14) has a water outlet opening (18) offset in the longitudinal direction of the pipes (1,14) against the upper opening (8), that an air injection pipe (11) of such length is introduced into the water suction pipe (1) from the outside that the air outlet opening of the air injection pipe (11) is located below the upper water passage opening (8) of the water suction pipe (1), and that the space (13) between water intake pipe (T) and the jacket pipe (14) an air outlet pipe (15) is connected through which the air contained in the room 13 is fed to a filter 4 ' (19) can be fed. 2. Device according to claim 1, characterized in that the water intake pipe (1) is closed at its upper end by a flange (7) which can be sealingly connected to the upper end of the casing pipe (14). 3. Device according to claim 2, characterized in that the flange (7) is at the same time a passage and holder for the air injection pipe (11). 236 F 190 1-4-05-90 4. Device according to claim 1, 2 or 3, characterized in that the water intake pipe (15) forms in its upper part a closed space (10) open at the bottom. 5- Device according to one of claims 1 - 4, characterized in that the injector tube (11) is adjustable in its longitudinal direction» 6- Device according to claims 1 - 5, characterized in that the water inlets and outlets (5,8,18) are formed by pressure regulators in the pipes (1,14). Device according to one of claims 1-6, characterized in that a water intake pipe (1) surrounded by a jacket pipe is provided, which is perforated in a lower region for water inlet and in an upper region for water outlet, that the jacket pipe (14) is perforated on its outside in order to rewind the sucked water emerging from the intake pipe (1) into the ground, and that an air injector pipe (11) is arranged in the intake pipe (1), which serves to generate a negative pressure in the intake pipe (1) between the perforated regions, which causes the suction, wherein an air outlet pipe (15) between the intake pipe and the jacket pipe (1,14) drains off the volatile pollutants separated from the water during the turbulent mixing of water and air and feeds them to a filter (19).