EP0555734A1 - Device for cleaning ground water - Google Patents

Abstract

In the arrangement for cleaning ground water and the earth through which it flows, the cleaning elements, in particular filter devices, are designed and arranged in such a way that they produce optimum efficiency and guarantee a long service life of the arrangement. This is achieved by largely avoiding vertical filter surfaces and screen walls defining filter chambers, filter chambers with exchangeable filter material, the arrangement and configuration of the conveying means for achieving ground-water circulation and/or by devices for cleaning screen walls of any deposits. <IMAGE>

Description

The invention relates to an arrangement for cleaning groundwater and the soil through which it flows, with a conveying device for generating a liquid circuit leading through filters between a well shaft driven into the area of the contaminated groundwater and the surrounding soil, the well shaft being in an upper and is divided into a lower area, which are separated from each other and each have at least in some areas a water-permeable shaft wall for water intake from or for reintroduction of the water into the ground, and the two areas are connected to one another by means of a through pipe in which the conveying device is effective.

An arrangement with the features mentioned above is known for example from DE-PS 40 01 011. In these arrangements, there is generally the problem that filter areas formed along the wall of the well shaft, for example filter gravel fillings arranged around a well pipe, can hardly be cleaned, can easily become clogged and thus soon impair the efficiency of the arrangement. In addition, an outer filter gravel jacket requires a larger bore diameter, which makes the arrangement more expensive. It has also been shown that filter layers, which are attached in front of the water-permeable vertical shaft wall areas, clog rapidly due to blockages and because of the vertical position of the filter surfaces, these deposits can be removed only with great effort using acid and a cleaning circuit with water under high pressure to let.

The invention has for its object to provide an arrangement of the type mentioned so that it allows the cheapest use of a well shaft cross-section without endangering the effectiveness and duration of the cleaning fountain.

The stated object is achieved with the arrangement mentioned according to the invention in that filter chambers are formed both in the upper and in the lower area of the well shaft, which take up the entire free drilling cross section of the well shaft and at least in the upper well shaft area rise above the upper edge of the water-permeable Extend the shaft wall into a shaft area that is closed off from the outside (well pipe). In this case, at least in one of the two shaft areas, a plurality of filter chambers can advantageously be arranged one above the other and in each case separated from one another by a screen wall.

In the case of an arrangement designed according to the invention, all filter areas are thus arranged within a drilling cross section of the well shaft and extend over the entire drilling cross section, insofar as it is not taken up by other parts of the arrangement, in particular by the mainly centrally arranged through pipe. An outer filter casing, which makes a larger bore diameter necessary and can subsequently be badly influenced, is omitted, as is filter walls with vertical filter surfaces, which experience has shown to be quick due to precipitation from the Add groundwater. Horizontal or inclined filter walls, as are provided between the several filter chambers, are far less exposed to the risk that they become tight due to blockages. The arrangement of several filter chambers one above the other also has the advantage that at least the uppermost filter chamber in the well shaft can be provided with exchangeable filter material that can be sucked off and / or instilled, as can be seen, for example, from DE-PS 41 38 414 by the applicant.

Despite the filter areas that extend over the entire free drilling cross section according to the invention, a relatively large free flow space for the groundwater within the well shaft can also be obtained with an arrangement designed according to the invention. For example, sieve walls delimiting the filter chambers can be designed in the form of conical rings concentrically surrounding the centrally arranged through-tube, which can be arranged in pairs in mirror image symmetry to one another and can be arranged with their outer edges touching. Either the interior of these double-conical structures can be kept free of filter material, or filter material can only be arranged within these structures, while the rest of the space - ie either inside the double-conical structures or outside of it - is filled with filter material. The sieve walls delimiting the filter chambers can, however, also run curved and, for example, be spherical or spherical segment-shaped wall structures which can likewise limit spaces for the groundwater that are free of filter material.

In one of the numerous possible embodiments of the arrangement designed according to the invention, a drum-shaped filter can be arranged in the lower shaft area in front of the end of the through pipe. To keep vertically aligned side walls small, the height of the drum body can be kept relatively low, so that the Main filter surfaces are formed by the two horizontal end faces of the drum.

The conveying device in an arrangement designed according to the invention can expediently be formed by at least one conveying pump, which can preferably be accommodated in the through-pipe. As a conveying device, however, an airlift device can also be provided exclusively or additionally, as can be formed in the previously proposed manner by a nozzle body which is arranged in the upper region of the well shaft and in which a gas, in particular fresh air, from outside the shaft Generating negative pressure in the upper shaft area is fed. The supplied gas causes an additional purification of the groundwater by absorbing and removing volatile contaminants as it passes through the groundwater. By means of concentric guide rings arranged individually or in groups above the nozzle body, a circulating movement of the groundwater inside the shaft can be forced, which increases the effectiveness of the additional gas treatment of the groundwater.

The solution to the problem can be favored by the fact that the sieve walls, which at least partially limit the filter chambers, have a special design and that devices for generating vibrations are arranged on the sieve walls and / or in the filter material of the filter chambers. Advantageously, the sieve walls can consist of a supporting and shaping web carrier and attached round wires that delimit the sieve openings. The sieve openings formed here with their rounded edges make clogging due to deposits difficult. Approaches for a non-stationary and mobile vibration generator can also be formed on the web supports, with which the screen walls can be vibrated from time to time. Are suitable as stationary or mobile vibration generators mechanical, electromechanical or ultrasonic devices.

Several exemplary embodiments of an arrangement designed according to the invention are explained in more detail below with reference to the accompanying drawing.

Fig. 1 - 4

schematische Längsschnitte durch vier Anordnungen für Grundwasser-Zirkulationsbrunnen, jeweils mit mehreren Filterkammern im oberen und unteren Brunnenschachtbereich und mit unterschiedlicher Gestaltung dieser Filterkammern;

Fig. 5 - 7

den oberen Teil einer Anordnung nach Fig. 4 mit einer näheren Darstellung der Filterkammern begrenzenden Siebwandungen;

Fig. 8 - 11

mehr oder weniger schematische Längsschnitte durch vier Anordnungen für Unterdruckvergaserbrunnen (UVB).

In detail show:

1-4

schematic longitudinal sections through four arrangements for groundwater circulation wells, each with several filter chambers in the upper and lower well shaft area and with different design of these filter chambers;

5 - 7

the upper part of an arrangement according to Figure 4 with a more detailed representation of the filter chambers delimiting sieve walls.

Figures 8-11

more or less schematic longitudinal sections through four arrangements for vacuum carburettor wells (UVB).

1 to 4 and 8 to 11 each show a drilled well shaft 12 which is driven into a soil 10 interspersed with contaminated groundwater. The well shaft 12 is lined with a well pipe 13 in its upper region. The well shaft is divided into an upper region 15 and a lower region 16 by a seal 14. A connection between the two areas is provided by a through tube 17 which is arranged centrally in the well shaft 12. Filter chambers are formed both in the upper and in the lower region 15, 16 of the well shaft 12, which cover the entire free bore cross section of the well shaft take in. These filter chambers are arranged or limited differently in the individual exemplary embodiments.

In the exemplary embodiment according to FIG. 1, a pump 18 is arranged in the upper end region of the through-pipe 17 and sucks the groundwater rising into the upper free shaft area surrounding the well pipe 13 into the through-pipe 17. The through pipe 17 ends at the bottom in the opening of a transverse wall 19, which brings about the separation into the upper shaft area 15 and the lower shaft area 16 and to which the seal 14 is connected in the form of an annular jacket. In the upper shaft area 15, two filter chambers 20, 21 are formed, which are separated from one another by a horizontal screen wall 22. Also in the lower shaft area 16, two filter chambers 23 and 24 are formed, which are separated from one another by a horizontal sieve wall 25 and of which the upper filter chamber 23 is located within the ring-shaped seal 14. In the upper shaft area 15 too, the upper filter chamber 20 is closed off from the outside, there by the well pipe 13. The two upper filter chambers 20 and 23, which can only flow in the vertical direction, are filled with an exchangeable filter material. The respective lower filter chambers 21 and 24, which are open towards the shaft wall, are completely filled with filter gravel, for example. The filter material can be exchanged from the upper filter chambers 20 and 23 by suctioning off the pourable and free-flowing material and subsequently infusing new filter material. After removal of the pump 18, the upper filter chamber 23 of the lower well shaft area 16 is accessible through the through pipe 17 for a suction or inflow hose, not shown.

The groundwater circulation well according to Fig. 1 is operated in the so-called left-hand rotation, because in the upper well shaft area 15 groundwater flowing into the lower filter chamber 21 there and rising through the upper filter chamber 20 is conveyed through the through pipe 17 into the lower shaft area 16, where it first flows through the upper filter chamber 23 with the exchangeable filter material filling and the sieve wall 25, then into the lower filter chamber 24 arrives and from there can flow back into the ground. In the upper tube chamber 20, further solid filter layers can be arranged in the well pipe 13 in the form of removable ring packs which can be easily replaced.

In the arrangement according to FIG. 2, a perforated distributor pipe 26 is arranged coaxially in the upper well shaft area 15 via the central through-pipe 17. It is expanded in the upper filter-free shaft end to a collecting cylinder 27, in which the through pipe 17 provided with a feed pump 28 ends. Downward into the lower shaft area 16, the through pipe 17 is extended beyond the seal 14 to the bottom of the well shaft and is formed in this area as a perforated collecting pipe 29. In both well shaft areas 15 and 16, filter chambers or filter areas are delimited by sieve walls 30, which are arranged in the form of conical rings between the perforated distributor pipe 26 and the wall of the well shaft 12 in pairs of mirror images of one another and with sieve walls 30 touching with their outer edges. The interior of the double-conical screen wall structure forms a free flow space for the groundwater. Granular filter material lies against the outside of these double-conical structures. Large filter areas are created, over which the groundwater is guided in a well-distributed manner. The filter mass that widens from the inside to the outside in the individual filter chambers prevents undesired vertical groundwater flow in the edge area of the well shaft. Easy-change filter chambers have been omitted here. The groundwater circulation well is operated in the so-called clockwise rotation, i.e. groundwater in the lower well shaft area 16 is sucked up, conveyed upwards and returned through the upper well shaft area 15 back into the ground.

3 and 4 show an arrangement, operated according to FIG. 3 in left-hand rotation and according to FIG. 4 in clockwise rotation. With this arrangement, both in the upper well pipe area 15 and in the lower well pipe area 16, outer filter chamber areas with changing filter material thickness are formed similarly to the exemplary embodiment according to FIG. 2. There are arranged around the distributor pipe 26 and around the perforated header pipe 29 to form a torus with a semicircular cross section and curved sieve walls 31. The interior 32 of the gates forms free flow spaces for the groundwater. The space between the outside of the curved sieve walls 31 and the shaft wall is filled with filter gravel. In the counterclockwise rotation of the groundwater circulation well shown in Fig. 3, the perforated manifold 26 has the function of a manifold, while the manifold 29 has the function of a manifold.

5 to 7 show the structure of a torus 33 formed by a curved sieve wall 31 and pushed onto the distributor pipe 26. Web supports 36 are clamped in an arcuate manner between two support rings 34 and 35. Round wires 37 are placed on this arched web carrier 36 at regular intervals, for example a single round wire is wound and connected to the web carriers 36 by spot welding or gluing. In addition, the two support rings 34 and 35 are connected to one another by means of rectilinear support webs 38, at least one of which is provided with a cam-like extension 39 which projects into the space between the distributor pipe 26 and the through pipe 17 (FIG. 5). However, the carrier webs 38 can also be connected to one another by an electromagnetically actuated vibration ring 40, as is also shown in FIG. 5.

A vibration rod 41 of a mobile vibration generator 42 can be attached to the lugs 39, which is shown in FIG. 5 with dash-dotted lines. With the vibration generators 40 or 42, the screen wall structures can be vibrated from time to time in order to detach precipitates that settle on the screen walls 31 or parts that have washed away from the groundwater or the soil from the screen walls.

8 to 11 show cleaning arrangements in which the groundwater is additionally subjected to a treatment by gases, in particular air, which are drawn through the groundwater in fine bubbles by the formation of negative pressure in the upper shaft area. The resulting airlift effect also has a pumping effect on the groundwater. In the exemplary embodiment according to FIG. 8, this is the only conveying device for the formation of the groundwater circuit through the filter chambers of the arrangement.

The well pipe 13 is closed to the outside by a cover 118, through which an air suction pipe 119 with a pump 120 and an air suction pipe 121 are guided. The pump 120 creates a negative pressure above the groundwater level 122 in the shaft 12, which is responsible for the pumping of the groundwater from the lower shaft area 16 into the upper shaft area 15. A drum-shaped filter body 123, which is surrounded by filter gravel 124, is arranged in the lower shaft area 16. The filter body 123 has a vertical side wall 125 and two horizontal filter surfaces 126 and 127, through which groundwater flows in from the surrounding soil 11 due to the negative pressure generated in the upper shaft area, which is indicated by the arrows 128. The water then passes through the passage pipe 17 into the upper shaft area 15, where it is received by a second pipe 130 inserted into an expansion 129 of the passage pipe 17, which widens like a pot and an air chamber 131, which is delimited by a nozzle body 132, and forms a water receiving space 133 below the air chamber. The water passes from the pipe 17 via the insert pipe 130 into the water receiving space 133 and from there via two tubes 134 and 135 guided through the air chamber 131 into a water treatment area 136 above the air chamber 131. The tubes 134 and 135 have openings at the level of the air chamber 131 through which air drawn in by the water flowing in the tubes can penetrate and be transported upwards into the treatment room 136. In the treatment room 136, two concentrically arranged guide rings 137 and 138 are arranged, which promote the laminar flow of the water during the upward and downward flow and thereby contribute to a part of the downward flowing water being caught again by the upward flowing air bubble stream and being cleaned a second time. After reaching the water level 122 in the well shaft, the air bubbles are sucked out of the shaft by the pump 120 together with the contaminations bound to them. At the same time, the negative pressure generated by the pump 120 in the shaft ensures that fresh air can flow through the suction pipe 121 into the air chamber 131.

The entire insert, consisting of the insert pipe 130, the water chamber 133, the air chamber 131, the air supply pipe 121 and the guide rings 137 and 138, is attached to a floating body with air chambers 139 in order to be able to compensate for fluctuations in the groundwater level 140 in the ground 11.

After the groundwater has been cleaned of volatile impurities by means of the air or gas bubbles in the treatment room 136, the groundwater flows down again along the edge of the shaft and seeps through a gravel fill 141 in the upper shaft region 15 before it leaves the well shaft 12 again laterally. When the water seeps through the gravel fill 141, other substances bound in the water, such as. B. iron can be solved from this. After backflow into the ground 11, the groundwater is again picked up by the suction effect in the lower shaft area 16 and thus forms a cycle between the well shaft 12 and the ground 11. New, not yet cleaned groundwater is constantly drawn in. The range of the circuit in the radial direction around the well shaft can be further increased by reducing the height of the side wall 125 of the drum filter 123 in the lower shaft area.

FIG. 9 shows an arrangement whose lower region 16 has a smaller diameter than the upper shaft region 15, i. H. the more expensive drilling of the well shaft is only necessary in the upper area in which the treatment of the water takes place.

In a widening 29 of the through pipe 17, which connects the two shaft areas 15 and 16 to one another, an insert pipe 130 and a feed pump 150 connected to it are inserted. At the outlet of the pump 150, a pipe 151 is arranged which conveys the water through an air chamber 131 in order to then discharge it into a treatment room 136 through lateral openings 152. At the level of the lateral openings 152, two concentric guide rings 137 and 138 are arranged to promote the laminar water flow.

The pipe 151 has in its upper region a transverse wall 153 which prevents the penetration of water into the end piece 154 of the pipe 151 reaching up to a manhole cover 118 and thus this end piece 154, the two connecting pipes 155 and 156, which extend into the air intake space 131 are guided, has, for the supply of fresh air into the air chamber 131. As in the exemplary embodiment in FIG. 8, the fresh air is sucked into the shaft by the negative pressure generated by means of a pump 120 above the shaft 12.

Also in the arrangement according to FIG. 9, the contaminated groundwater is first cleaned of volatile contaminants in the treatment room 136 before it undergoes a second cleaning when flowing downward through a gravel fill 141. Subsequently, the groundwater leaves the shaft 12 in the upper region 15 again and forms a circuit to the water suction point in the lower shaft region 16, the flow rate of the water in the exemplary embodiment according to FIG. 9 through the feed pump 150 being greater than in the exemplary embodiment according to FIG. 8, in which the circuit is created solely by generating negative pressure in the well shaft.

To clean the gravel, 141 vibration generators 157 are arranged in the gravel fill, the pressure waves of which dissolve impurities in the gravel, which can then be suctioned off.

In the exemplary embodiments according to FIGS. 10 and 11, in addition to the feed pumps 18 or 28 arranged in the through-pipe 17, additional feed pumps 45 or 46 are provided which amplify and control the movement of the groundwater in the gas treatment area of the arrangements. The structure of the filter part of the arrangement is very similar to that of the exemplary embodiment according to FIG. 1, which is why the same reference numbers as in FIG. 1 are used for corresponding device parts. In the gas treatment area, parts corresponding to the embodiment according to FIG. 8 are designated with the same reference numbers as there. In the arrangements according to FIGS. 10 and 11, the two pumps 18, 45 and 28, 46 cause a multiple circulation of the groundwater within the upper shaft area closed off from the outside by the well pipe 13. The additional pump 45 or 46 is arranged in a tube 47, which is passed through the air chamber 131 and a little way through the air intake tube 121, and which is below the liquid level 122 and above the guide ring 138 into a central region of the upper well shaft region exit. This central area is delimited by a guide tube 48 which projects beyond the liquid level 122 and acts in the liquid area like a third guide plate between the two other guide plates 137 and 138. Through the baffles, the groundwater is led several times through the area with the rising gas bubbles and redirected. In the exemplary embodiment according to FIG. 10, the groundwater is pumped up by the pump 45 into the gas treatment area and then flows back downward past the air chamber 131. In the exemplary embodiment according to FIG. 11, the groundwater is drawn down from the gas treatment area by the pump 46 and rises again along the air chamber 131 into the gas treatment area, insofar as it is not detected by the pump 28 and into the lower well shaft area 16 and the filter chambers there is subtracted. The pumps can be operated with different capacities depending on the type and extent of contamination of the groundwater.

Claims (21)

Arrangement for the purification of groundwater and the soil through which it flows, with a conveying device for producing a liquid circuit leading through filters between a well shaft driven into the area of the contaminated groundwater and the surrounding earth, the well shaft being divided into an upper and a lower area ( 15, 16) which are separated from each other and each have at least in some areas a water-permeable shaft wall for water intake from or for reintroduction of the water into the soil, and the two areas (15, 16) being connected to one another by means of a through-pipe (17) are in which the conveyor is effective, characterized in that both in the upper and in the lower region (15, 16) of the well shaft (12) filter chambers (20, 21; 23, 24, 124) are formed, which the entire free Take the cross section of the well shaft and at least in the upper well shaft area (15) extend upwards over the upper edge of the water-permeable shaft wall into a shaft area (well pipe 13) which is closed off from the outside. Arrangement according to claim 1, characterized in that at least in one of the two shaft areas (15, 16) a plurality of filter chambers are arranged one above the other and each is separated from one another by a sieve wall (22, 25, 30, 31). Arrangement according to claims 1 and 2, characterized in that at least the uppermost filter chamber (20) in the well shaft (12) is provided with exchangeable filter material. Arrangement according to one of Claims 1 to 3, characterized in that the filter walls (30) delimiting the filter chambers are designed in the form of conical rings concentrically surrounding the centrally arranged through-pipe (17). Arrangement according to claim 4, characterized in that the conical sieve wall rings (30) are arranged in pairs in mirror image symmetry to each other and touching with their outer edges. Arrangement according to one of Claims 1 to 5, characterized in that the sieve walls (31) delimiting the filter chambers are curved. Arrangement according to claim 6, characterized in that the filter chambers are delimited inwards by sieve walls (31) which are in the form of spherical or spherical segments. Arrangement according to one of claims 4 to 7, characterized in that the filter material is arranged between the screen walls (30, 31) and the wall of the drill shaft (12) and there are free spaces (32) for the groundwater between adjacent screen walls. Arrangement according to one of claims 1 to 8, characterized in that a drum-shaped filter (123) is arranged in the lower well shaft region (16) in front of the end of the through pipe (17). Arrangement according to claim 9, characterized in that the side walls (125) of the drum-shaped filter (123) have a height which is less than the filter diameter. Arrangement according to one of claims 1 to 10, characterized in that the upper shaft area (15 ') has a larger diameter than the lower shaft area (16') (Fig. 9). Arrangement according to one of claims 1 to 11, characterized in that the through tube (17, 17 ') has an expansion (129, 129') at its upper end. Arrangement according to claim 12, characterized in that a feed pump (150) is arranged in the widening (129, 129 '). Arrangement according to one of claims 1 to 13, characterized in that in the upper region (15, 15 ') of the well shaft an air chamber (131, 131') delimited by a nozzle body (132, 132 ') for supplying gases, in particular fresh air , from the outside of the well shaft (12, 12 ') by generating negative pressure in the upper shaft area (15, 15'). Arrangement according to claim 14, characterized in that one or more concentric guide rings (37, 38; 37 ', 38'; 48) are arranged above the nozzle body (132, 132 '). Arrangement according to claims 14 and 15, characterized in that the nozzle body (132, 132 ') and the guide rings (137, 138; 137', 138 ') are fastened to a common floating body (139). Arrangement according to claim 14, characterized in that an additional through-pipe (47) for the groundwater is passed through the nozzle body (132), in which a feed pump (45, 46) acts as an additional conveying device. Arrangement according to one of claims 1 to 17, characterized in that the through-pipe (17) projects beyond the filter chambers (20, 21) of the upper shaft area (15) and has a reversible feed pump as the conveying device. Arrangement according to one of claims 1 to 18, characterized in that the screen walls (31) consist of a supporting and shaping web carrier (34, 35, 36, 38) and attached round wires (37) delimiting screen openings. Arrangement according to one of claims 2 to 19, characterized in that devices (40, 157) for generating vibrations are arranged on the sieve walls of the sieve chambers and / or in the filter material of the sieve chambers. Arrangement according to claims 19 and 20, characterized in that the web supports (38) are provided with at least one extension (39) for a vibration generator (41/42) (Fig. 5).

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