FI117554B - Device for creating an oxidation and precipitation zone or a reduction zone in a groundwater-bearing layer - Google Patents

Description

117554

Apparatus for forming an oxidation and precipitation zone or a reduction zone in a groundwater channel - Anordning för att i et grundvattenförande lager skapa en oxidations- och utfallningszon eller en reductionen 5

The present invention relates to an apparatus for carrying out a method such as that described in claim 1 of WO 92/00918, that is, an apparatus for forming an oxidation and precipitation zone or a reduction zone in a groundwater conduit between a plurality of injection wells for on-site precipitation or reduction of the undesirable substances present, wherein the zone may be intermittently formed between each adjacent pair of injection wells such that (i) oxygen, oxygen-containing gas or oxygen donor material is introduced into water in the wells when an oxidation and precipitation zone is formed , or the oxygen donor agent can be introduced into the water in the wells when a reduction zone is formed, and (ii) the water in the other well can be pumped from below upwards whereas the water in the second well can be pumped from above downwards, whereby a circulation circuit can be formed in the groundwater pipe with -20 groundwater height (11) - between the wells, the injection well having an outer pipe (1) an opening and has a water-permeable first conduit (3) extending to · · · the upper portion of the groundwater section and located at a distance above the orifice ί · ί: provided with a pressure inlet member (5) to form an upper ejector; extends to the groundwater section half or halfway of the portion of the outer pipe (1) with the openings, and the second pipe (4) has a pressure inlet member (*) immediately above the body (7) to form a second ejector.

. ·. The device known from WO 92/00918 has been found to perform satisfactorily in a variety of applications. Sometimes, when groundwater has been mixed with "annoying" or very large amounts of impurities, it has been found that the ejector is filled to a relatively large extent, which has resulted in the process being slowed down.

In particular, the Welding zones between the pipes are clogged.

. *! : 35 The outer tube has only its inside in contact with water • ·· \, while the inner tube is surrounded by "annoying" water on both the outside and inside. These annular spaces thus form a precipitate on both the outside and the inside so that they are filled to a large extent and the flow stops.

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It has also been shown that due to the relatively small tube diameter of the injection wells, it has been difficult to rinse off this precipitate or to otherwise get rid of it.

The present invention relates to the elimination of this drawback by a device adapted for this purpose but implemented in another way. The invention is characterized by the fact that at the upper end of the outer tube (1) is provided a rotation tank (2), from which the first tube (3) extends downwardly inside the outer tube (1) and a 10 spherical body (10) 7) which can be inflated by blowing so as to be tight against the inner wall of the tube (1), both of said pressure inlets (5, 6) and the spherical body (7) being in contact with one or more suitable pressure sources.

The invention will be further described below with reference to the accompanying drawing, in which Figure 1 shows a schematic axial portion of a couple of wells and Figure 2 shows a longitudinal cross-section of the device according to the invention.

The drawing thus shows an inwardly directed and preferably cylindrical outer pipe 1 which, at least in its portion of the groundwater outlet beginning at the height of groundwater 11, is partially provided with openings and is thus permeable to water. At the upper end 1 of this pipe, or at or above the ground level, is a circulating tank 2, from which downwardly a first pipe 3 extends into the upper part of the groundwater section within the outer pipe 1. Somewhat above this orifice 3 of the pipeline 3, a pressure inlet means 5 is formed to form the upper * · · • ejector. In addition, inside the outer tube 1 is a downwardly conducting second tube 4 which extends through the openings of the inserted tube 1 · * · *; mid-range or below. At the bottom of this pipeline * is fitted a tightly spaced outer spherical body 7 which can be inflated. . ·. 30 so that it sits snugly against the inner surface of the wall of the tube 1. This second • · * conduit 4 has a pressure inlet member 6 immediately above the body 7 to form another • * “* ejector. Both of said pressure inlet members 5, 6, ·, ·, and the spherical body are connected to suitable pressure sources. When forming an oxidation zone, pressure media are formed of air which, ·. *; For example, the compressor medium is formed from the compressor, while in the reduction process, the pressurized medium of the j ectors is formed from a suitable, non-shown pumped water or * *: aqueous solution, while the spherical body 7 is still connected to the compressed air source

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The circulating container 2 has softly rounded corners, which improves flushing and thus reduces the risk of precipitation inside the container walls. In addition, the container 2 may have a curved vent tube 8 whose cross section 5 of the mouth opening 1 can be adjusted by the vent device 9.

Preferably, the conduits 3 and 4 consist mainly of plastic hoses.

Figure 1 shows an example of how wells can be positioned, and Figure 10 shows well water pipes A and B, between which an oxidation and precipitation zone or a reduction zone is formed, where the device of the invention is now intended to provide desirable and efficient circuits.

15 The operation of a device such as the one described above is as follows. As a starting point, the spherical body 7 is inflated and thus sealed against the inner surface of the outer tube 1 is supplied with air or water to the upper ejector or pressure inlet member 5, after which the water is pumped up into a circulating tank 2 for air removal. The outlet valve 9 20 in the vent pipe 8 of the container 2 is then closed to a suitable extent. The water is then squeezed downwards through the conduit 4 into the lower part of the conduit 1 below the spherical body 7. From here the water. is led to the surrounding land.

Conversely, air or water / aqueous solution may be introduced into a lower ejector or pressure inlet member 6 and squeezed through a conduit 4 into a reservoir 2 for dewatering M · · · · · · · · · · · · · . The water then continues to flow downwardly through the conduit 3 so that it is pressed into the groundwater in the ground above the block 7.

. , ·, 30 If unwanted precipitate is formed inside the pipe and in the pipelines 3 and 4, purging can be easily performed after the spherical • 1 * .2 section 7 has been purged of air.

• · • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ● present. . ..

• · · 2 • · • · · · · ····. ' • ♦

Claims (5)

An apparatus for forming an oxidation and precipitation zone or a reduction zone in a groundwater-bearing layer between a plurality of injection wells, which may be arranged around one or more purified water outlet wells, which zone is intended for precipitation or in situ reduction of undesirable substances present in the groundwater, the zone being periodically formed between respective pairs of adjacent injection wells such that (i) oxygen, oxygen-containing gas or an oxygen-releasing substance can be directed to the water in the wells when an oxidation and precipitation zone has been formed, or acid-releasing agent can be directed to the water in the wells as a reduction zone has. . -f formed, and (ii) the water in one well can be pumped from below upwards while the water. in the second well can be pumped from the top downwards, whereby an orbital circuit can be formed in the groundwater-bearing layer between the wells in the height of the groundwater (11), wherein the injection well comprises an outer tube (1) which is at least partially in the part which is / located in the groundwater-bearing layer is provided with an opening and is water-permeable, a first conduit (3), which culminates in the height of the upper part of the • · groundwater-bearing layer and as above. The orifice is provided with a pressure inlet means (5) for forming an upper ejector, and a second conduit (4), which opens at the center of the perforated portion of the outer tube (1) or below the center: in the groundwater-bearing layer. , while the second conduit (4) just above the body (7) has a pressure inlet member (6) for forming a second ejector, · · · *. characterized in that a circulating container (2) is provided at the upper end of the outer tube (1), from which the first pipe (3) extends downwards inside the outer tube (1) and wherein outside the lower part of the second pipe (4) is tightly sealed: T: a balloon body (7) is provided which can be filled by inflating to lie tightly against the inner wall of the pipe (1), whereby both said pressure inlet means (5, 6) and the balloon body (7) is in communication with one or more suitable pressure sources. 6 117554 2. Device according to claim 1, characterized in that the circulation container (2) has soft rounded hem to improve flushing and to reduce the deposition of precipitation on the inner surfaces of the walls of the container. Device according to claim 1 or 2, characterized in that the circulating container (2) comprises a ventilation tube (8), the orifice of which can be controlled by means of a valve device (9). Device according to any of claims 1-3, characterized in that most of the length of the pipelines (3, 4) consists of a plastic hose. Device according to any one of claims 1-4, characterized in that a pressure medium can be formed during the oxidation process of air, which can be conducted from a compressor, while a pressure medium can be formed during the reduction process in the pressure inlet means (5, 6) of water. or other suitable medium which can be conducted with a suitable pump. • · · • · · · · <····. ' • · · · · · 1 · · · 1 · • 9 ··· · «» 1 • · * · ♦ ···. • · · • · · · · 1 * ·· • 1 ♦ · I · »• · · * 1 1 • ·« • · • · ··· • · · * · · 1 ·. * · · · · · · ·