Method and system for introducing at least one liquid infiltration medium into an aquifer

Abstract

Method for introducing at least one liquid infiltration medium (3) into an aquifer (15) by means of an infiltration-side pipe or shaft connection which has an infiltration lance (5B), the at least one liquid infiltration medium (3) to be introduced is fed via the infiltration lance (5B), the infiltration lance (5B) is further inserted into a subsurface (11) until a pressure equalization (13) occurs between the hydrostatic pressure of the aquifer (15) and a predetermined flushing pressure, and thus the at least one liquid infiltration medium (3) to be introduced is fed into the aquifer (15) via the infiltration lance (5B).

Description

[0001] The invention relates to a method and a system for introducing at least one liquid infiltration medium into an aquifer.

[0002] Groundwater is the water that fills the spaces beneath the Earth's surface and is subject only to the hydrostatic pressure of gravity. It originates from precipitation seeping into the ground or from water being forced into the soil at the banks of surface waters (such as rivers or lakes). As it percolates through the soil, the groundwater undergoes physical and chemical purification; biological processes also occur. The groundwater sinks through the various soil layers until it encounters impermeable barriers.

[0003] Like surface water, groundwater also flows depending on the gradient and the aquifer it flows through. In gravel, the flow rate is 5 to 20 m / day; in finer-pored sediments such as sand, it is only about 1 m / day, as capillary action and pore suction forces impede the flow. The surface of the groundwater flow is called the groundwater table. State of the art

[0004] Several methods for lowering (extracting) the groundwater level and transferring the groundwater to nearby discharge points are already known from the state of the art.

[0005] Generally, a structure is constructed in an open, dry excavation, which provides the space for the foundation and construction of the building below ground level. Construction in an open, dry excavation offers clear visibility and a high degree of safety, as the excavation base, slopes, and shoring are visible to every client and engineer. If these advantages are to be realized where structures or parts thereof are located below the groundwater table, groundwater lowering must be carried out. This involves a localized reduction of the normal, static groundwater level in the soil to a lower level in the form of a cone of depression, thereby dewatering the excavation.

[0006] The most commonly used methods for carrying out construction, assembly and earthworks in water-bearing soils include local, temporary soil drainage.

[0007] Closed groundwater management systems distinguish between gravity drainage and vacuum lowering. In simple cases, this can be achieved with drains, seepage lines, and sumps. For greater lowering depths, deep drainage systems, deep wells, or needle filters are available.

[0008] Whether a system operates as a vacuum system or according to the principle of gravity depends essentially on the properties of the soil to be drained, which is determined by the water permeability value k. f is characterized. The larger kf, the greater the particle spacing in the soil. The vacuum method is used for fine soils with permeability values ​​of k. f= 10⁻² to 10⁻⁸ cm / s Applications include so-called silty soils, loams, and clays. By introducing a vacuum into the filter pipe, the water contained in the soil is drawn into the filter and then pumped out. The process usually involves drawing water and air together through an airtight pipe system before the vacuum pump.

[0009] For coarser soils, such as sandy and gravelly soils with permeability values ​​of k f For speeds of 10-2 to more than 1 cm / s, the system operates according to the principle of gravity, and the water flows freely to the filter.

[0010] Common types of wells include dug wells, drilled wells, and needle screen systems. For example, with a dug well, a vertical shaft is excavated manually or mechanically down to the groundwater level. As the well is sunk deeper, the shaft is lined with masonry or prefabricated (steel) concrete sections. Groundwater flows into the well through the bottom of the shaft and / or a vertical filter section.

[0011] In a drilled well, a borehole is driven down to the groundwater table. A filter section is installed in the water-bearing layer. The disadvantages of this method lie in the time-consuming and costly excavation of the shaft or well drilling. Needle filter systems consist of closely spaced, small-diameter, vacuum-operated groundwater intakes connected to a pump unit via manifolds. The needle filters can be installed by jetting or drilling, with the delivery head of the external pump limiting the excavation depth (DE 40 40 803 A1).

[0012] The water, pumped at a predetermined flow rate, is usually discharged from the excavation area into a receiving water body (sewage / stormwater drain or open water). In practice, the resulting discharge fees are a disadvantage.

[0013] Alternatively, dug or drilled wells (filter wells, infiltration wells, or injection wells) can also be used for water return (infiltration) by manually or mechanically excavating a shaft or borehole down to the groundwater table. A filter section is provided in the area of ​​the deeper water-bearing layer, through which the extracted water is returned to the groundwater. However, due to the need for a large filter area for effective water return from the drilled well, which is achieved via an extensive filter section, there is a risk of encountering different soil layers and groundwater types.

[0014] In addition to surface infiltration, all types of wells used for groundwater lowering are also employed for infiltration. These include shallow wells, wellpoint systems, deep wells, and horizontal infiltration systems.

[0015] Shallow wells are wells where a suction pump is used to lower the groundwater level and which, due to the pump's suction capacity, are a maximum of 8 m deep. They are lined with filter pipes, usually DN 150, and surrounded with gravel.

[0016] Wellpoint systems are a very simple type of shallow wellhead system, in which the filter pipe simultaneously serves as a suction arm (for water extraction) and is flushed into the aquifer. The filter section is only about 1 to 2 meters long. No gravel pack is installed; in some cases, woven fabric may be used.

[0017] Deep wells have bore diameters between 500 and 800 mm and filter diameters of 125 to 300 mm. They are lined with a filter gravel pack. A downpipe is installed in the deep wells, through which the water to be infiltrated is transferred to the well. The wells can also be constructed so that filter sections are located in different aquifers, allowing water flowing from the upper aquifers to infiltrate into the lower aquifer. Horizontal infiltration systems, in addition to surface infiltration trenches, consist of filter pipes installed in shallow slots, connected to collection shafts from which the infiltrated water is collected.

[0018] All the described common methods for water infiltration have in common that the water is transferred to the mountains via pipes that are closed at the bottom and equipped with filter sections.

[0019] For conventionally constructed infiltration wells, as already mentioned, the filter area—that is, the filter length for a given borehole diameter—is a crucial factor influencing the infiltration rate. The water velocity at the transition to the surrounding rock must also be relatively low to prevent turbulence and oxygen ingress, thereby reducing the risk of iron oxide deposits and blockages. The maximum permissible velocity is considered to be 1.5 m / h. Particular attention must also be paid to preventing water recirculation, which is achieved by carefully closing and sealing the annular space. Furthermore, ecological considerations have also come into play.Against the backdrop of an already strained hydrological situation with declining groundwater levels, studies on the effects of climate change on the water balance show that by 2055, several key water balance parameters will change significantly – and for the worse. A further decline in the already meager annual precipitation, coupled with increasing evaporation, would lead to drastic consequences, particularly in summer. With intensifying summer evaporation losses over open water surfaces and in wetlands, seepage water formation by 2055 would be more than half of what it is today.

[0020] The widespread decrease in seepage and surface runoff would lead, particularly during the dry summer months, to a serious reduction in groundwater reserves, a noticeable drop in surface water levels (lakes and rivers), and a significant decline in water quality (fish kills).

[0021] Furthermore, a method and a system are known from DD 239 235 A1 in which individual downpipe filter wells for groundwater lowering are controlled by the water level in the well and the representative level in the lowering area, and secondly by the required water quantity in the infiltration filter and the system level in the infiltration area. This is achieved by an integrator that regulates the control of the system levels in the area of ​​the downpipe filter wells in the lowering area and the infiltration filter in the infiltration area.

[0022] DE 2 323 537 A discloses a special method for backwash filter systems in which filters equipped with riser pipes are flushed into the soil to be drained by means of a backwash pump by introducing pressurized water, thereby optimizing this method.

[0023] Furthermore, DE 2 318 102 A discloses a transfusion well in which the water balance is disturbed as little as possible due to groundwater lowering, and groundwater extraction is limited to a minimum. This is essentially achieved by dividing a well pipe into a lowering section and an infiltration section by means of the outer and inner seals in the area of ​​the barrier layer. When the water level of the upper aquifer drops, the pump draws groundwater from the lower aquifer into the lower aquifer, and conversely, when the water level of the lower aquifer drops, it draws groundwater from the lower aquifer into the upper aquifer.

[0024] In addition to the commercial uses and known methods described above, the essential elements of a future-oriented supply strategy also include the use of this technology from an ecological perspective for rational water use, such as increasing area water retention.

[0025] In this way, it may be possible to ensure ecologically necessary minimum groundwater levels and a sustainable drinking water supply in the future, even under changing climatic and water-related conditions.

[0026] The invention is based on the objective of offering a method and a system which, for technical use, takes ecological aspects into account, makes it possible to infiltrate the largest possible quantity of groundwater into an aquifer as efficiently as possible with minimal technical effort.

[0027] The problem is solved by a method for introducing at least one liquid infiltration medium into an aquifer with the features specified in claim 1 and a system according to claim 6.

[0028] Depending on existing and / or exploratory data – such as the permeability properties and flow direction of the aquifer – the method can determine an optimal immersion depth and infiltration rate for the infiltration of a liquid medium into an aquifer, whereby at least one pipe or shaft connection inserted into the subsurface at the determined optimal immersion depth enables targeted infiltration of the medium, whereby at the optimal immersion depth a pore water pressure in the groundwater upstream of the aquifer is increased and thereby a reduction in infiltration resistance in the groundwater downstream area occurs, increasing the infiltration rate.

[0029] The increased pore water pressure caused by the pipe or shaft connection can then propagate statically to the next aquifer.

[0030] The system according to the invention is referred to as the nozzle suction infiltration system or nozzle spray infiltration system “DSI system”.

[0031] The term clarifies that infiltration occurs via nozzles at a contact point with increased flow velocity in an infiltration aquifer transfer zone. The term "suction system" emphasizes that infiltration utilizes the attractive forces of the flowing groundwater in the pores of the groundwater outflow. The term "infiltration" denotes the transfer of liquid media into the aquifer.

[0032] First, the optimal immersion depth of the infiltration-side pipe or shaft connection to be installed in the subsurface can be determined based on the permeability properties, in particular the previously known or determined hydraulic conductivity of the subsurface. This determination is based on existing data or practical investigations in the respective application area.

[0033] The optimal immersion depth – also known as the infiltration well installation depth – can then be determined using the available hydraulic conductivity data via a table of values ​​( Fig. 4) are determined and calculated separately ( Fig. 3) [Formula 3 and 12].

[0034] The theoretical pre-calculation of the infiltration water quantity (Q) l) and dimensioning of the specially equipped wells belonging to the nozzle suction infiltration system or the infiltration-side lance and the associated process can be determined using existing data, the diameter (d) of the infiltration lance, the infiltration-side pipe or shaft connection, the infiltration-side delivery head (F H ), the hydraulic conductivity (k f ) and the theoretically determined optimal physical immersion depth (E ph ). The corresponding calculation formulas are in Fig. 3 is specified and explained in more detail in the exemplary embodiment.

[0035] After the design, the infiltration-side part of the pipe or shaft connection is brought to the theoretically determined optimal immersion depth until a pressure equalization occurs between the hydrostatic pressure of the aquifer and a predetermined flushing pressure of a pump conveying the medium into the infiltration-side pipe or shaft connection.

[0036] The optimal immersion depth is practically determined by inserting the infiltration-side pipe or shaft connection into the aquifer until pressure equalization is achieved between the hydrostatic pressure of the aquifer and a predetermined flushing pressure. Targeted infiltration of the medium is possible even at this stage, as reaching the optimal immersion depth increases the pore water pressure in the groundwater upstream of the aquifer, thereby reducing infiltration resistance in the downstream area and increasing infiltration capacity.

[0037] The process is characterized by the fact that, due to the predetermined flushing pressure of the infiltration-side part of the pipe or shaft connection, a non-permeable area for the groundwater of the aquifer is formed at the optimal immersion depth in the groundwater flow, which leads to a change in flow direction with an increase in time and distance and an increase in the pore water pressure of the groundwater-conducting pores of the groundwater in the groundwater flow [high-pressure area].

[0038] This results in a reduction of infiltration resistance in the groundwater outflow area of ​​the non-permeable zone, thereby increasing the infiltration capacity, which is caused on the one hand by the predetermined flushing pressure of the infiltration-side part of the pipe or shaft connection and / or on the other hand by a negative pressure or vacuum zone [low pressure area] arising in the groundwater outflow zone in the aquifer.

[0039] Furthermore, in a preferred embodiment of the invention, it is possible, on the one hand, to introduce suspensions that are not permeable to groundwater flow in the area [high-pressure zone] up to the pressure equalization zone between the inflow zone and the inflow zone, wherein the suspensions are mixed with the medium to be infiltrated. This mixing prevents precipitation in the inflow zone and reduces the energy required for infiltration of the medium enriched with the suspension, or, with the same energy input, increases the infiltration rate of the medium mixed with the suspension into the groundwater outflow zone (low-pressure zone).

[0040] Advantageously, the suspensions located in the non-permeable area [high-pressure area], which are subject to the forces of the groundwater outflow area, can be designed in a storage-like manner and dissolved again in the groundwater outflow area by the forces of the natural aquifer through pressure exposure of the pump conveying the medium mixed with the suspension to be infiltrated, the infiltration-side pipe or shaft connection.

[0041] However, it is also possible to deliberately place the storage-like suspensions, which do not obey the forces of the groundwater outflow area in the non-permeable area [high-pressure area] and which are not dissolved by pressure exposure, the pump conveying the medium to be infiltrated with suspension, the infiltration-side pipe or shaft connection, in the groundwater outflow area, in the subsoil of the infiltration area.

[0042] To achieve the most continuous possible operation, the method in one variant is characterized by the fact that, by installing a barrier device that opens in the direction of conveyance and a filter section upstream of the barrier process in the infiltration-side pipe or shaft connection, periodic operation between infiltration and return conveyance of the medium is enabled to prevent soil erosion in the infiltration area.

[0043] To carry out the process, a system is designed for the transfer of at least one liquid infiltration medium, in particular water, via an infiltration-side pipe or shaft connection, in which at least one infiltration lance is used, which is connected via a pump to generate a necessary predeterminable flushing pressure with at least one identical extraction lance.

[0044] In a preferred embodiment of the invention, each lance of the system has a transport tube and a filter section arranged above a buoyancy control valve, wherein the buoyancy control valve is located above an infiltration control piece of an immersion depth control tube with a flushing head arranged for extraction or infiltration.

[0045] Finally, the buoyancy control valve can be designed to open in the direction of groundwater flow for periodic operation.

[0046] The extraction-side and infiltration-side lances are preferably operated in combination as the "nozzle-suction-infiltration system". The term refers to the suction-induced negative pressure or vacuum zone (low-pressure area) of the aquifer that arises in the groundwater outflow area and is created according to the invention by the method and the associated system.

[0047] The extraction-side and infiltration-side lances can also be operated independently of each other, whereby, according to the infiltration-side method, the pipe or shaft connection on the infiltration side allows an increase in the infiltration performance.

[0048] The use of nozzle suction infiltration as a novel infiltration method results in the following positive aspects with regard to the environment, material usage, energy consumption and thus also economic efficiency.

[0049] A conventional infiltration well requires drilling with a large borehole diameter (depending on the planned infiltration capacity), fitting it with a suitable filter, and filling it with a matched filter gravel pack. The filters need to be cleaned at relatively short intervals, which incurs significant costs.

[0050] Only water purified of iron and suspended solids can be used for infiltration, as otherwise clogging and iron oxide deposits in the filter slots would occur much more quickly. Infiltration elements for jet suction infiltration consist solely of a pipe, essentially an infiltration lance, which, in suitable aquifers, is flushed into the aquifer without drilling. It does not undergo graveling or any further construction. No maintenance is required, and iron oxide deposits and clogging are not a concern.

[0051] These innovative infiltration wells achieve very high infiltration rates despite their small diameter. Consequently, significantly fewer and less extensive structures are required compared to conventional injection wells to infiltrate the same amount of water into the aquifer. This results in further savings in materials, labor, and energy.

[0052] Drainage measures also require the removal of the pumped water. This often necessitates the use of long pipelines and corresponding pumping systems. With the new method, infiltration near the extraction point is possible. Consequently, the use of pipelines and pumps is reduced, leading to savings in materials and energy.

[0053] In many cases, disregarding the use of innovative infiltration wells, extracted groundwater can only be discharged into the receiving water body. In some instances, this presents permitting challenges due to the extraction and discharge volumes, as well as the water quality (iron content). By employing jet suction technology, the extracted water can be infiltrated into the source aquifer in close proximity to the extraction wells, ideally reducing net extraction and discharge volumes to zero. This makes problematic projects eligible for water permits.

[0054] The effects of infiltration using this method can reduce the amount of groundwater flowing into an excavation pit, resulting in a reduction in gross extraction volume. This, in turn, leads to a reduced number of production wells with their associated pumps, electrical supply lines, and pipelines for pumping and transporting the water. This, in turn, results in reductions in materials, energy, labor, and therefore costs.

[0055] These innovative infiltration wells make it possible to implement infiltration even outside of large-scale projects (e.g., for rainwater infiltration). This can support soil moisture levels and groundwater availability, particularly in problematic areas, which can be especially advantageous in light of future groundwater issues and problems with rising saline water in northern parts of Germany.

[0056] Due to the process's demonstrated insensitivity to solids in the infiltration water, as revealed in tests, even water previously problematic for infiltration can now be used. This reduces the treatment effort required for the water to be infiltrated, leading to savings in materials, energy, and costs, and thus to environmental protection. The volume of water discharged into receiving waters can also be reduced.

[0057] The new jet suction infiltration method makes it possible to selectively mix water with solids and induce infiltration to influence specific properties of the subsurface. This provides a simple and cost-effective way to remediate, for example, by altering the chemical conditions in the aquifer.

[0058] The following are application examples where the method according to the invention can be used.

[0059] By correctly identifying natural processes, theoretically understanding them, and successfully implementing them in practice, the DSI system provides the foundation for its wide range of applications. This success results from the combination of precise pre-planning and the experience of the on-site installation team. Utilizing the water transport capacity of the existing aquifers allows for the lowering and simultaneous discharge of the extracted groundwater into a nearby aquifer. This significantly reduces the extent of the drawdown cone and prevents discharge into surface watercourses. The thickness of the aquifer and the infiltration requirements form the basis for dimensioning the infiltration pipes (8 mm to 1000 mm). By coupling the released natural forces with variable-speed booster pumps, optimized energy consumption can be expected.Soil surveys and / or exploratory jet suction infiltration tests form the basis for preliminary dimensioning and project planning. In-house technical data and characteristic curves of the pumps and infiltration pipes used guarantee cost-effective water management success.

[0060] In the construction industry, groundwater lowering (GWA) is used where buildings, excavations, and pipelines are located in the groundwater zone. The goal of GWA is to temporarily keep the groundwater in the area of ​​the excavations free of perched and groundwater by means of a drawdown cone. Pumps and filter systems are installed around and below the excavation for the future structure to remove the water. Impacts on the natural environment, the stability of adjacent buildings, and adverse effects on the receiving watercourse, e.g., through iron precipitation, cannot be ruled out.

[0061] By combining GWA and DSI systems, the impact on the water balance can be reduced to an acceptable level through the immediate return of the extracted groundwater.

[0062] For example, 1.6 m should not be permissible 3 Millions of groundwater were extracted from the groundwater balance in the Spreewald Biosphere Reserve due to lowering operations during construction work. The use of the DSI system enabled the extracted groundwater to be completely infiltrated, resulting in reduced drawdown cone depths. Iron concentrations of up to 20 mg / l were successfully returned to the groundwater balance via the DSI system without complications.

[0063] Rainwater runoff from roofs with a gutter inlet height of approximately 10 m or more can be atomized directly via fine filters and pressure-resistant drainpipes without the use of pumps. For sealed surfaces and low-rise buildings, pumps integrated into the system must be used.

[0064] The building drying system (DSL) can be used where building waterproofing is damaged or deteriorates, leading to water ingress in the basement and resulting in structural damage. Instead of renovation, the system can be implemented as a technical solution. Precisely calculated stub needle filters are installed in the groundwater zone at the basement floor level. Groundwater is extracted using pumps, and the basement is drained. The extracted water is then infiltrated into the groundwater system via the nozzle suction infiltration lance using the pump pressure. By integrating the system with a heat pump, there are no ongoing operating costs for groundwater lowering.

[0065] Vegetation, trees, parks, and biotopes affected by water level drops can be targeted with water using the new system. Acupuncture-like arrangements of the infiltration nozzles enable a precisely dosed water supply, compensating for the disrupted water balance. Simultaneously, the introduction of water-related substances into the infiltration system can counteract diseases and growth disorders. If needed, infiltration water can be used as a storage and transport medium for liquid fertilizer, reducing the required fertilizer application rate through direct root contact. This prevents widespread drift into the groundwater. The use of computer technology allows for needs-based and cost-effective groundwater regulation measures.

[0066] In the drawdown zone of open-pit mines, jet suction infiltration (DSI) systems can be used to safeguard the groundwater level in populated areas and wetlands. The DSI system infiltrates the extracted groundwater in the outflowing drawdown cone, forming a wall. Level control systems adjust the drawdown cone and the infiltration wall's reach. In the long term, the circulation of the drawdown and infiltration leads to self-purification and de-icing of the aquifer. Extracted groundwater from the open-pit mine's pre-dewatering can be conveyed via pipeline systems to the jet suction infiltration system and into the drawdown cone's edge zone.

[0067] During a construction project, a vacuum was used to create a k f -Changes in value were carried out in the excavation pit edge area, resulting in a reduction of the water pumping volume to 80 m³ 3 / h achieved. Preliminary pumping tests had yielded water volumes from deep wells at a depth of 400 m. 3The result was a flow rate of [per hour]. Limited drainage capacity led to the denial of the water permit by the Upper Water Authority. In contrast, the combination of vacuum wall and jet suction infiltration was approved by the Lower Water Authority without further conditions.

[0068] Jet suction infiltration is a particularly advantageous in-situ technology when contamination occurs in built-up areas, workshops at great depths, and under roads and paths. The foundations of biological soil and groundwater remediation lie in the mechanisms developed by nature for the degradation or transformation of pollutants. The goal of these technical measures is to create optimal conditions for remediation activity by microorganisms. Jet suction infiltration consistently follows the natural pathway of in-situ technology.

[0069] Types of contamination requiring remediation are: - Mineral oil hydrocarbons (MOH) including heavy oil contamination - aromatic compounds (e.g. BTEX aromatics, styrene) - Polycyclic aromatic hydrocarbons (PAHs) - volatile chlorinated hydrocarbons (VHCs) - substituted phenols (e.g. pentachlorophenol PCP) - substituted aromatics and cyclic compounds (e.g. chlorobenzenes)

[0070] To obtain data for the technically most successful and economically advantageous planning and execution of DSI plants, exploratory jet spray filtration tests can be carried out. These tests are cost-effective and require no large-scale equipment, as they are performed in geological formations. f -Value ranges up to 10 -5m / s using the mini-DSI lance, manual drilling operations were carried out to a depth of 50 m within one hour and the results analyzed. The data were evaluated using an infiltration kf value table. The use of the mini-nozzle provides information about the type, composition, extent, and thickness of the soil layers, subsoil properties, and groundwater conditions. The DSI system in the test field also reveals small-scale variations in k f -values ​​within the aquifer.

[0071] The depth of the infiltration zone is determined by the volume of water to be infiltrated. The minimum physical nozzle immersion depth is determined by hydrological and geological in-situ methods at the infiltration site. The nozzle insertion point is established when the required infiltration zone surface area and the resulting volume are reached. The natural immersion depth of the infiltration nozzle can be increased by using a flushing pipe with subsequent installation of the infiltration lance. Another way to achieve the required calculated installation depths is by using drilling fluid.

[0072] Based on experience gained from completed DSI projects, it can be assumed that a new drawdown strategy can be implemented for large-scale projects, including open-pit mines. Geological analyses indicate that groundwater aquifers can be used for the removal of the extracted groundwater. Staged pumping stations within the open-pit mines can discharge directly into deeper groundwater aquifers. This would result in substantial savings in energy, treatment, and drainage costs. The impact on the groundwater system would be minimized. Water permits and environmental impact assessments (EIAs) would have fewer grounds for refusal. With this new drawdown technology (field pumping tests are currently underway), groundwater is no longer extracted; instead, the water table is lowered, and the groundwater is diverted into water-bearing strata at the center of the drawdown cone below the excavation pit.

[0073] As a consequence of open-pit lignite mining, the reshaping of the lignite overburden landscapes leads to a mixing of the in-situ hydraulic conductivity (kf) ranges. Chemical processes in the resulting spoil heaps, influenced by air, rain, and groundwater, lead to the formation of sulfuric acid. The formation of lakes in the open-pit mine pits results in acidification of the aquatic environment, which cannot be degraded naturally. Jet suction infiltration tests show that no infiltration zone forms in the spoil heap area. From these findings, it can be deduced that there is only a slight horizontal flow in the spoil heap, with increased vertical flow due to hydraulic factors. Differences in elevation between the natural groundwater level at the lake's edge and the lake's water level result in loosened lakebed conditions due to buoyancy.It must be assumed that sulfuric acid is introduced into the lake during the recharge of the main aquifer beneath the lakebed. By utilizing the chemical and physical conditions, including the artesian-hydraulic conditions, lime injections can be administered into the aquifer in various ways for remediation. Targeted lime jet suction infiltration zones, located in the aquifer's inflow area, can lead to the desired lake water quality in the long term.

[0074] Garden, domestic, or technical supply wells can be installed near the water table using the infiltration suction filter in combination with a continuous riser pipe. The special filter is flushed in manually via a standard household water connection (prerequisite: hydraulic conductivity kf > 10⁻⁵ m / s). Reaching the productive water-bearing layer is indicated by water loss during flushing, at which point the special filter can be switched to pumping mode. The continuous riser pipe is cut at ground level, and a pump of the operator's choice can be connected. The dimensions of the riser pipe and the amount of flushing water used determine the planned pumping capacity (up to 10 m³ / h). The well can be installed by the user without the need for any additional equipment.

[0075] In the jet grouting method (HDI), used since the 1960s, a jet of fluid emerges laterally from the drilling pipe above a drill bit at high pressure (200 to 600 bar) and high velocity (up to 200 m / s). The surrounding soil is cut, relocated, and mixed with the injected grout. Using the established single- to triple-stage methods, maximum elements with a diameter of 3 m can be constructed. With the new DSI method, injection materials can be introduced into the natural groundwater flow without pressure. The choice of injection material depends on the hydrogeological conditions and the application of the pore-filling injection. Injection materials can be placed in the aquifer beyond the infiltration zone. Injection materials can be introduced into the ground to be modified in the form of a solution or a gel mass as a long-term donor (e.g.,...)Fine cement, suspension, lime solution, ground coal, water glass solution, bentonite, and fine binders). Nozzle injection tests based on preliminary engineering discussions form the basis for achieving the project requirements. An in-situ balance of forces between pores, injection material, and groundwater flow ensures the desired success. Successful tests with the mini nozzle suction infiltration lance PE DN 32 / 20 demonstrate that groundwater discharge can be completely ruled out in the "pipe lowering" application. Three suction filters are installed in extraction lances and one infiltration lance in a 3:1 ratio. The infiltration lances are positioned in the supply and return lines of the pipe trench, with the infiltration depth corresponding to the filter arrangement used for groundwater extraction. The material from the lowering area is used for the infiltration system.The infiltration and groundwater lowering systems are arranged in a mirror-image configuration within the construction site. In challenging site conditions, the mini-DSI system can also be positioned where protected objects, wooden foundations, trees, or biotopes would be negatively impacted by the water level reduction. The pumping systems from the lowering area are used for infiltration, thus eliminating additional installation and energy costs. A safety emergency overflow system secures the excavation in the event of an infiltration failure. Infiltration lances were installed manually and can be adjusted, activated, and repositioned by the pump attendant during operation without the need for technical equipment.

[0076] In the former GDR, problems with the drinking water supply arose in the catchment areas of several waterworks during the 1980s due to salt upwelling. Attempts to infiltrate surface water through the forest floor were unsuccessful. Projected climate changes (e.g., the Potsdam Institute for Climate Impact Research study) suggest that such groundwater shortages in the catchment areas of waterworks will continue to increase in the future.

[0077] Controlled DSI systems in the cone-shaped depressions of waterworks intakes can compensate for the groundwater loss from the waterworks pumps. By utilizing the pumping head energy, the infiltration water can be drawn from hydrogeological and surface water sources without additional energy input and conveyed to the waterworks area via pipelines. Using the hydraulic re-jet suction infiltration system, groundwater from areas with uncontaminated aquifers can be pumped from self-priming wells and then into active aquifers in waterworks protection zones via jet suction infiltration lances.

[0078] The latest development for the primary application of "trench lowering" is the suction and infiltration system with lance dimensions DIV 32-50. This dual function results in optimized discharge and pumping fees, as well as savings in energy costs and installation time. The suction valve setting in the lance, which creates a cone of depression, dewaters the water-bearing strata when operating in the trench. Simultaneously, in the supply or return line of the construction site, the same lances, set to infiltration mode, return the extracted groundwater to the aquifer. Standard construction site vacuum pumps or piston pumps can be used for groundwater extraction and return. A grit chamber and pressure booster system are no longer required for the operation of this new system.

[0079] Further advantageous embodiments of the invention result from the additional features mentioned in the dependent claims. Example of implementation

[0080] The nozzle-suction infiltration system for extracting and / or transferring (introducing, diverting, and settling) a liquid medium is explained in more detail with the help of several figures. These show: Fig. 1 Nozzle-suction infiltration system, communicating vessels, system diagram cross-section, Fig. 2A Nozzle suction infiltration system, system diagram for system description with exemplary infiltration lance as pipe or shaft connection, Fig. 2B Nozzle-suction infiltration system, example cross-section through a sampling lance, Fig. 3 Nozzle suction infiltration system, design formulas, Fig. 4 Excerpt k f -value table, Fig. 5 Dependence of the infiltration performance of the nozzle spray lance on the lance diameter, k f -value and the operating pump delivery head Fig. 6. Operating pump delivery rate depending on the delivery head, Fig. 7 Nozzle suction infiltration system, system diagram cross-section, Fig. 8 Suction and infiltration lance system DN 12-200, system diagram cross-section, Fig. 9. Subsidence and infiltration system, system diagram cross-section

[0081] Fig. Figure 1 shows a schematic representation of an infiltration-side pipe and shaft connection with groundwater inflow 18 and the area of ​​increased pore water pressure 17. At the same time, the Fig. 1 the resulting negative pressure area 25 in the groundwater outflow area 22.

[0082] Fig. 2A and Fig. Figure 2B also shows the nozzle-suction infiltration system on its infiltration-side side, according to Fig. 1, where based on the Fig. 2A and Fig. 2B the effects according to the invention can be explained in detail.

[0083] The nozzle-suction infiltration system can be used to introduce, drain, and settle liquid media, including suspensions, into the pores of the aquifer. During the installation process of an infiltration lance 5B, hydraulic conductivity (kf) ranges can be analyzed and groundwater flow rates calculated. Groundwater flow direction can be determined by arranging pore water pressure sensors (not shown) on the infiltration lance 5B. Preferably using submersible wastewater pumps 1 with a high pressure characteristic 2, liquid infiltration media 3, including suspensions 4, can be introduced (in-situ) into groundwater-bearing pores 8 using the infiltration lance 5B, preferably with an integrated, high-level inlet and buoyancy control valve 6 and a groundwater flushing water purification pipe 7.

[0084] When the infiltration media 3 exits the flushing head 9 in the area of ​​the physical or technical immersion depth 10, the pressure 2 spreads abruptly and spherically 12 until the pressure equalization point 13 is reached in the pore water 14 of the aquifer 15, depending on the hydraulic conductivity kf-value 16. The pore water pressure 17 continues statically until the next anticoagulant 43 of the aquifer 15.

[0085] In the upstream flow area 18, due to the increased pressure equalization 13, a zone 19 forms through which the groundwater flow 18 cannot pass. This condition leads to a change in the groundwater flow direction 20 of the upstream flow 18 and results in an increase in time and distance 21. In the downstream flow area 22, the pressure 2 simultaneously increases the groundwater flow velocity 23, thereby increasing the infiltration rate 24 due to the resulting situation 21 of a negative pressure 25 in the aquifer 15. A vacuum zone 26 forms, which leads to a further increase in infiltration rate 24.

[0086] During infiltration, groundwater exchange with infiltration media and their precipitation can occur in the area 19 which is not permeable to the inflow 18.

[0087] Upon addition of suspensions 4, the pores 14 close up to the pressure equalization zone due to the low flow velocity, thereby reducing the pressure energy requirement, and the excess shifts into the outflow zone 22. The resulting accumulation of the suspensions 4 in the non-flowable zone 19 acts like a reservoir and can be released into the groundwater flow 22 by applying pressure 2.

[0088] When using suspensions 4 that are not subject to the forces of the groundwater flow 22, targeted placement can influence the subsoil. Due to the dual function of the infiltration lance 5B, the installation of a filter section 31 upstream of the infiltration and buoyancy control valve 6 allows for alternating groundwater extraction 27 and infiltration. Infiltration tests show that the use of the infiltration and buoyancy control valve 6 prevents clogging of the flushing head 9 during periodic operation and installation of the infiltration lance 5B.

[0089] In infiltration tests with aerated infiltration water 3 with an iron content of up to 20 mg / l at a constant pressure input 2, no iron ochre formation occurs in the infiltration area 32. Infiltration performance tests show that, with the effect of the vacuum 26, a much higher infiltration performance 24 with a targeted infiltration point 27 in the aquifer 15 is achieved compared to a gravity injection well.

[0090] In the Fig. 3 are the calculation formulas for the individual physical values ​​that are necessary in practice for the design and operation of the infiltration-side well or the infiltration-side lance 5B.

[0091] As already explained, the soil permeability value k is relevant for the design of the installation of the infiltration-side lance 5B. f of particular importance. This k fThe value is to be considered a given or to-be-determined quantity. It can, of course, be calculated if other quantities are available [Formula 4].

[0092] The K f If the soil value is already available through a soil survey, then the value can be further determined by the following: Fig. 4. Partially shown table about the known k f -value at a specific operating pressure - in the exemplary embodiment, for example, 2 bar (0.2 MPa) - the expected infiltration performance 24 in m 3 / h can already be quantified.

[0093] The expected amount of infiltrating water Q l , can after Fig. 3 can also be calculated with a safety margin S of, for example, 30%. [Formula 1]. From the soil permeability value k f and the amount of infiltration water Q lThe radius r [Formula 2] can then be determined with a safety value S of, for example, 30%, which according to Formula 6 is first a theoretical physical immersion depth E. ph corresponds.

[0094] At the same time, depending on the k, which may be known from a soil survey or determined in experiments, the f -value the pore pressure-increased circular area A KR [Formula 3] in aquifer 15.

[0095] For the infiltration well installation depth to be maintained later I BL , [Formula 12] is an allowance Z divided by the length L IK of the groundwater level W SP to the edge of the infiltration sphere 44 Fig. 2a (Formula 5) must be observed.

[0096] By selecting an infiltration pipe diameter with a specific associated nominal width NW DN 32, taking into account the infiltration water flow velocity I FG[Formula 7] an associated infiltration nozzle diameter d [Formula 8] and an infiltration nozzle orifice A Kd [Formula 9] can be determined.

[0097] The infiltration water quantity Q l of a single well 5B - infiltration-side lance 5B - is determined according to formula 10, where the number QIB / piece 5B [formula 11] of infiltration-side lances 5B to be installed depends on the desired total amount of water to be infiltrated Q l Legally directed.

[0098] The infiltration well installation depth I BL (Formula 12) results, as mentioned, from the sum of the distance W from the top of the terrain to the water level SP , the radius r and the length L IK of the groundwater level W SP to the edge of the infiltration sphere 44 ( Fig. 2A).

[0099] The construction of a barrier for the inflowing groundwater, the infiltration well barrier spacing I RAThe distance between the individual infiltration-side lances 5B can be calculated with a safety factor S of, for example, 20% according to formula 13. The infiltration bar length R L This is calculated according to formula 14.

[0100] The total infiltration quantity Q IGes. [Formula 15] is calculable, so that by preliminary calculations it can be determined whether a desired quantity of water to be infiltrated QI Ges. is infiltrable, whereby the required number of infiltration wells QIB / piece [Formula 11] and design of the individual infiltration-side lances 5B can be determined.

[0101] Fig. Figure 5 shows that, depending on the pumping height and with increasing soil permeability kf from 10-5 to 10-2, the pumping capacity for infiltration of the medium, i.e. the infiltration water quantity Q, l according to Fig. 5 increases.

[0102] Fig. 5 further shows that the pumping capacity for infiltration of the infiltration water quantity Q l in m 3 / h also increases with the increase in the nominal diameter NW of the infiltration lance 5B, for which in Fig. The diagram shows four characteristic curves, displayed from left to right. The four curves on the left thus indicate, for the same nominal diameter DN 15 (1 / 2"), the increase in flow rate as a function of the soil permeability value K. f out of 10 -5 up to 10 -2 The curves increase in size and their effect corresponds to the Y-axis with regard to the expected delivery head. Curves five to eight indicate another nominal diameter DN 32 (514") and lines nine to twelve the largest nominal diameter DN 40 (1.5") with the same dependencies.

[0103] Fig. Figure 6 further clarifies that with the same soil permeability value k fThe delivery rate for infiltration of a medium in the infiltration lance 5B can be increased by increasing the delivery head to be set.

[0104] To illustrate, shows Fig. 7. A classic application is the dewatering of an excavation pit for house construction. To create a cone of depression, groundwater extraction lances 5A are inserted into the aquifer 15 near the excavation pit, depending on their design as described above. In order to infiltrate the corresponding amount of extracted water, the multiple extraction lances 5A are arranged, as shown schematically in a separate diagram, in Fig. Figure 8 is shown, connected to several infiltration lances 5B, where the infiltration performance of the infiltration water quantity Q lThe discovered method and the associated principle of the nozzle suction infiltration system (DSI) allow large quantities of the material to be easily returned to the aquifer in the groundwater downstream area, i.e., infiltrated.

[0105] Fig. Figure 8 shows the schematic basic structure of the system consisting of the extraction lance 5A and the infiltration lance 5B. The extraction lance 5A and the infiltration lance 5B are connected to each other via a pump 1, preferably a submersible wastewater pump.

[0106] The delivery head for infiltration of the infiltration medium 3 is adjustable on the submersible wastewater pump. Lances 5A and 5B each have suction and discharge ports 38 and 39, respectively. The discharge lances 5A have a transport pipe 37 in a known manner, in which a filter section 31 with a corresponding filter length 41 is arranged. The direction of flow of the medium in lances 5A and 5B is indicated by arrows. Buoyancy control valves 6 are arranged below the filter sections 31, and an infiltration control piece 34 is additionally provided above the buoyancy control valves 6. The buoyancy control valves 6 ensure that the medium can only be supplied to the respective discharge lance 5A or infiltrated via the infiltration lance 5B in the direction of flow.

[0107] Fig.Figure 9 shows a system consisting of several extraction lances 5A and infiltration lances 5B, which can be used particularly for larger areas to be lowered. Reference symbol list: 1 pump [submersible dirty water pump] 2 Pressure exposure / pressure characteristic curve 3 Infiltration media (water, aerated water) 4 Suspensions 5 lances 5A Sampling lance 5B Infiltration lance 6 Buoyancy control valve 7 Rinse water cleaning pipe / immersion depth control pipe 8 groundwater-conducting pores 9 flush head 10 Immersion depth (E ph ) 11 Floor 12. Spread (spherical) 13 Pressure equalization 14 Pore closure 15 aquifers 16 Hydraulic conductivity (K f ) 17 Pore water pressure 18 Groundwater inflow 19 non-flowable area 20 Change in flow direction 21 Time and distance extension 22 Groundwater outflow area 23 Groundwater flow velocity 24 Infiltration performance 25 negative pressure range 26 Vacuum area 27 Groundwater extraction 28 aquifer (groundwater layer) 29 Water level rise 31 Filter section 32 Infiltration area 33 Measuring water level 34 Infiltration regulating piece 35 Stocking or slit width 36 Groundwater flow direction 37 Transport pipe 38 suction ports for 5A 39 pressure nozzles for 5B 40 Transport pipe length 41 filter length 42 Immersion tube length 43 Stauer 44 infiltration balls

[0108] (The following abbreviations have been rearranged alphabetically) AKD Infiltration nozzle throughput area A Kr Circular area with increased pore pressure in the aquifer D Infiltration nozzle diameter DSI nozzle suction infiltration system GWA groundwater lowering I BL Infiltration well installation depth I Fg Infiltration water flow rate I RA Infiltration well bar spacing K f Soil permeability value L IK Length from the groundwater level to the infiltration sphere NW nominal diameter Q I Infiltration water quantity Q IB Infiltration water volume (single well) Q IB / Stück Number of infiltration wells Q Iges Total infiltration volume r radius of the circular area in the aquifer with increased pore pressure R L Infiltration bar length S percentage-based safety W SP Water level

Images