Tecnologie

La circolazione coassiale dell'acqua sotterranea (KGB) viene utilizzata per risanare i bacini di acqua sotterranea e le acque sospese contaminate da idrocarburi volatili. Questo sistema può inoltre essere utilizzato per iniettare gas nel suolo, al fine di stimolare il processo di decomposizione microbiologica. Il sistema KGB utilizza una fase di disaerazione dell'aria del suolo, abbinata ad una tecnologia di strippaggio in situ dell'acqua di falda (la cosiddetta tecnica di "push and pull").

Aree possibili di applicazione
L'UVB è un sistema in loco per il risanamento di falde acquifere contaminate, in special modo quelle contaminate di idrocarburi volatili e semivolatili o da metalli pesanti. Tale sistema utilizza una combinazione di processi chimici, fisici e biologici. L'UVB è un processo brevettato dalla IEG mbH, Reutlingen, Germania.

La tecnica di estrazione a vuoto si è rivelata un metodo pratico e poco costoso per l'eliminazione degli idrocarburi volatili e semivolatili dalla zona vadosa.

L'estrazione a vuoto convenzionale viene effettuata praticando fori di trivellazione di piccolo diametro, anche appena sotto il livello della falda freatica, e provvisti di elementi filtranti di diametro non superiore a 50 millimetri. A seconda delle dimensioni dell'installazione e delle caratteristiche del suolo, vengono azionati compressori, solitamente con differenze di pressione comprese tra 40 e 120 pollici di acqua. L'elevata pressione negativa risucchia nell'impianto di disaerazione l'acqua capillare o l'acqua vadosa.

IEG-Desorption-Stripping-Units (DSU) are used to remove volatile contaminants from groundwater or groundwater. According to the required effluent concentration the desorption units (or packed stripping towers) have to be either one-stage or multiple-stage.

The Multi-Functional Well (IEG MFW) has been implemented for the remediation of subsurface contamination caused by hydrocarbon spills. Four different remediation processes can be operated within the same well. At optimal efficiency of each remediation process, successive treatment of the capillary fringes, the vadose zone, and the aquifer can be accomplished. Each treatment process requires only simple modifications of the well configuration. Removal of the contaminants is done primarily through in situ air stripping.

The IEG Groundwater Circualtion Well (IEG GCW) process is an in-situ system for the remediation of contaminated aquifers, especially those contaminated with volatile and semi-volatile hydrocarbons, using a combination of chemical, physical and biological processes. An IEG GCW process unit consists of a specially-adapted groundwater well, at least one submersible pump, a negative pressure stripping reactor located in a sub-surface vault, an above-ground mounted blower, and a waste air decontamination system (for example disposable filters or regenerative activated carbon filters).

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The sphere of influence of GCW (Groundwater Circulation Well) depends on the distance of the two screen sections or, in case of a fully penetrating well, on the aquifer thickness. The larger the circulation cell is, the larger the travel time is for the circulation. For thick aquifers it may be beneficial to install several circulation cells, one upon another. This produces smaller circulation cells and shortens circulation flow time.

The GCW-MPPE process is an in situ system for the remediation of groundwater contaminated with dissolved or dispersed aromatic, aliphatic, poly aromatic and halogenated hydrocarbons using a combination of a hydraulic controlled flushing/extraction system with a high efficient physical purification system based on macro porous polymer extraction.

IEG-vPRB In-situ Virtual Permeable Reactive Barrier with Overlapped Circulation Cells.
When a GCW is situated within the body of a groundwater contamination plume, this creates effective hydraulic control across a large diameter spherical capture zone within the aquifer. The polluted upstream groundwater is systematically captured by the GCW and treated in the well and within the aquifer.

The Reactive Well Technology (GCW-R) significantly enhances the ability to combine a dynamic hydraulic flow system (GCW) with different reactive treatment areas under anaerobic conditions.

The specially designed remediation wells enable easy change to the reactive materials, such as controlled-release carbon plus zero-valent iron (ZVI) or other reduced metals, which is the subject of our EHC technology. One major difference between the GCW-R technology and a typical permeable reactive barrier (PRB) is

IEG's Compact Vacuum Stripper (IEG CVS 1000) is an innovative system for the removal of volatile organic compounds (VOCs) from contaminated groundwater. Highly efficient in its design and effective in operation, the system is capable of receiving and treating up to a maximum of 15 m /h of highly contaminated water, with a VOC removal efficiency of up to 99.5%.

When a number of IEG-MLSW systems are used at a site, they allow a very detailed three-dimensional soil and groundwater contamination profile to be developed, at a reasonable cost, since fewer boreholes are required, which itself reduces well purging and sampling time on site, at a much reduced cost. The patented modular system can be customised for the needs of each project, depending on the findings of a geoenvironmental investigation, or alternatively based on predetermined depths of interest. This IEG MLSW can be removed from the monitoring well.

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In the unsaturated zone, bioremediation is critically affected by the soil moisture content. For most natural biological degradation processes, the optimal water content is in range between 50% - 80%. With the Soil Circular Flushing Wella vertical multi-phase flow increases the saturation of water in the unsaturated zone. The remaining volatile hydrocarbons are either removed by in-situ stripping in the well, adsorbed on an optional activated carbon bed on top of the outer casing, or biodegraded in the well and unsaturated zone.

Vacuum-Enhanced Liquid Recovery (IEG VLR) process is an innovative technology underpinned by a detailed knowledge of how hydrocarbons actually behave in the subsurface. Using IEG VLR maximum recovery of free-phase product floating on top of the groundwater can be achieved quickly and cost effectively using a specially adapted well screened above the groundwater surface combined with one of several possible hydrocarbon recovery systems.