IEG Technologie GmbH products

The conventional technique of Soil Vapour Extraction has proven to be a practical and inexpensive method for the removal of volatile and semi-volatile hydrocarbons from the unsaturated zone. Soil Vapour Extraction is conventionally carried out using small-sized boreholes which extend to just under the groundwater table and are outfitted with screens of diameters up to 50 mm. Depending on the size of the equipment and the properties of the soil, blowers are usually operated at pressure differences of 100 to 300 millibars. This high negative pressure draws perched or capillary water into the venting system.

Directed Soil Air Circulation systems (SAC) are employed for the remediation by Bioventing of soil contaminated with volatile hydrocarbons by enhancing the IEG Vacuum Vapor Extraction (IEG VVE) technique. In addition, they can be used to inject gas into the soil for the stimulation of biological or chemical degradation. If only biodegradable substances are to be removed from the subsoil, a SAC-Bioventing system (without an above-ground extraction unit) consisting of an axial ventilator in the screened well can be implemented. Two screens built into the borehole are separated into an upper and a lower section, each of which is connected to an above-ground blower.

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.

The remediation of a chlorinated hydrocarbons (CHC) contaminated aquifer always contains a risk, because of the possibility of uncontrolled downwards mobilization of the CHC into deeper parts of the aquifer. This scenario would be even more harmful to the environment. The application of well known remediation techniques for CHC as e. g. pump-and-treat is not useful because of its extremely long duration caused by the low solubility of CHC.

Due to the minimal environmental impact and low cost of implementation, biological remediation technologies have become increasingly popular during the last few years. In an ideal case, depending on the type of contaminants on the site, naturally occurring microorganisms degrade organic compounds to carbon dioxide and water. The rate of biodegradation is determined by the existing chemical and physical conditions. The goal of in-situ biological remediation technologies which IEG implements is to optimise the existing degradation potential. By improving the environmental conditions needed by the degrading bacteria, an effective reduction of contaminants is achieved.

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.

IEG Coaxial Groundwater Circulation Sparging (IEG CGC-Sparge) is a combination technique which is used for the effective remediation of shallow aquifers and perched groundwaters at depths of up to 3 to 7 metres which are contaminated with a range of volatile organic substances, including petroleum hydrocarbons and solvents. An IEG CGC-Sparge process unit consists of a specially-designed groundwater well incorporating an IEG double-cased screen, a compressor, a special pressurised air distributor, a low-vacuum extraction system, and a waste air decontamination system (typically regenerative GranularActivated Carbon).