|IEG - UVB (Unterdruck-Verdampfer-Brunnen) "Standard Flow"
Possible Areas of Application
The IEG GZB®-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.
The UVB process unit consists of a specially adapted groundwater well, a stripping reactor located in a sub-surface vault or in the well itself, an above-ground mounted vacuum blower, and a waste air decontamination system, for example disposable filters or regenerative activated carbon filters.
Description of Method
A UVB well has at least two screen sections which are separated by a solid casing. Negative pressure generated by a blower is applied to the air-tight vault or well head. Through a pipe connected to the stripping reactor located in the vault, ambient air is being pulled through the stripping reactor.
The rising air bubbles enhance the suction effect at the well bottom (air-lift-pump) and a hydraulic current within the well from bottom to top develops. By adding a support pump to the UVB System, a specific flow direction can be induced, which produces a vertical flow either upward or downward within the well. The oscillating hydraulic pressure forces the water horizontally back into the formation and in the surrounding aquifer a circulation cell develops with water entering at the base of the well and leaving through the upper screened segment or vice versa, depending on the desired flow direction.
The strippable contaminants are removed from the groundwater. When the contaminated exhaust air passes through the activated carbon filter, no water condensation occurs due to the low humidity of the air. Therefore, a significantly greater part of the activated carbon filter can be utilized for adsorption of pollutants as compared to conventional air stripping.
Sphere of Influence
A flow pattern with a calculable horizontal and vertical component is produced in the aquifer to compensate for the directed water flow within the UVB well. The circulation pattern can be adjusted (normal-reverse flow direction) depending on the location of the submersible pump(s). Thus, treated groundwater circulates through the sphere of influence (within the aquifer) before returning to the well. This causes an intense flushing of less permeable layers or lenses, which would not be treated with conventional pump & treat systems.
Simultaneous Soil Air Venting and free product (LNAPL) recoverys
The UVB-method is capable of extracting soil air and/or removing LNAPL during ground water treatment. The amount of soil air and groundwater passing through the decontamination system can be adjusted according to the type of contamination and the well construction. A UVB well can effectively treat the vadose zone, the capillary fringe, and the saturated zone simultaneously.
The following advantages can be specified: