Horizontal insulating barriers as a way to protect groundwater

• Published in: Proceedings of the International Association of Hydrological Sciences Vol. 379; pp. 181 - 186
• Main Authors: Cicha-Szot, Renata, Labus, Krzysztof, Falkowicz, Sławomir, Madetko, Norbert
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Gottingen Copernicus GmbH 01.01.2018; Copernicus Publications
• Subjects: Aquifers; Barriers; Carbon dioxide; Computer simulation; Forces (mechanics); Gelation; Gels; Geochemistry; Groundwater; Groundwater management; Groundwater pollution; Groundwater protection; Groundwater table; Inflow; Interactions; Mechanical properties; Modelling; Organic chemistry; Parameter identification; Parameters; Pollutants; Rocks; Saturation; Saturation zone; Silicates; Sodium; Sodium silicates; Technology; Trenchless technology; Water inflow; Water pollution prevention; Water protection; Water table; Working fluids
• ISSN: 2199-899X; 2199-8981; 2199-899X
• DOI: 10.5194/piahs-379-181-2018

Trenchless Technology of Forming Horizontal Insulating Barriers (TFHB) can be considered a method of groundwater protection against inflow of pollutants. In TFHB technology, the working fluid (sodium silicate solution) and the gelling agent (CO2) are injected separately, using one tool, to different zones of the aquifer profile. Carbon dioxide injected into the saturation zone rises due to buoyancy forces and reaches the silicate which was injected at the water table level. This initiates the process of silicate gelation, resulting in the formation of an insulating barrier. For technological purposes, the gelation time must be controlled, and the resulting gel must have certain mechanical properties. In order to apply THFB in real conditions it was necessary to identify important technological and technical parameters, as well as to define interactions between the injected fluid and the aquifer rocks. Geochemical modelling (equilibrium, reaction path and reactive transport) was used to identify potential geochemical effects of the application of TFHB in sandy aquifers. Certain petrophysical parameters and mineralogical assemblages of aquifers were addressed, taking into account both low and strongly mineralized groundwater. The simulations revealed that TFHB does not have a negative impact on the chemistry of rock-water systems described in this work.