Clean Access Technology and Procedures
The WISSARD project has developed a set of tools, processes, and procedures to protect the environment and samples to be collected. They use proven off-the-shelf technology, and have been configured based on prior field experience and results from laboratory testing of new equipment and processes.
WISSARD hot water drilling efforts will include a custom filtration system designed to 1) remove particles (biotic and abiotic), 2) irradiate the borehole water with ultraviolet (UV) radiation, and 3) subsequently pasteurize the water to reduce microbial contamination. WISSARD clean access protocols will also include methods to clean the surfaces of cables/hoses and down-borehole equipment using Hydrogen peroxide spray, pure water rinse, and germicidal UV radiation.
Prior to drilling through the base of the ice sheet, the borehole water level will be lowered below the hydrostatic equilibrium level, thus on breakthrough subglacial water will continuously be pushed into the borehole, eliminating any exchange from the borehole water into the subglacial environment.
An overview is provided in Information Paper 72, presented to the 2011 Antarctic Treaty Consultative Meeting in Buenos Aires, Argentina, and a full description is provided in the Antarctic Science paper; A microbiologically clean strategy for access to the Whillans Ice Stream subglacial environment. (in review).