One of our major tasks this season has been to construct a new containment area to store and clean-up (aka remediate) fuel contaminated soil. Avid followers of the project over the years (yes, we know you exist!) will be familiar with the long rectangular shape of our biopiles adjacent to the waste water treatment plant. This thin and long design (see picture) was used for the first iterations of biopile design. It was selected for ease of construction, limitation of the available plant and to trial different types of liners and combinations thereof. This was important as the types of liners needed to be proved and tested for this use in Antarctica. It had never been done before!
Real estate at Casey is very tight so as soil has become remediated and ready to be used on station, we’ve needed to look at ways to contain and remediate more soil while staying within the biopile site. So this year we designed a larger area for construction, colloquially known as the ‘megapile'. This was possible through the years of testing, monitoring and operating the first iterations of the Casey biopiles. Through that we have since developed the capability to build a storage area that can store more soil and can be driven into by our specialised plant to more aggressively remediate the soil. Importantly, the design itself, from the preparation of the subgrade, to the types of liners used, to construction techniques including heat welding the plastic panels of liners together at Casey temperatures, has been informed by the research and monitoring conducted over many years. We have also been using our drone to get detailed elevation profiles to ensure we get the correct construction grades to maximize our storage space while minimising ponding of leachate (see images).
While the construction may look particularly plant heavy, the design and build process is quite complicated, given the conditions, lack of space in which to build and operate heavy plant, and the fact that part of the area where the biopile being built this year had to be excavated first (because it was heavily contaminated with fuel). Therefore, the construction of the megapile required a delicate dance of plant and personnel, science and application, that could not have been done safely without the skills and excellent support from station personnel. Thank you everyone!
- AAD Remediation Team
