Pre-Packed Wells
MORE SUSTAINABLE INSTALLATION OF MONITORING WELLS
Pre-packed wells represent an alternative to conventional monitoring systems in unconsolidated and unstable formations. Compared to conventional methods, the installation of pre-packed wells is considerably quicker, simpler, and produces minimal investigation-derived waste (IDW). These advantages contribute to build sound conceptual site models (CSMs) in contaminated sites.
Pre-packed wells are installed with direct push technology. After advancing the rods into the subsurface to the desired depth, the well assembly is installed and the rods are retracted. Subsequently, the well can be grouted (a sand barrier prevents grout from entering the screen), developed, purged, and sampled. Well development produces lower amounts of water and is faster than in the case of conventional monitoring wells.
MAJOR BENEFITS
Rapid installation leading to denser monitoring networks.
Minimal investigation-derived waste (IDW).
Minimal disturbance of natural formation conditions.
Effective filter pack placement.
High integrity of groundwater samples.
Technology applicable in sites contaminated with PFAS and other environmental contaminants.
Well diameters up to 2 in.
Good integration with High-Resolution Site Characterisation (HRSC) and dynamic work strategies.
Legion Drilling has direct push machines operating full time in Brisbane, Melbourne, Sydney and Cairns and provides drilling, characterisation, and remediation services Australia wide.
REPRESENTATIVE GROUNDWATER SAMPLES IN SITES CONTAMINATED WITH PFAS AND OTHER CONTAMINANTS
Chemical analysis of samples collected at direct push wells suggests that improved integrity and representativeness can be achieved with this method. Furthermore, a recent investigation corroborated that the pre-packed wells installed by Legion Drilling do not interfere with the assessment of PFAS contaminated sites. The analysis of water samples collected with this system resulted in non-detects for the 36 PFAS compounds considered.
FURTHER INFORMATION
Our technical specialists will be happy to provide further information and discuss in detail any specific project requirements.
In the meantime, we recommend you to consult the following documents:
ESTCP (2009). Demonstration/Validation of Long-Term Monitoring Using Wells Installed by Direct Push Technologies and Enhanced Low-Flow Groundwater Sampling Methods. ER-0011. Arlington, USA: Environmental Security Technology Certification Program. https://www.serdp-estcp.org/Program-Areas/Environmental-Restoration/Contaminated-Groundwater/Monitoring/ER-200011
Geoprobe (2020). Testing the Geoprobe® Prepacked Well Screens for PFAS Contamination. Geoprobe Technical Bulletin No. 2020DI04. https://geoprobe.com/sites/default/files/storage/pdfs/Prepack%20PFAS%20Tech%20Bul%202020DI04.pdf
ITRC (2008). An Overview of Direct-Push Well Technology for Long-term Groundwater Monitoring. Washington, D.C., USA: Interstate Technology & Regulatory Council, SCM Team. https://clu-in.org/conf/itrc/directpush_121108
McCall, W., & Christy, T. (2018). Direct Push Sampling. Enviro Wiki. https://www.enviro.wiki/index.php?title=Direct_Push_Sampling&oldid=11358