Glen Vallance is an Associate Hydrologist and Environmental Services manager for CGRS Inc. in Fort Collins, Colorado, with 14 years’ experience in the industry. He specializes in site assessment and remedial technologies including traditional single and multiphase extraction remediation methods; injection technologies such as ISCO and carbon-based approaches; and gas-thermal remediation. He is always seeking out innovative and optimized remediation-delivery methods to better serve clients.
Site Remediation Using Segmented Horizontal Well Systems in Areas without Ready Access
Horizontal well systems provide more linear contact area than vertical wells and provide generalized assessment and focused treatment along the entire targeted interval. New segmented well systems offer discrete control over pre-defined intervals, filling data gaps and allowing for adjustments as needed. The flow rate to or from each segment can be individually controlled, allowing for variable treatment thus improving remediation efficiency. A site in Greeley, Colorado, was impacted with diesel and gasoline range organics in a dissolved phase and LNAPL configuration. A segmented horizontal well system was installed to remediate with air sparging (AS) and soil vapor extraction (SVE). Installation went under highways, roadways and complex infrastructure, maintaining full operational status of business operations and traffic movement. The system became fully operational in March 2018. The first quarterly sampling event was conducted in June 2018 and demonstrated significant reductions in measurable free product and the dissolved contaminant plume.