Remediation of Free Product with Horizontal Bioremediation Systems - Case Study
- Project Location: Northern New York
- Client: Private Corporation – Petroleum Distribution Center
- Contamination: Gasoline
- Site Size: 10+ Acres
Project Description: Seeking to excavate a trench to install an underground pipe, the client’s contractor severed a buried, and greatly mislocated, 10-inch gasoline header. The header was under significant head pressure, being fed by a large bulk fuel tank located across the highway several hundred yards away. Unfortunately, even acting as quickly as possible to halt the flow, an estimated 10,000+ gallons of fresh fuel spilled into the ground, quickly spreading into a multi-acre free product plume. We were asked to help.
Assessing the situation, the problem grew larger as time progressed as the free product plume expanded on either side of the highway nearly engulfing the client’s land and impinging upon an adjacent farm. Having a fresh water stream down-gradient, it became clear that a concurrent contain and remediate strategy was required.
Using SPARGE and SYSTEM DESIGN’R, we designed 6 separate bioremediation systems deploying horizontal air sparge wells. Four wells were positioned around the perimeter of the site to act as bioremediation air curtains, while two internal systems focussed on the bulk of the plume. Each well was fed by a dedicated blower, allowing great flexibility in metering the right amount of air into the formation.
Unbeknownst to all, the site was underlain by huge boulders, remnants of the Great Glacier eons before. These boulders spelled difficulty for the well driller, who had difficulty following the required bore paths. During system start up, it became clear that one well was severely cut mid-span, causing further concern.
We quickly assessed the extent and location of well screen damage, and using SPARGE, engineered an internal sleeve to bridge the well screen cut. The sleeve included provisions to utilize the well’s undamaged screened sections both prior and distal to the damaged section.
With the damaged well repaired, each system was energized – each performed as required and as previously modeled and predicted by SPARGE. Contamination quickly degraded and the spread of the plume into the stream and farm was abated. The site was declared fully remediated within 60 months.