Project Highlight: Tackling Persistent Petroleum Contamination at a Former Gas Station

Long-standing contamination can stall redevelopment and frustrate stakeholders—especially when past efforts haven’t delivered results. At a former gas station site in Colorado, petroleum hydrocarbons and BTEX contamination persisted above reporting limits. Cascade was contracted to implement a targeted in situ chemical oxidation (ISCO) solution using Klozur One, a sodium persulfate amendment. The amendment was emplaced via direct push technology (DPT) in a grid pattern to address the contamination across the site.

The project came with unique logistical and technical challenges, from security concerns to subsurface complexity.

Innovative Use of DPT for Corrosive Chemistry: Although typically applied via wells, Cascade successfully injected Klozur One using DPT tooling—minimizing tooling loss and maintaining injection precision.
Urban Site Security & Material Management: To prevent vandalism and material surfacing, Cascade stored amendment offsite, transported it daily, and used granular bentonite backfill at potholing locations to protect shallow injection zones.