In-Situ Slurry Injection for Site Remediation

In situ carbon and bacteria injection is an emerging remediation technique for treating contaminated sites, offering a sustainable alternative to traditional methods like excavation or pump-and-treat systems. This approach involves injecting a sorbent (activated carbon or modified bentonite), nutrients and bacterial amendments directly into the subsurface using a Geoprobe drilling rig to target contaminants such as petroleum hydrocarbons, chlorinated solvents, and even immobilise PFAS.

The AC or bentonite enhance sorption of contaminants, rapidly reducing their mobility and bioavailability, while the bacteria degrade any hydrocarbons over time, ensuring long-term treatment. This dual mechanism—sorption and biodegradation—minimises environmental disruption and reduces the need for energy-intensive processes, enhancing its sustainability credentials.

Unlike ex situ methods, in situ treatment avoids large-scale soil removal, transportation, and replacement, significantly lowering the carbon footprint and preserving local ecosystems. Additionally, it generates minimal secondary waste, further reducing environmental impact.

The sustainability of this method is bolstered by its ability to treat contaminants in place, even beneath infrastructure. It’s particularly effective for persistent contaminant mass in low-permeability zones, where conventional treatments often fail. The use of biodegradable carbon sources and naturally occurring or introduced bacteria aligns with ecological restoration goals, making it a preferred choice for environmentally conscious projects.

The growing list of successful projects underscores its reliability. Since the first AC-based product was developed in the early 2000s, applications have expanded across North America and Europe. Small retail gas stations have seen effective treatment of BTEX compounds, while larger federal sites, like Superfund locations, have tackled chlorinated solvents. These projects highlight the technology’s versatility and effectiveness, positioning in situ carbon and bacteria injection as a proven, sustainable solution for contaminated site remediation, with increasing adoption worldwide and now an option for Australian sites with Legion Drillings partnership with AST Environmental, Inc. and Remediation Products, Inc.