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DNAPL Remediation: Trap & Treat® Strategies That Close the Gap

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Chlorinated DNAPL behaves differently from petroleum LNAPL. It pools in fractures and low‑permeability zones while driving deeper into the geology when physical opportunities arise. It also diffuses from these matrices, keeping groundwater above standards for years to decades. RPI®‘s Trap & Treat® platform is built for this reality. We pair fast, in situ adsorption with powerful reductive chemistry to accelerate DNAPL remediation while controlling mass diffusion. That’s a DNAPL remediation strategy that protects the public and meets remediation goals. 

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How Does BOS 100® Work?

BOS 100® is an activated carbon, iron technology designed for DNAPL source areas and dissolved phase plumes common to chlorinated solvents. Structurally integrated metallic iron within the activated carbon structure ensures that abiotic dechlorination occurs in the carbon where the chlorinated solvent is adsorbed. The end products of degradation, such as dissolved iron, chloride, and unregulated gases such as ethylene and methane, support clean closure without harmful degradation products. 

This is how Trap & Treat® works underground:

  • At‑capture containment and flux control: The activated carbon surface adsorbs chlorinated ethenes, controlling exposure while mass electron transfer reduces the chlorinated solvents.
  • Point‑of‑capture abiotic destruction: Structurally integrated metallic iron drives reductive dechlorination on the internal surface of the activated carbon, producing chloride, unregulated gases, and ethene and ethane. As mass is degraded, adsorption sites are made available to adsorb additional compounds, sustaining DNAPL remediation.
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Bedrock DNAPL Remediation 

Fractured rock requires precise remedy emplacement. RPI®‑approved field teams have applied BOS 100® in bedrock using pre‑drill/DPT hybrids, angled boreholes, and PRB configurations to reach depth, bypass refusal, and treat fracture networks. Projects have documented high‑percent destruction of chlorinated solvents at depth and sustained performance over multi‑year monitoring — evidence that bedrock DNAPL remediation can be practical, predictable, and successful. 

When to Use CAT 100® 

Some DNAPL source zones are co‑mingled or recalcitrant. CAT 100® fuses BOS 100® with biotechnology to enhance electron transfer and sustain catalytic degradation across complex mixtures. It is suitable where DNAPL remediation technologies must address wide contaminant lists, residual mass in tight media, or require very long-term residence times. 

Field Results That Inform Design 

Across chlorinated source areas, including bedrock, BOS 100® has demonstrated sustained concentration declines with clear destruction indicators. Established data support stepwise DNAPL source zone remediation characterized by contaminant stabilization, dissolved phase reduction, reduced flux, and contracted monitoring footprints. Ultimately, BOS 100® meets remediation goals and closes sites.

Where Our Approach Excels 

Use the scenarios below to align product and placement with your conceptual site model:

  • DNAPL source areas with persistent rebound: Establish a reactive, adsorptive treatment zone to control exposure and drive on‑contact dechlorination.
  • Bedrock DNAPL remediation with refusal and depth constraints: Employ pre‑drill/DPT or angled injection to place BOS 100® along fracture pathways.
  • Sites needing measurable progress under DNAPL remediation regulations: Combine RDC, surgical placement, and clear lines of evidence to document mass reduction and risk control. 

Bedrock-Ready Design and Installation

High‑resolution RDC pinpoints DNAPL mass, fracture pathways, and back‑diffusion. RPI‑Group Approved Installers then place BOS 100® by in situ injections, so the media reaches the controlling fractures. The RPI® Support Lab provides no‑charge GC/MS during deployment to verify distribution and early performance.

Why RPI® for DNAPL Remediation? 

When DNAPL cleanup has to work in rock and tight formations, RPI®‘s Trap & Treat® media are built for the job. BOS 100® embeds reactive iron within activated carbon, bringing capture and on‑contact dechlorination to the same surface — without relying on narrow geochemical windows. 

For co‑mingled or stubborn constituents, CAT 100® adds enhanced electron transfer to “catalyze” the reaction, increasing longevity and carry degradation through to meet remediation goals. Paired with surgical placement methods in fractured and low‑permeability settings, this is DNAPL source zone remediation engineered to produce results.

Frequently Asked Questions About DNAPL Remediation

DNAPLs (Dense Non-Aqueous Phase Liquids) are heavier than water, so they sink in water. Common DNAPLs are chlorinated solvents (PCE, TCE, TCA), coal tar, and creosote. As DNAPLs sink, they pool in fractures and low-permeability zones in the aquifer and bedrock. DNAPL trapped in such low-permeability zones acts as a long-term source, slowly back-diffusing into flowing groundwater and re-contaminating it even after the accessible/mobile DNAPL has been treated. Pump-and-treat and in-situ chemical oxidation approaches fail to consistently reach DNAPL trapped in fractures/matrix. And when they do perturb trapped DNAPL, the reactive amendment is consumed too quickly to keep pace with a persistent source. This is why BOS 100® and CAT 100 are designed to adsorb contaminants and drive their chemical reduction e.g., dehalogenation, persisting in the subsurface as long as the source does.

BOS 100® combines fast, in situ adsorption with powerful reductive chemistry to accelerate DNAPL remediation while controlling mass diffusion. The activated carbon adsorbs chlorinated solvents at capture, while structurally integrated metallic iron drives reductive dechlorination on the internal carbon surface, producing only harmless end products like ethene, ethane, and chloride.

Yes, RPI® has successfully applied BOS 100® in bedrock using specialized techniques including pre-drill/DPT hybrids, angled boreholes, and permeable reactive barrier (PRB) configurations to reach depth, bypass refusal, and treat fracture networks. Field results document high-percent destruction of chlorinated solvents at depth with sustained multi-year performance.

Design DNAPL Remediation That Works

If bedrock, tight formations, or rebound are stalling progress, connect with RPI® to scope a DNAPL source zone approach built around your geology. We’ll help you select fit‑for‑purpose DNAPL remediation technologies and define a monitoring plan that supports clear lines of evidence.

Request an estimate or call 720-821-6569.

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