What is a Permeable Reactive Barrier?

A permeable reactive barrier (PRB) is a technology designed for passive in situ treatment of groundwater. It is an underground barrier that intersects the contaminant plume, and is comprised of reactive materials that target dissolved phase contaminants as the plume flows through the barrier. When necessary, an impermeable wall is installed to direct the flow of groundwater through the PRB.

What is a Permeable Reactive Treatment Zone?

A permeable reactive treatment zone (PRTZ) is similar to a PRB in that it is a passive (or active) in situ treatment of contaminated groundwater, designed to intersect with the contaminant plume. However, unlike a PRB, it is comprised not of a barrier structure for water to flow through, but a zone of the subsurface where reactive materials have been applied. When the water flows through this zone, contaminants are exposed to those amendments and the reaction process begins.


PRB & PRTZ Services

Cascade can support the design, testing, installation, and monitoring of PRB and PRTZ solutions.

To do so, we utilize column reactivity data and iron permeability design data to design a PRB or PRTZ appropriate for your site’s lithology. Then, a bench scale treatability test can determine if the remedy is suited for the site before full-scale implementation. Our experts monitor groundwater contamination levels during implementation to ensure forecasted results are achieved.

We provide remedial options utilizing either liquid or solid slurry amendments. There are many ways these amendments can be applied, including:


PRB & PRTZ Technologies


PRB & PRTZ Applications

  • Cut off of contaminant flux to sensitive receptors including…
    • Chlorinated solvents: utilizing zero valent iron (ZVI), activated carbon, or bio amendments like emulsified oils
    • Benzene, MTBE: utilizing solid oxidants like potassium persulfate
    • PFAS: using activated carbon
    • Hazardous metals: utilizing ZVI or bio amendments like emulsified oils
  • Treatment of large plumes through multiple PRBs/PRTZs
  • Combined spatial remedies for chlorinated solvent source zones including other remediation technologies like…
    • Thermal
    • ISCO
    • Excavation

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