Permeable Reactive Barriers, or PRBs, are similar to a “wall” that is constructed or injected at a site to intercept and treat contaminated groundwater plumes.
The PRBs are permeable in that they allow groundwater to flow through them unimpeded, which prevents the need for hydraulic control measures (e.g. pump and treat) to avoid redirecting the contaminant plume to other areas. PRBs are constructed using materials such as Zero-Valent Iron (ZVI) or Oxygen Releasing Compounds, that treat the contaminant plume as it passes through the PRB, chemically, biologically, or through adsorption or precipitation.
PRBs are an effective method for preventing contamination from crossing property boundaries or otherwise spreading to uncontaminated areas while the source area of the contamination is being remediated. Depending on the construction type and design, PRBs can last from years to decades with little to no maintenance requirements since they are designed to be passive systems.
Vertex is one of Canada’s most experienced companies in the design and installation of PRBs. Vertex staff has been involved in many world-first designs and installations and are considered experts in PRB design and installation. Geologic environments that Vertex staff has implemented PRBs within include:
- Fractured rock
- Glacial till
- Sand and gravel deposits
- Silt and clay
The types of PRBs that can be considered for implementation at a site include:
- ZVI Barriers
- Oxygen-Releasing Barriers
- Hydrogen-Releasing Barriers
- Precipitation and Co-Precipitation Barriers
- Sulfate Reducing Barriers
- Ion Exchange and Adsorption Barriers
- Aerobic Biobarriers
- Anaerobic Biobarriers
- Compounds treated using PRBs include:
- Chlorinated ethylenes (PCE, TCE, DCE, VC, etc.)
- Chlorinated ethanes (TCA, DCA, etc.)
- BTEX and petroleum hydrocarbons
- Heavy metals such as arsenic, selenium and hexavalent chromium
The keys to the successful design and installation of PRBs is to understand the hydrogeology and geochemistry of the system and then designing the lifespan of the PRB accordingly. Vertex is always exploring the use of new and innovative reactive materials for PRBs as well as installation methods. Vertex is experienced in using continuous trenching, biodegradable slurries such as guar, cut and fill methods and temporary support measures such as trench boxes. Vertex staff has experience with the following reactive mixtures:
- Zero-valent iron (ZVI)
- Ion exchange resin
- Blast furnace slag
- Oxygen releasing materials
- Phosphate-based materials
Vertex combines strong theoretical understanding with practical experience to properly plan and implement the right remedial program for your site. Selecting Vertex to undertake your remediation project allows you to access a wealth of in‑situ remediation knowledge and experience.