PRB

Permeable Reactive Barriers (PRBs) may provide a cost-effective solution for Wellfleet Harbor.  Recent pilot project results in the Town of Orleans suggest that high attenuation rates (90%) are achievable.  A PRB installed adjacent to Waquoit Bay has also demonstrated high removal rates.  This project is also providing some indication of the probably lifespan of the woodchip bioreactor.  The project has been in place for over 15 years with little appreciable decay of the bioreactor materials (Ken Foreman).

     According to the Cape Cod 208 Plan there are two types of PRBs available to communities.  These include the trench method where woodchips are backfilled into an excavation to intercept groundwater and the use of injection wells to introduce a carbon-based fluid to provide the reactive….

     Commercial Street provides a possible location for a PRB oriented perpendicular to groundwater flow that could intercept and attenuate nitrogen loads from the high-density downtown Wellfleet center.  Its location near the shoreline discharge area provides an optimal location to capture upgradient nitrogen loads and a relatively thin groundwater lens that may enable a trench-method PRB at reduced costs.