Disadvantages

• PRBs are currently restricted to shallow depths of emplacement, typically less than 50 feet below ground surface due to construction limitations.
• The plume must be well characterized and its extent in the aquifer well defined.
• The longevity of the reactive zone within the PRB may limit its suitability if the time required for remediation of the plume is long.
• Once constructed, modifications to the PRB are extremely limited unlike the range of possible modifications that can be applied in the pump and treat method.
• Up gradient and down gradient monitoring wells must be installed and sampled periodically to assess PRB performance.