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Two Decades of Application of PRBs to Groundwater Remediation
installations involving construction may involve substantial capital investment. However, the benefit of low or negligible costs post construction allow
a life cycle analysis to conclude that economic value comes from designing
the PRB for successful operation over as long a time as possible.
An important lesson with respect to overall costs for a PRB is that it is
much easier to test the functionality of PRB treatment media under laboratory conditions than it is under field conditions. However, this does not preclude the occasional “investment” of a small-scale pilot test to assure a final
PRB design that will meet long-term remedial objectives. We anticipate that
cost performance data will be collected from a greater number of sites—in
particular those involving novel reactive media—to better confirm the longterm efficacy of PRB technology for treating groundwater plumes. Finally,
while a return on investment (ROI) is important for any application, past
experience indicates that compared to active energy-intensive remedies, the
ROI likely is only a few years compared to the overall several decade life of
typical contaminated site.
2.4 Recent Advances
When considering what recent advances in PRB technology have been valuable, what future improvements would be beneficial is also an important
exercise. Because the PRB technology now is approaching 25 years in use,
and many may consider the technology to be a “developed” remedial measure, we may in fact find more utility in discussing potential future improvements. In this vein, a discussion of future improvements may follow the
outline of advancement categories proposed herein and as considered by
ITRC in its 2011 PRB Technology update (ITRC, 2011):
• Construction methods
• Reaction rates
• Hydraulic design improvements
• Monitoring improvements
• Treatment of mixed plumes and emerging contaminants
• Longevity enhancements
• Cost performance improvements
• Closure and decommissioning methods
Over the past 20 years, we have seen improvements in construction methods by use of one-pass trenching, injection methods, and the use of recycled or
“green” treatment materials. Reaction rates are generally not much different
Two Decades of Application of PRBs to Groundwater Remediation
installations involving construction may involve substantial capital investment. However, the benefit of low or negligible costs post construction allow
a life cycle analysis to conclude that economic value comes from designing
the PRB for successful operation over as long a time as possible.
An important lesson with respect to overall costs for a PRB is that it is
much easier to test the functionality of PRB treatment media under laboratory conditions than it is under field conditions. However, this does not preclude the occasional “investment” of a small-scale pilot test to assure a final
PRB design that will meet long-term remedial objectives. We anticipate that
cost performance data will be collected from a greater number of sites—in
particular those involving novel reactive media—to better confirm the longterm efficacy of PRB technology for treating groundwater plumes. Finally,
while a return on investment (ROI) is important for any application, past
experience indicates that compared to active energy-intensive remedies, the
ROI likely is only a few years compared to the overall several decade life of
typical contaminated site.
2.4 Recent Advances
When considering what recent advances in PRB technology have been valuable, what future improvements would be beneficial is also an important
exercise. Because the PRB technology now is approaching 25 years in use,
and many may consider the technology to be a “developed” remedial measure, we may in fact find more utility in discussing potential future improvements. In this vein, a discussion of future improvements may follow the
outline of advancement categories proposed herein and as considered by
ITRC in its 2011 PRB Technology update (ITRC, 2011):
• Construction methods
• Reaction rates
• Hydraulic design improvements
• Monitoring improvements
• Treatment of mixed plumes and emerging contaminants
• Longevity enhancements
• Cost performance improvements
• Closure and decommissioning methods
Over the past 20 years, we have seen improvements in construction methods by use of one-pass trenching, injection methods, and the use of recycled or
“green” treatment materials. Reaction rates are generally not much different