GROUNDWATER REMEDIATION AND THE COST EFFECTIVENESS OF PHYTOREMEDIATION

Abstract

In 1999, phytoremediation was applied at the site of a Belgian car factory to contain two BTEX plumes. This case study evaluates the cost effectiveness of phytoremediation compared to other remediation options, applying a tailored approach for economic evaluation. Generally, when phytoremediation is addressed as being cost effective, the cost effectiveness is only determined on an average basis. This study however, demonstrates that an incremental analysis may provide a more nuanced conclusion. When the cost effectiveness is calculated on an average basis, in this particular case, the no containment strategy (natural attenuation) has the lowest cost per unit mass removed and hence, should be preferred. However, when the cost effectiveness is determined incrementally, no containment should only be preferred if the value of removing an extra gram of contaminant mass is lower than €320. Otherwise, a permeable reactive barrier should be adopted. A similar analysis is provided for the effect determined on the basis of remediation time. Phytoremediation is preferred compared to ‘no containment’ if reaching the objective one year earlier is worth €7 000.

KEY WORDS::

• economics
• site clean-up
• hydrogeological modelling
• BTEX

ACKNOWLEDGMENTS

The authors would like to thank Marnix De Smet and Tom Vermeiren at Sita Remediation NV for cost information.

The supporting information provides more detail concerning the mathematics behind the economic analysis. The determination of the required operation time of the PRB and P&T is described and observed and simulated concentrations are compared.