Critical aspects related to Fe and Fe/pumice PRB design

A permeable reactive barrier (PRB) is a consolidated in situ technology for groundwater decontamination, but its long-term effectiveness, and thus the success of any remediation project, depends on the correct design in terms of geotechnical, chemical and hydraulic aspects. This paper examines the performance of a PRB and presents the results of an investigation into its long-term behaviour by using column tests. In particular, the geotechnical aspects involved in the design of a PRB and the effects of hydraulic conditions and contaminant concentration (nickel) are discussed. Moreover, the results of laboratory column tests carried out at various flow velocities and initial contaminant concentrations are discussed. The reactive media used in the tests are zero valent iron (ZVI) and a granular mixture of ZVI and pumice.