Are accelerated column tests used in permeable reactive barrier design sufficiently reliable?

Column tests are usually carried out to gather information for the design of permeable reactive barriers (PRBs). In order of reducing the duration of column tests and to obtain information about long term performance of a PRB, they are usually accelerated by increasing the mass of contaminant in input into the column. The purpose of this study is to evaluate the effect of the acceleration of column tests by increasing flow rate and/or contaminant concentration respect to typical field conditions. In particular, it is evaluated if an increase in contaminant concentration produces the same effect of an increase in flow rate on the short and long term behaviour of a reactive medium constituted by a granular mixture of Zero valent iron and Pumice with a weight ratio of 30:70 and using nickel as model pollutant.