Design and cost estimation of permeable reactive barriers

Cost‐effective use of permeable reactive barriers for groundwater treatment requires properly estimating the amount of reactive material required and choosing the best means of emplacing it. The weight of reactive material per unit cross section of the plume can be estimated from laboratory reaction kinetics data and basic knowledge of the plume and the remediation goals. This parameter has implications regarding the choice of permeable barrier design and emplacement method. The use of tremie tubes, trenching machines, high‐pressure jetting, and deep soil mixing may be appropriate for different situations depending on the amount of reactive material required, the dimensions of the plume, and other factors. The specific application considered here is the use of granular iron to treat groundwater contaminated with chlorinated solvents.