Permeability versus surface reactivity on the longevity of granular iron reactive barriers.

摘要

The longevity of granular iron permeable reactive barriers (GIPRB) depends on the loss of permeability and the loss of reactivity of the iron grains. These losses may occur as a consequence of precipitate and hydrogen gas formation that coat the iron surface and fill pore spaces, reducing reactivity and hydraulic conductivity. The effects of six geochemical conditions on these processes were considered. The solutions were anaerobic sulfate, anaerobic chloride, anaerobic nitrate, anaerobic carbonate, aerobic perchlorate, and anaerobic perchlorate (control anion). Decreased hydraulic conductivity was the most likely cause of barrier failure in sulfate or chloride rich waters. Reactivity loss was most likely to be the cause of GIPRB failures in aerobic perchlorate, anaerobic nitrate, and anaerobic carbonate waters. Results from this study indicate solution geochemistry plays a vital role when determining whether loss of permeability or reactivity will cause GIPRB to malfunction first.