Impact of Microorganisms on the Performance of Laboratory-Scale Permeable Reactive Iron Barriers

摘要

Degradation efficiencies of column-scale zero-valent iron barriers containing different microbial inocula were compared with sterile non-inoculated iron columns. Contaminant removal capacities and hydrogen production rates indicated an increasing reactivity in time for all inoculated iron column material, while reactivity of the non-inoculated column material remained more or less the same. The main mineral precipitates, including carbonate green rust, ferrous hydroxy carbonate, aragonite, and to a lesser extent also goethite, were observed under all imposed conditions. The higher reactivity of the inoculated column material probably resulted from the higher amount of carbonate green rust that was observed, which might be explained by reduction of ferric iron species by iron(Ⅲ)-reducing bacteria. Furthermore, bioaugmentation of columns with an iron(Ⅲ)-reducing Geobacter sulfurreducens strain seemed to result in thinner precipitate layers, probably by an increased solubilization of corrosion products.