Filtermedier for rensing av tungmetaller i avrenningsvann fra skytebaner - feltforsøk ved Steinsjøen skytefelt

Abstract

To reduce the impact of heavy metal runoff from shooting ranges, the Norwegian Defence Research Establishment (FFI) did a field study with different filter media. The tests were performed during summer 2005 and 2006 at a heavy metal polluted creek at Steinsjoen shooting area. The aim of the work was to study reduction in concentration of Pb, Cu and Sb in water filtrated trough columns filled with filter medias. Six different filter medias were tested in a field laboratory placed at a shooting range with high concentrations of heavy metals in runoff water. The six filter medias were: A) granulated peat, B) same type as A but coated with micro algae, C) activated coal, D) olivine, E) Iron oxide coated olivine (Ioco), F) Lightweight Expanded Clay Aggregate (Leca). In 2006 the field work included a pre-filter made of sand and gravel for particle filtration. The result from the filter media tests shows that the filtration efficiency changes with the water regime and time. In periods with high precipitation the filtration efficiency for Pb and Cu is greater compared to dry periods. This is probably due to the change in Pb and Cu species. For all three metals the iron coated olivine (IOCO) had the best cleaning efficiency, but in the filtrate pH was unfavorable high. The average (and standard deviation) of the filtration efficiency for Pb, Cu and Sb trough the IOCO was, 56% (23), 58% (21) and 59% (26) respectively. Of the six filter medias in this study it was only IOCO that had any sorption of antimony of importance.