Colloidal activated carbon and carbon-iron-novel materials for in-situ groundwater treatment

Two novel materials have been developed and tested in initial studies for the in-situ
generation of sorption and reactive barriers for subsurface water treatment at low cost by
introducing sorbents or reagents via injection wells. Both materials are based on finely-ground
activated carbon with a particle size of D50 = 0.8 μm which is quasi-soluble, i.e. it forms stable
colloidal solutions in water over a wide concentration range. With these activated carbon
colloids, an approved material of environmental technology is now applicable for injection into
contaminated aquifers to form sorption barriers by controlled deposition on aquifer sediment
directly in the flow passages. A new remediation strategy can be followed – the in-situ
generation of a permeable AC sorption barrier in contaminated aquifers.
Based on the colloidal carbon particles, a second material has been developed which
combines the sorption properties of the activated carbon carrier and the reactivity of the zerovalent
iron deposits. This CARBO-IRON (20 wt-% zero-valent iron) has proved its suitability as
a dehalogenation reagent applicable for both plume and source treatment.