Authors: Winther, Aina
Reference: Winther (2011) Thin layer capping with biochar on marine sediments contaminated with PAHs, and the effect of different caps on marine sediment contaminated with dioxins; Thesis Norwegian University of Life Sciences
Summary: Capping contaminated sediment with clean materials is a remediation method that has proved efficient. Passive capping materials physically isolate the contaminated sediment from the receiving environment and active materials sorb the contaminants, thereby making them inaccessible. Activated carbon is one active capping material that is effective in reducing the diffusion of contamination from the sediment. The objective of this thesis was to investigate if biochar could be applied as an active capping material in remediating contaminated sediment. Another part of the thesis was to investigate thin layer capping with three different materials on dioxin contaminated sediment in the Grenland fjords, as a part of the Opticap project. Field work was conducted in the Ormerfjord and the Eidangerfjord in the Grenland fjords. The aim was to test the efficiency of the capping materials 1) activated carbon and clay, 2) crushed limestone, and 3) clay in order to reduce dioxin diffusion. According to the results, all caps were efficient in reducing the dioxin flux from the sediment, and the flux was the lowest in the crushed limestone field, though there are variations between the measurements. Dioxins in free aqueous phase were also reduced in the capped fields, but there were no clear trends in which cap was the most efficient, due to currents and exchange of sea water. The dioxin flux from the sediment was measured with semi-permeable membrane device (SPMD) and the dioxins in free aqueous phase were measured with polyoxymethylene (POM). The measurements were done by employing a flux chamber which was put on the sea floor and collected at different time points.
What You Will Find Here: Remediation p. 10, Thin layer capping p. 21, 40, 59 Design p. 15, (Freundlich Isotherms p. 35 )