Reduction of sediment micro-pollution by means of a pilot plant

Solutions need to be found to manage polluted (organic matter, trace elements, hydrocarbons and PAHs) stormwater sediments while complying with stringent economic and environmental requirements. The cost of transport is a relatively large part of the treatment cost for such sediments, hence the development of a pilot unit that could provide their in situ treatment. Seven stormwater sediments were treated by means of the ATTRISED pilot plant, based on sieving and attrition. The objective is to apply a treatment procedure by which as much clean material as possible is recovered, while the pollutants are concentrated in a small volume ready for final destruction or isolation from the environment. Application of the attrition process serves to remove fine particles and contaminants from the surface of sediments and hydrocyclone separations allow to isolate fine contaminated particles (< 60 μm). The results show that particle size separations coupled to an attrition step allow decontamination efficiencies of 76% and 70% for street sweeping and pond sediments, respectively. Although the experiments were carried out on stormwater sediments, all kinds of sediments may be treated by the ATTRISED pilot plant if the mean particle size is greater than 60 μm.