Déshydratation des produits de décontamination des cendres volantes d'incinérateur de déchets municipaux

Abstract

Municipal solid waste combustion fly ash handling costs are increasingly expensive because of the increase of the landfilling cost. A research team from the Institut national de la recherche scientifique (INRS-Eau) developed, in association with the private sector, a fly ash decontamination process. Once treated by this process, two types of sludges are produced. The first type of sludge consists of a decontaminated ash, while the second is a residual metal sludge. This research project aimed to show that these sludges could be dewatered economically with standard filtration devices, under normal operating conditions. This paper demonstrates that sludge conditioning can easily be achieved by adding a small amount of commercial polymers, [Formula: see text]0.5 kg per ton of dry weight. Two types of commercial dehydration equipment were compared: a filter press and a vacuum filter. For the ash sludge, these two types of equipment produced a filtration cake containing more than 40% in total solids. For the metal sludge, total solids were 20% for the filter press. Vacuum filter efficiency was significantly lower with a total solids of only 13%. An economic analysis showed that the use of a filter press for both sludges was the best choice.Key words: fly ash, decontamination, dehydration, filter press, vacuum filter, conditioning, metal.