Stabilization/solidification of galvanic sludges by asphalt emulsions

A combination of two-aqueous asphalt emulsions was proposed for stabilization/solidification treatment of galvanic sludges prior to landfilling. The presented procedure comprises mixing the galvanic sludge with a slow setting nonionic asphalt emulsion and subsequently forming a secondary asphalt barrier by means of a rapid setting anionic asphalt emulsion. The method was tested on four samples of galvanic sludge from various galvanizing plants, with various water and pollutant contents. Stabilization efficiency was assessed by water-leaching test, TCLP test and by determining ecotoxicity of leachates. Leachate parameters exhibited very low values and favorable results of ecotoxicological tests indicate high efficiency of the developed procedure for galvanic sludge disposal.