Evaluation of the stability of cadmium [Cd] in slags from the Waste Thermal Treatment Plant [WTTP] in Kraków

Abstract

The purpose of the research was to evaluate the mobility of cadmium [Cd] in slags from municipal waste incineration. The evaluation was based on TVA's two-stage wash-out test on fresh samples and on samples exposed to atmospheric factors’ influence for a period of two weeks. The tested slag samples were collected from the municipal Waste Thermal Treatment Plant [WTTP] in Kraków. Total Cd content in the waste was determined by the decomposition of samples in aqua regia. The Cd concentration in post-extraction solutions was determined by the AAS method. On the basis of the obtained results, it was found that prolonged contact with water causes leaching (washing out) of significant amounts (5.6–11.8% of the total content) of the element from the tested fresh waste. Prolonged contact with water, together with the influence of other atmospheric factors (temperature changes, sunshine, wind), has a negative influence on Cd stability in the examined waste, causing the release of significant amounts of that element into the surroundings, which may pose a threat to the environment.