HEAVY METALS IN THE ASH FRACTION FROM MEDICAL WASTE INCINERATION

RODRIGUEZ R.; PALACIOS C.; UDAQUIOLA S. ; HEKTOR K.

Río de Janeiro

Congreso; ICHMET XIIIINTERNATIONAL CONFERENCE ON HEAVY METALS IN THE ENVIRONMENT; 2005

Centro de Tecnologia Mineral - CETEM

Most of heavy metal contents in medical waste are present in the ash, powders and slug fraction produced by incineration. These fractions represent a potential risk to human health. The ashes are withdrawm the slug at the incinerator bottom. The powders are particles dragged out by the gaseous flow. Their quantity depends on the waste composition and incineration method. To evaluate the waste stability in the final disposition it is neccesary to know the heavy metals behaviour during the incineration. Three alternatives are possible: vaporization, reaction and inert behaviour. In the last case, metals remain unaffected inside the waste particles. The heavy metals leaching capacity for landfill disposition may cause environmental problems, such as underground water contamination. Due to that fact is very important to simulate this phenomena using leaching tests to determine if these fractions are dangerous materials. The aim of this paper is to present the determination of heavy metal concentration in ashes and to perform the leaching test on them. The sampling technique, the sample preparation, the analitical methods and results will be discussed. The concentrations of Pb, Cd, Hg, Fe, Cu, Cr and Zn were obtained using atomic absortion spectrometry. Most of the results indicate values higher than the limits imposed by regulatory laws. This fact allows to conclude that the ash fraction produced by the incineration of medical wastes should be categorized as hazardous waste and therefore special care should be taken in its final disposition.