Contribution of Each Combustible Waste to the Element Content of MSW Incineration Residue

To investigate the origin of toxic/beneficial metals in incineration residues, we tried to estimate the contribution of each combustible waste to various elements in incineration residue. Municipal solid waste (MSW) sample to be incinerated was collected from a waste pit of incineration plant A by a crane and compressed according to the quarter method. After excluding metals and incombustibles, the MSW sample was divided along with the material such as kitchen waste, vinyl and plastic, wood, rubber, and so on. Each sample was dried at 105°C for 2 hours to obtain the water content, and cut into small piece. Each sample was placed in a magnetic crucible and closed with a lid, then, heated at 650°C in a muffle furnace to obtain constant weight after ignition loss. After the heat-up and cool down, two-stage extraction consisting of aqua regia decomposition and alkali fusion was carried out on each ash. Each extract was subject to ICP-OES and ICP-MS to determine the element content in each combustible. Element composition of the ash was well correlated with the element composition of actual incineration residues collected at the same incineration plant on the same day of sampling. As a source of toxic metals, 68% of Pb was proved to originate from vinyl and plastic. As for Cd, woods accounted for 38% and rubber and leather accounted for 29%, respectively.