Keywords: ash, earth construction, extraction, flue gas, heavy metals, wet scrubber residue, district heating, wood, peat, fluidised bed boilers
Heavy metals in wet scrubber residue from a medium–sized (32 MW) municipal district heating plant incinerating wood and peat in a fluidised bed boiler
Due to the low total concentrations of heavy metals and extractable compounds, it is recommended that the wet scrubber residue be used as a construction agent instead of being disposed of in landfills. According to five–stage sequential extraction, the highest concentrations of most of the heavy metals occurred in the residual fraction (i.e., HF + HNO3 + HCl), which means that the heavy metals in the wet scrubber residue are tightly bound to the matrix. This is a favourable phenomenon, if the residue is utilised in earth construction.