Effect of weathering treatment on the fractionation and leaching behavior of copper in municipal solid waste incinerator bottom ash

This work describes the effect of weathering of fresh quenched municipal solid waste incinerator (MSWI) bottom ash on the fractionation and leaching behavior of Cu. A sequential extraction procedure was used to characterize the fractionation of Cu in the fresh and weathered MSWI bottom ash samples. It showed that the organic matter bound fraction of Cu decreased drastically from 69% to 37% during the weathering treatment, while the residual fraction, Fe–Mn oxides bound fraction, carbonate bound fraction and exchangeable fraction increased from 24% to 54%, 3% to 4%, 2% to 3% and 2% to 3%, respectively. Furthermore, two standard leaching procedures, synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP), were carried out on the fresh and weathered samples. The leaching of Cu was attenuated with the process of weathering treatment in the SPLP procedure, but was enhanced in the TCLP procedure. The results suggested that the weathering treatment could change the fractionation and leaching behavior of Cu in MSWI bottom ash. Further research is required to correlate weathering of ash and mobility of Cu.