Effect of weathering on the mobility of zinc in municipal solid waste incinerator bottom ash

Abstract

This work describes the effect of weathering of fresh quenched municipal solid waste incinerator (MSWI) bottom ash on the mobility and leaching behavior of zinc (Zn). A sequential extraction procedure (SEP) was used to characterize the fractionation of zinc in the fresh and weathered MSWI bottom ash samples. It showed that the stable fraction of Zn, including organic matter bound fraction and residual fraction decreased from 62.4% to 30.9% during the weathering treatment, while the mobile fraction, including exchangeable fraction, carbonate bound fraction and Fe–Mn oxides bound fraction, increased from 37.6% to 60.1%. 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 Zn was attenuated with the weathering treatment in the SPLP procedure, but enhanced in the TCLP procedure. The SEP and TCLP results suggested that the weathering treatment could enhance the mobility of Zn, which was distinct from previous work.