ABSTRACT
ABSTRACT: Waste materials contaminated with inorganic contaminants are usually remediated by chemical immobilisation where the contaminants are chemically bound in the waste as insoluble minerals. Chemical immobilisation is generally a better alternative to stabilisation or physical encapsulation (solidification), such as cement or other pozzolanic materials, as the stability of the contaminants is not dependent on maintaining the structure of the physical encapsulation. The aim of chemical immobilisation is to reduce the leachability of the contaminants in order to facilitate disposal of the waste to landfill at a reduced hazard classification. This paper investigates the use of chemical immobilisation to treat complex industrial waste co-contaminated with high levels of seven different inorganic contaminants with a wide range of solubility characteristics. The most leachable contaminant in the untreated waste was arsenic (As TCLP = 350 mg/L), which was reduced to below 0.2 mg/L (>99.9% reduction) in the treated waste.
