Solidified or stabilized waste mixed above ground is either used to fill in the excavation or transported to a landfill for disposal. Waste mixed in situ is usually covered with a “cap” to prevent water from contacting treated waste (See A Citizen’s Guide to Capping [EPA 542-12-004].) How Long Will It Take? Solidification and stabilization may take weeks or months to complete. The actual time it takes will depend on several factors. For example, they may take longer where: • The contaminated area is large or deep. • The soil is dense or rocky, making it harder to mix with the binding agent. • Mixing occurs above ground, which requires excavation. • Extreme cold or rainfall delays treatment.