M.S. Thesis: Concrete Blocks Produced from the Mineral Fraction of Waste to Energy Bottom Ash.

By Lianna Aharon

Advisors: Dr. A.C. (Thanos) Bourtsalas and Prof. Nickolas J. Themelis

Department of Earth and Environmental Engineering
Fu Foundation School of Engineering & Applied Science
Columbia University

December 2018

Waste management is an important factor in the future of sustainability. Waste-to-Energy (WTE) plants provide an alternative to landfill use that provides energy from the
combustion of urban residues. However, the residues from Waste-to-Energy plants are not fully utilized. The ash residues from WTE plants can be used for civil engineering applications, typically as a substitute of sand and aggregates in concrete manufacturing. This study explored the viability of this use in terms of leaching assessments.

This study completed the first phase of the Leachability Environmental Assessment Framework (LEAF) Method. The resulting Acid Neutralization Capacity (ANC) graph is a function of leachate pH and the acid added (mmol/kg of acid) to achieve the targeted pH value. The trend that was found was that as more acid or base is added, the final pH is lowered, which can be explained from the decomposition of CaCO3 to CO2 and CaO. Additionally, there were little changes between final pH’s from the 24-hour rotation and 48-hour rotation, indicating that the equilibrium of the solution is achieved sooner than the time suggested by the standard.

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