Disposal of high-water content sludge wastes can pose problems in landfill operations due to trafficability of compaction equipment, long-term slope stability, and generation of odors. As sludge wastes become increasingly solidified with binding agents, such as cements and fly ashes to improve strength characteristics, the corresponding hydration process of calcium oxide generates heat. The study presents the use bench-scale semi-adiabatic tests to estimate the time required for the heat to dissipate from solidified sludge waste stockpiles. Calorimeters used in hydration testing were made from Dewar flasks which greatly minimizes heat loss to the environment. Heat loss to the environment was estimated using resistor wires. Semi-adiabatic test results are converted to adiabatic time temperature curves using the heat loss estimated from the calorimeter. Materials used in the study include various industrial sludge wastes and ashes. Heat generation of ash and waste mixtures at various ash to waste ratios were performed. A numerical model was developed to estimate the period of heat loss in waste stockpiles so it can be safely landfilled. Climate data was incorporated as boundary conditions in the numerical model.
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