Geological disposal of energy-related waste

Abstract

The production of waste materials during energy recovery processes is an unavoidable consequence of the need for energy; consequently, safe and efficient disposal or reuse alternatives for these waste materials is essential for sustainable development. For waste streams that must be geologically disposed, the largest volumes of energy related waste include Coal Combustion Products (CCPs) such as fly ash, coal mining wastes, and processed water and drill cuttings from oil and gas exploration, with relatively small amounts of silica resulting from pipe scaling in geothermal energy production. The fate of the vast majority of these energy-related wastes is geologic disposal, which ranges from placement in landfills (lined or unlined) or surface impoundments, to deep injection within geologic units. Applications for productive reuse of energy-related wastes are cost effective alternatives to disposal, and are gaining popularity as sustainability of processing becomes more critical. This review paper examines geologic disposal and reuse of energy-related waste streams within the U.S., and provides insight into fuel-to-waste production ratios, preferred disposal or productive reuse alternatives, and associated geotechnical/environmental considerations.