Sustainable Approaches for Closure of Coal Ash Impoundments: A Quantitative Assessment

In the past two decades, large coal ash spills (e.g., Tennessee Valley Authority Kingston plant in Tennessee in 2008, the Dan River Coal Ash spill in North Carolina in 2014) spurred a national interest in regulating how the coal combustion residuals, CCR, (i.e., coal ash) impoundments (i.e., ash basins/ash ponds) are managed across the United States (US). These events were a major impetus for the development and promulgation of the federal and state regulations (e.g., CCR Federal Rule in April 2015 and the Coal Ash Management Act in September 2015 by the State of North Carolina) that require safe disposal of coal ash in coal ash impoundments/ponds along with safe closure of all the existing ash impoundments. However, the safe disposal or safe closure of existing coal ash impoundments involves high energy and resource intensive activities which may in turn lead to significant negative environmental impacts. In this regard, quantitative sustainability assessment should be incorporated as a critical component of the decision making process of the coal ash management strategies. This study demonstrates the significance and the importance of incorporating sustainability in the decision making process by performing a quantitative life cycle sustainability assessment (LCSA) to evaluate the sustainability of alternative options for restoration and/or management of coal ash management at a Site in the US. The environmental, economic, and social impact assessment of each alternative option is performed, and the results are compared to identify the most sustainable option for safe management of the coal ash at the Site. The quantitative LCSA methodology used in this study can be generally applied and adapted to assess the overall sustainability of coal ash management strategies at other similar sites.