DOI: 10.1002/rem.21527 RESEARCH ARTICLE Incorporating green and sustainable remediation analysis in coal combustion residuals (CCR) surface impoundment closure decision making Ali Boroumand Grace Greenberg Kurt Herman Ari Lewis Correspondence K. Herman, Gradient, 20 University Road, Cambridge, MA 02138, USA. Email: KHerman@gradientcorp.com Funding information Electric Power Research Institute. Abstract In response to new coal combustion residuals (CCR) disposal regulations, many coal-fired utilities have closed existing unlined surface impoundments (SIs) that were traditionally used for disposal of CCR. The two primary closure options are closure-in-place (CIP), which involves dewatering and capping, and closure-by-removal (CBR), which includes excavation, transportation, and disposal of the CCR into a lined landfill. This article provides a methodology and a case study of how green and sustainable remediation concepts, including accounting for the life cycle environmental footprints and the physical risks to workers and community members, can be incorporated into the closure decision-making process. The environmental impacts, occupational risks, and traffic-related fatal- ities and injuries to workers and community members were calculated and compared for closure alternatives at a hypothetical site. The results demonstrated that the adverse impacts of the CBR option were significantly greater than those of the CIP option with respect to the analyzed impact pathways. 1 INTRODUCTION Coal combustion residuals (CCR) are the materials that remain after coal is burned in coal-fired power plants. CCR is one of the largest types of industrial waste generated in the United States Environmental Pro- tection Agency (US EPA, 2017). For example, according to the Ameri- can Coal Ash Association, over 117 million tons of CCR was generated in 2015 (ACAA, 2016). Power plants traditionally dispose of the pro- duced CCR in landfills or surface impoundments (SIs). CCR contains constituents, such as mercury, selenium, and arsenic, which, without proper management, can potentially impact surface water, groundwa- ter, and air in the vicinity of the disposal facility. Recognizing the poten- tial risks that can be associated with CCR disposal, and in the wake of a large CCR spill in Kingston, Tennessee, in 2015, the US EPA established minimum federal requirements for the regulation of CCR disposal (US EPA, 2017). On April 17, 2015, the US EPA published 40 CFR 257, Subpart D, referred to as the CCR Rule, to establish technical requirements for new and active landfills and SIs, and certain inactive SIs. The new CCR Rule sets technical criteria for disposal unit location and structural integrity. It also sets groundwater protection requirements, including groundwater assessment and corrective action. According to the CCR Rule, closure is mandatory for any unlined active or inactive CCR SI that causes statistically significant groundwater concentrations of cer- tain CCR constituents to rise above relevant standards or that cannot meet the structural integrity or location criteria. According to a 2009 US EPA survey, there are currently more than 735 SIs in the United States actively used for CCR disposal (US EPA, 2017). In addition to those, there are many more inactive SIs that no longer receive CCR, but will be subject to the CCR Rule. It is expected that the CCR Rule will lead to closure of a significant number of SIs over the next decade. Closure alternatives fall into two main categories: Option 1: Closure-in-place (CIP), involving leaving the CCR in an existing impoundment and dewatering, backfilling, and capping the impoundment; or Option 2: Closure-by-removal (CBR), involving excavating, transport- ing, and redisposing the CCR in a landfill, in addition to backfilling and capping the former impoundment. Groundwater and surface water impacts are the principal concerns associated with existing SIs with respect to drinking water and ecolog- ical impacts. Therefore, these impact pathways are often the primary factors that shape public opinion about SI closure options. Accordingly, there is strong public support for Closure Option 2 based on the belief that CIP does not mitigate risk to the same extent that redisposal of CCR in a lined landfill does. To fully understand the human health and environmental ben- efits under either closure option, however, requires a methodical, Remediation. 2017;27:29–38. c 2017 Wiley Periodicals, Inc. 29 wileyonlinelibrary.com/journal/rem