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Coal Ash Basin Dewatering Presentation

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Later this week, DTD Vice President, David Bardsley, will present a case study on Coal Ash Basin Dewatering. He will speak at the American Groundwater Trust (AGWT) “Conference on Coal Combustion Residuals and Groundwater Contamination Solutions” in Atlanta Georgia. The one day conference will cover a number of critical issues relating to CCR policy/regulation as well as technical challenges for site operators.

Turning Coal Ash Basin Dewatering on Its Side

David’s presentation is titled “Horizontal Well Used for Coal Ash Basin Dewatering” and provides an overview of a project DTD completed in the Midwest in late 2016. The case study was quite an interesting technical challenge. A closed CCR impoundment facility required dewatering; however, the client wanted to avoid an extensive network of vertical wells. Modelling showed that a single horizontal well would be significantly more cost effective and require far less surface infrastructure.

DTD installed the well to a total length of ~643ft long with 550ft of screen. Materials consisted of 6″ diameter fusible PVC and were installed in a “double-ended” configuration. Once installed, the dewatering well performed above and beyond expectations. The system currently operates at a rate of ~20gpm. Dewatering lowered the leachate levels within the landfill to target levels significantly faster than originally anticipated by the model.

horizontal coal ash basin dewatering well casing and screen is pulled into the borehole at a CCR impoundment

Bird’s eye view of the horizontal coal ash basin dewatering well installation.

Conference Will Focus on Coal Ash Regulatory Challenges

CCR impoundment facilities present a number of significant environmental challenges. Two major failures (in 2008 and 2014) highlighted the risks posed to surface water and the environment. Increased awareness of CCR issues has helped bring regulatory issues to the forefront of environmental policy discussions, but challenges remain. From the AGWT conference announcement:

There has been an uneven and mixed regulatory response to water quality concerns with ongoing uncertainty about how best to provide water resources protection. The Federal Government issued a CCR Rule in 2015 and has recently delegated to states the task of developing programs for future implementation. 

The motivation for this conference is AGWT’s education mission to provide objective information to inform management and regulatory decisions leading to source water protection. Groundwater resources in America are limited and therefore understanding potential threats to groundwater resources is imperative.
The conference will provide transparency in information with free exchange of legal, hydrological, regulatory and technical opinions. A collegial dialog among all parties concerned in finding solutions can help provide realistic expectations for strategies to remediate the effects of past practices and to develop economically feasible regulatory protocols.  

If you’re going to be in the Atlanta area on Wednesday, January 16th, consider attending this event. The conference will cover a number of great topics in addition to David’s talk on coal ash basin dewatering.

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