Due to the new state CCR regulations, the CCR basin at this retired, coal-fired facility required clean closure. This large volume, high visibility project had a state-mandated completion date and almost constant scrutiny by the media and both government and non-government environmental groups.
“Before excavation began, Trans Ash restructured the basin surfaces and worked cooperatively with the client to re-evaluate the schedule and task priority list.”
Project Challenges & Solutions
The timing of the excavation, proximity to the river and the state-mandated schedule created the following challenges:
- Trans Ash was assuming the scope of work from a previous contractor who was not meeting the mandated schedule. Before excavation began, Trans Ash restructured the basin surfaces and worked cooperatively with the client to re-evaluate the schedule and task priority list.
- Due to the state-mandated schedule, Trans Ash started the project during the winter months, with less than favorable weather. As a result, the CCR material did not respond to conventional dewatering techniques. Trans Ash employed a drying agent and multiple application techniques to stabilize the material and allow for timely excavation and placement.
- Due to previous environmental issues and proximity to the river, this was a heavily scrutinized project with considerable local interest. Trans Ash’s construction plan ensured environmental and engineering compliance. Extensive erosion control safeguards and containment systems were used throughout the project.
- Due to size and air space restrictions, the landfill footprint available for placement was limited. To aid in placement, Trans Ash ensured that the CCR material was within the optimum moisture range and provided ample staffing, a dedicated traffic control pattern and sufficient equipment to safely and effectively complete the task.
- The landfill leachate discharge was restricted as the primary discharge was routed through the local city water treatment system. Trans Ash worked cooperatively with the client to establish another discharge point and employed an on-site chemical treatment system to treat the discharged water.
- An on-site wetland created some traffic flow and accessibility issues. Trans Ash followed a strict ES&C plan to address this issue and protect the wetland.
- There were no original basin construction drawings. Trans Ash performed additional borings and exploratory excavations, along with continuous progress surveys to ensure the basin was properly mapped and all CCRs were removed.