Project Overview
Two process water basins were constructed to provide long term treatment of process flows at a retired, coal fired, power plant. This work scope included modifications to the existing water treatment plant, and the installation of a pump station to direct all process flows to the newly constructed basins. Lastly, the basins required the installation of a new discharge line, including a new NPDES outfall.
“Even after a delayed start that pushed the project into winter, Trans Ash was able to meet the regulatory deadlines of the project. By expediting the earthwork and working cooperatively with us to prioritize the critical path tasks, the project was completed on time and on budget.”
Project Challenges & Solutions
Several items were encountered throughout the project life cycle, creating the following challenges:
- Permitting delays pushed the project into less favorable working months. Trans Ash expedited the earthwork of the first cell to allow for concrete installation throughout the winter. When spring arrived, Trans Ash quickly completed the earthwork on the second cell to allow for the concrete subcontractor to continue work without a shut down.
- A pump station, approximately 20 feet deep, was to be installed between a pond and natural gas plant which would not allow for the slopes to be laid back. Trans Ash partnered with a geotechnical subcontractor to install a sheeting wall. This allowed for the installation to take place in the smaller footprint, while also keeping the excavation stable and prevent water migration from the adjacent pond.
- The project site was covered by multiple, overhead powerlines which crossed the active work area. To mitigate the concern of a powerline strike, all equipment was equipped with SigAlarms, to alert the operator of a powerline in proximity. Physical powerline “goal posts” were also installed at road crossings to indicate to the operator that the machine could contact the powerline. Alternative construction techniques were also used to limit impact to the utilities including the use of Jack and Bore Pipe Installation.
- Over 9,400 linear feet of pipe was to be installed per OSHA standards at depths of up to 20 feet. This required multiple installation techniques including jack and bore, directional drilling, open cut, and utilizing a trench box. All sections of pipe to be installed were analyzed to determine which technique offered the most efficient and safe installation process.
