Sequoia was awarded the contract to excavate two existing wastewater settling ponds and haul the impacted material to an offsite landfill and collecting all industrial process and stormwaters from the site and directing them to the new ponds. Once the area was certified as ‘clean closed’ by the State of South Carolina, Sequoia began the construction of three new lined ponds in the same footprint. The new ponds total 3 acres and feature a compacted soil liner overlain by geomembrane and concrete lining systems. The system will support future coal ash basin and landfill excavation on the site.
Sequoia removed 14,000 cubic yards of impacted soil material and hauled them 60 miles to a captive industrial landfill operated by the Owner. Once the ponds were cleaned, over 25,000 cubic yards of new soils were imported, and 135,000 square feet of lined basins were constructed in the existing ponds footprint. In addition, over 1,600 of gravity storm sewer as installed around the power generating facility which crossed railroad rights of way in three places. Over 200 feet of force main piping and 2 cast in place and 20 precast concrete structures were installed to monitor and treat plant process water discharges. The new treatment system was integrated into existing plant power supplies and the control room for visibility of the treatment process.