Closure of Wastewater Treatment Plant

URS Corporation Closure of Wastewater Treatment
Laurel, MS

SEMS, Inc. was contracted by URS to close the existing wastewater treatment plant and facilities located at the Masonite Corporation facility in Laurel.  The facilities that were closed included:

• • Wastewater treatment plant settling basin (T-4)
  • Wastewater treatment plant aeration basins
  • Water Reclamation Equipment Area
  • T-12 and T-13 Clarifiers
  • Bio Solids Basins
  • Masonex Basin
  • Former Solid Waste Area (Pond 5)

The closure consisted of solidifying 20,000 cubic yards of material and establishing a cover system.  The material was consolidated within the basin on the south end, and a final cover system was constructed consisting of a clay barrier layer and an erosion control layer.  The barrier layer was constructed of 24 inches of compacted clay with a permeability no greater than 1×10 minus 7 cm/sec.  The clay was placed in loose lifts not exceeding 8-inches and compacted using the appropriate equipment.  The barrier layer was constructed of a CL or CH material.   The barrier layer was compacted to a minimum of 95% of the Standard Proctor maximum dry density at moisture contents of 1-7% above optimum moisture. The erosion control layer was constructed of soil that naturally or by amendment was capable of sustaining vegetative growth. The final cover system was graded to a minimum slope of 4% and erosion control measures were implemented on the slopes. All water was removed from demolition areas and pumped onsite for water treatment.  Catwalks, piping, pumps, aerators, control panels, and other appurtenances were removed, salvaged, recycled, or disposed of properly.  The aeration basins, bio solids basins, and clarifiers were all above grade structures with earthen levees surrounding them.  The concrete walls of the basins were pushed inward and stacked on the bottom.  The earthen levees were used as fill material and were pushed in to grade along with approximately 6,000 yards of on-site fill material.  SEMS utilized a hydraulic shear mounted on an excavator to perform the demolition activities. SEMS cleared and grubbed the former solid waste area that comprised an area of approximately eight (8) acres.  The area was shaped and graded to drain.  Two feet of fill material was placed on the former solid waste area from off-site borrow pit.  Upon completion the area was seeded and mulched for erosion control.