Yuma Proving Ground (YPG), Yuma, AZ
GCA was subcontracted to remove and dispose of approximately 5,300 cy or 7,500 tons dry non-hazardous sewage sludge from Pond #1 at YPG. GCE provided a backhoe with a wide bucket or Gannon for the final clean-up of the pond floor and the access ramp into the pond. There was approximately 3” - 5” of existing dried sludge at the Sewage Lagoon that measured approximately 1015 feet by x 570 feet. GCE had to avoid the protective sand layer that protects the liner. The removal of the dried sludge from bottom of the cell was done carefully, ensuring only sludge is removed and liner is not damaged. GCE used aggregate base course (ABC) and native materials to construct an access ramp into the pond using a front-end loader to load trucks on top-side of the pond.
GCE also removed materials in the fermentation pit within Lagoon #1, being cautious to protect the existing soil cement and liner on the slopes. The fermentation material was mixed with pond floor materials for removal and disposal. The facility is authorized by the Arizona Department of Environmental Quality (ADEQ) under an Aquifer Protection Permit (APP) to treat mostly domestic wastewater with minor input of brine water from the water treatment plant and wash racks attached to oil water separators. Per the APP permit, the sludge removed from the ponds had to be disposed at a state-approved landfill in accordance with state and federal waste disposal rules and regulations.