Verdantas (formerly Project Navigator, Ltd.) was the general environmental contractor for the Cox Road Landfill remediation in Dayton, Texas. Cox Road Landfill is an 80-acre industrial solid waste landfill impacted by hydrocarbons, metals, pesticides, and other organic products. Verdantas was the general environmental contractor from project inception in 2004 through Remedial Action completion in 2011. As such, Verdantas staff performed the site investigation work, data analysis, and submission of Affected Property Assessment Report (APAR) and Response Action Plan (RAP) to the Texas Commission on Environmental Quality. The site was initially identified as a State Superfund site and was negotiated into the TCEQ VCP program utilizing the Texas Risk Reduction Program (TRRP) for investigation, remediation and closure. Verdantas currently performs and manages annual monitoring, O&M site activities and prepares/submits an annual Post Response Action Care Report (PRACR) to the TCEQ. 

The final remedy for the site consisted of a site-wide, fully vegetated clay and soil cover. Verdantas also negotiated a reduced groundwater monitoring program during the early post-closure phase, leading to complete elimination of groundwater monitoring 3 years post closure. 

Technical Milestones 

• Extensive borehole and soil sample investigation 
• 50-hole CPT and proof-roll geotechnical assessment 
• Cap and cover 80-acre landfill with 2' cover 
• Geosynthetic fabric placement on 40 acres below soil cover for increased cover stability 
• Groundwater monitoring reduced from 30 to 7 wells, then eliminated GW monitoring completely. 
• Site in O&M

Stakeholder Relations 

• Initial strong public interest that diminished through time as remedy completed 
• Public information website established with periodic updates 
• Close coordination with County officials

Key Take-aways 

• 80-Acre Landfill Site (TCEQ VCP, TRRP) 
• Negotiated form State Superfund into TCEQ VCP 
• Verdantas operated as General Contractor from RI through RA 
• Procured borrow source from adjacent landowner 
• Soil cover and Containment Remedy