Client: Naval Facilities Engineering Command
Location: 29 Palms, California
Completion Year: 1998
Scope of Work:
- Treatability study
- Soil remediation (washing)
Three ranges at the small arms range complex at Marine Corps Air Ground Combat Center (MCAGCC) had been in active use for over 30 years for rifle and pistol training. The Navy’s desire to redesign the ranges required that soils from the ranges be treated prior to reuse. In the redesign, impacted berm soils required processing to reduce the lead concentrations below a health risk level that was determined using the LeadSpread model.
Working as a first-tier subcontractor to Battelle Memorial Institute and the Naval Facilities Engineering Service Centers, Brice provided turnkey soil treatment services from initial sample collection and treatability testing through soil processing, including process equipment, engineering personnel, onsite laborers and operators, and heavy equipment for feeding and stockpiling material.
Brice conducted treatability testing in our minerals processing lab in Fairbanks, Alaska. The study indicated the contaminants could be isolated in a small fraction of the total range soil, enabling effective removal using density separation techniques borrowed from the mining industry, while increasing plant throughput. Once we completed treatability testing, the appropriate soil washing components were configured to provide a site-specific system to treat the range soil and meet the site’s risk-based cleanup requirements.
Equipment mobilization and plant erection were delayed until June due to ongoing live-fire operations at the range. This delay pushed site operations into the summer months. With the site in the heart of the Mojave Desert, temperatures regularly exceeded 120° F. Brice overcame this through shift adjustment to use pre-dawn hours, as wells as engineered controls, shade structures and evaporative cooling systems, to reduce temperatures at operator work stations during daylight hours.
Soil processing commenced in early July to identify performance and production limiting unit operations. During initial processing operations, it was discovered that organic matter and fine sand volumes in site soils exceeded those of the samples tested in the treatability study, and hindered initial field operations and productivity.
Within three days, Brice located, procured, shipped and integrated into the system additional humates screens and a larger sand classifier to deal with these unforeseen soil conditions. These “on-the-fly” changes not only resulted in the soil meeting reuse criteria but increased throughout by 30%, allowing Brice to make up the initial lost time and complete the project two weeks ahead of schedule, despite a 10% increase in the volume of soil to be treated.
In all, 12,000 tons of soil was treated. Daily analytical results from stockpiles of treated soil showed process consistency and positive correlation to results obtained during the treatability study. All soil processed met re-use criteria without any re-runs and was subsequently used as part of the replacement bullet trap installation. Treated soil analyses showed that the plant performed as expected and correlated with results predicted in the laboratory. Daily production averaged 220 to 275 tons over a nine-hour processing time.
This adaptation of existing technologies to meet site-specific risk-based cleanup requirements resulted in a no-net-waste approach that met both aggressive schedule requirements and was less expensive than traditional stabilization/disposal methods. Since the particulate contaminants were physically removed and recycled, the long-term liability associated with stabilization/disposal options was also eliminated.
Upon project completion, plant process water was treated onsite and discharged locally.