Client: National Guard Bureau
Location: MMR, Massachusetts
Value: $1 million
Completion Year: 2001
Scope of Work:
- Soil remediation (washing)
The Environmental Protection Agency (EPA) issued an Administrative Order to the National Guard Bureau (NGB) mandating that a series of rapid response actions and remedial measures be implemented to protect the groundwater at the Massachusetts Military Reservation (MMR). The EPA identified six problem locations at MMR where explosives, metals, and pesticides were detected in soils at concentrations calculated to pose a leaching threat to groundwater.
In an earlier MMR project, Brice implemented a water-based physical treatment process for reducing total lead concentrations in approximately 6,000 tons of soil excavated from a rifle and pistol firing range. As part of that system, a water treatment method was implemented for recovering suspended soil fines in the process water. The fines recovery circuit treated an average of 300,000 gallons of water per day over a 14-day period. Based on the successful outcome of this work, Brice was contracted to develop a soil treatment process for mixed-waste soils slated for treatment under the Administrative Order.
Brice developed a project work plan and submitted it to the NGB, EPA, and the State of Massachusetts. Brice subsequently attended public meetings to present preliminary remedial approaches. After acceptance of the initial work plan, Brice conducted a field investigation and collected samples from the site for evaluation at our Fairbanks, Alaska, laboratory. Since several locations were impact areas, unexploded ordnance (UXO) avoidance briefings prior to sample collection were mandatory.
Brice determined the most economical and efficient treatment approach and submitted the findings. Those findings revealed that soils from the six areas included discrete particulate metals and organic matter containing high concentrations of sorbed contaminants, whose removal would result in soils meeting the cleanup goals. The most practical treatment approach was to recover the particulate metals using gold mining technology and recover the contaminated organic matter using flotation and screening technology with a water-based, closed-loop process. In addition, explosive contaminants such as TNT, RDX, HMX and nitroglycerin were found to be soluble in solution, thus water treatment for dissolved contaminants was required as well. Brice engineered the complete treatment process.
After acceptance of the plan, the soil processing plant was constructed on a bermed asphalt pad. The plant included a soil fines recovery process consisting of flocculant mix tanks, dosing pumps and clarifier, as well as a sand filter system and carbon unit for water treatment of the soluble explosives and metals. The treatability studies indicated that Nalco products generated rapid flocculation of the soil fines. Flocculation and rapid soil settling were crucial because over 600 gallons of water per minute (300,000 gallons per day) required fines removal before it could be reused in the closed-loop treatment process. Water treatment for dissolved contaminants was also crucial in that all organic and inorganic contaminants had to be at non-detectable concentrations for free discharge, again being aware that live ordnance was present in the soils and personnel at the site had UXO awareness training.
