Bioremediation of TNT & DNT in Homogenized Soil
DARAMEND® bioremediation technology was applied at pilot scale to approximately 100 tons of soil from the former Raritan Arsenal in Edison, New Jersey. Area 4 at the Raritan Arsenal was formerly used as a high explosives salvage and melt-out area from World War I through the 1920s.
Homogenized soil from the site contained approximately 600 mg/kg of TNT/DNT.
Soil excavated from Area 4 was placed in an Engineered Biotreatment Cell (EBC) constructed in a small building on the former arsenal property. The EBC was built using portable barrier walls overlain with a 40-mil HDPE liner. The liner was protected with an 8-inch layer of sand, and a 2-foot layer of soil from Area 4 was placed on the sand layer. The EBC also included an irrigation system and decontamination pad. Because the pilot was conducted in the winter months, the building was insulated and heated.
The pilot was scheduled to run for about 75 days. After 28 days of treatment, however, TNT concentrations had been reduced to an average of 74 mg/kg and amino-DNT was reduced to 25.9 mg/kg. These levels met the proposed Remedial Goals for the site. After 56 days, the concentration of TNT was reduced to <5 mg/kg and amino-DNT was reduced to <3 mg/kg. Because of rapid rate of treatment, the demonstration ended after only 56 days.
Based on the results of the pilot demonstration, full-scale treatment costs were estimated at $68/ton of soil treated. This estimate assumed that the soil treated during the pilot-demonstration was representative of the entire site and that a total of approximately 5,000 tons of soil would be treated. Estimated treatment costs included all construction costs for the treatment cell, manufacture and delivery of all amendments and turnkey application of the technology to site soil. The estimate excluded excavation, UXO clearance, delivery of the soil to the treatment cell, and confirmatory analytical cost.
Treatment cell construction began on November 8, 1998 and continued through December 2, 1998. Immediately following construction the pilot-demonstration was initiated. Four fourteen (14) day treatment cycles were applied to the soil, and treatment was completed on February 5, 1999. A short break (8 days) was scheduled late in December 1998.