Why the technology was selected:
This is still a research project

Other technologies used:
The plume was treated with a permeable reactive barrier. The PRB is a continuous reactive wall that varies between 2 and 3 ft wide and is 74 ft long. The wall was constructed by drilling a line of overlapping 3-ft-diameter boreholes which were filled with reactive media up to the water table, and with clean soil to ground surface level. The wall uses two reactive media: 69 tons of granular zero-valent iron mixed with gravel at a 1:2 volume ratio in 33 ft of the wall and 85 tons of iron sponge in 41 ft of the wall ( Iron sponge consists of wood shavings or wood chips impregnated with hydrated iron oxide.

Results to date:
The effluent concentration of PCE from the granular iron section of the wall is 500 µg/L (down from 5,000 µg/L)and 10 µg/L from the iron sponge section of the wall (down from 5,000 µg/L). No vinyl chloride was observed. There are significant changes in the degradation efficiency of the both sections of the PRB. The degradation effiency of the the iron sponge section is still increasing after 4 years of running. The PCE effluent concentration is about 10 µg/l The remediation results of the granular iron sections are decreasing. The effluent PCE-concentration changed from 33 µg/l to 500 µg/l. There are metabolits observered in the effluent (1,2-cis-DCE, TCE). Still no VC is detected. During the research periode the affluent concentration decline form 30,000 to 5,000 µg/l because of running source remeadiation.

Next Steps:
The research and developement project is scheduled to be terminated in March 2004.

Cost to Design and Implement:
$30,000 (design); $93,000 (reactive material and construction)