NC0085979_Site Summary_20100105

NORTH CAROLINA DEPARTMENT OF TRANSPORTATION
ROSMAN MAINTENANCE FACILITY
100 OLD CALVERT LANDFILL ROAD
BREYARD,NC 28716
TRANSYLVANIA COUNTY
Site Summary
In 1992, chloride contamination in groundwater was discovered at the site because of a nearby
residential supply well was found to be contaminated. The site is located about 1 mile east of the
town of Rosman and is shown on the enclosed map. The source of the chloride was the stockpile
of road salt used for de-icing roads. A comprehensive site assessment determined the limits of
contamination in excess of the 2L Standards,both onsite and offsite.
Aquaterra installed a pumping system at this site in early 1998 that discharges effluent directly
into the French Broad River about a mile away. The system consisted of three recovery wells,
pump controllers, flow meters, and a discharge line (1 outfall). For the first few years, the
effluent concentration averaged about 3,000 ppm and the flow rate averaged 0.007 MGD. Then
the chloride concentration in the effluent slowly increased to over 4000 ppm, the point where the
toxicity tests failed. The system was then turned off in May 2004. In April 2008, the pumping
system was modified by adding a fourth pumping well with lower chloride concentrations and a
mixing tank to blend water from all 4 wells. Since then the toxicity tests have passed and the
chloride levels have been much lower.
In the last 12 months, the effluent concentration of chloride has averaged 1140 ppm and the flow
rate has averaged 0.010 MGD. An effluent sample collected January 5, 2010 was analyzed by
Prism Laboratories by EPA Methods 624, 625, and 300.0 (chlorides). No listed compounds were
detected on the 624 and 625 analyses. The Method 300.0 analysis shows 960 ppm of chlorides.
There is no sludge produced from this system.
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