PILOT SCALE TREATMENT OF A WETLAND DRAINAGE CREEK IN QUANTICO, VA
A pilot test was initiated in 2015 at a wetlands drainage creek contaminated with Aroclor 1254/1260 at concentrations up to 5 mg/kg. Initial in situ treatments in 400 sq. m. plots achieved up to 52% reduction in total PCB mass and 78% reduction in porewater concentrations within 13 months. No significant changes were observed in untreated sediment plots.
BIOREMEDIATION OF HIGH LEVELS OF PCBS IN A SLUDGE DIGESTION POND, VA
Pilot tests to determine the efficacy of bioaugmentation have been ongoing since 2012 at a 6 acre emergency overflow pond containing Aroclor 1248 at concentrations up to 2400 mg/kg. Initial in situ tests in 2.8 sq. ft. caissons showed 275 mg/kg (80%) reduction of PCBs in the top 6 inches and 569 mg/kg (42%) reduction of PCBs in the denser bottom 6 inches 519 days after treatment. A Phase II pilot test begun using 80 sq. ft. caissons with bioamendment mixed into top and bottom sediments with a sump pump. to ensure distribution of the bioamendment throughout the sediment column. Total PCB mass decreased by 77% (1031 to 240 mg/kg) in 50 months. Caissons not treated with bioamendment showed initial PCB degradation of 40% possibly due to aeration and stimulation of indigenous PCB degrading microbes but further degradation was not observed after 12 months.
LANDFILL ON KURE ATOLL, HI
The goal of the treatment was to reduce potential PCB exposure from a scrap metal dump contaminated with Aroclor 1260 to marine life in the vicinity of Green Island in the Kure Atoll. Due to the very remote location this contaminated material was transferred to a lined landfill on the island and treated by in-situ bioremediation. Total PCB mass was reduced by 48% (1.8 to 0.9 mg/kg) after 32 months.
RIVER SEDIMENTS IN SOUTHEAST MICHIGAN SUPERFUND SITE
Aroclor 1248 was discharged in industrial wastewater into a river and nearby wetlands until the late 1970s and the site was placed on the National Priorities List (NPL; aka Superfund) in 1983. Treatability studies conducted in 2 L sediment mesocosms from two sites in the river demonstrated that treatment with bioaugmented AC reduced PCB mass 78 % in 180 days. Bioaugmentation also reduced bioavailable PCB levels by 90 and 93% in sediments from the two sites tested.
A STREET CHANNEL, WILMINGTON DE
For this Delaware Department of Natural Resources & Environmental Control sponsored project a tidal wetlands channel contaminated with PCBs was treated with bioamended GAC to reduce the potential for contamination of the Christiana River. Approximately 6.5MT of bioaugmented SediMite was applied with a modified venturi air mover. Treatment effectiveness is being monitored in sediment cores and by passive sampling. For more info: https://www.facebook.com/rembacenvironmental/videos/477699982996365/?modal=admin_todo_tour
FORMER INDUSTRIAL COOLING POND, ANNE ARUNDEL CO., MD
A former cooling pond with a surface area approximately 22,072 ft2 and average water depth between 2 and 4 feet treated with 15 MT bioaugmented SediMite. Primary contaminants were Aroclor 1254 and 1260 at an average concentration of 704 μg/kg. The goal was to reduce the risk of the pond serving as a point source of dissolved PCBs into the Severn River watershed. Total mass of PCBs decreased by 72% (703.8 to 317.6 μg/kg) and dissolved PCBs decreased by 97-99% 15 months after treatment effectively reducing the risk of PCBs from contaminating the downstream watershed.
SMALL BOAT HARBOR, OAHU, HI
Preliminary testing of large-scale deployment of bioamended SediMite was conducted at a marine boat harbor contaminated primarily with Aroclor 1260. 45 MT of bioamended SediMite were deployed over approximately over 1 acre. Results are pending.