HR: 1340h
AN: H33E-1695    [Abstracts]
TI: Field Scale Transport of Chromate in Groundwater From Cooling Tower Wastes
AU: * Gladding, S M
EM: sgladding@berkeley.edu
AF: University of California at Berkeley, Department of Civil and Environmental Engineering Davis Hall, Berkeley, CA 94720-1710, United States
AU: Hunt, J R
EM: hunt@ce.berkeley.edu
AF: University of California at Berkeley, Department of Civil and Environmental Engineering Davis Hall, Berkeley, CA 94720-1710, United States
AB: Chromate (Cr(VI)) was used extensively in evaporative cooling systems to prevent corrosion and scale formation. Waters from the cooling systems were discharged to ponds that were intended as evaporation ponds, but there were instances where the wastewaters infiltrated into the soil and released chromate to groundwater. Cooling tower discharges containing chromate also have elevated salt concentrations compared to the ambient groundwater because of the intended evaporative cooling process. Density driven flow and emplacement of contaminated brines should thus be expected. This conceptual model is being evaluated by the analysis of field data at two natural gas compressor facilities in the deserts of southeastern California. These facilities continuously released chromate containing water to unlined evaporation ponds for more than a decade, and subsequent investigations have identified groundwater plumes containing chromate. At one site, extensive remediation over a 15 year period has limited the plume migration but has not reduced groundwater concentrations. At the other site, density-stratified flow is observed. While there are uncertainties in the amounts released, the data available at these sites suggest that remedial approaches based on groundwater extraction are not effective in removing the source of chromate contamination from emplaced pockets of highly concentrated cooling tower discharge. Long term data sets collected during site investigations and remediation are valuable sources of data on field scale transport of highly mobile contaminants such as chromate.
DE: 1832 Groundwater transport
DE: 1839 Hydrologic scaling
SC: Hydrology [H]
MN: 2007 Fall Meeting