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Reduction of nitrate in aquifer microcosms by carbon additions

January 1, 1991

Aquifer microcosms were used to examine the effects of NO3 and C amendments on groundwater from the Claiborne aquifer. Nitrate concentrations of 12.17 mg L−1 in aquifer microcosms were reduced 0.92%/d to 5.84 mg L−1 by the addition of 10 mg C L−1 for 35 d. Nitrate disappearance correlated with increases in number of denitrifiers and dissolved N2O concentration and decreases in dissolved oxygen, suggesting biological denitrification. Nitrate/chloride ratios decreased in microcosms with 10 mg C L−1 added and then increased when the C addition was removed. Carbon additions of 0.4 mg C L−1 had no effect on the microbial or chemical properties of the microcosms. Nitrous oxide levels in wells sampling the Claiborne aquifer showed an increase with depth, indicating N2O production within the aquifer. Microcosms are useful tools to examine biological transformations of chemical contaminants in unconsolidated aquifer material. The remediation of NO3 contaminated aquifers by organic infusion is possible and appears to be a function of microbial denitrification.

Publication Year 1991
Title Reduction of nitrate in aquifer microcosms by carbon additions
DOI 10.2134/jeq1991.00472425002000010041x
Authors Donald C. Obenhuber, Richard Lowrance
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Environmental Quality
Index ID 70185495
Record Source USGS Publications Warehouse
USGS Organization Toxic Substances Hydrology Program