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Reduction of Nitrate in Aquifer Microcosms by Carbon Additions
Author(s) -
Obenhuber Donald C.,
Lowrance Richard
Publication year - 1991
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1991.00472425002000010041x
Subject(s) - microcosm , aquifer , nitrate , denitrification , environmental chemistry , groundwater , chemistry , dissolved organic carbon , total organic carbon , chloride , environmental remediation , nitrogen , environmental science , contamination , ecology , geology , biology , geotechnical engineering , organic chemistry
Aquifer microcosms were used to examine the effects of NO − 3 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 N 2 O 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 N 2 O production within the aquifer. Microcosms are useful tools to examine biological transformations of chemical contaminants in unconsolidated aquifer material. The remediation of NO − 3 contaminated aquifers by organic infusion is possible and appears to be a function of microbial denitrification.