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Comparing Carbon Substrates for Denitrification of Subsurface Drainage Water
Author(s) -
Greenan Colin M.,
Moorman Thomas B.,
Kaspar Thomas C.,
Parkin Timothy B.,
Jaynes Dan B.
Publication year - 2006
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/jeq2005.0247
Subject(s) - denitrification , nitrate , chemistry , environmental chemistry , cardboard , woodchips , pulp and paper industry , carbon fibers , nitrogen , environmental science , waste management , materials science , organic chemistry , engineering , composite number , composite material
Nitrate in water from tile drained corn ( Zea mays L.) and soybean [ Glycine max (L.) Merr.] fields in the U.S. Midwest contributes to nitrate contamination of surface waters. Denitrification‐based biofilters are a promising strategy for reducing nitrate concentrations, but these systems require an external carbon supply to sustain denitrification. The ability of four organic materials to serve as carbon substrates for denitrification biofilters was evaluated in this laboratory study. Wood chips, wood chips amended with soybean oil, cornstalks, and cardboard fibers were mixed with subsoil (oxidized till) and incubated anaerobically for 180 d. Periodically, 15 NO 3 –N was added to maintain nitrate N concentrations between 10 and 100 mg L −1 All of the materials stimulated NO 3 –N removal and the degree of removal from highest to lowest was: cornstalks, cardboard fibers, wood chips with oil, and wood chips alone. Analysis of 15 N showed that immobilization and dissimilatory nitrate reduction to ammonium accounted for <4% of NO 3 –N removal in all treatments, therefore denitrification was the dominant NO 3 –N removal process. Cardboard fibers, wood chips and oil, and wood chips alone did not support as much denitrification as cornstalks, but their rates of NO 3 –N removal were steady and would probably continue longer than cornstalks. The addition of soybean oil to wood chips significantly increased denitrification over wood chips alone.