Role of anaerobic ammonium oxidation (anammox) in nitrogen removal from a freshwater aquifer

Environmental Science & Technology
By: , and 

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Abstract

Anaerobic ammonium oxidation (anammox) couples the oxidation of ammonium with the reduction of nitrite, producing N2. The presence and activity of anammox bacteria in groundwater were investigated at multiple locations in an aquifer variably affected by a large, wastewater-derived contaminant plume. Anammox bacteria were detected at all locations tested using 16S rRNA gene sequencing and quantification of hydrazine oxidoreductase (hzo) gene transcripts. Anammox and denitrification activities were quantified by in situ 15NO2tracer tests along anoxic flow paths in areas of varying ammonium, nitrate, and organic carbon abundances. Rates of denitrification and anammox were determined by quantifying changes in 28N229N230N215NO315NO2, and 15NH4+ with groundwater travel time. Anammox was present and active in all areas tested, including where ammonium and dissolved organic carbon concentrations were low, but decreased in proportion to denitrification when acetate was added to increase available electron supply. Anammox contributed 39–90% of potential N2 production in this aquifer, with rates on the order of 10 nmol N2–N L–1 day–1. Although rates of both anammox and denitrification during the tracer tests were low, they were sufficient to reduce inorganic nitrogen concentrations substantially during the overall groundwater residence times in the aquifer. These results demonstrate that anammox activity in groundwater can rival that of denitrification and may need to be considered when assessing nitrogen mass transport and permanent loss of fixed nitrogen in aquifers.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Role of anaerobic ammonium oxidation (anammox) in nitrogen removal from a freshwater aquifer
Series title Environmental Science & Technology
DOI 10.1021/acs.est.5b02488
Volume 49
Issue 20
Year Published 2015
Language English
Publisher American Chemical Society
Publisher location Easton, PA
Contributing office(s) Toxic Substances Hydrology Program, National Research Program - Central Branch
Description 9 p.
First page 12169
Last page 12177
Online Only (Y/N) N
Additional Online Files (Y/N) N
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