ARS | Publication request: Denitrification and nitrous oxide emissions in riparian buffers

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2008
Publication Date: October 5, 2008
Citation: Hunt, P.G., Matheny, T.A., Ducey, T.F., Ro, K.S., Lowrance, R.R. 2008. Denitrification and nitrous oxide emissions in riparian buffers [abstract]. American Society of Agronomy-Crop Science Society of America-Soil Science Society of America Annual Meeting, November 5-9, Houston, Texas. 2008 CDROM

Technical Abstract: Anaerobic lagoons are typically used for treatment of swine wastewater. Although these anaerobic lagoons were once thought to be relatively simple in their physical, chemical, and biological processes, they are actually very sophisticated. Recent reports of high levels of di-nitrogen emissions and high levels of potential surficial oxygen transfer indicated that large amounts of nitrogen may be removed via denitrification in these anaerobic lagoons. If classical denitrification is occurring in these lagoons, the denitrification enzyme levels should be correspondingly high. Our objective was to quantify denitrification enzyme activity (DEA) in several lagoons. Denitrification enzyme activity was measured on eight commercial swine wastewater lagoons. Wastewater samples were taken at four quadrants of each lagoon from the surface, midway to the bottom, and just above the bottom of the lagoon. Although lagoons have sufficient surficial oxygen transfer to potentially produce precursors for denitrification, there was relatively little DEA or potential DEA measured in these eight commercial lagoons. The oxygen in these commercial lagoons may have been used to oxidize BOD. Also, the oxygen might have been used to form precursors that supported alternate nitrogen removal processes such as ANAMMOX. It is also possible that the denitrification is associated more with the bottom sludge layer. Further research needs to be conducted on DEA, enzyme activation, and microbial communities from lagoons in order to better understand the nitrogen cycling process of swine wastewater lagoons.