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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #151895
Title: DENITRIFICATION ENZYME ASSAY IN CONSTRUCTED WETLANDS TREATING SWINE WASTEWATER

Author
item Hunt, Patrick
item Matheny, Terry
item REDDY, G. - NC A&T STATE UNIV.
item Poach, Matthew

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/3/2003
Publication Date: 11/3/2003
Citation: HUNT, P.G., MATHENY, T.A., REDDY, G.B., POACH, M.E. DENITRIFICATION ENZYME ASSAY IN CONSTRUCTED WETLANDS TREATING SWINE WASTEWATER. AGRONOMY ABSTRACTS [abstract]. 2003 CDROM.

Interpretive Summary:

Technical Abstract: Constructed wetlands can be very effective in removing nitrogen from swine wastewater via denitrification, under proper conditions. Generally, the limiting factor for denitrification in such wetlands is slow formation of nitrate via nitrification because anaerobic soil conditions are prevalent and ammonia is the major nitrogen component in swine wastewater. Soil aeration and the associated nitrification can be promoted by short interruptions of wastewater application, if the wetland has a sloped bottom. However, if the wetland bottom is flat, the period of interrupted application must be longer, and the period of application shorter. We investigated the impact of a one week drying cycle followed by one, two, or three weeks of wastewater applications vs. continual application. The study was conducted at North Carolina A&T State University on marsh-pond-marsh wetlands with flat bottoms and cattails vegetation. We measured soil redox, nitrogen treatment efficiency, and denitrification enzyme potential. Although soil redox potential values were higher during the drying cycle, the one week interruption of application was insufficient to promote the prevalence of aerated soil conditions, nitrogen removal efficiencies, or denitrification enzyme assay (DEA) values. There were no significant differences in DEA values among continuous or intermittent application treatments. However, there were highly significant increases in DEA values from addition of nitrate.