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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 #272304
Title: Denitrification enzyme activity in swine wastewater effluent of a nitrification/denitrification treatment system

Author
item Hunt, Patrick
item MATHENY, TERRY - Retired ARS Employee
item Vanotti, Matias
item Stone, Kenneth - Ken
item Szogi, Ariel

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2011
Publication Date: 1/15/2012
Citation: Hunt, P.G., Matheny, T.A., Vanotti, M.B., Stone, K.C., Szogi, A.A. 2012. Denitrification enzyme activity in swine wastewater effluent of a nitrification/denitrification treatment system. Transactions of the ASABE. 55(1):159-165.

Interpretive Summary: Intensification of swine production in the USA and around the world requires advanced manure management. For swine manure management in the state of North Carolina, one system met all of the required advanced management criteria, and it was qualified as a superior technology. As part of the testing for this superior technology, this investigation of denitrification was conducted. It specifically addressed the denitrification enzyme activity (DEA) in the treatment system’s homogenization tank and the denitrification tank. Wastewater in the homogenization tank was fresh-flushed directly from the swine houses. Consequently, it was more concentrated than wastewaters in either the denitrification tank or typical swine wastewater lagoons. The DEA in the homogenization tank was significantly limited by the low nitrate nitrogen. Conversely, the DEA of the denitrification tank was limited by its lower level of soluble carbon. When non-limiting carbon and nitrate were added to the wastewaters of the homogenization and denitrification tanks, the homogenization tank had a significantly higher level of DEA. The findings of this investigation document that the DEA within this treated swine wastewater can be altered by manageable constituents of the processed swine wastewater, in particular soluble carbon and oxidized nitrogen.

Technical Abstract: Intensification of swine production in the USA and around the world requires advanced manure management. For swine manure management in the state of North Carolina, one system met all of the required advanced management criteria, and it was qualified as a superior technology. This investigation was part of the testing for this superior technology. The objectives of this investigation were to assess 1) the denitrification enzyme activity (DEA) in the treatment system’s homogenization tank and the denitrification tank and 2) the impact of the wastewater characteristics on this DEA. The DEA was measured by the acetylene inhibition method. Wastewater in the homogenization tank was fresh-flushed directly from the swine houses. Consequently, it was more concentrated than wastewaters in either the denitrification tank or typical swine wastewater lagoons; it had soluble biochemical oxygen demand (sBOD) of 676 mg/L and an electrical conductivity (EC) of 8.9 mS/cm. However, the DEA in the homogenization tank was significantly limited by the low level of NO3-N which was 0.1 mg/L. Conversely, the DEA of the denitrification tank was limited by its lower level of carbon; it had only 53 mg/L sBOD. However, it had a NO3-N concentration of 150 mg/L. When non-limiting glucose-C and NO3-N were added to the wastewaters of the homogenization and denitrification tanks, the homogenization tank had a significantly higher level of DEA; 17,943 vs. 10,055 mg N2O-N m-3/d, respectively. The DEA was generally well correlated by stepwise regression to the measured physiochemical characteristics. The findings of this investigation document that the DEA within this treated swine wastewater can be altered by manageable constituents of the processed swine wastewater, in particular soluble carbon and oxidized nitrogen.