Denitrification by Anaerobic Sludge in Piggery Wastewater
- 1 March 1996
- journal article
- research article
- Published by Taylor & Francis in Environmental Technology
- Vol. 17 (3) , 293-300
- https://doi.org/10.1080/09593331708616387
Abstract
Piggery wastewater contains high organic carbon and nitrogen concentrations. These compounds can be removed by anaerobic digestion associated with biological nitrification-denitrification. Anaerobic digestion and denitrification can be carried out in the same reactor. Dissimilatory nitrate or nitrite reduction by anaerobic sludge in swine wastewater was studied in flasks with different available carbon/ nitric or nitrous nitrogen ratios. In all cases, the nitrate reduction pathway was denitrification, no ammonium appeared in the media. When the TOC/NO3-N ratio was lower than 1.56, nitrate reduction was not completed. When the ratio was between 1.56 and 2.38, nitrate was totally reduced but there was nitrous oxide in the gas produced. Finally, when the TOC/NO3-N ratio was higher than 2.38 and up to 18.04, nitrate was completely reduced to molecular nitrogen. Nitrite reduction was studied at initial TOC/NO3-N ratios of 6.24, 3.34 and 1.57; in all cases, nitrite was completely reduced to molecular nitrogen.Keywords
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