Denitritation of a high-strength nitrite wastewater in a sequencing batch reactor using different organic carbon sources

The use of different carbon sources (ethanol, acid-fermented primary sludge centrate, acid-fermented secondary sludge centrate, glycerol and landfill leachate) in heterotrophic denitrification from nitrite (denitritation) was studied in a sequencing batch reactor, operated without pH control. Complete denitritation of a high-strength nitrite wastewater was achieved using these organic carbon sources with the exception of fermented secondary sludge centrate. Loading rates around 0.2gNL -1d -1 were obtained for glycerol, landfill leachate and ethanol after a short start-up period of 20 days. The maximum specific nitrite removal rate of 0.25gNg -1VSSd -1 was achieved for glycerol, while values between 0.13 and 0.17gNg -1VSSd -1 were obtained using ethanol, landfill leachate and fermented primary sludge centrate. The COD/N ratio consumed varied between 3.0 for ethanol and 8.8 for landfill leachate. The denitritation rates and the required COD/N ratio for each carbon source are reported for the first time - they can be used for the scale-up of the denitritation process. © 2011 Elsevier B.V.