Control of carbon and ammonium ratio for simultaneous nitrification and denitrification in a sequencing batch bioreactor

This study shows how the carbon and nitrogen (C/N) ratio controls the simultaneous Occurrence of nitrification and denitrification in a sequencing batch reactor (SBR). Data demonstrated that a low C/N ratio resulted in a rapid carbon deficit, causing an unbalanced simultaneous nitrification-denitrification (SND) process in SBR. When the initial COD/NH4+-N ratio was adjusted to 11.1, the SND-based SBR achieved complete removal of NH4-N and COD without leaving any NO2--N in the effluent. The nitrogen removal efficiency decreases gradually with increasing ammonium-loading rate to the SND-SBR system. Altogether, data showed that appropriate controls of carbon and nitrogen input are required to achieve an efficient SND-SBR. An established SND technology can save operation time and energy, and might replace the traditional two-stage biological nitrification and denitrification process. (c) 2006 Elsevier Ltd. All rights reserved.