MODELING RESPIRATION RATE AND NITRATE REMOVAL IN A NITRIFYING-DENITRIFYING SBR TREATING DOMESTIC WASTE-WATER

This investigation aimed to present a mathematical model for the behav iour of respiration rate and nitrate removal in an activated sludge se quencing batch reactor (SBR) with nitrification, denitrification and c arbon oxidation. This model is based on the response of respiration ra te (r) measured during nitrification and carbon oxidation and the nitr ate removal rate during the post-denitrification period. For model val idation, an SBR pilot plant (1 m(3)) receiving domestic wastewater was operated for three months, and the results were compared with the mod el. The respiration rate was used to calibrate several parameters of t he model. The simulation values matched well with the measured respira tion rate and nitrate removal. The model was able to predict respirati on rate and denitrification in one cycle with parameters taken from th e previous cycle. Parameter changes were followed during long-term ope ration, and significant variations were observed that were too complex to be predicted. It can be concluded that r is a good parameter for o n-line monitoring of an activated sludge SBR with nitrification-denitr ification processes. (C) 1998 Elsevier Science Ltd. All rights reserve d.