A method to estimate denitrification potential for predenitrification systems using NUR batch test

Nitrate utilisation rate (NUR) batch tests with wastewater and acetate as c arbon sources were carried out. A pulse dosage of wastewater to activated s ludge in anoxic conditions enables to distinguish the denitrification rates on subsequent wastewater fractions and to determine the concentrations of readily (Ss) and slowly biodegradable COD (Xs). The anoxic substrate utilis ation rates of Ss and X-S under anoxic conditions can be calculated. Using mentioned parameters the overall denitrification rate can be modelled as a function of the anoxic sludge loading rare in the predenitrification volume . The denitrification potential of the wastewater, defined as the amount of nitrate which can be reduced with the biodegradable GOD-fractions in the i nfluent and endogenous denitrification potential allow to calculate the den itrification potential of the treatment plant and to predict the nitrate ef fluent quality. If the denitrification potential of the plant is not suffic ient the addition of an external carbon sourer has to be considered to enha nce the denitrification. In this study, batch NUR tests with acetate were c arried out to extract process kinetics, The relation between the obtainable denitrification rate and the anoxic sludge loading rate san be used to des ign the rate of dosage of acetate and can be a base for developing control strategies. In ail denitrification NUR batch tests a precaution should be t aken concerning accumulation of nitrite and biological phosphorus removal a ctivity. The possible transfer of the results to full-scale treatment plant s is discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.