A kinetic study of hydrogenotrophic denitrification

The progress of hydrogenotrophic denitrification in batch assays with a mixed culture was examined. The aim was to study the performance of the culture for hydrogenotrophic denitrification of drinking water at various NO3− concentrations. The kinetics of the process were studied in batch experiments. The rates of the process were found to be inhibited at high nitrate concentrations. The nitrite concentration remained at very low values throughout the process but it still affected biomass growth. A kinetic model was developed and its kinetic parameters were determined from the batch experiments. The growth kinetics could be very well described by using expressions for double nutrient limitation (nitrate, nitrite) with inhibition from nitrate. The proposed model is capable of describing accurately enough cellular growth, nitrate and nitrite utilization and utilization rates under anoxic conditions in the presence of various concentrations of nitrate in the range of 7 to about 200 mg N/l.