On-line estimation of nitrification and denitrification capacity at Avedøre wastewater treatment plant

Abstract

In this paper, on-line nitrification and denitrification rate estimation in an alternating wastewater treatment plant is discussed. The nitrification/denitrification rates are estimated on-line using continuous measurements of ammonia and nitrate. From the rate estimates, the plant capacity is derived. This information is useful in various ways: for early warning to prevent severe disturbances such as nitrification inhibition; for optimising phase lengths and distribution of the phases in the alternating operation; and directly for the control system of the treatment plant. The estimation is based on the derivatives of the measurement signals combined with a simplified model of nitrogen dynamics of the plant. In the paper, we show examples of a successful application of the estimation methods to full-scale operation of the treatment plant and are today incorporated in the control system