INTERACTION BETWEEN COMPUTER SIMULATIONS AND CONTROL USING ON-LINE NITROGEN MEASUREMENTS

Mathematical models are a useful tool to help in the prediction of results of operation changes in activated sludge plants. Some calibration of the models is usually necessary, but there is often a lack of data describing the influent wastewater sufficiently. Combining the modelling with continuous measurements of ammonia and nitrate gives a good basis of data in connection with biological nitrogen removal. In this study, phased oxygen control is introduced in a recirculation plant and on-line ammonia measurements in the aeration tank are used to estimate the variations in influent load. After the influent is described the calibration of process constants is done using the on-line data. The calibrated model is used to test the effect of varying recirculation and phase lengths. A mobile monitoring station supplied the on-line data of ammonia and nitrate.