Estimating nitrate concentration in the post-denitrification unit of a municipal wastewater treatment plant

摘要

Due to stringent environmental regulations, wastewater treatment plants are always challenged to meet new constraints in terms of water pollution prevention. In such an effort, the number of sensors and data available in the plants have increased considerably during the last decades. However, the quality of the collected data and the sensor reliability are often poor mainly due to the hostile environment in which the measurement equipment has to function. In this work, we present the design of an array of soft-sensors to estimate the nitrate concentration in the post-denitrification filter unit of the Viikinmaki wastewater treatment plant in Helsinki (Finland). The developed sensors aim at supporting the existing hardware analysers by providing a reliable back-up system in case of malfunction. After a careful selection of suitable observations and variables to be used for calibrating the estimation models, the experimental results show the accuracy of the developed soft-sensors and their potential for an on-line implementation in the plant's control system.