A unified protocol for sensor calibration and verification in applications of WWTPs and sewer systems monitoring

PREPARED, Enabling Change, is an EU-funded Collaborative Project under the Seventh Framework Programme (FP7). The project aims to gather urban utilities in Europe and worldwide to develop an advanced strategy in meeting the upcoming challenges for water supply and wastewater treatment brought by climate change. This work aims to increase technological capacity and improve performance of traditional water supply and wastewater treatment systems via better use of sensors. For newly developed multivariate sensors, calibration procedures are quite different from manufacturer to manufacturer. Manual operation during calibration and verification is commonly practised in this field due to complexity of the calibration procedure and occurrence of unpredictable events. In addition, many of the sensor manufacturers have not developed detailed instructions for sensor calibration. Therefore, a calibration and verification protocol is needed to guide and unify practice in this area where diversified practice is commonly observed. In this work, a unified protocol for sensor calibration and verification was developed and applied. Two sensor products, an optical sensor and an electronic nose sensor, are discussed as examples for calibration procedures, regression methods and verification methods of calibration in the application of wastewater treatment plant monitoring.