Data analytics methodology for monitoring quality sensors and events in the Barcelona drinking water network D. García, R. Creus, M. Minoves, X. Pardo, J. Quevedo and V. Puig ABSTRACT Water quality management is a key area to guarantee drinking water safety to users. This task is based on disinfection techniques, such as chlorination, applied to the drinking water network to prevent the growth of microorganisms present in the water. The continuous monitoring of water quality parameters is fundamental to assess the sanitary conditions of the drinking water and to detect unexpected events. The whole process is based on the assumption that the information retrieved from quality sensors is totally reliable, but due to the complexity of the calibration and maintenance of these chemical sensors, several factors affect the accuracy of the raw data collected. Consequently, any decision might be based on a non-solid base. Therefore, this work presents a data analytics monitoring methodology based on temporal and spatial models to discover if a sensor is detecting a real change in water quality parameters or is actually providing inconsistent information due to some malfunction. The methodology presented anticipated by 12.4 days, on average, the detection of a sensor problem before the fault was reported by the water utilities expert using knowledge accumulated with visual analysis. The proposed methodology has been satisfactorily tested on the Barcelona drinking water network. D. García (corresponding author) J. Quevedo V. Puig Supervision, Safety and Automatic Control Research Center (CS2AC), Universitat Politècnica de Catalunya (UPC), Terrassa Campus, Gaia Research Bldg., Rambla Sant Nebridi, 22, 08222 Terrassa, Barcelona, Spain E-mail: diego.garcia@upc.edu R. Creus M. Minoves X. Pardo Aigües de Barcelona, Empresa Metropolitana de Gestió del Cicle Integral de l’Aigua S.A., Barcelona, Spain Key words | Barcelona drinking water network, critical infrastructure, data-driven approach, fault detection, time series INTRODUCTION One of the main tasks of the water utilities (WU) is to trans- port and supply drinking water to users throughout water distribution systems (WDS). Two of the WU’s main areas of concern are, on the one hand, the operations department, to manage hydraulic infrastructure (e.g., pumping stations, reservoirs, pipes, etc.), and on the other hand, the water quality control department, to manage drinking water safety. Furthermore, different legal frameworks regulate the quality of drinking water supplied. Water quality monitoring and control management pro- grammes involve several tasks. As detailed in Bartram & Ballance (), such tasks are monitoring network design (e.g., which parameters have to be measured, how often, etc.), laboratory work (e.g., chemical analysis, laboratory tests, etc.) and analytical quality assurance (e.g., production of reliable data), among other elements. There are several techniques to treat the water in WDS and keep it healthy for human consumption. One common disinfection technique is the chlorination of water. This process consists of injecting chlorine or derivatives in the water. The injected chlorine is consumed (i.e., by chemical reaction) in the WDS due to two main factors (Powell et al. ): on the one hand, due to reactions in the bulk water as, for example, by the presence of organic content in the water, by decay of the initial chlorine concentration because of the physical conditions (e.g., temperature); on 123 © IWA Publishing 2017 Journal of Hydroinformatics | 19.1 | 2017 doi: 10.2166/hydro.2016.048 Downloaded from http://iwaponline.com/jh/article-pdf/19/1/123/1107562/jh0190123.pdf by guest on 16 September 2022