BACKGROUND: In recent years water scarcity has become more prominent, increasing the need for new practices in terms of efficient water management. Reuse and valorization of water from wastewater treatment plants (WWTPs) can help solve the problem. RESULTS: The traditional denitrification/nitrification scheme followed by a natural disinfection/storage tank has been studied in order to optimize the process for irrigation reuse. The study is based on data produced by an experimental pilot-scale plant, located in Trebbo di Reno (BO, Italy) and from a recent field campaign carried out on internal fresh water of the Allacciamento Channel inside the basin of Porto Canale Cesenatico (FC, Italy). Using WEST software to model the first phase and a dispersed flow equation to model the Escherichia coli (E. coli) removal rate in the following basin, the overall process has been optimized to test the capacity of a Business Process Management (BPM) approach to model the water storage management for irrigation reuse. CONCLUSIONS: High pollutants removal efficiencies and a water storage system able to fulfill the irrigation needs are two essential requirements for water reuse. The study shows how to achieve those aims using a combined system with a natural disinfection basin analyzing the hydraulic parameters effects on pollutants removal throughout the water column. Moreover, the management optimization of the process has been studied suggesting different management policies for different scenarios. (C) 2016 Society of Chemical Industry.