Surrogate modeling for water reuse planning in complex water systems

Integrated management of water reuse technologies and coordinated operations with other water system components is fundamental to fully exploiting reuse potential. Yet, these technologies are primarily designed considering their individual efficiency more than possible synergies with traditional water management practices. In this paper, we introduce a general-purpose framework that couples physical and surrogate modelling with optimal control methods to support policy-makers in selecting robust and efficient water planning portfolios, integrating traditional water management strategies and water loops. The framework is developed for the case study of the Apulia Region, Southern Italy, characterised by the presence of a complex water distribution network and multiple conflicting users across irrigation districts, industry, and urban water supply. In addition, the Apulia system shares strategic reservoirs in a drought-prone area. Numerical computations, here performed for the historical period 2010-2019, can be directly applied to consider future climatic scenarios (i.e., modification in precipitation and temperature patterns), socio-economic changes (i.e., variation in the water demand), and technological innovation (i.e., different water reuse strategies). This work represents a first step towards enabling a circular water economy by integrating water management and treatment-reuse technologies.