Water use performance of water technologies: the Cumulative Water Demand and Water Payback Time indicators

The effective management of fresh water through the use of water technologies is central to international debate. However, available indicators used to measure the performance of water technologies have several limitations: they do not comprehensively assess the quantity and quality of water use; they are not able to measure the benefits of locally recovered resources; and they are not simple to apply in a life-cycle perspective. als of this paper are to develop a set of indicators based on the Cumulative Energy Demand (CED) and Energy Pay-Back Time (EPBT) models used in the energy sector to compare the performances of water-use technologies in different locations and therefore measure their benefits in term of recovered water resources in different contexts. mulative Water Demand (CWD) and Water Pay-Back Time (WPBT) indicators were developed and tested in a case study of a water-collection system produced in Padova (Italy) and installed in Rovigo (Italy). To determine their effectiveness, a simulation of their application to the same technology in different Italian locations was performed. sults confirmed the applicability of the designed set of indicators and the effectiveness of the WPBT in measuring their performance in different contexts. To obtain comprehensive information on the quantity and quality of water used, it is recommended that CWD and WPBT be used together.