Evaluation of the Water-Energy nexus in the treatment of urban drinking water in Chile through exergy and environmental indicators

This research assessed water-energy nexus (WEN) efficiency in Chile's drinking water treatment plants by integrating the life cycle concept and exergy analysis principles. The cumulative exergy consumption (CExC) attributed to freshwater and the energy required by drinking water facilities during the whole life cycle were determined. Water-related indicators, such as the water stress index (WSI) and blue water footprint (BWF), differentiated by region, were used to highlight the critical role of water resources within the nexus. The CExC depicted significant differences between regions (10-30 MJex/m(3)), depending on the quality of raw water sources, pumping, and drinking water treatment (DWT) configurations. The WSI and the BWF varied spatially across the country due to climatic variability. Regions with a higher WSI (0.4-1) also implied higher CExC. This pattern can be justified by low water availability and poor water quality, which, at the same time, implied more energy-intensive technologies. Improving water and energy efficiency were identified as critical strategies for reducing the water and energy demand in the urban DWT systems.

Automated summary

This study assessed the water-energy nexus efficiency in Chile's drinking water treatment plants by integrating life cycle concept and exergy analysis principles. Significant differences were found between regions depending on the quality of raw water sources, pumping, and drinking water treatment configurations. Regions in Chile with higher water stress and poor water quality also implied higher energy consumption.