Life cycle analysis of urban water cycle in two Spanish areas: Inland city and island area

In this paper, the results of the complete life-cycle assessment (LCA) analysis of the water cycle in two Spanish urban areas are presented. First case study was Zaragoza city (700,000 inhabitants), with enough surface water resources for drinking purpose. Second case was the Mancomunidad del Sureste, a highly populated and touristic area in a water-scarce island (Gran Canaria). Main objective of the paper was to show, from an environmental global perspective, which was the relative pollutant weights of the diverse water cycle stages in an urban area, in order to put the efforts in reducing the environmental penalties associated to the water cycle. Results showed that environmental load associated to energy consumed in dwelling uses (to produce hot sanitary water) exceeded by far the environmental impact provoked by water cycle infrastructures (water treatment plants, water supply and drainage networks, and wastewater treatment plants). Additionally, it is very important to remark that new water supply alternatives (seawater desalination plant as well as reclaimed wastewater) studied here were energy intensive solutions, and the environmental charge during its life cycle was also very significant.