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Analysis of water use impact assessment methods (part B): applicability for water footprinting and decision making with a laundry case study

Boulay, Anne-Marie, Bayart, Jean-Baptiste, Bulle, Cecile, Franceschini, Helen, Motoshita, Masaharu, Muñoz, Ivan, Pfister, Stephan, Margni, Manuele
The international journal of life cycle assessment 2015 v.20 no.6 pp. 865-879
acidification, business enterprises, case studies, computer software, databases, decision making, ecosystems, ecotoxicology, eutrophication, human health, humans, industry, inventories, laundry, life cycle assessment, models, pollution, wastewater treatment, water analysis, water deprivation, water footprint
PURPOSE: The integration of different water impact assessment methods within a water footprinting concept is still ongoing, and a limited number of case studies have been published presenting a comprehensive study of all water-related impacts. Although industries are increasingly interested in assessing their water footprint beyond a simple inventory assessment, they often lack guidance regarding the applicability and interpretation of the different methods available. This paper aims to illustrate how different water-related methods can be applied within a water footprint study of a laundry detergent and discuss their applicability. METHODS: The concept of water footprinting, as defined by the recently published ISO Standard (ISO 2014), is illustrated through the case study of a load of laundry using water availability and water degradation impact categories. At the midpoint, it covers scarcity, availability, and pollution indicators such as eutrophication, acidification, human, and eco-toxicity. At the endpoint, impacts on human health and ecosystems are covered for water deprivation and degradation. Sensitivity analyses are performed on the most sensitive modeling choices identified in part A of this paper. RESULTS AND DISCUSSION: The applicability of the different methodologies and their interpretation within a water footprint concept for decision making is presented. The discussion covers general applicability issues such as inventory flow definition, data availability, regionalization, and inclusion of wastewater treatment systems. Method-specific discussion covers the use of interim ecotoxicity factors, the interaction of scarcity and availability assessments and the limits of such methods, and the geographic coverage and availability of impact assessment methods. Lastly, possible double counting, databases, software, data quality, and integration of a water footprint within a life cycle assessment (LCA) are discussed. CONCLUSIONS: This study has shown that water footprinting as proposed in the ISO standard can be applied to a laundry detergent product but with caveats. The science and the data availability are rapidly evolving, but the results obtained with present methods enable companies to map where in the life cycle and in the world impacts might occur.