Use of the Life Cycle Approach for the Evaluation of Industrial Water Management Alternatives
Authors: Boeira J. S. , Boulay A. M. , Jacob M. , Dardor D. , Pedenaud P. , Margni M. 
Published: March 2024

In a context of more and more stress on the water resource, the industries are pushed to improve their water efficiency. Water management must reconcile legal requirements with technical and environmental performances to ensure that one does not compromise the other. Therefore, a fundamental question arises: What are the environmental impacts associated with different industrial water management alternatives? To address this inquiry, this research conducts a case study, analyzing different water management alternatives using a Life Cycle Analysis approach.

A Combined Cycle Power Plant was chosen due to its simplicity and significance in terms of water use. The scenarios compared are based on the functional unit "managing water necessary to produce 1 MWh of electricity". Only water treatment associated structure, energy and chemicals to fulfill the defined functional unit were considered. Three distinct water recovery systems were analyzed and subsequently combined with different water supply and release options. Zero-recovery scenario, representing base case; partial recovery scenario through reverse osmosis, and total recovery scenario under Zero Liquid Discharge, in which thermo-distillation is applied. Furthermore, all scenarios were virtually reassigned to another water-scarce context for a more comprehensive geographical sensitivity analysis.

In this research a Life Cycle Analysis was performed. Results are presented as carbon footprint (in CO2-eq) and water footprint (in m3 world-eq using AWARE) as mid-point indicators. A damage assessment has also been conducted to evaluate the relative contribution of global warming potential and water scarcity relative on Human Health and Ecosystem Quality Areas of Protection, among the contribution of all other midpoint impact categories.

Withdrawn and released water volumes decrease with higher recovery rates while water consumption remains unaltered. Thus, the water footprint, based on freshwater consumption, substantially changes with different recovery rates only if non-freshwater resource is involved. CO2-equivalent emissions are caused mainly due to natural gas burned to produce the required electricity. Human health impacts are primarily dominated by global warming potential in non-water-scarce or highly developed countries. In this aspect, lower energy intensive water treatment routes should be prioritized over freshwater savings. However, the water scarcity footprint impacts dominate human health impacts for scarce and less developed countries. Thus, freshwater savings become important in those cases. Ecosystem quality exhibits lower geographical variation compared to human health impacts, and the differences between scenarios are dominated by global warming potential variation.

Recycling does not necessarily lead to lower water scarcity footprints and can result in higher greenhouse gas emissions. It is crucial to consider the water scarcity context and trade-offs before making decisions about water management. Legislation based solely on water withdrawal and release volumes may lead to undesirable environmental impacts, beyond not ensuring water savings. Nevertheless, when debating water management options, the present work aims to facilitate informed decision-making regarding potential environmental impacts.