Sustainability as the quantitative norm for water desalination impacts

Water desalination continues to evolve exponentially in magnitude and importance to a currently mature stage that, like all large human endeavors, must be planned, designed and operated according to the quantitative holistic sustainability paradigm and criteria that are defined by the interrelated aspects of the environmental, economic and social pillars of the endeavor. This integrates but also transcends the currently separately employed and analyzed methods such as Environmental Impact Assessment (EIA), Life Cycle Analysis (LCA), and Best Available Technology (BAT), for selection, design, economic analysis, social impact analysis, and regulation planning. This paper quantitatively introduces the sustainability paradigm and its application to water desalination. It includes a critical review of the state of sustainability analysis as related to desalination, and proposes a methodology for such evaluation that results in calculation of composite sustainability indices, which is much better as a quantitative measure for the evaluation of desalination processes than the current practice of addressing the economic, environmental, and sometimes social aspects separately without their coherent integration. A method and equations for formulating a composite sustainability index as a function of relevant parameters, which thus allows mathematical analysis in general and sensitivity analysis and optimization in particular, are described.