Concrete Water Footprint Assessment Methodologies

Abstract

Concrete is the single most widely used material in the world and is only surpassed by water in terms of consumption. By 2013, 4 billion tonnes of Portland cement were produced worldwide, enough to produce about 32 billion tonnes of concrete, which represents more than 4.6 tonnes of concrete per person per year. The high water consumption and large amount of wastewater generated in the concrete industry has become a very important environmental issue. Due to the large global use of concrete, it is essential to correctly assess the environmental impacts of this material including impacts related to water consumption. Life cycle perspective is important because it allows identifying and reducing water related potential environmental impacts associated with products. In concrete life cycle assessment, these impacts are not considered mostly because of lack of data. There are several methodologies for water footprint assessment, as The Water Footprint Assessment Tool and the ISO 14046:2014 standard -that is based on life cycle assessment (ISO 14044)-, as well as sustainable reporting guidelines, which include water assessment for organizations. The aim of this paper is to evaluate existing water footprint methodologies based on life-cycle assessment, their concepts and difficulties, and link them to concrete industry. Out of at least eighteen existing water footprint methodologies, it was found that four of them are feasible for cement based materials industry, however there are differences between the definitions and criteria adopted by each methodology.