Implementation of the water footprint as a water performance indicator in industrial manufacturing units located in Greece: challenges and prospects

Abstract

Global water resources are under great pressure, so sustainable water and wastewater management is essential for every industrial unit. The water footprint (WF) is a multidimensional indicator of volumetric water use and pollution and is applied throughout the production cycle from the supply chain to the end user. The state-of-the art method of calculating the direct (operational) WF requires detailed records of water consumption and wastewater production per process, that are usually not available. In order to effectively implement the indicator, modifications to the standard calculation method are usually necessary, to meet the requirements and characteristics of each production unit. The present study focuses in three production units in Greece (i.e., cement, brewery, and natural cosmetics) and analyzes the modifications and assumptions required for the operational WF assessment, calculated for each production process where possible and for the whole unit. The WF assessment performed for the three case studies showed that both water consumption rates and operational WFs are within the lowest values (4.7 hL water/hL beer for brewery case study and 0.155 L/kg cement for cement case study) of the ranges reported in the international literature (4-8.8 hL water/hL beer and 0.14-0.413 L/kg cement). The total operational WF of the brewery after applying mass balances was calculated at 23.8 hL water/hL beer with virtual grey WF contributing at 79.7% and blue WF at 20.3%. For the cement manufacturing unit, using estimations from the plant operators and data from international literature, the total operational WF of the plant was assessed at 0.159 L/kg cement with blue WF contributing at 95.8%, green WF at 1%, and virtual grey WF at 3.2%. For the natural cosmetics unit, after modifying the system boundaries properly, the total operational WF was assessed at 81.6 L/kg bulk with virtual grey WF contributing at 88.8%. Through WF assessment, strategic actions could be identified to reduce water consumption and a benchmark could be provided to assess water performance between companies of the same branch.

Keywords: Brewery; Cement production; Cosmetics; Sustainable water management; Water footprint.