Water footprint assessment in an industrial symbiosis system based on environmental, economic, and social sustainability indices

Integrated water resource management requires a comprehensive assessment of all water uses, both direct and indirect, which can be captured by the Water Footprint (WF) concept, especially in Industrial Symbiosis (IS). IS creates links between different industries to reduce resource consumption. This article analyses the environmental, social, and economic sustainability aspects of the WF in an IS system. First, the inventories of these three aspects were carried out simultaneously with the WF inventory. Sustainability indices were presented based on the relative comparison of current WF and sustainably oriented WF (SOWF). SOWF in an IS system is defined as the situation with minimum total WF and is obtained by mathematical programming. The proposed framework was applied to an IS involving three industries in southeastern Iran: steel production, coal concentrate, and power generation. The blue WFs of these industries were calculated as 11.77 m3/ton of steel, 0.87 m3/ton of coal, and 8.31 m3/MWh of power. The sustainability indices revealed that the steel industry exhibited a more favorable environmental and social performance than other industries, while the power generation was economically superior with a higher cost ratio of current WF to SOWF. Subsequently, several sustainabilityenhancing solutions were evaluated based on environmental, economic, and social criteria. Among these, solar energy usage, wastewater reuse, and recycling in iron ore processing emerged as effective strategies to enhance overall sustainability by reducing WFs and improving social criteria. Ultimately, the wastewater reuse option was given the highest priority.