Industry drives economic activity by converting raw materials into products within an extensive network of factories. These are segmented into specialized sectors, each focusing on distinct products or services and employing specific processes and technologies that contribute to the society and the economy. While these sectors are essential for development, they also generate industrial wastewater. This wastewater is a mix of discharges containing harmful elements such as heavy metals (HMs), including chromium (Cr) and zinc (Zn), as well as other pollutants like chemical oxygen demand (COD), biochemical oxygen demand (BOD), and nitrogen and phosphorus compounds, which pose risks to both aquatic and terrestrial ecosystems. Understanding and mitigating the water quality impacts of these industries are crucial for their cleaner production. Notably, sectors such as textile and dyeing, metal-working, food and dairy production, chemicals, plastics, and electrical and electronics manufacturing make extensive contributions to the industrial water footprint (WF). The WF of a product is the total volume of water used to produce it, summed over the various steps of the production chain. Industries exert significant pressure on water bodies due to their excessive water consumption. This is particularly evident in sectors like textile and dyeing or food and dairy units, which require substantial amounts of water for production, cleaning, and packaging. Moreover, these enterprises introduce a wide range of pollution. For example, textile and dyeing industries discharge contaminants such as copper (Cu), lead (Pb), and COD, while metal-working industries release HMs like Cr and Pb during cooling and processing. Since WF represents the water used in production, the combined water usage and pollution discharges of these industries can increase the overall WF of the industry, posing substantial environmental challenges. The industrial WF is accounted for based on water quantity and quality, through the blue WF (BWF) and grey WF (GWF). The BWF represents the water used in manufacturing and direct freshwater consumption during production processes, while the GWF accounts for pollutants discharged into water bodies, impacting water quality and ecosystems as a result of industrial activities. In addition to the principles and methods, this chapter explains the calculated industrial WF of an industrial park located in Isfahan Province, Iran. It covers an area of 3.09 km2 and includes 554 units: iron and metal-working, textile and dyeing, chemical and fertilizer production, food and dairy production, cellulose industry and pulp and paper, electrical and electronic, administration and other industrial units, and non-metallic minerals. For its GWF assessment, multiple pollutants were evaluated over a period of 6 months (October 2022 to March 2023). Regarding the production yields of the Industrial Park, the average WF of production (WFP) is 1.76 m3/ton, derived from a net BWF of 1668 ± 54 m3/day and a GWF of 2.155 ± 0.285 million cubic meters (MCM)/month, attributed to NH4. Based on the analyzed conventional pollutants, the dilution factor indicator (Df) measured how many times polluted water needs to be mixed with fresh water to achieve a safe concentration level, which is typically around 50 times for NH4 in this study. It has been argued that the industrial WF faces various challenges in standards, experimentation, and accounting. Furthermore, mitigating GWF and WF requires a more holistic approach, incorporating technological innovations, recycling initiatives, and sustainable practices. Although these challenges and future trends, as well as the methods applicable to the industrial park, are discussed in this chapter, they are also calculable for various and specific individual industries. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.
