Grey water footprint of stone-cutting and processing industry

Grey water footprint (GWF) indicates the equivalent freshwater volume required for assimilating the pollution load discharged from a production. This study evaluated the GWF of stone cutting and processing (SCP) industry by analyzing multiple hazardous pollutants in wastewater directly. Here, the contaminants were bisphenol-A (BPA), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and cresols. Samples were collected separately from the effluent of three large factories at a specialized SCP industrial park, located at Isfahan province, central Iran. These factories use typical processes for cutting and polishing raw marble and travertine derived from three different mines. Results revealed that BPA was the critical pollutant for GWF assessment in all factories as its concentration reached about 2.3 mg/l due to resin application. Yet, the pollutants concentrations were not significantly different among the three effluents. The GWF ranged between 674.9 m³/ton (marble) and 597.9 m³/ton (travertine) with an average of 638.1 m³/ton. The calculated Hazard Quotient (HQ) for BPA was also 936 ± 17. Therefore, optimizing epoxy resin application and controlling its discharge can simultaneously reduce the GWF and associated environmental risks. Future research should focus on developing efficient treatment strategies to mitigate the impacts of hazardous pollutants in SCP wastewater.