The environmental management of highly saline coal mine wastewater presents a critical challenge for European mining regions, particularly under the constraints of the EU Water Framework Directive. This study presents a cradle-to-grave life cycle assessment of a novel zero liquid discharge (ZLD) system developed under the EU-funded LIFE Brine-Mining project and deployed at the Ziemowit mine in Poland. The system was designed to treat coal mine brine (TDS ~80 g/L) and recover valuable resources, including high-purity water, sodium chloride, magnesium hydroxide, calcium carbonate, and calcium sulphate. The assessment was conducted in accordance with EN 15804 using the Environmental Footprint v3.1 methodology, ecoinvent v3.10, and a functional unit of 1 m3 of saline wastewater inflow, covering all life cycle stages from raw material extraction to end-of-life and resource recovery (Module D). The results indicate a fossil-based global warming potential of 73.86 kg CO2 eq. per functional unit, with 66% attributed to operational electricity consumption (module B6, 44 kWh/m3) and 29% to auxiliary chemical consumption (module B1). Three key environmental hotspots were identified: module B1 dominates ozone depletion potential (67%), module B6 dominates acidification potential (66%), and raw material extraction (module A1) dominates abiotic depletion of minerals and metals (43%). Resource recovery credits (Module D) offset 11.80 kg CO2 eq. of GWP-fossil, cause the ADP-minerals and metals indicator to become net negative, and reduce the water deprivation potential by approximately 50%. A sensitivity analysis confirmed that results are robust to ±10% variations in wastewater inflow, with GWP-total varying within a narrow −0.5% to +0.6% range once the volume-proportional nature of chemical and electricity consumption is correctly accounted for. These findings provide a quantitative sustainability baseline for the scale-up and replication of integrated ZLD technologies in the European mining sector, demonstrating that circular brine treatment can simultaneously address regulatory water quality targets, reduce primary resource consumption, and deliver measurable environmental credits aligned with EU circular economy and sustainable development objectives.
Avramidi et al. (Tue,) studied this question.