Process engineering and techno-economic evaluation of integrated hybrid treatment systems for mining wastewater reuse in arid and semi-arid regions

Mining operations in arid and semi-arid regions face increasing pressure to improve water-use efficiency owing to freshwater scarcity, rising operational costs, and stricter environmental regulations. This review evaluates integrated treatment strategies for mining wastewater reuse, with emphasis on process engineering, techno-economic performance, and fit-for-purpose water management. Mining wastewater, including acid mine drainage, saline groundwater, tailings decant water, wash-bay effluent, and pit-lake water, exhibits highly variable water quality, with total dissolved solids ranging from <1 to >180 g L −1 and sulfate concentrations exceeding 17,000 mg L −1 in Australian mining operations. Conventional treatment technologies effectively remove suspended solids and dissolved metals but are generally insufficient for salinity control, whereas membrane processes achieve >95% dissolved-solids removal and 70–95% water recovery but are constrained by fouling, scaling, energy consumption, and concentrate management. This review demonstrates that staged hybrid treatment systems integrating conventional, biological, membrane, and resource-recovery technologies provide greater operational flexibility, improve treatment reliability, and reduce lifecycle costs by approximately 20–40% compared with standalone desalination systems. A process-engineering framework and an Australian mine site case study are presented to illustrate technology selection, system optimisation, and fit-for-purpose water reuse under remote operating conditions. The review highlights integrated treatment and resource recovery as practical pathways for improving water security, reducing environmental impacts, and advancing sustainable mine water management in arid mining regions.