Acid mine drainage (AMD) with high sulfate requires treatment trains that balance discharge compliance, cost, and resource recovery. Using a consistent design basis of 100 m 3 ·h −1 (pH 3. 5; 14 g·L −1 SO₄ 2−), we quantify the feasibility and economics of precipitation, reverse osmosis (RO) concentration, sulfate-reducing bacteria (SRB) wetland polishing, and bipolar-membrane electrodialysis (BMED). Order-of-magnitude Faradaic sizing shows full-flow electrodialysis (ED) /BMED is infeasible, demanding more than 10 6 A and more than 10 3 m 2 membranes; by contrast, 0. 1–1 m 3 ·h −1 side stream BMED is practical, producing acids/bases at specific energies near 6. 8 MWh·t −1 H₂SO₄. For 1 m 3 ·h −1 of AMD flow, precipitation followed by BMED hybrid reduces the BMED area to 65 m 2 as opposed to the large area required for full-flow treatment. Energy price dominates operational expenditures (OPEX) ; at less than 0. 05 kWh −1 and with on-site substitution of recovered chemicals, pilot BMED approaches breakeven. We provide consistent mass/cost bases, product-quality targets, and sludge-management pathways, offering a decision framework for AMD sulfate control with credible circular-economy value. • Precipitation treats acidity and metals effectively but with high costs. • RO polishing lowers TDS after pretreatment but does not enable sulfate valorization. • ED/BMED is infeasible at 100 m 3 h −1 ; side stream BMED is viable for recovery. • Wetlands and SRB suit partial treatment but sidestream avoids excessive land use. • Energy dominates costs; internal acid–base reuse and renewables reduce OPEX by ~58%. • Hybrid trains (precipitation–RO–BMED) best balance performance, cost, circularity.
Jegatheesan et al. (Sun,) studied this question.