• Cyclic biomineralization-reduction strategy for simulated AMD treatment. • The biogenic sulfide could effectively reduce Fe 3+ with the formation of Fe 2+ and S 0 . • Successive biomineralization–reduction cycles achieved 89% of iron removal from AMD. • Biomineralization pretreatment reduced lime consumption and minimized sludge volume. • Integrated validation for iron removal and sulfur recovery from sulfate-rich AMD. The management of acid mine drainage (AMD) remains a global challenge faced by mining industry due to its severe environmental impact. Cyclic biomineralization has emerged as a promising method for the iron removal, but its application is constrained by the lack of efficient strategies for the residual Fe 3+ reduction to sustain the cyclic process. Herein, a novel cyclic biomineralization strategy that incorporates iron-oxidizing and sulfate-reducing microorganisms was proposed to achieve sustainable iron removal and sulfur recovery. The final removal efficiency of iron ions reached 89.35% after three cycles biomineralization treatment with Na 2 S as the Fe 3+ reducing agent, and 27.6% of the sulfate was removed simultaneously. Jarosite was identified as the main phase of the biomineralization sludge, and sulfur was formed as the oxidation product of S 2- . Moreover, biogenic sulfide produced in the sulfate reduction process effectively substituted for Na 2 S in the Fe 3+ reduction process, simultaneously producing sulfur as a recoverable by-product. After the cyclic biomineralization treatment, lime consumption for neutralization was reduced by 63.6% and the volume of sludge decreased by 70.1%. This work provides a promising integrated approach for the sustainable treatment of acid mine drainage, with efficient iron removal and sulfur recovery, being environmentally friendly and reducing the cost of neutralization.
Wang et al. (Fri,) studied this question.