Acid mine drainage (AMD) treatment has become a major environmental issue confronting the global mining industry. For treating AMD economically and efficiently, a novel AMD passive treatment system consisting of cascaded aeration based biomineralization process driven by Acidithiobacillus ferrooxidans (A. ferrooxidans) LX5 followed by lime neutralization was developed. Compositions and structures of precipitates were measured through a scanning electron microscope equipped with an energy-dispersive X-ray spectrometry (SEM-EDS) and X-ray powder diffraction (XRD). Results showed that the biogenic Fe-minerals, with 1–1.5 μm diameter and 17.5 m²/g specific surface area, belonged to jarosite expressed as KFe₃(SO₄)₂(OH)₆ with Fe/S molar ratios between 1.61 and 1.68. The density and Fe²⁺ bio-oxidation rate of A. ferrooxidans LX5 immobilized on the surface of jarosite (namely immobilized cells) were approximately 8.3 × 10⁸ cells/g and 7.3 mmol L⁻¹ h⁻¹, which were approximately 10 and 2.2 times higher than those of cultivating A. ferrooxidans LX5 solution used as the control (namely suspension cells). The constructed water-dropping system could supply sufficient oxygen for the Fe²⁺ bio-oxidation. The initial Fe²⁺ in the AMD was completely oxidized into Fe³⁺ and 41.8% of total Fe was removed during biomineralization. In addition, it was found that 34% of Zn²⁺, 21% of Cd²⁺, 42.7% of Cr³⁺, and 23.8% of Cu²⁺ were removed by co-precipitation or adsorption to jarosite simultaneously. With this novel treatment system, the amounts of lime addition required for AMD neutralization and toxic solid waste production were drastically decreased by about 70 wt% and 81.3 wt%, respectively, in comparison to the control (without biomineralization). These results show water-dropping aeration and A. ferrooxidans LX5 play a significant role in the Fe²⁺ bio-oxidation and removal of metal ions, and the integration of cascaded aeration and neutralization is a possibility for cost-effective treatment of highly acid and toxic metal-loaded AMD.

酸性矿山排水 (AMD) 处理已成为全球采矿业面临的主要环境问题。为了经济有效地治疗 AMD，开发了一种新型的 AMD 被动处理系统，该系统由基于氧化亚铁硫杆菌( A. ferrooxidans ) LX5驱动的级联曝气生物矿化过程和石灰中和组成。通过配备能量色散 X 射线光谱仪 (SEM-EDS) 和 X 射线粉末衍射 (XRD) 的扫描电子显微镜测量沉淀物的组成和结构。结果表明，生物成因的铁矿物，直径为 1-1.5 μm，比表面积为 17.5 m ² /g，属于黄钾铁矾，表达为 KFe ₃ (SO ₄) ₂ (OH) _{6 ，}其中 Fe/S 摩尔比在 1.61 和 1.68 之间。固定在黄钾铁矾表面（即固定细胞）的A. ferrooxidans LX5的密度和Fe ²⁺生物氧化速率约为8.3 × 10 ^{8 个}细胞/g和7.3 mmol L ^-1  h ^-1，约为10 和比培养A.ferrooxidans LX5溶液作为对照（即悬浮细胞）高2.2倍。构建的滴水系统可以为Fe ²⁺生物氧化提供足够的氧气。AMD中最初的Fe ²⁺完全氧化成Fe ³⁺41.8%的铁在生物矿化过程中被去除。此外，发现34%的Zn ²⁺、21%的Cd ²⁺、42.7%的Cr ³⁺和23.8%的Cu ²⁺通过共沉淀或吸附到黄钾铁矾同时去除。使用这种新型处理系统，与对照（无生物矿化）相比，AMD 中和和有毒固体废物产生所需的石灰添加量分别显着减少了约 70%（重量）和 81.3%（重量）。这些结果表明滴水曝气和A. ferrooxidans LX5 在 Fe ²⁺ 金属离子的生物氧化和去除，以及级联曝气和中和的整合是一种经济有效地处理高酸性和有毒金属负载 AMD 的可能性。