The eco-friendly treatment of cyanide tailings (CT) using microorganisms is a cost-effective and promising technology. However, this process often generates the secondary pollutants, such as ammonia nitrogen (NH₄⁺–N), which can adversely impacts the surrounding environment. The accumulation of NH₄⁺–N is also toxic to cyanide-degrading microorganisms, presenting a significant challenge in achieving simultaneous cyanide degradation and NH₄⁺–N mitigation. In this study, a group of functional bacteria CG305-1 with the ability to degrade cyanide and perform nitrification and denitrification was successfully enriched for the first time and used to treat CT by in situ microbial drenching technology. Results demonstrated that the total cyanide (CN_T) concentration in the leaching solution decreased from 49.96 ± 1.51 mg/L to 0.19 ± 1.11 mg/L. NH₄⁺–N was degraded to 0.25 ± 0.18 mg/L, and nitrate nitrogen (NO₃^––N) was reduced to 0.41 ± 0.20 mg/L. Furthermore, CN_T in the CT leachate was reduced to 0.94 ± 0.11 mg/L, meeting the storage standard for CT leachate (CN_T < 5 mg/L). The potential synergistic microbial degradation mechanisms were elucidated through scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and metagenomic sequencing. This study provides significant insights into green and sustainable methods for the harmless treatment of CT.

中文翻译：

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功能性菌对氰化物尾矿的无害化处理：氰化物和二次污染氨氮的降解


使用微生物对氰化物尾矿 （CT） 进行环保处理是一种经济高效且前景广阔的技术。然而，这个过程通常会产生二次污染物，例如氨氮 （NH ₄ ⁺ –N），这会对周围环境产生不利影响。NH ₄ ⁺ –N 的积累对氰化物降解微生物也具有毒性，对同时实现氰化物降解和 NH₄⁺–N 缓解提出了重大挑战。在本研究中，一组具有降解氰化物和进行硝化反氮化作用能力的功能菌 CG305-1 首次成功富集，并采用原位微生物淋洒技术处理 CT。结果表明，浸出液中总氰化物 （CN _T ） 浓度从 49.96 ± 1.51 mg/L 降至 0.19 ± 1.11 mg/L，NH₄⁺–N 降解至 0.25 ± 0.18 mg/L，硝态氮 （NO ₃ ^– –N） 降至 0.41 ± 0.20 mg/L。此外，CT 渗滤液 _T 中的 CN 降至 0.94 ± 0.11 mg/L，满足 CT 渗滤液的贮藏标准 （CN _T < 5 mg/L）。通过扫描电子显微镜 （SEM） 、傅里叶变换红外光谱 （FTIR） 和宏基因组测序阐明了潜在的协同微生物降解机制。这项研究为无害化处理 CT 的绿色和可持续方法提供了重要的见解。