Abstract：
The remediation of groundwater subject to in situ leaching (ISL) for uranium mining has raised extensive concerns in uranium mill and milling. This study conducted bioremediation through biostimulation and bioaugmentation to the groundwater in an area in northern China that was contaminated due to uranium mining using the CO2 + O2 neutral ISL (NISL) technology. It identified the dominant controlling factors and mechanisms driving bioremediation. Findings indicate that microorganisms can reduce the uranium concentration in groundwater subject to NISL uranium mining to its normal level. After 120 days of bioaugmentation, the uranium concentration in the contaminated groundwater fell to 0.36 mg/L, achieving a remediation efficiency of 91.26 %. Compared with biostimulation, bioaugmentation shortened the remediation timeframe by 30 to 60 days while maintaining roughly the same remediation efficiency. For groundwater remediation using indigenous microbial inoculants, initial uranium concentration and low temperatures (below 15 °C) emerge as the dominant factors influencing the bioremediation performance and duration. In settings with high carbonate concentrations, bioremediation involved the coupling of multiple processes including bioreduction, biotransformation, biomineralization, and biosorption, with bioreduction assuming a predominant role. Post-bioremediation, the relative abundances of reducing microbes Desulfosporosinus and Sulfurospirillum in groundwater increased significantly by 10.56 % and 6.91 %, respectively, offering a sustainable, stable biological foundation for further bioremediation of groundwater.
摘要：
进行铀矿开采的原位浸出（ISL）修复地下水引起了铀磨矿和制矿的广泛关注。这项研究通过使用CO2O2中性ISL（NISL）技术对由于铀矿开采而受到污染的中国北方地区的地下水进行了生物刺激和生物增强，从而进行了生物修复。它确定了驱动生物修复的主要控制因素和机制。研究结果表明，微生物可以将进行NISL铀矿开采的地下水中的铀浓度降低到正常水平。经过120天的生物强化，受污染地下水中的铀浓度降至0.36mg/L，达到91.26%的修复效率。与生物刺激相比，生物强化将修复时间缩短了30至60天，同时保持了大致相同的修复效率。对于使用本地微生物接种剂的地下水修复，初始铀浓度和低温（低于15°C）是影响生物修复性能和持续时间的主要因素。在高碳酸盐浓度的环境中，生物修复涉及多个过程的耦合，包括生物还原，生物转化,生物矿化，和生物吸附，生物还原占据主导地位。生物修复后，地下水中还原性微生物Desulfosporosinus和Sulfurospirillum的相对丰度分别显著增加了10.56%和6.91%,分别,提供一个可持续的，为进一步的地下水生物修复奠定了稳定的生物基础。
