Biofilm Detection in a Model Well-Bore Environment Using Low-Field NMR
Biofilm Detection in a Model Well-Bore Environment Using Low-Field NMR
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DOI：
10.1111/gwmr.12117
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发表时间：
2015-09-01
影响因子：
1.9
通讯作者：
Codd, Sarah L.
中科院分区：
文献类型：
--
作者：
Kirkland, Catherine M.;Hiebert, Randy;Codd, Sarah L.
这项研究解决了缺乏非侵入性方法和与监测地下污染物生物修复核心的生物地球化学活动相关的时空分辨率差的挑战。修复工作通常包括生长生物膜以容纳或降解化学污染物，例如硝酸盐、碳氢化合物、重金属和一些氯化溶剂。先前的研究表明，核磁共振（NMR）对生物膜积累的生物地球化学过程敏感。目前的研究重点是开发使用低成本核磁共振技术的方法来支持地下生物膜生长和地球化学修复过程的原位监测。生物膜在实验室规模的径向流生物反应器中生长，该反应器旨在模拟近井筒地下环境。 Vista Clara Javelin NMR 测井仪是一种细长的钻孔探头，在沙子填充反应器中培养生物膜的同时，在八天内收集了 NMR 测量结果。测得的 NMR 平均 log T-2 弛豫时间从大约 710 毫秒减少到 389 毫秒，表明孔隙环境和整体流体特性由于生物膜生长而发生变化。采用滴板微生物种群分析和扫描电子和立体显微镜进行的破坏性取样证实了生物膜的形成。我们的研究结果表明，NMR 测井工具可以检测到与石英砂中环境相关生物膜数量相关的 T-2 分布的小到中度变化。
This research addresses the challenges of the lack of non-invasive methods and poor spatiotemporal resolution associated with monitoring biogeochemical activity central to bioremediation of subsurface contaminants. Remediation efforts often include growth of biofilm to contain or degrade chemical contaminants, such as nitrates, hydrocarbons, heavy metals, and some chlorinated solvents. Previous research indicates that nuclear magnetic resonance (NMR) is sensitive to the biogeochemical processes of biofilm accumulation. The current research focuses on developing methods to use low-cost NMR technology to support in situ monitoring of biofilm growth and geochemical remediation processes in the subsurface. Biofilm was grown in a lab-scale radial flow bioreactor designed to model the near wellbore subsurface environment. The Vista Clara Javelin NMR logging device, a slim down-the-borehole probe, collected NMR measurements over the course of eight days while biofilm was cultivated in the sand-packed reactor. Measured NMR mean log T-2 relaxation times decreased from approximately 710 to 389 ms, indicating that the pore environment and bulk fluid properties were changing due to biofilm growth. Destructive sampling employing drop plate microbial population analysis and scanning electron and stereoscopic microscopy confirmed biofilm formation. Our findings demonstrate that the NMR logging tool can detect small to moderate changes in T-2 distribution associated with environmentally relevant quantities of biofilm in quartz sand.