Improving the spatial control of soil biocementation using indigenous microorganisms: Column experiments and reactive transport modeling
Improving the spatial control of soil biocementation using indigenous microorganisms: Column experiments and reactive transport modeling
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DOI：
10.1016/j.enggeo.2023.107104
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发表时间：
2023-03
影响因子：
7.4
通讯作者：
Minyong Lee;M. G. Gomez;Charles M. R. Graddy;Alexandra C. M. San Pablo;J. DeJong;D. Nelson
中科院分区：
文献类型：
--
作者：
Minyong Lee;M. G. Gomez;Charles M. R. Graddy;Alexandra C. M. San Pablo;J. DeJong;D. Nelson
微生物诱导方解石沉淀 (MICP) 或生物水泥是一种生物介导的土壤改良过程，利用微生物尿素分解活性使 CaCO3 沉淀在土壤颗粒表面和接触面上。随着该技术朝着实际应用的方向发展，能够调节生物水泥的空间均匀性和最大化处理范围的方法对于降低实施成本和影响至关重要。在本研究中，利用厘米级和米级土柱实验和反应输运模拟，探讨了能够在受控尿素分解活性下富集本地尿素分解微生物的处理策略，以及这些技术对 MICP 空间分布的影响。在柱实验中，处理溶液提供的酵母提取物浓度的差异被证明可以可靠地控制本地尿素分解微生物的富集并实现广泛的尿素分解活性。反应运输模拟进一步证明，刺激尿素分解速率的降低可以实现更均匀的改善，并增加改善程度，同时降低对溶液注射速度变化的敏感性。提出了反应与注射持续时间比（RTIDR）参数，并捕获了注射速率和尿素分解反应速率变化对反应性运输条件的集体影响，从而统一了模拟和实验的结果。还引入了不均匀面积 (NA) 参数来定量表征生物胶结均匀性的差异，与长度尺度和 CaCO3 大小无关。这项研究的结果共同证明了受刺激的尿素分解活性的变化对于控制米级距离上生物胶结的空间均匀性和程度的效用。
Microbially-Induced Calcite Precipitation (MICP), or biocementation, is a biomediated soil improvement process that uses microbial ureolytic activity to enable the precipitation of CaCO3on soil particle surfaces and contacts. As the technology advances towards practical adoption, approaches that can modulate the spatial uniformity of biocementation and maximize treatment extent will be critical towards reducing implementation costs and impacts. In this study, treatment strategies capable of enriching indigenous ureolytic microorganisms at controlled ureolytic activities and the effects of these techniques on resulting spatial distributions of MICP were explored using centimeter- and meter-scale soil column experiments and reactive transport simulations. In column experiments, differences in treatment solution supplied yeast extract concentrations were shown to reliably control the enrichment of indigenous ureolytic microorganisms and achieve a wide range of ureolytic activities. Reactive transport simulations further demonstrated that reductions in stimulated ureolytic rates could enable more uniform improvement and increases in the extent of improvement with reduced sensitivity to changes in solution injection velocities. A reaction-to-injection duration ratio (RTIDR) parameter was proposed and captured the collective impacts of changes in injection rates and ureolytic reaction rates on reactive transport conditions thereby unifying outcomes from both simulations and experiments. A nonuniformity area (NA) parameter was also introduced to quantitatively characterize differences in biocementation uniformity independent of length scale and CaCO3magnitudes. Results from this study collectively demonstrate the utility of changes in stimulated ureolytic activities towards controlling the spatial uniformity and extent of biocementation over meter-scale distances.