Factors Affecting Efficiency of Microbially Induced Calcite Precipitation
Factors Affecting Efficiency of Microbially Induced Calcite Precipitation
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DOI：
10.1061/(asce)gt.1943-5606.0000666
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发表时间：
2012-08-01
影响因子：
3.9
通讯作者：
Santamarina, Carlos
中科院分区：
文献类型：
--
作者：
Al Qabany, Ahmed;Soga, Kenichi;Santamarina, Carlos
微生物诱导碳酸盐沉淀（MICP）使用尿素分解细菌在岩土工程领域的几个不同的应用，如地面改良和地下水控制显示出希望。本研究探讨了最佳使用和有效的控制孢子八叠球菌巴氏菌诱导沉淀的碳酸钙在开放的环境中。实验室试验进行了调查的影响，改变处理因素，如化学品浓度，停留时间，和有效输入速率（mol/L/h）的化学效率。基于CaCO 3沉淀的重量测量与注入样品的化学反应物的量相比来测量化学效率。根据实验结果，确定了在特定细菌光密度范围内，在多孔介质中发生沉淀过程所需的最佳时间。结果表明，低于一定的尿素和CaCl 2输入速率（0：042 mol/L/h）和细菌光密度（OD 600）在0.8和1.2之间，反应效率保持高，沉淀量不受液体培养基浓度（输入浓度高达1 M）的影响。然而，在孔隙尺度上的沉淀模式被发现是由注入浓度的影响。扫描电子显微镜图像采取的不同样品在不同的水平的胶结表明，对于相同数量的沉淀，使用较低的化学浓度注入导致更好的分布方解石沉淀，特别是在较低的胶结水平。预计降水模式的这种变化将影响MICP在不同应用中的使用。DOI：10.1061/（ASCE）GT.1943-5606.0000666。(C)2012年美国土木工程师学会。
Microbially induced carbonate precipitation (MICP) using ureolytic bacteria shows promise in the field of geotechnical engineering for several different applications, such as ground improvement and groundwater control. This study examined optimal use and efficient control of Sporosarcina pasteurii to induce the precipitation of CaCO3 in open environments. Laboratory tests were conducted to investigate the effect of changing treatment factors, such as chemical concentrations, retention times, and effective input rates (mol/L/h) on chemical efficiency. Chemical efficiency was measured based on weight measurements of CaCO3 precipitation compared with the amount of chemical reactants injected to samples. Based on the experimental results, the optimal time required for the precipitation process to take place in porous media for a specific range of bacterial optical density was determined. Results show that, below a certain urea and CaCl2 input rate (0:042 mol/L/h) and for a bacterial optical density (OD600) between 0.8 and 1.2, the reaction efficiency remained high and the amount of precipitation was not affected by the liquid medium concentration (for input concentrations up to 1 M). However, the precipitation pattern at the pore scale was found to be affected by the injected concentration. Scanning electron microscopy images taken of different samples at different levels of cementation showed that, for the same amount of precipitation, the use of lower chemical concentrations in injections resulted in better distribution of calcite precipitation, especially at lower cementation levels. This variation in precipitation pattern is expected to affect the use of MICP for different applications. DOI: 10.1061/(ASCE)GT.1943-5606.0000666. (C) 2012 American Society of Civil Engineers.