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标题：Investigating Ammonium By-product Removal for Ureolytic Bio-cementation Using Meter-scale Experiments
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作者：Minyong Lee ; Michael G. Gomez ; Alexandra C. M. San Pablo 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2019
卷号：9
期号：1
页码：1-15
DOI：10.1038/s41598-019-54666-1
出版社：Springer Nature
摘要：Microbially Induced Calcite Precipitation (MICP), or bio-cementation, is a promising bio-mediated technology that can improve the engineering properties of soils through the precipitation of calcium carbonate. Despite significant advances in the technology, concerns regarding the fate of produced NH 4 + by-products have remained largely unaddressed. In this study, five 3.7-meter long soil columns each containing one of three different soils were improved using ureolytic bio-cementation, and post-treatment NH 4 + by-product removal was investigated during the application of 525 L of a high pH and high ionic strength rinse solution. During rinsing, reductions in aqueous NH 4 + were observed in all columns from initial concentrations between ≈100 mM to 500 mM to final values between ≈0.3 mM and 20 mM with higher NH 4 + concentrations observed at distances furthest from the injection well. In addition, soil V s measurements completed during rinse injections suggested that no significant changes in cementation integrity occurred during NH 4 + removal. After rinsing and a 12 hour stop flow period, all column solutions achieved cumulative NH 4 + removals exceeding 97.9%. Soil samples collected following rinsing, however, contained significant sorbed NH 4 + masses that appeared to have a near linear relationship with surrounding aqueous NH 4 + concentrations. While these results suggest that NH 4 + can be successfully removed from bio-cemented soils, acceptable limits for NH 4 + aqueous concentrations and sorbed NH 4 + masses will likely be governed by site-specific requirements and may require further investigation and refinement of the developed techniques.