Investigating Ammonium By-product Removal for Ureolytic Bio-cementation Using Meter-scale Experiments
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...
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Published in | Scientific reports Vol. 9; no. 1; pp. 18313 - 15 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Nature Publishing Group
04.12.2019
Nature Publishing Group UK |
Subjects | |
Online Access | Get full text |
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Summary: | 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
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
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
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
concentrations observed at distances furthest from the injection well. In addition, soil V
measurements completed during rinse injections suggested that no significant changes in cementation integrity occurred during NH
removal. After rinsing and a 12 hour stop flow period, all column solutions achieved cumulative NH
removals exceeding 97.9%. Soil samples collected following rinsing, however, contained significant sorbed NH
masses that appeared to have a near linear relationship with surrounding aqueous NH
concentrations. While these results suggest that NH
can be successfully removed from bio-cemented soils, acceptable limits for NH
aqueous concentrations and sorbed NH
masses will likely be governed by site-specific requirements and may require further investigation and refinement of the developed techniques. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2045-2322 2045-2322 |
DOI: | 10.1038/s41598-019-54666-1 |