Controlling the Distribution of Microbially Precipitated Calcium Carbonate in Radial Flow Environments.

Author(s) Zambare, N.M.; Lauchnor, E.Grace; Gerlach, R.
Journal Environ Sci Technol
Date Published 2019 Apr 22
Abstract

Bacterially driven reactions such as ureolysis can induce calcium carbonate precipitation, a well-studied process called microbially induced calcium carbonate precipitation (MICP). MICP is of interest in subsurface applications such as sealing leaks around wells. For effective field deployment, it is important to study MICP under radial flow conditions, which are relevant to near-well environments. In this study, a laboratory-scale radial flow reactor of 23 cm diameter, with a 1 mm glass bead monolayer serving as porous medium, was used to investigate effects of fluid flowrates and calcium concentrations on the mass and distribution of MICP by the ureolytic bacterium Sporosarcina pasteurii. Experiments were performed at hydraulic residence times of 14, 7 and 3.5 minutes and calcium-to-urea molar ratios of 0.5:1, 1:1, 2:1. The total amount of CaCO3 precipitated in the reactor increased with increasing residence time and with decreasing Ca2+:Urea molar ratios. Increased bacterial attachment and increased CaCO3 precipitation were observed with distance from the center inlet of the reactor in all experiments. More uniform calcium distribution was achieved at lower flowrates. The relationship between reaction and transport rate (i.e. the Damköhler number) is identified as a useful parameter for the prediction of MICP in radial flow environments.

DOI 10.1021/acs.est.8b06876
ISSN 1520-5851
Citation Zambare NM, Lauchnor EG, Gerlach R. Controlling the Distribution of Microbially Precipitated Calcium Carbonate in Radial Flow Environments. Environ Sci Technol. 2019.

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