Higgins, D, Curtin, T, Burke, IT et al. (1 more author) (2018) The potential for constructed wetlands mechanisms to treat alkaline bauxite residue leachate: carbonation and precipitate characterization. Environmental Science and Pollution Research, 25 (29). pp. 29451-29458. ISSN 0944-1344
Abstract
Leachates emanating from bauxite residue disposal areas are alkaline and require neutralisation prior to discharge. The use of passive technologies such as constructed wetlands has received increasing interest as possible treatments for alkaline leachates, including bauxite residues. Mechanisms proposed for wetland effectiveness have included calcite precipitation but it is not clear if such a pathway is feasible in the relatively low Ca residue leachates. Carbonation of Ca-spiked residue leachate treatments was conducted to observe rates of pH decrease and precipitate formation. For all treatments, carbonation effectively decreased pH to ca. 10.5 which remained stable following aeration. Decreases in Al content of 83–93% were also observed. Precipitates retrieved from carbonation experiments and from a constructed wetland trial were characterised using XRD, SEM, XPS and EDX. Calcium carbonates formed in Ca-spiked treatments and dawsonite precipitation occur in the absence of Ca. Rinsing of precipitates removes surface calcium indicating soluble forms adsorbed on precipitates. The results demonstrate that carbonation of bauxite residue leachate is an important component of passive treatments and neutralisation.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Springer-Verlag GmbH Germany, part of Springer Nature 2018. This is an author produced version of a paper published in Environmental Science and Pollution Research. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Alkaline drainage; Bauxite residue; Constructed wetlands; Neutralisation; Carbonation |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Earth Surface Science Institute (ESSI) (Leeds) |
Funding Information: | Funder Grant number NERC NE/L01405X/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 24 Aug 2018 11:03 |
Last Modified: | 21 Aug 2019 00:42 |
Status: | Published |
Publisher: | Springer Nature |
Identification Number: | 10.1007/s11356-018-2983-1 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:134955 |