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Treatment of zinc-rich acid mine water in low residence time bioreactors incorporating waste shells and methanol dosing.

Mayes, Will; Davis, J.; Silva, V.; Jarvis, A. P.

Authors

J. Davis

V. Silva

A. P. Jarvis



Abstract

Bioreactors utilising bacterially mediated sulphate reduction (BSR) have been widely tested for treating metal-rich waters, but sustained treatment of mobile metals (e.g. Zn) can be difficult to achieve in short residence time systems. Data are presented providing an assessment of alkalinity generating media (shells or limestone) and modes of metal removal in bioreactors receiving a synthetic acidic metal mine discharge (pH 2.7, Zn 15 mg/L, SO(4)(2-) 200mg/L, net acidity 103 mg/L as CaCO(3)) subject to methanol dosing. In addition to alkalinity generating media (50%, v.v.), the columns comprised an organic matrix of softwood chippings (30%), manure (10%) and anaerobic digested sludge (10%). The column tests showed sustained alkalinity generation, which was significantly better in shell treatments. The first column in each treatment was effective throughout the 422 days in removing >99% of the dissolved Pb and Cu, and effective for four months in removing 99% of the dissolved Zn (residence time: 12-14 h). Methanol was added to the feedstock after Zn breakthrough and prompted almost complete removal of dissolved Zn alongside improved alkalinity generation and sulphate attenuation. While there was geochemical evidence for BSR, sequential extraction of substrates suggests that the bulk (67-80%) of removed Zn was associated with Fe-Mn oxide fractions.

Journal Article Type Article
Publication Date Oct 15, 2011
Journal Journal of hazardous materials
Print ISSN 0304-3894
Electronic ISSN 1873-3336
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 193
Pages 279-287
APA6 Citation Mayes, W., Davis, J., Silva, V., & Jarvis, A. P. (2011). Treatment of zinc-rich acid mine water in low residence time bioreactors incorporating waste shells and methanol dosing. Journal of hazardous materials, 193, (279-287). doi:10.1016/j.jhazmat.2011.07.073. ISSN 0304-3894
DOI https://doi.org/10.1016/j.jhazmat.2011.07.073
Keywords Environmental Engineering; Waste Management and Disposal; Pollution; Health, Toxicology and Mutagenesis; Environmental Chemistry
PMID 21864976
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