Evaluation of the ASTERTM process in the presence of suspended solids

dc.contributor.authorvan Zyl, Andries W
dc.contributor.authorHuddy, Robert
dc.contributor.authorHarrison, Susan T L
dc.contributor.authorvan Hille, Robert P
dc.date.accessioned2016-08-25T10:30:54Z
dc.date.available2016-08-25T10:30:54Z
dc.date.issued2014
dc.date.updated2016-08-23T10:11:23Z
dc.description.abstractThe ability to recycle and reuse process water is a major contributing factor toward increased sustainability in the mining industry. However, the presence of toxic compounds has prevented this in most bioleaching operations. The ASTERTM process has been used for the bioremediation of cyanide (CN) and thiocyanate (SCN−) containing effluents at demonstration and commercial scale, increasing the potential for recycling of the treated effluent. The process relies on a complex consortium of microorganisms and laboratory tests have shown that the biomass retention, in suspended flocs or attached biofilm, significantly improved SCN− degradation rates. The current research evaluated the process performance in the presence of suspended solids (up to 5.5% m/v) ahead of implementation at a site where complete tailings removal is not possible. Experiments were performed in four 1 l CSTRs (with three primary reactors in parallel at an 8 h residence time, feeding one secondary reactor at a 2.7 h residence time). Stable operation at the design specifications (5.5% solids, 100 mg/l SCN− feed, effluent SCN− <1 mg/l) was achieved within 50 days, including a period of adaptation. The pH had the most significant effect on performance, with significant inhibition below pH 6. The presence of gypsum and anhydrite phases in the fresh tailings was most likely responsible for the observed decrease in pH. A maximum SCN− degradation rate of >57 mg/l/h was achieved, despite no obvious floc formation. Microbial ecology studies (16S rRNA clone library) revealed reduced diversity relative to reactors operated without suspended solids.en_ZA
dc.identifierhttp://dx.doi.org/10.1016/j.mineng.2014.11.007
dc.identifier.apacitationvan Zyl, A. W., Huddy, R., Harrison, S. T. L., & van Hille, R. P. (2014). Evaluation of the ASTERTM process in the presence of suspended solids. <i>Minerals Engineering</i>, http://hdl.handle.net/11427/21540en_ZA
dc.identifier.chicagocitationvan Zyl, Andries W, Robert Huddy, Susan T L Harrison, and Robert P van Hille "Evaluation of the ASTERTM process in the presence of suspended solids." <i>Minerals Engineering</i> (2014) http://hdl.handle.net/11427/21540en_ZA
dc.identifier.citationvan Zyl, A. W., Huddy, R., Harrison, S. T., & van Hille, R. P. (2015). Evaluation of the ASTER TM process in the presence of suspended solids. Minerals Engineering, 76, 72-80.en_ZA
dc.identifier.issn0892-6875en_ZA
dc.identifier.ris TY - Journal Article AU - van Zyl, Andries W AU - Huddy, Robert AU - Harrison, Susan T L AU - van Hille, Robert P AB - The ability to recycle and reuse process water is a major contributing factor toward increased sustainability in the mining industry. However, the presence of toxic compounds has prevented this in most bioleaching operations. The ASTERTM process has been used for the bioremediation of cyanide (CN) and thiocyanate (SCN−) containing effluents at demonstration and commercial scale, increasing the potential for recycling of the treated effluent. The process relies on a complex consortium of microorganisms and laboratory tests have shown that the biomass retention, in suspended flocs or attached biofilm, significantly improved SCN− degradation rates. The current research evaluated the process performance in the presence of suspended solids (up to 5.5% m/v) ahead of implementation at a site where complete tailings removal is not possible. Experiments were performed in four 1 l CSTRs (with three primary reactors in parallel at an 8 h residence time, feeding one secondary reactor at a 2.7 h residence time). Stable operation at the design specifications (5.5% solids, 100 mg/l SCN− feed, effluent SCN− <1 mg/l) was achieved within 50 days, including a period of adaptation. The pH had the most significant effect on performance, with significant inhibition below pH 6. The presence of gypsum and anhydrite phases in the fresh tailings was most likely responsible for the observed decrease in pH. A maximum SCN− degradation rate of >57 mg/l/h was achieved, despite no obvious floc formation. Microbial ecology studies (16S rRNA clone library) revealed reduced diversity relative to reactors operated without suspended solids. DA - 2014 DB - OpenUCT DP - University of Cape Town J1 - Minerals Engineering LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 SM - 0892-6875 T1 - Evaluation of the ASTERTM process in the presence of suspended solids TI - Evaluation of the ASTERTM process in the presence of suspended solids UR - http://hdl.handle.net/11427/21540 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/21540
dc.identifier.vancouvercitationvan Zyl AW, Huddy R, Harrison STL, van Hille RP. Evaluation of the ASTERTM process in the presence of suspended solids. Minerals Engineering. 2014; http://hdl.handle.net/11427/21540.en_ZA
dc.languageengen_ZA
dc.publisherElsevieren_ZA
dc.publisher.institutionUniversity of Cape Town
dc.sourceMinerals Engineeringen_ZA
dc.source.urihttp://www.journals.elsevier.com/minerals-engineering/
dc.subject.otherhiocyanate destruction
dc.subject.otherBIOX® process
dc.subject.otherBiomass retention
dc.subject.otherMicrobial ecology
dc.titleEvaluation of the ASTERTM process in the presence of suspended solidsen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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