Combined abiotic and biotic in-situ reduction of hexavalent chromium in groundwater using nZVI and whey: A remedial pilot test
Language English Country Netherlands Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
26292054
DOI
10.1016/j.jhazmat.2015.07.056
PII: S0304-3894(15)00593-2
Knihovny.cz E-resources
- Keywords
- Geofixation, Hexavalent chromium, Microbial community, PLFA, nZVI,
- MeSH
- Water Pollutants, Chemical chemistry MeSH
- Chromium chemistry MeSH
- Phospholipids analysis MeSH
- Water Microbiology MeSH
- Environmental Monitoring MeSH
- Oxidation-Reduction MeSH
- Pilot Projects MeSH
- Groundwater chemistry MeSH
- Reducing Agents chemistry MeSH
- Environmental Restoration and Remediation methods MeSH
- RNA, Ribosomal, 16S chemistry genetics MeSH
- Whey chemistry MeSH
- Ferric Compounds chemistry MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Water Pollutants, Chemical MeSH
- Chromium MeSH
- chromium hexavalent ion MeSH Browser
- Phospholipids MeSH
- Reducing Agents MeSH
- RNA, Ribosomal, 16S MeSH
- Ferric Compounds MeSH
The paper describes a pilot remediation test combining two Cr(VI) geofixation methods - chemical reduction by nanoscale zero-valent iron (nZVI) and subsequent biotic reduction supported by whey. Combination of the methods exploited the advantages of both - a rapid decrease in Cr(VI) concentrations by nZVI, which prevented further spreading of the contamination and facilitated subsequent use of the cheaper biological method. Successive application of whey as an organic substrate to promote biotic reduction of Cr(VI) after application of nZVI resulted in a further and long-term decrease in the Cr(VI) contents in the groundwater. The effect of biotic reduction was observed even in a monitoring well located at a distance of 22 m from the substrate injection wells after 10 months. The results indicated a reciprocal effect of both the phases - nZVI oxidized to Fe(III) during the abiotic phase was microbially reduced back to Fe(II) and acted as a reducing agent for Cr(VI) even when the microbial density was already low due to the consumed substrate. Community analysis with pyrosequencing of the 16S rRNA genes further confirmed partial recycling of nZVI in the form of Fe(II), where the results showed that the Cr(VI) reducing process was mediated mainly by iron-reducing and sulfate-reducing bacteria.
ENACON s r o Na holém vrchu 708 3 Prague CZ 14300 Czech Republic
Technical University of Liberec Studentská 2 CZ 46117 Liberec Czech Republic
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