Biological iron oxidation by Gallionella spp. in drinking water production under fully aerated conditions |
| |
Authors: | de Vet W W J M Dinkla I J T Rietveld L C van Loosdrecht M C M |
| |
Affiliation: | a Oasen Drinking Water Company, PO Box 122, 2800 AC Gouda, The Netherlands b Bioclear bv. Rozenburglaan 13, 9727 DL Groningen, The Netherlands c Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands d Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands |
| |
Abstract: | Iron oxidation under neutral conditions (pH 6.5-8) may be a homo- or heterogeneous chemically- or a biologically-mediated process. The chemical oxidation is supposed to outpace the biological process under slightly alkaline conditions (pH 7-8). The iron oxidation kinetics and growth of Gallionella spp. - obligatory chemolithotrophic iron oxidizers - were assessed in natural, organic carbon-containing water, in continuous lab-scale reactors and full-scale groundwater trickling filters in the Netherlands. From Gallionella cell numbers determined by qPCR, balances were made for all systems. The homogeneous chemical iron oxidation occurred in accordance with the literature, but was retarded by a low water temperature (13 °C). The contribution of the heterogeneous chemical oxidation was, despite the presence of freshly formed iron oxyhydroxides, much lower than in previous studies in ultrapure water. This could be caused by the adsorption of natural organic matter (NOM) on the iron oxide surfaces. In the oxygen-saturated natural water with a pH ranging from 6.5 to 7.7, Gallionella spp. grew uninhibited and biological iron oxidation was an important, and probably the dominant, process. Gallionella growth was not even inhibited in a full-scale filter after plate aeration. From this we conclude that Gallionella spp. can grow under neutral pH and fully aerated conditions when the chemical iron oxidation is retarded by low water temperature and inhibition of the autocatalytic iron oxidation. |
| |
Keywords: | qPCR Gallionella spp Groundwater trickling filtration Biological and chemical iron oxidation |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|