Biological As(III) oxidation in rapid sand filters

Biological As(III) oxidation in rapid sand filters

Gude, J.C.J. (TU Delft Sanitary Engineering)
Rietveld, L.C. (TU Delft Sanitary Engineering)
van Halem, D. (TU Delft Sanitary Engineering)

2018-02-01

The objective of this study was to investigate whether arsenic-oxidising bacteria (AsOB) will grow and survive in rapid sand filters. Additionally, the interdependence of other groundwater constituents (Fe(II), Mn(II), NH₄) with biological As(III) oxidation was investigated. For this purpose As(III) oxidation was monitored in pilot-scale filter sand columns fed with raw groundwater, as well as treated groundwater (drinking water) with spikes of either As(III), Mn(II) or NH₄. It was concluded that biological As(III) oxidation rapidly developed in the rapid sand filter columns. With a typical lag and log phase, decreasing As(III) and increasing As(V) concentrations in the effluent of the sand columns were observed in a timeframe of weeks. The growth of biomass in the sand columns was confirmed with ATP analysis. ATP concentrations on the sand grains increased from 0.7 ng/g to 16, 8 and 2 ng/g filter sand stratified from the top of the sand filter to the bottom, respectively. Additionally, a microbial community analysis (16S rRNA) showed a high relative abundance of α- and β-Proteobacteria; the same classes where most AsOB are phylogenetically placed. This study establishes that AsOB are able to grow and maintain their population on low As(III) concentrations, either in presence, or absence, of other common groundwater bacteria and mineral precipitates, directly leading to an increased As removal in the filter bed.

Arsenic removal
Biological As(III) oxidation
Groundwater treatment
Rapid sand filtration

http://resolver.tudelft.nl/uuid:68c46212-b644-458b-b401-6cdc2290245d

https://doi.org/10.1016/j.jwpe.2017.12.003

2214-7144

Journal of Water Process Engineering, 21, 107-115

Institutional Repository

journal article

© 2018 J.C.J. Gude, L.C. Rietveld, D. van Halem