Bromate reduction by iron(II) during managed aquifer recharge: A laboratory-scale study

Feifei Wang, V.A. Salgado Ismodes, Jan Peter van der Hoek, Doris van Halem

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)
36 Downloads (Pure)

Abstract

The removal of bromate (BrO3 -) as a byproduct of ozonation in subsequent managed aquifer recharge (MAR) systems has so far gained little attention. This preliminary study with anoxic batch experiments was executed to explore the feasibility of chemical BrO3 - reduction in Fe-reducing zones of MAR systems and to estimate potential inhibition by NO3 -. Results show that the reaction rate was affected by initial Fe2+/BrO3 - ratios and by pH. The pH dropped significantly due to the hydrolysis of Fe3+ to hydrous ferric oxide (HFO) flocs. These HFO flocs were found to adsorb Fe2+, especially at high Fe2+/BrO3 - ratios, whereas at low Fe2+/BrO3 - ratios, the mass sum loss of BrO3 - and Br- indicated intermediate species formation. Under MAR conditions with relatively low BrO3 - and Fe2+ concentrations, BrO3 - can be reduced by naturally occurring Fe2+, as the extensive retention time in MAR systems will compensate for the slow reaction kinetics of low BrO3 - and Fe2+ concentrations. Under specific flow conditions, Fe2+ and NO3 - may co-occur during MAR, but NO3 - hardly competes with BrO3 -, since Fe2+ prefers BrO3 - over NO3 -. However, it was found that when NO3 - concentration exceeds BrO3 - concentration by multiple orders of magnitude, NO3 - may slightly inhibit BrO3 - reduction by Fe2+.

Original languageEnglish
Article number370
JournalWater
Volume10
Issue number4
DOIs
Publication statusPublished - 24 Mar 2018

Keywords

  • Bromate reduction
  • Drinking water treatment
  • Iron-reducing zones
  • Managed aquifer recharge
  • Nitrate
  • Ozonation
  • OA-Fund TU Delft

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