Vortex Impeller-Based Aeration of Groundwater

Maarten V. van de Griend, Francis Warrener, Meike van den Akker, Yanru Song, Elmar C. Fuchs*, Willibald Loiskandl, Luewton L.F. Agostinho

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Iron oxidation and removal from groundwater is a necessary and costly process in drinking water production. In most cases, iron removal is done via aeration, succeeded by precipitation. Most systems for aeration are based on increasing the interfacial area via injecting air in the system or spraying. Both methods have disadvantages, like clogging and formation of aerosols. In this study, a new vortex-based flow-through reactor consisting of a cylindrical tank with an impeller located at the bottom was studied regarding its aeration and iron oxidation capabilities in groundwater. During the aeration experiments, the flow rate, impeller rotation and aerated volume were varied. A nondimensional constant α was proposed to relate the system’s physical characteristics and its aeration capabilities, expressed in dissolved oxygen and system volumetric mass transfer coefficient (KL a). Three distinct operational regimes were defined: formation, complete and bubble regime. These regimes showed very specific characteristics regarding the air–water interface structure and the area to volume ratio, resulting in different aeration capabilities and iron oxidation efficiency values. The system presented KL a values similar to commercially available aeration systems, especially inside the bubble regime. By using dimensionless coefficients, the presented analysis provided the basis for the design of continuous impeller aeration and oxidation systems of arbitrary size.

Original languageEnglish
Article number795
Pages (from-to)795
JournalWater (Switzerland)
Volume14
Issue number5
DOIs
Publication statusPublished - 3 Mar 2022

Keywords

  • Aeration
  • Groundwater treatment
  • Impeller
  • Iron oxidation
  • Vortex

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