Decolorization and control of bromate formation in membrane ozonation of humic-rich groundwater

Jakob Kämmler; Garyfalia A Zoumpouli; Jörn Sellmann; Y M John Chew; Jannis Wenk; Mathias Ernst

doi:10.1016/j.watres.2022.118739

Decolorization and control of bromate formation in membrane ozonation of humic-rich groundwater

Water Res. 2022 Aug 1:221:118739. doi: 10.1016/j.watres.2022.118739. Epub 2022 Jun 11.

Authors

Jakob Kämmler¹, Garyfalia A Zoumpouli², Jörn Sellmann³, Y M John Chew⁴, Jannis Wenk⁵, Mathias Ernst⁶

Affiliations

¹ Hamburg University of Technology, Institute for Water Resources and Water Supply, Am Schwarzenberg-Campus 3, 21073 Hamburg, Germany; DVGW Research Centre TUHH, Am Schwarzenberg-Campus 3, 21073 Hamburg, Germany.
² Centre for Doctoral Training, Centre for Sustainable Chemical Technologies, University of Bath, Bath BA27AY, United Kingdom; Department of Chemical Engineering, University of Bath, Bath BA27AY, United Kingdom; Water Innovation & Research Centre (WIRC), University of Bath, Bath BA27AY, United Kingdom.
³ Hamburg University of Technology, Institute for Water Resources and Water Supply, Am Schwarzenberg-Campus 3, 21073 Hamburg, Germany.
⁴ Department of Chemical Engineering, University of Bath, Bath BA27AY, United Kingdom; Water Innovation & Research Centre (WIRC), University of Bath, Bath BA27AY, United Kingdom.
⁵ Department of Chemical Engineering, University of Bath, Bath BA27AY, United Kingdom; Water Innovation & Research Centre (WIRC), University of Bath, Bath BA27AY, United Kingdom. Electronic address: jhw46@bath.ac.uk.
⁶ Hamburg University of Technology, Institute for Water Resources and Water Supply, Am Schwarzenberg-Campus 3, 21073 Hamburg, Germany; DVGW Research Centre TUHH, Am Schwarzenberg-Campus 3, 21073 Hamburg, Germany. Electronic address: mathias.ernst@tuhh.de.

PMID: 35716412
DOI: 10.1016/j.watres.2022.118739

Abstract

Membrane ozonation of bromide-containing, high-color natural organic matter (NOM) containing groundwater was performed using single-tube polydimethylsiloxane (PDMS) and multi-tube polytetrafluoroethylene (PTFE) membrane contactors, and compared to batch ozonation. For membrane ozonation, dissolved ozone concentration, water color (VIS₄₃₆), ultraviolet light absorption (UV₂₅₄) and bromate formation were correlated with ozone dose, ozone gas concentration, hydraulic retention time and Hatta number (Ha). NOM color removal of up to 45 % for the single-tube contactor and 17 % for the multi-tube contactor were achieved while containing bromate formation below 10 µg L^-1. Higher color removal using higher ozone doses was associated with high bromate formation i.e. >>10 µg L^-1. In membrane ozonation, low ozone gas concentrations, long hydraulic retention times and high Ha resulted in low dissolved ozone concentrations due to quenching of ozone by NOM. At specific ozone doses of < 0.5 mg O₃/mg DOC and Ha > 1, single-tube ozonation resulted in comparable results to batch ozonation while bromate formation was higher in the single-tube contactor at specific ozone doses > 0.5 mg O₃/mg DOC and Ha < 1. At comparable ozone doses and Ha, bromate formation in the multi-tube contactor was always higher compared to single-tube and batch ozonation. This could be associated with the uneven ozone distribution within the multi-tube contactor. Results show that ozone dose is the major driver for selectivity between bromate formation and NOM color removal in both membrane and batch ozonation. Bromate formation in membrane ozonation may be controlled by adjusting gas concentration, Ha and hydraulic retention time. Membrane module design and process parameters of membrane ozonation reactors significantly affect treatment performance and should be optimized for selective target compound removal over by-product formation.

Keywords: Bromate; Color; Groundwater; Membrane ozonation; NOM; Ozone.

MeSH terms

Bromates
Groundwater*
Ozone*
Water Pollutants, Chemical* / analysis
Water Purification* / methods

Substances

Bromates
Water Pollutants, Chemical
Ozone