Issue 9, 2020

Comparison of the impact of ozone, chlorine dioxide, ferrate and permanganate pre-oxidation on organic disinfection byproduct formation during post-chlorination

Abstract

Pre-oxidation is commonly used to mitigate the formation of byproducts during post-disinfection. A comparative study of the impact of four pre-oxidants, ozone (O3), chlorine dioxide (ClO2), permanganate (Mn(VII)) and ferrate (Fe(VI)), on the formation of trihalomethanes (THMs), haloacetonitriles (HANs) and adsorbable organic halogens (AOX) in chlorinated synthetic and real waters was conducted. The pre-oxidant doses were based on their impact on natural organic matter reactivity measured by the electron donating capacity before chlorination. The influence of pH (6.5–8.1) and bromide (0–500 μg L−1) was evaluated in terms of disinfection byproduct (DBP) formation and theoretical toxicity assessment (based on THM and HAN formation). All oxidants were efficient in mitigating chlorinated DBPs, except Mn(VII) which had little impact on THM formation. O3 was generally more efficient than the other oxidants in mitigating AOX and THM formation, all pre-oxidants readily reduced the formation of HANs (>45% reduction at high dose). pH depression improved AOX mitigation by O3 and Fe(VI) but diminished Mn(VII) efficiency for all DBPs. Pre-oxidation was less efficient in mitigating brominated DBPs and generally enhanced the bromine substitution factor. Although HANs were formed at low concentrations compared to THMs, they dominated the calculated toxicity, particularly the brominated HANs. The increased dibromoacetonitrile formation after pre-oxidation was a major factor counteracting the benefits of the overall DBP mitigation. In the presence of bromide, the pre-oxidant dose should be optimized to decrease the reactivity of the matrix while controlling the toxicity induced by formation of brominated DBPs, notably brominated HANs.

Graphical abstract: Comparison of the impact of ozone, chlorine dioxide, ferrate and permanganate pre-oxidation on organic disinfection byproduct formation during post-chlorination

Supplementary files

Article information

Article type
Paper
Submitted
29 apr 2020
Accepted
15 jún 2020
First published
16 jún 2020

Environ. Sci.: Water Res. Technol., 2020,6, 2382-2395

Comparison of the impact of ozone, chlorine dioxide, ferrate and permanganate pre-oxidation on organic disinfection byproduct formation during post-chlorination

V. Rougé, U. von Gunten, M. Lafont de Sentenac, M. Massi, P. J. Wright, J. Croué and S. Allard, Environ. Sci.: Water Res. Technol., 2020, 6, 2382 DOI: 10.1039/D0EW00411A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements