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Trihalomethanes (THMs) Formation in Point of Use Surface Water Disinfection with Chlorine or Chlorine Dioxide Tablets

Lookup NU author(s): Professor David WernerORCiD, Maria Valdivia-Garcia



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


In remote or underdeveloped areas, natural disaster emergencies and armed conflict zones, point-of-use surface water disinfection with chlorine tablets provides microbiologically safe water, but disinfection by-products such as trihalomethanes (THMs) are formed. While the health risks from THMs are much less than the risks from consuming microbiologically unsafe water, it is nonetheless desirable to understand and minimize THM formation. We show that THM concentrations in surface water samples from the Northern British Isles disinfected with chlorine tablets increased with contact time, in some cases to significantly exceeded EU, US EPA and WHO drinking water guidance values after more than an hour. More stagnant water from ponds and lochs had higher THM formation than river water. Doubling the chlorine tablet dose slightly enhanced THM formation, and passing water through coffee filter paper reduced it. Chlorine dioxide tablets produced minimal amounts of THMs.

Publication metadata

Author(s): Werner D, Valdivia-Garcia M, Weir P, Haffey M

Publication type: Article

Publication status: Published

Journal: Water and Environment Journal

Year: 2016

Volume: 30

Issue: 3-4

Pages: 271-277

Print publication date: 01/09/2016

Online publication date: 06/10/2016

Acceptance date: 12/09/2016

Date deposited: 21/09/2016

ISSN (print): 1747-6585

ISSN (electronic): 1747-6593

Publisher: Wiley-Blackwell Publishing Ltd


DOI: 10.1111/wej.12209


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Funder referenceFunder name
Scottish Water through a STREAM studentship award
EP/G037094/1Engineering and Physical Sciences Research Council (EPSRC)