The efficacy of chlorine-based disinfectants against planktonic and biofilm bacteria for decentralised point-of-use drinking water

Clayton, Gillian E.; Thorn, Robin; Reynolds, Darren

Abstract

Chlorine solutions are used extensively for the production of biologically safe drinking water. The capability of point-of-use [POU] drinking water treatment systems has gained interest in locations where centralised treatment systems and distribution networks are not practical. This study investigated the antimicrobial and anti-biofilm activity of three chlorine-based disinfectants (hypochlorite ions [OCl-], hypochlorous acid [HOCl] and electrochemically activated solutions [ECAS]) for use in POU drinking water applications. The relative antimicrobial activity was compared within bactericidal suspension assays (BS EN 1040 and BS EN 1276) using Escherichia coli. The anti-biofilm activity was compared utilising established sessile Pseudomonas aeruginosa within a Centre for Disease Control [CDC] biofilm reactor. HOCl exhibited the greatest antimicrobial activity against planktonic E. coli at >50 mg L−1 free chlorine, in the presence of organic loading (bovine serum albumen). However, ECAS exhibited significantly greater anti-biofilm activity compared to OCl- and HOCl against P. aeruginosa biofilms at ≥50 mg L−1 free chlorine. Based on this evidence disinfectants where HOCl is the dominant chlorine species (HOCl and ECAS) would be appropriate alternative chlorine-based disinfectants for POU drinking water applications.

• Journal Article Type: Article
• Acceptance Date: Oct 8, 2021
• Online Publication Date: Nov 4, 2021
• Publication Date: Nov 4, 2021
• Deposit Date: Oct 8, 2021
• Publicly Available Date: Nov 5, 2021
• Journal: npj Clean Water
• Electronic ISSN: 2059-7037
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 4
• Issue: 1
• Article Number: 48
• DOI: https://doi.org/10.1038/s41545-021-00139-w
• Public URL: https://uwe-repository.worktribe.com/output/6653781
• Publisher URL: https://www.nature.com/npjcleanwater/