Predatory bacteria in combination with solar disinfection and solar photocatalysis for the treatment of rainwater

Monique Waso, S. Khan, Anukriti Singh, Stuart McMichael, W. Ahmed, Pilar Fernandez-Ibanez, John Byrne, Wesaal Khan

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The predatory bacterium, Bdellovibrio bacteriovorus, was applied as a biological pre-treatment to solar disinfection and solar photocatalytic disinfection for rainwater treatment. The photocatalyst used was immobilised titanium-dioxide reduced graphene oxide. The pre-treatment followed by solar photocatalysis for 120 min under natural sunlight reduced the viable counts of Klebsiella pneumoniae from 2.00 × 10 9 colony forming units (CFU)/mL to below the detection limit (BDL) (<1 CFU/100 μL). Correspondingly, ethidium monoazide bromide quantitative PCR analysis indicated a high total log reduction in K. pneumoniae gene copies (GC)/mL (5.85 logs after solar photocatalysis for 240 min). In contrast, solar disinfection and solar photocatalysis without the biological pre-treatment were more effective for Enterococcus faecium disinfection as the viable counts of E. faecium were reduced by 8.00 logs (from 1.00 × 10 8 CFU/mL to BDL) and the gene copies were reduced by ∼3.39 logs (from 2.09 × 10 6 GC/mL to ∼9.00 × 10 2 GC/mL) after 240 min of treatment. Predatory bacteria can be applied as a pre-treatment to solar disinfection and solar photocatalytic treatment to enhance the removal efficiency of Gram-negative bacteria, which is crucial for the development of a targeted water treatment approach.

Original languageEnglish
Article number115281
Pages (from-to)1
Number of pages9
JournalWater Research
Issue number1
Early online date8 Nov 2019
Publication statusPublished - 1 Feb 2020



  • Bdellovibrio bacteriovorus
  • Biological pre-treatment
  • Harvested rainwater
  • Photocatalysis
  • Solar disinfection

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