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A paradigm-shift in water treatment: in-reservoir UV-LED-driven TiO2 photocatalysis for the removal of cyanobacteria: a mesocosm study.

Pestana, Carlos J.; Capel-Neto, Jose; Hui, Jianing; Robertson, Peter K.J.; Oliveira, Samylla; Rogers, Ricardo; Santos, Allan; Azevedo, Sandra M.F.O.; Edwards, Christine; Irvine, John T.S.; Lawton, Linda


Jose Capel-Neto

Jianing Hui

Peter K.J. Robertson

Samylla Oliveira

Ricardo Rogers

Allan Santos

Sandra M.F.O. Azevedo

John T.S. Irvine


Potentially harmful cyanobacteria challenge potable water treatment globally, with high biomass events, and dissolved toxic and nuisance metabolites. Retrofitting existing water treatment infrastructure is often impractical (if not impossible) and often prohibitively expensive. In a paradigm-shifting move, we propose in-reservoir pre-treatment of cyanobacteria-contaminated raw waters to ease the burden on existing water treatment infrastructure. In an iterative design approach over three years, treatment modules have been designed, refined and optimised, in bench and pilot-scale studies for in-reservoir deployment. TiO2-coated beads made from recycled glass are employed in conjunction with UV-light emitting diodes (LEDs), to create highly reactive hydroxyl radicals that preferably remove cyanobacteria and subsequently released cyanotoxins from raw water. In a mesocosm study using a drinking water reservoir in Brazil, water quality parameters were markedly improved within 72h of deployment and cyanobacterial presence was decreased by over 90% without affecting other phytoplankton communities. The treatment system is virtually plastic-free, low cost, utilises recycled materials and could ultimately be powered by renewable energies, thus providing a true green treatment option. We have conclusively demonstrated that a paradigm-shift towards in-reservoir treatment is not only possible but feasible and can provide a valuable addition to conventional water treatment methods.


PESTANA, C.J., CAPELO-NETO, J., HUI, J., ROBERTSON, P.K.J., OLIVEIRA, S., ROGERS, R., SANTOS, A., AZEVEDO, S.M.F.O., EDWARDS, C., IRVINE, J.T.S. and LAWTON, L.A. 2022. A paradigm-shift in water treatment: in-reservoir UV-LED-driven TiO2 photocatalysis for the removal of cyanobacteria: a mesocosm study. Presented at the 12th International conference on toxic cyanobacteria (ICTC 2022), 22-27 May 2022, Toledo, USA.

Presentation Conference Type Lecture
Conference Name 12th International conference on toxic cyanobacteria (ICTC 2022)
Conference Location Toledo, USA
Start Date May 22, 2022
End Date May 27, 2022
Deposit Date Oct 5, 2022
Publicly Available Date Jan 23, 2023
Keywords Cyanobacteria; Water treatment; Photocatalysis; Titanium dioxide
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