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

Abstract

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.

Citation

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
• Public URL: https://rgu-repository.worktribe.com/output/1769140