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Inactivation of water pathogens with solar photo-activated persulfate oxidation

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posted on 30.09.2019, 13:15 by LC Ferreira, M Castro-Alférez, S Nahim-Granados, MI Polo-López, MS Lucas, Gianluca Li-PumaGianluca Li-Puma, P Fernández-Ibáñez
The effect of solar activated persulfate oxidation and solar mild thermal heating on water disinfection (PS/solar) was demonstrated for the inactivation of E. coli and E. faecalis in both isotonic water (IW) and synthetic urban wastewater (SUWW). The process was studied in both bench-scale and pilot-scale (60 L CPC solar compound parabolic collector) reactors. The impact of solar ultraviolet (UV) and thermal increase on bacterial inactivation were separately studied. The thermal inactivation at 40 °C and 0.5 mM-PS shows a 3-log reduction value (LRV) for E. coli without lag phase and 5-LRV for E. faecalis with a lag phase of 1 h, during 4 h solar exposure. The thermal effect at 50 °C played a dominant role, with fast bacterial decay for both bacteria, which dominates the kinetics over the thermal activation of PS. In the presence of PS and solar irradiation, the combined thermal and UVA effects, accelerated the bacterial process. 6-LRV in E. coli and E. faecalis was observed after solar exposure periods of 20 min (solar dose), using 0.5 and 0.7 mM of PS in IW, respectively. Longer solar exposure times were required to attain similar LRV in synthetic urban wastewater, in the presence of 25 mg/L of organic matter, i.e. 80 and 100 min (solar dose) for E. coli and E. faecalis, respectively. These results were confirmed at pilot scale, where 60 L of IW were treated with 0.5 mM of PS in 50 min (solar dose). The PS/solar process uses low cost chemical reagents (0.5 mM-PS) and a free source of energy (solar radiation) for the treatment of wastewater and is able to achieve the high removals (6-LRV) of the two model faecal indicators of water contamination. This process opens a clear alternative to treat polluted water with organic matter and pathogens with implications in water-energy reclamation field.

Funding

SFERA – Solar Facilities for the European Research Area (228296) and the FCT-Portuguese Foundation for Science and Technology (PD/BD/128270/2017), under the Doctoral Programme “Agricultural Production Chains – from fork to farm” (PD/00122/2012) and the CQVR through PEst-C/QUI/UI0616/2014

European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 660969

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering

Published in

Chemical Engineering Journal

Volume

381

Publisher

Elsevier

Version

AM (Accepted Manuscript)

Rights holder

© Elsevier B.V.

Publisher statement

This paper was accepted for publication in the journal Chemical Engineering Journal and the definitive published version is available at https://doi.org/10.1016/j.cej.2019.122275.

Acceptance date

16/07/2019

Publication date

2019-07-19

Copyright date

2019

ISSN

1385-8947

Language

en

Depositor

Prof Gianluca Li Puma

Article number

122275