Elsevier

Water Research

Volume 186, 1 November 2020, 116387
Water Research

Enhancing solar disinfection (SODIS) with the photo-Fenton or the Fe2+/peroxymonosulfate-activation process in large-scale plastic bottles leads to toxicologically safe drinking water

https://doi.org/10.1016/j.watres.2020.116387Get rights and content
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open access

Highlights

  • SODIS and solar-assisted oxidative treatments were assayed in large scale plastic bottles.

  • 5-log bacterial inactivation was attained both in 25-L PET and 19-L polycarbonate bottles.

  • The choice of material influences the oxidative processes of E. coli inactivation pathways.

  • Testing of leachables showed no mutagenicity & estrogenicity was higher for polycarbonate.

  • The levels of estrogenic activity detected were not a threat to human health.

Abstract

Solar disinfection (SODIS) in 2-L bottles is a well-established drinking water treatment technique, suitable for rural, peri‑urban, or isolated communities in tropical or sub-tropical climates. In this work, we assess the enlargement of the treatment volume by using cheap, large scale plastic vessels. The bactericidal performance of SODIS and two solar-Fe2+ based enhancements, namely photo-Fenton (light/H2O2/Fe2+) and peroxymonosulfate activation (light/PMS/Fe2+) were assessed in 19-L polycarbonate (PC) and 25-L polyethylene terephthalate (PET) bottles, in ultrapure and real water matrices (tap water, lake Geneva water). Although SODIS always reached total (5-logU) inactivation, under solar light, enhancement by or both Fe2+/H2O2 or Fe2+/PMS was always beneficial and led to an increase in bacterial elimination kinetics, as high as 2-fold in PC and PET bottles with tap water for light/H2O2/Fe2+, and 8-fold in PET bottles with Lake Geneva water. The toxicological safety of the enhancements and their effects on the plastic container materials was assessed using the E-screen assay and the Ames test, after 1-day or 1-week exposure to SODIS, photo-Fenton and persulfate activation. Although the production of estrogenic compounds was observed, we report that no treatment method, duration of exposure or material resulted in estrogenicity risk for humans, and similarly, no mutagenicity risk was measured. In summary, we suggest that SODIS enhancement by either HO- or SO4-based advanced oxidation process is a suitable enhancement of bacterial inactivation in large scale plastic bottles, without any associated toxicity risks.

Keywords

Solar disinfection (SODIS)
Drinking water
Oxidation process
Toxicity
Plastic leachables
E. coli

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