Solar Disinfection of Viruses in Polyethylene Terephthalate Bottles

Abstract

b Solar disinfection (SODIS) of drinking water in polyethylene terephthalate (PET) bottles is a simple, efficient point-of-use technique for the inactivation of many bacterial pathogens. In contrast, the efficiency of SODIS against viruses is not well known. In this work, we studied the inactivation of bacteriophages (MS2 and X174) and human viruses (echovirus 11 and adenovirus type 2) by SODIS. We conducted experiments in PET bottles exposed to (simulated) sunlight at different temperatures (15, 22, 26, and 40°C) and in water sources of diverse compositions and origins (India and Switzerland). Good inactivation of MS2 (>6-log inactivation after exposure to a total fluence of 1.34 kJ/cm 2 ) was achieved in Swiss tap water at 22°C, while less-efficient inactivation was observed in Indian waters and for echovirus (1.5-log inactivation at the same fluence). The DNA viruses studied, X174 and adenovirus, were resistant to SODIS, and the inactivation observed was equivalent to that occurring in the dark. High temperatures enhanced MS2 inactivation substantially; at 40°C, 3-log inactivation was achieved in Swiss tap water after exposure to a fluence of only 0.18 kJ/cm 2 . Overall, our findings demonstrate that SODIS may reduce the load of single-stranded RNA (ssRNA) viruses, such as echoviruses, particularly at high temperatures and in photoreactive matrices. In contrast, complementary measures may be needed to ensure efficient inactivation during SODIS of DNA viruses resistant to oxidation.

Comparison of Trihalomethane Formation Using Chlorine-Based Disinfectants Within a Model System; Applications Within Point-of-Use Drinking Water Treatment

“…Chlorine is the most widely used disinfectant in drinking water treatment due to its availability, low cost, and broad spectrum antimicrobial efficacy (Rodriguez and Serodes, 2001;Farghaly et al, 2013;Kumari and Gupta, 2015). Decentralized point-of-use (POU) drinking water treatment systems typically utilize alternative disinfectant solutions (Mbilinyi et al, 2005;Peter-Varbanets et al, 2009;Domènech, 2011;Attisani, 2016;Carratalà et al, 2016;Pooi and Ng, 2018) or chlorine release tablets (Jain et al, 2010;Werner et al, 2016), rather than conventional chlorination solutions (i.e., NaOCl) for the production of biologically safe water. Alternatives to conventional chlorination are adopted due to quicker disinfection times, ease of transport and storage (Clasen and Edmondson, 2006;Jain et al, 2010).…”

“…Other considerations such as temperature, pH, and contact time within the distribution network (World Health Organization, 2000) are also known to drive THM formation (Brown et al, 2010(Brown et al, , 2011bRasheed et al, 2017). As the knowledge of the toxicological effects of THMs on human health has increased, so has the need to investigate alternative disinfection techniques such as ozonation (Schlichter et al, 2004;Zhu et al, 2014) and UV sterilization (Carratalà et al, 2016). Electrochemical disinfection, either direct or via the application of electrochemically activated solutions (ECAS) has also gained interest (Kerwick et al, 2005;Ghebremichael et al, 2011).…”

Sunlight-mediated inactivation of health-relevant microorganisms in water: a review of mechanisms and modeling approaches

“…5 The most common approach involves lling plastic beverage bottles (e.g., 1.5 L polyethylene terepthlalate (PET)) with water to be treated and exposing them to sunlight for one day; if the weather is cloudy the recommended exposure time is 2 d. 5 The main photochemical mechanism through which bacteria are inactivated during conventional SODIS is via endogenous indirect inactivation; direct inactivation is likely minimal because PET bottles do not transmit UVB light, 222 and exogenous inactivation is likely minimal in most waters used for drinking because few exogenous sensitizers are present. In the absence of high temperatures, inactivation of most viruses during conventional SODIS is likely to be poor, 245 particularly in waters with low photoreactivity, 222 given that sunlight-mediated inactivation of viruses occurs via direct and exogenous mechanisms. The use of container materials that are more transparent to sunlight, in particular UVB wavelengths, can increase photoinactivation of indicator bacteria and viruses by SODIS.…”

Wastewater reuse in agriculture and health risk in Vietnam

“…As water is exposed to sunlight, its temperature increases and microorganisms can be thermally inactivated (See section on heat inactivation). There are some synergetic effects between optical and thermal effects of solar water treatment (Šolić and Krstulović 1992;Wegelin et al, 1994;McGuigan et al, 1998;Berney et al, 2006;Gómez-Couso et al, 2010;Theitler et al, 2012;Giannakis et al, 2014;Carratalà et al, 2015). Most methods of improving the efficiency of sunlight-based water treatment involve maximizing or concentrating sunlight interaction with water (Saitoh and El-Ghetany, 2002;Rijal and Fujioka, 2004;Mani et al, 2006), increasing temperature of the water (Sommer et al, 1997;Rijal and Fujioka, 2001;Rijal and Fujioka, 2004;Martín-Domínguez et al, 2005), or augmenting the concentration of sensitizers in solution by adding photoinducers, photocatalysts, or oxygenating the liquid matrix (Heaselgrave et al, 2006;Fisher et al, 2008;Harding and Schwab, 2012).…”