Comparison of different solar reactors for household disinfection of drinking water in developing countries: evaluation of their efficacy in relation to the waterborne enteropathogen Cryptosporidium parvum.

Solar water disinfection (SODIS) is a type of treatment that can significantly improve the microbiological quality of drinking water at household level and therefore prevent waterborne diseases in developing countries. Cryptosporidium parvum is an obligate protozoan parasite responsible for the diarrhoeal disease cryptosporidiosis in humans and animals. Recently, this parasite has been selected by the WHO as a reference pathogen for protozoan parasites in the evaluation of household water treatment options. In this study, the field efficacy of different static solar reactors [1.5 l transparent plastic polyethylene terephthalate (PET) bottles as well as 2.5 l borosilicate glass and 25 l methacrylate reactors fitted with compound parabolic concentrators (CPC)] for solar disinfection of turbid waters experimentally contaminated with C. parvum oocysts was compared. Potential oocyst viability was determined by inclusion/exclusion of the fluorogenic vital dye propidium iodide. The results demonstrate that static solar reactors fitted with CPCs are an excellent alternative to the conventional SODIS method with PET bottles. These reactors improved the efficacy of the SODIS method by enabling larger volumes of water to be treated and, in some cases, the C. parvum oocysts were rendered totally unviable, minimising the negative effects of turbidity.

Gómez-Couso H ，Fontán-Sainz M ，Navntoft C ，Fernández-Ibáñez P ，Ares-Mazás E ... -  《-》

Speeding up the solar water disinfection process (SODIS) against Cryptosporidium parvum by using 2.5l static solar reactors fitted with compound parabolic concentrators (CPCs).

Water samples of 0, 5, and 100 nephelometric turbidity units (NTU) spiked with Cryptosporidium parvum oocysts were exposed to natural sunlight in 2.5l static borosilicate solar reactors fitted with two different compound parabolic concentrators (CPCs), CPC1 and CPC1.89, with concentration factors of the solar radiation of 1 and 1.89, respectively. The global oocyst viability was calculated by the evaluation of the inclusion/exclusion of the fluorogenic vital dye propidium iodide and the spontaneous excystation. Thus, the initial global oocyst viability of the C. parvum isolate used was 95.3 ± 1.6%. Using the solar reactors fitted with CPC1, the global viability of oocysts after 12h of exposure was zero in the most turbid water samples (100 NTU) and almost zero in the other water samples (0.3 ± 0.0% for 0 NTU and 0.5 ± 0.2% for 5 NTU). Employing the solar reactors fitted with CPC1.89, after 10h exposure, the global oocyst viability was zero in the non-turbid water samples (0 NTU), and it was almost zero in the 5 NTU water samples after 8h of exposure (0.5 ± 0.5%). In the most turbid water samples (100 NTU), the global viability was 1.9 ± 0.6% after 10 and 12h of exposure. In conclusion, the use of these 2.5l static solar reactors fitted with CPCs significantly improved the efficacy of the SODIS technique as these systems shorten the exposure times to solar radiation, and also minimize the negative effects of turbidity. This technology therefore represents a good alternative method for improving the microbiological quality of household drinking water in developing countries.

Gómez-Couso H ，Fontán-Sainz M ，Fernández-Ibáñez P ，Ares-Mazás E ... -  《-》

Efficacy of the solar water disinfection method in turbid waters experimentally contaminated with Cryptosporidium parvum oocysts under real field conditions.

Gómez-Couso H ，Fontán-Saínz M ，Sichel C ，Fernández-Ibáñez P ，Ares-Mazás E ... -  《-》

Disinfection of drinking water contaminated with Cryptosporidium parvum oocysts under natural sunlight and using the photocatalyst TiO2.

Méndez-Hermida F ，Ares-Mazás E ，McGuigan KG ，Boyle M ，Sichel C ，Fernández-Ibáñez P ... -  《JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY》

Batch solar disinfection inactivates oocysts of Cryptosporidium parvum and cysts of Giardia muris in drinking water.

McGuigan KG ，Méndez-Hermida F ，Castro-Hermida JA ，Ares-Mazás E ，Kehoe SC ，Boyle M ，Sichel C ，Fernández-Ibáñez P ，Meyer BP ，Ramalingham S ，Meyer EA ... -  《JOURNAL OF APPLIED MICROBIOLOGY》