Disinfection of drinking water contaminated with Cryptosporidium parvum oocysts under natural sunlight and using the photocatalyst TiO2.
The results of a batch-process solar disinfection (SODIS) and solar photocatalytic disinfection (SPCDIS) on drinking water contaminated with Cryptosporidium are reported. Cryptosporidium parvum oocyst suspensions were exposed to natural sunlight in Southern Spain and the oocyst viability was evaluated using two vital dyes [4',6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI)]. SODIS exposures (strong sunlight) of 8 and 12h reduced oocyst viability from 98% (+/-1.3%) to 11.7% (+/-0.9%) and 0.3% (+/-0.33%), respectively. SODIS reactors fitted with flexible plastic inserts coated with TiO2 powder (SPCDIS) were found to be more effective than those which were not. After 8 and 16 h of overcast and cloudy solar irradiance conditions, SPCDIS reduced oocyst viability from 98.3% (+/-0.3%) to 37.7% (+/-2.6%) and 11.7% (+/-0.7%), respectively, versus to that achieved using SODIS of 81.3% (+/-1.6%) and 36.0% (+/-1.0%), respectively. These results confirm that solar disinfection of drinking water can be an effective household intervention against Cryptosporidium contamination.
Méndez-Hermida
Fernando
F
Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain.
Ares-Mazás
Elvira
E
McGuigan
Kevin G
KG
Boyle
Maria
M
Sichel
Cosima
C
Fernández-Ibáñez
Pilar
P
D000818:Animals; D002384:Catalysis; D002470:Cell Survival / Q000502:physiology / Q000528:radiation effects; D016785:Cryptosporidium parvum / Q000254:growth & development / Q000528:radiation effects*; D004203:Disinfection / Q000379:methods*; D033661:Oocysts / Q000254:growth & development / Q000528:radiation effects*; D013472:Sunlight; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*; D014881:Water Supply
C009495:titanium dioxide; D014025:Titanium