Capability of 19-L polycarbonate plastic water cooler containers for efficient solar water disinfection (SODIS): Field case studies in India, Bahrain and Spain

[Display omitted] •19L water dispenser containers (WDCS) are effective solar disinfection reactors.•Bacterial log unit reductions>4.0 observed for water in WDCs.•Results confirmed under strong natural sunlight in Spain, Bahrain and India.•WDC SODIS reactors can be used for larger community SODIS applications. The small treated volume (typically ∼2L) associated with polyethylene terephthalate (PET) bottles that are most frequently used in solar water disinfection (SODIS), is a major obstacle to uptake of this water treatment technology in resource-poor environments. In order to address this problem we have conducted a series of experiments in Spain, Bahrain and India, to assess the efficacy of large volume (19L) transparent plastic (polycarbonate) water cooler/dispenser containers (WDCs) as SODIS reactors to inactivate Escherichia coli and Enterococcus faecalis, under strong natural sunlight. Reduction values of 6 log10 units (LRV=6.0) have been observed using WDCs in each location. Additional comparisons between 2-L PET bottles and 19-L indicate that WDCs provide bacterial inactivation similar in both systems. SODIS disinfection experiments in turbid water (100NTU) in both reactors showed very good inactivation efficiency. LRVs of 6 were obtained for E. coli in both WDC and 2-L PET bottles, and in the case of E. faecalis LRV=5 and 6 were observed in Spain and Bahrain, respectively. These studies demonstrate that under conditions of strong sunlight and mild temperature, 19L water dispenser containers can be used to provide adequate volumes of SODIS treated water for households or larger community applications such as schools or clinics in the developing world.