The objective of this study was to examine three well designs: drilled wells (20–30 m deep), closed dug wells (>5 m deep), and hand-dug open wells (<5 m deep), to determine the water quality for improving access to safe and clean water in rural communities. Heterotrophic plate count (HPC), total coliforms (TC), Escherichia coli (E. coli) and turbidity, were used to assess the water quality of 97 wells. Additionally, the study looked at the microflora diversity of the water, focusing on potential pathogens using outgrowth, PCR, and genome sequencing for 10 wells. Concentrations of TC for the open dug wells (4 × 104 CFU/100 mL) were higher than the drilled (2 × 103 CFU/100 mL) and closed dug wells (3 × 103 CFU/100 mL). E. coli concentration for drilled and closed dug wells was <22 MPN (most probable number)/100 mL, but higher for open wells (>154 MPN/100 mL). The drilled well turbidity (11 NTU) was within the standard deviation of the closed well (28 NTU) compared to open dug wells (49 NTU). Drilled and closed wells had similar microbial diversity. There were no significant differences between drilled and closed dug wells. The covering and lining of hand-dug wells should be considered as an alternative to improve access to safe and clean water in rural communities.
The household biosand filter (BSF) is a highly utilized point-of-use water treatment tool. The effect of ambient temperature on the ability of the BSF to remove microbes from water is unclear. Model filters were distributed among different temperature-controlled laboratories and dosed daily with surface water amended with sewage. Comparison of the total coliform and Escherichia coli counts in the influent versus effluent revealed an immediate drop in the removal efficiencies of filters held in colder rooms. This performance difference, however, became less pronounced over the course of the experiment until no significant performance difference was detected between filters regardless of their ambient temperature, perhaps due to microbial adaptation within the BSFs. Subsequently, two-thirds of the filters were exposed to freezing temperatures, thawed, and re-tested for microbial removal. All filters exposed to freezing temperatures showed significant drops in microbial removal compared to control filters. Filters exposed to the most extreme temperatures showed the greatest drop in performance.
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