Field and Laboratory Assessment of a New Electrolytic Point-of-Use Water Treatment Technology

Abstract

This research creates and implements a new electrolytic point-of-use water treatment (POUWT) device. Device development began by applying two voltages common to commercially available batteries to an apparatus with either two silver or copper wires submerged into synthetic groundwater. The effects of wire diameter, ionic strength of groundwater, and other POUWT parameters on metallic ion release were analyzed. We determined that the silver wire apparatus need only to be run for 2 min at 9 V to yield the target 50 µg/L concentration for water treatment. The 50 µg/L silver yielded up to a 5-log reduction in E. coli bacteria. The copper wire apparatus was excluded in prototype fabrication because it required 62 min to release the target 500 µg/L for disinfection when nine volts were applied to the system and was less effective in disinfection than silver wires. The electrolytic prototype was evaluated in 20 households in Limpopo, South Africa, over a four-week period. The device achieved a 2-log reduction in total coliform bacteria in household drinking water, which is comparable to the field performance of other POUWT devices in low-resource settings. The device also consistently released enough silver sufficient for disinfection while remaining below the WHO drinking water guideline.