Enhancing Microbial Disinfection in Household Water Treatment by Combining a Silver–Ceramic Tablet with Copper and Chlorine Technologies

The World Health Organization (WHO) estimates that microbiologically contaminated drinking water is estimated to cause 485,000 diarrheal deaths each year. Household water treatment is a low-cost method for reducing the pathogen load in drinking water to decrease instances of diarrhea and sometimes death. This study developed and evaluated a new silver and copper water treatment product that meets WHO one-star performance criteria for household water treatment without using electricity: the MadiDrop+Cu. First, we tested different configurations of a copper mesh and a copper screen with the MadiDrop to evaluate the effects of their proximity to one another on copper and silver concentrations in water. Wrapping the copper mesh around the MadiDrop decreased silver concentrations in water compared with the MadiDrop alone. Folding the copper screen into smaller dimensions decreased the copper concentrations in water compared with the copper screen unfolded. The MadiDrop and copper screen, coined MadiDrop+Cu, provided an average of 125–415 μg/L copper and 4–21 μg/L silver daily for 150 days of use. When tested individually and in combination against E. coli, MadiDrop+Cu removed the most bacteria together rather than separately after 8 h. A previous study found a prototypic chlorinated polymer gel removed more E. coli with the MadiDrop than either intervention alone after 8 h. This study tested the viral (MS2 Bacteriophage) disinfection from the chlorinated polymer and MadiDrop+Cu by themselves and in combination with one another. The MadiDrop alone removed <1 log (90%) of viruses, whereas MadiDrop+Cu removed >3 log (99.9%) after 24 h. The greatest viral disinfection occurred when the MadiDrop+Cu and chlorine-charged polymer gel were used together, removing >4 log (99.99%) after 24 h.