Survival of the "Filteresses": Innovative Bangladeshi Women Fashion Water Filters from Old Saris--and Flush Out Cholera in the Process

By: Lizi Jones

Forget thrift stores and etsy--Bangladeshi women have come up with a novel way of repurposing old clothing, with life-saving consequences. Using old saris folded several times to filter water, women in areas without access to safe drinking water have cut rates of cholera by drastic amounts.

Cholera results from infection by a waterborne bacteria that breeds in unsanitary surface water. Clean water is scarce In impoverished areas like Bangladesh, as fuel to boil away contaminants is expensive and hard to find, and frequent floods further inundate the land and dirty what little clean water exists. Cholera runs rampant in these waters, fetching a mortality rate as high as 50 percent in poor countries without adequate medical resources.

This simple innovation, of a sari folded eight times, has the power to remove a staggering [99 percent](http://www.plexusinstitute.org/blogpost/656763/140508/Sustainable-Way-to-Purify-Water-Folded-Saris-Filter-Out-Pathogens) of particulate matter, microbes, and the bacteria that cause cholera from unfiltered water. What’s more, [old saris work better](http://www.sswm.info/category/implementation-tools/water-purification/hardware/point-use-water-treatment/straining-and-fi), as washing them--a simple matter of rinsing and drying in the sun--brings the fibers closer together, creating an even more stringent filter. Dr. Rita Colwell of the Bloomberg School of Public Health at Johns Hopkins [conducted a study in Bangladesh](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC298724/) to model the effectiveness of the sari filtering regimen.

When she returned to Bangladesh [five years later], she found that 60-70 percent of the women she’d taught in her initial study still filtered their water, and had taught women in the neighboring villages to do the same. Even those who did not filter water benefited, as with the reduced incidence of cholera (ensured by the filterers) comes reduced chance of infection for everyone in a community.

While the cloth filter cannot protect against viruses or chemicals in water, it has the ability to block not only cholera, but other waterborne parasites, as well. The [guinea worm that plagues sub-Saharan Africa](http://www.ajtmh.org/content/67/4/415.long) and is generally passed through infected water, for example, cannot pass through mesh created by folded saris.

Colwell’s study was so effective in large part because it educated women in villages about the dangers of unfiltered water, and the effect of that teaching has persisted and multiplied. Following that model and adding simple cloth filters to the education roster of existing public health programs already in the field will reduce the incidence of the highly-preventable cholera worldwide.

It would be interesting to figure out how far the messages travel on their own and where the messages need to be re-introduced! Pass it on!