Inexpensive Arsenic Filtration System Based on Cattails Could Help Clean Up the Drinking Water of 57 Million People
Photos: Jon Clark/Flickr, CC
Awesome Discovery!According to the World Health Organization's fact sheet about arsenic in drinking water, there are between 46-57 million people globally who are exposed to levels of arsenic higher than the "safe" 0.01 mg/l. Many of those are in poor countries where expensive filtration systems are out of reach, which is why Jeremiah Jackson's invention is so important! The civil and environmental engineer created a cheap filtration system based on cattails, and he didn't patent it so that it is more accessible. Read on for more details on how it works.
It all started when Jeremiah's brother told him about the big problem of arsenic in drinking water in eastern India and Bangladesh. These areas were encouraged to stop drinking surface water years ago because it was contaminated by various pathogens, so people started drinking water from wells. What wasn't known at the time was that the ground water was naturally contaminated by arsenic ("about six times the world recommended [safe] maximum amount of arsenic").
In India, it chronically shortened people's life spans to 55 years, which is about 35 years less than what we have; and primarily that's attributed to the arsenic poisoning. It's a terrible way to live and die. You eventually get cancer and it affects a whole series of organs in your body.
How to Get that Arsenic Out?First he started by looking at what was already known about arsenic removal by aquatic plants, and found pretty much nothing. So he set up an experiment on his patio, with some buckets containing cattails. In some buckets he added arsenic, and in others he didn't (as a control). After taking regular measurements, he found that the cattails were absorbing the arsenic and cleaning up the water.
The next step was to build a prototype cheap enough that an average Indian family could build it to filter about 50 liters of drinking water each day. No moving parts, nothing fancy. He built it out of a kiddie pool: "about 18 inches deep and about 3.5 feet in diameter or about 12 square feet of surface area accommodating about 12 cattails."
Photo: Flickr, CC
After 6 weeks of running the experiment, he found that the filtration system removed about 89% of the arsenic in the water and brought it below levels considered safe.
He said: "The cattail actually thinks the arsenic is a nutrient. It absorbs it as if were a nutrient, a fertilizer. And I found the plants actually flourished."
If that's not awesome, I don't know what is. This could help millions of people cheaply and in an environmentally friendly way. Of course, the cattails probably will have to be disposed of properly at some point after they have absorbed a certain amount of arsenic, but that's a much smaller problem than drinking arsenic-poisoned water on a daily basis.
And this is just a start! Maybe other plants are even better at removing arsenic from water.
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