Ferns could be the key to a sorely needed low-cost, electricity-free purification system for millions.
Over 150 million people globally are exposed to arsenic contamination on a daily basis. Figures are ballpark — in Bangladesh, for example, where 35 to 88 million people are affected by the poison, data is hard to come by since autopsies aren’t performed. But no one should mess around with arsenic. Just one drop can leave a swimming pool’s worth of water unsafe for human consumption, with prolonged or increased exposure leading to cancer and death.
Stephen Goodwin Honan, 24-year-old U.S. Navy officer and Oxford University doctoral student, has proposed a novel solution he calls Clean Water. It was voted ‘Idea That Will Change The World’ at London’s Global Design Forum.
Many before him have come up with other water systems, but due to its low cost and simplicity, Honan’s is most feasible. He proposes using locally sourced ferns to filter arsenic. Contaminated water is poured over the plants, whose roots absorb the toxin and produce clean water. After a while, the ferns become saturated with poison and must be retired, but their cache can be harvested in a chemical process and, since arsenic is used to make semiconductors and mobile phones, sold at a profit to companies that need it.
For just $10 worth of starter plants — which can be grown in any watertight container — a typical user can harvest $85 worth of arsenic in a year. The only requirement for success is a green thumb. Honan’s system was tested in Bangladesh with overwhelmingly positive results, he explained:
The paradigm shift is that people will be able to earn money from producing their own clean water as opposed to paying to have clean water. That’s a really big stickiness factor for the design itself.
While Clean Water doesn’t have set plans to move forward with the filter system, Honan said that he is working on developing partnerships so that all parts of the filters can be upcycled — arsenic for computer devices, plant biomass for fertilizer, and plastic containers for future filter systems.
Photos via Wired.