A Bucket Solution

Ken Evans, technology director for Canada-based aluminum giant Alcan, read about the Bangladeshis’ plight 10 years ago in an Indian news-paper and started noodling. The answer he came up with was an exceedingly simple system: two buckets connected by a hose. The red bucket is filled with granules of alumina, an aluminum oxide. When arsenic-laced water is poured in, the alumina molecules bond with the arsenic, removing the poison. The purified water then flows into the green bucket, ready to drink.

The product, called Actiguard, is actually a simplified version of a product Alcan already sells to communities in the United States for filtering well water laced with a variety of impurities from arsenic to zinc. Alcan developed an enhanced alumina granule that’s shaped in such a way as to maximize the amount of exposed surface. That increases contact between the water and alumina molecules, giving the alumina more opportunities to grab onto them.

Maintenance of the two-bucket system is easy enough. The buckets need to be cleaned periodically to remove gunk, and the alumina granules have to be replaced when they lose their zap. (The old ones can be mixed into concrete and used to pave roads.) All told, Alcan estimates that the buckets cost about $3.20 per person per year. That’s a pretty cheap answer to an otherwise pricey problem.

title: “A Bucket Solution” ShowToc: true date: “2023-01-01” author: “Cynthia Wood”

BECAUSE BANGLADESH’S WELLS weren’t dug deep enough to avoid arsenic, up to 80 million people may already be poisoned. The obvious solution is to dig the wells deep enough to hit the arsenic-free aquifers. But even with $44 million earmarked from the World Bank to fight arsenic poisoning, the government still doesn’t have the money, equipment or expertise to tackle the problem.

Ken Evans, technology director for Canada-based aluminum giant Alcan, read about the Bangladeshis’ plight 10 years ago in an Indian news-paper and started noodling. The answer he came up with was an exceedingly simple system: two buckets connected by a hose. The red bucket is filled with granules of alumina, an aluminum oxide. When arsenic-laced water is poured in, the alumina molecules bond with the arsenic, removing the poison. The purified water then flows into the green bucket, ready to drink.

The product, called Actiguard, is actually a simplified version of a product Alcan already sells to communities in the United States for filtering well water laced with a variety of impurities from arsenic to zinc. Alcan developed an enhanced alumina granule that’s shaped in such a way as to maximize the amount of exposed surface. That increases contact between the water and alumina molecules, giving the alumina more opportunities to grab onto them.

Maintenance of the two-bucket system is easy enough. The buckets need to be cleaned periodically to remove gunk, and the alumina granules have to be replaced when they lose their zap. (The old ones can be mixed into concrete and used to pave roads.) All told, Alcan estimates that the buckets cost about $3.20 per person per year. That’s a pretty cheap answer to an otherwise pricey problem.