In the Cambodian village of Prek Toal, everything floats. Houses, schools, grocery stores, a police station, and even beauty salons and a mechanics shop all rest on boats in the middle of a sprawling lake, relocating with the lake's expansion as the water rises and falls 30 feet throughout the year.
This mobile village, one of 200 on the lake, doesn't have modern plumbing. And that leads to a major challenge: Nearly 100,000 people who live on or near the lake use the water as an open bathroom, spreading bacteria that cause deadly illnesses like diarrhea and cholera. Now, an organization called Wetlands Work is hoping to scale a new technology that can help: floating toilets that use wetland plants to filter and clean the waste.
Wastewater goes into a pod, where plants like water hyacinth, which have trillions of beneficial microorganisms attached to the surface area of the roots, can reduce harmful bacteria like E. coli by 99.999%. This microbial treatment process works especially well in warm climates like Cambodia.
The floating toilets can be made cheaply from local materials. "Our technical invention is the first truly appropriate sanitation technology for a floating household," says Taber Hand, founder and director of Wetlands Work. The tech is low-cost, needs very little maintenance (or none at all), needs no power source or chemicals, and doesn't require much behavior change.
Right now, Hand argues that it's the only viable solution for floating households, even though countless other designs exist for better sanitation on land.
The organization is working through a grant to WaterAid Cambodia from the Grand Challenges Canada program to start marketing HandyPods to the floating villages on the lake. Local businesses will be trained how to source materials and make and market the pods, and then Wetlands Work will introduce educational programs within the communities to increase demand.
It isn't an easy challenge—many people in the isolated floating villages may have never even seen a toilet, and they'll have to be convinced that it's something that they want. Manufacturing will cost at least $30, not cheap by local standards, but the organization plans to use microfinance programs to let people pay over time.
After scaling up in Cambodia, Wetlands Work! hopes to bring it to other floating or flood-prone communities around the world, especially as populations swell in cities near water in places like Bangladesh or Nigeria.
"Because most cities are established along waterways and estuaries, I anticipate many more people will be living on water and on the most marginal, high water table and flood-prone lands," says Hand. "While there is yet to be any planning for such a human predicament, WW expects that both the floating HandyPod and our new land-based flood prone treatment system can provide templates for the sanitation solution."