Getting a drink of water in rural Kenya might mean a six-mile walk to a well. But a new kit for a DIY water filter makes it possible to cheaply purify polluted water from nearby sources instead.
Most water filters rely on chemicals that quickly run out. But the Sustainable Filtration Kit lets anyone make their own carbon filter from free local materials. “All you need is scrap wood to produce the carbon, then any old plastic bottle can be turned into an effective water filter,” says designer Christopher Rothera, a student at the University of Nottingham.
“It doesn’t make use of chemicals, which many other water filters do,” he says. “The issue with these chemical filters is that, though they do work, it is often the case that people … don’t know how to replace them, how to use them properly, or most likely, simply can’t afford it.”
The kit comes with a container that someone can pack with dry wood, close up, and then put on an open fire while cooking dinner. After the container cools, they can crush the carbon into a fine powder and add it into a provided filter with gravel and sand. The instructions are provided in simple illustrations.
Because the container cooks the wood without oxygen, the result is high purity carbon equivalent to what a company like Brita might sell in their filters. Without a tool like this, it isn’t possible to make carbon safely. “The reason you can’t simply use the charcoal you find at the end of your cook fire, or in bags of charcoal for barbecues, is that that is not pure in the slightest and full of contaminants that would poison you and make you very ill, if ingested,” says Rothera.
Rothera was inspired by conversations he’d had with students when he volunteered as an English teacher in a town north of Nairobi. With the kit, he hopes that children who once might have spent time helping gather water can spend that time in school, and women can work.
The filtration kit itself is five liters, and that will produce enough carbon to filter water for one family for weeks. It takes about an hour to produce the carbon and that can be used to make multiple filters. Rothera thinks that the kit could also turn into a small business, as some women focus on making carbon for others.
For now, the design is still a concept, but Rothera hopes to produce it. The design was a recent winner in the RSA Student Design Awards, and he plans to leverage new connections to take the project forward.
“Until these communities get real plumbing and access to clean water, this design could really help people feel safer about the water they drink,” he says.