In May, 2012, I returned to Nicaragua with Aqua Clara International and Fairmount Minerals. We worked with the slow sand filters that Aqua Clara and a group called AMOS have been installing throughout the country. Access to safe drinking water is a major health issue Nicaragua and in many other places around the world. Slow sand filtration is not new, nor is it unique to Aqua Clara or Nicaragua. The ones I’m talking about provide drinking water to a single household but they can also be bigger to serve a school or community. Household filters come in different shapes and sizes, depending on whose design it is and what materials are available. Basically, it is a container with a layer of coarse gravel at the bottom with smaller and small gravel on top of that, until finally the topmost layer is fine sand. Dirty water is poured in at the top and displaces filtered water so the good stuff just pours out the tap. The sand does more than simply strain out the bad stuff – it supports a biological environment that gives the harmless microbes the opportunity to eat or out-compete the ones that make people sick. It’s a simple but highly effective technology for the prevention of water-borne diseases.
Household slow sand filters are normally made by local people with locally available materials, which serve an overarching goal of helping people to help themselves. When parts and materials are not specially imported, a drinking water filter becomes more financially accessible to the end user and more serviceable. Another important benefit of this strategy is that the builders develop an intimate understanding of how these things are supposed to work – this enables them to also teach about and repair the units.
One of the interviews we had in May included a family that had been using the slow-sand filter for about six months. The father reported that he can now work every day because he no longer feels weak, and specific health issues were better than they had been in years. He felt this was because he was now drinking the filtered water. That made sense considering the consequences for an adult body to be constantly fighting off infections in the gut.
Simply put, slow sand filters can and do change and save lives every day. If you’re interested in exploring further, here are just a few links to some of the many resources available on the subject.
An additional list of resources for slow sand filters can be found here.
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