Lack of access to clean water is a growing problem all over the developing world. The United Nations Millennium Development Goals recognize the importance of clean water and so aim to half the world’s population without sustainable access to safe drinking water by 2015. The following info graphic provides more statistics on the effects of clean water.
In order to reach this goal, multiple organizations have taken to designing water filters and water distribution systems in areas where simply digging a well is inefficient or not possible. As a team, we looked into these filters to help brainstorm for our design.
The most common type of filter is a Slow-sand filter. Under suitable conditions, this is often the simplest and cheapest option for water treatment with costs ranging from $15-60 per filter on average. It consists of layers of sand which remove particulates from the water and gravel that supports the sand.
An adaptation to the slow sand filter is the Bio-Sand filter. The differentiating factor is a thin bio-layer that grows on top of the sand. Bacteria and other microorganisms present in this layer eat the pathogens present in water, improving the level of water treatment. Slow-sand and Biosand filters have been successfully implemented in a number of developing countries including Cambodia, Honduras, Haiti, India, Afghanistan and many more. The picture below depicts a typical BioSand Filter.
Ceramic Filters are another type of water filtration technology that are gaining popularity in places like Cambodia where rice husk produced by rural farmers is molded into a pot and fired up, producing a porous filter element. This filter is an example of developing appropriate technology or technology that makes efficient use of local resources to minimize cost.
There are also more generic short-term solutions such as the LifeStraw water filter. Named Time Magazine’s “Best Invention of the year” in 2005, the filter is designed to enable users to drink water from contaminated sources during emergencies such as flooding.
The development and research of so many water filters provides a good base from which more location-specific filters can be designed to serve a population for a longer time period based on community needs, available resources and cultural/environmental/political restraints.