Water Filtration in Rural Nicaragua

Approximately 60% of households in the rural village of El Triumfo, Nicaruaga, have their own personal wells, but the water is not clean enough for drinking. Thus villagers resort to travelling long distances to a World Vision certified community well. Furthermore, families are forced to either boil or purchase purified water for their newborns to prevent illness, which adds additional economic stress.The capstone team was tasked with considering ways of providing clean drinking water to El Triunfo, with cooperation from the local NGO Seed of Learning (SoL) and Winds of Change. The focus of the design was affordability, while leveraging locally sourced materials and labour.

After considering different systems, the group settled on the Clay Disk Filtration technology which uses a precise combination of fired clay-dirt and organic material to create a selectively permeable material that can effectively filter out bacteria contaminates. The final design culminated in a week-long trip to the community to build a full-scale prototype with the help of the local Mederano family. To produce the final filters, a high temperature kiln is required and was produced using an oil drum, bricks, steel rebar, and a propane torch. This kiln provides long term infrastructure for producing low cost filters. The final product is a 200mm diameter clay disk that is 6:1 ratio clay-dirt to rice husks- our locally sourced organic material of choice. Once these filters are created, two stacked buckets with a concentrically cut hole in the top bucket and a spigot inserted into the bottom bucket, creates a counter top reusable water filter that can easily be used by a family.

After the research trip, it was crucial to test whether the design was practical from a performance and cost perspective.  Iodine testing was conducted on prototype filters in both Toronto and Nicaragua showing initial filter efficacy of 93%, although lab testing will be required to get a full picture of bacterial removal rates.

With an infrastructure cost of $779 and a unit cost of $10, the filters can be locally made and sold at a 60% profit, creating a sustainable business. This is a great success, since clean water could be available in the community for as little as 2 cents per day.