biosand water filters
Filtration systems have been studied extensively for decades and there are many ways to succeed. And to fail. Studies indicate bio-sand comes out consistently as the best system for impoverished populations, IF the local agent has enough cost in its sell price to educate the users and monitor results pre and post installation, and developing continuous education and user engagement. Los Buenos Vecinos, after consultation with several successful NGOs on similar projects, has projected costs three years forward for monthly service, maintenance, education, monitoring and evaluating in the communities.
Survey takers involved in this project noted alternative filter systems had been delivered a few years ago to some homes but are in disuse now due to lack of funds for replacement liners. Home bio-sand such as those developed by CAWST number in the millions around the world. Maintenance is simple; the friendly microbes which kill 98.5% of the pathogens are kept alive by daily watering. Simple maintenance at no cost. CAWST estimates a 20 year lifespan for a biosand filter.
The sum is greater than the parts: Used stand alone, a home filter is tested to 98.5% purity but reduces water borne infectious diseases 60%. And tippy taps reduce those diseases 47%. Both are effective. But together these simple devices are 90%* effective in reducing the transmission of infectious disease. In other words, clean hands and potable water go together.