2.6 billion people, or 38% of the world, lacks access to what the Word Health Organization (WHO) calls “adequate sanitation.” Inadequate sanitation made diarrhea the top 5 cause of death in the entire world in 2008 followed only by heart disease, stroke, respiratory infection and pulmonary disease. If you narrow your focus to just the developing world, diarrhea is the number 2 cause of death (WHO).
While diarrhea is a preventable disease, clean water systems relying on improved infrastructure are slow and costly to deploy. Recently, I started reading more about some of the challenges facing water and sanitation initiatives in the developing world. Mari and I have also reached out to a couple of incredible organizations including Potters for Peace and Engineers without Borders and hope to work with them further when we are on site in Ecuador.
I have been reading about something called Point of Use (POU) water treatment in low income areas. This is essentially water treated on site, something like a Brita filter or Iodine tablet, rather than relying on larger infrastructure. There is an incredibly illustrative article in Environmental Science and Technology by two professors at the University of North Carolina in Chapel Hill, Mark Sobsey and Christine Stauber called A Practical Solution for Providing Sustained Access to Safe Drinking Water in the Developing World.
The study compares several POU methods based on it’s consistency in producing sufficient quantities of safe water to meet daily household needs. The team also weighed cost, reliability, filtering time and data on continued use after implementation to identify the most promising.
Chlorination – A treatment using a small amount of bleach, has been promoted for some time by Center for Disease Controls (CDC) but is costly and harder to deploy in the developing world. In addition, another drawback is that it requires a constant supply of chemicals that frequently are not available in more remote areas.
Solar Water disinfection (SODIS) – A very accessible form of water treatment is shown to reduce diarrhea rates by 31%. Also, it is as effective as chlorination at killing bacteria. This treatment is simple and easy to deploy. Two liter water bottles are agitated and then left in the sun for 6 hours, often laid on the corrugated roof of the home. Clear disposable water bottles are readily available and the process is simple to teach to end users.
The major drawback with SODIS appeared from field studies that showed that it could not be the only form of water treatment for a community. Because water needed to be bottled in small volumes and left for an extended period of time, people would often supplement their water needs with unfiltered water. All water for washing hands and food preparation ideally should be treated. In the end, users were at a higher risk to a disease-borne illnesses than studies predicted. Even so, I appreciate the simplicity of SODIS. Learn more about it in the following video.
Ceramic Filter – Potters for Peace developed a low-tech manufacturing process to create water filters for remote areas. Check out this inspiring video on Potters for Peace. By mixing sawdust and unfired clay bricks a mixture of clay is developed that is semipermeable. This clay is used to create a filter with small pockets of air distributed in the ceramic, created when the sawdust burned away in the firing process. The ceramic filter lasts for about 2 years and due to its low cost and simplicity in deployment it did not have the same problems as SODIS in user adoption. The study mentioned above rated it as the second best method of water treatment in the developing world.
Biosand Filter – These filters mimic the naturally purification process of water. As water travels through sand and gravel bacteria and protoza become blocked. While this filtering process was less effective than some of the other filters (SOIDS kills 100 times the number of bacteria) it was rated as the most feasible systems in the developing world. People continued to use and maintain the filter after implementation and due to its low cost and accessibility it was possible to deploy these filters to remote areas. Check out this website to read more about biosand filtering.
Those volunteers seeking funding for water and sanitation initiatives note that USAID recently received funding from the Gates foundation and is accepting project applications here.