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.

• World Health Organization, Water Sanitation and Health, "Slow Sand Filtration"
• Surfers Without Borders, "Slow Sand Filtration"
• National Environment Service Center, National Drinking Water Clearinghouse, "Slow Sand Filtration"
• Biosand Filter
• Centre for Affordable Water and Sanitation Technology (multiple resources on Biosand Filters)

An additional list of resources for slow sand filters can be found here.

Contact Mark B.

Aqua Clara provides point-of-use water filters to impoverished people in developing countries. Kinetico hosted an information session where employees from Kinetico and Fairmount Minerals learned how these slow-sand water filters are made and about the programs that train people in rural communities how to make and maintain them. 

Nicaragua is the second poorest nation in the western hemisphere: the average income is about three dollars a day. There are major health problems, especially in rural areas, caused by drinking contaminated water. As a result, people have to spend money on medicines to treat water-borne diseases. Because they are sick so often, they have less time for work or going to school. This reinforces a cycle of poverty and disease that can be difficult to break without outside resources.

The Aqua Clara program includes educating the end-users on why the slow-sand filters are important and how to build, use and maintain them. A key part of program success is regular follow-up visits for additional support. In November 2011, I went to Nicaragua to be part of a team that included folks from Fairmount Minerals, Aqua Clara and Nicaraguans. We went to remote villages to see whether existing slow-sand filters were being used properly and to find out how effective they actually were. Deep in the tropical volcanic hills, we were greeted by village leaders and taken to homes where filters had been installed. The water filters were frequently located in a hot, dark kitchen that was sometimes just 6’ x 7’, had a swept dirt floor, a tin roof, and walls made from whatever was available. Often chickens and other animals were present. 

The filters we examined ranged from months to years old. Our assessments included household interviews mostly with the matriarchs. In many places, it is not unusual for women and older girls to be responsible for making sure the home has enough water for their cooking and cleaning as well as for the family to drink. In many African villages this can mean a child has to walk for miles to bring the water back home, though where we were in Nicaragua water was drawn from nearby wells. Our site visits also included measuring turbidity and taking water samples from the raw source and the filter outlet so we could grow bacteria on special plates and find out just how bad the situation was.

As you can see from the photo, these filters dramatically reduced the amount of bacteria in the water. The blue spots are actually colonies of dangerous E. coli, and the red spots are coliform bacteria.

Once the bacteria plates had time to incubate and I saw the results, I took a moment to look around again. What I saw were toddlers exploring and children laughing, playing and going to school. I saw families who depend on being healthy enough to make whatever living they could from small plots of land way out in the hinterlands. As a former Peace Corps Volunteer, it not only brought back memories, but also reinforced why this kind of work continues to be so important. Health in rural communities like the ones we were in starts with clean water. It’s good to be part of a company that intimately knows the value of water and is committed to sharing our knowledge to help others gain access to safe and adequate supplies.

Photos courtesy of Dave Chew.

Contact Mark B.

A boil water alert (BWA) is issued when there is a threat of disease causing microorganisms such as Giardia lamblia and Cryptosporidium entering a water system. Contamination can be caused by several different factors, most commonly due to water main breaks or severe flooding which might allow the possibility of foreign substances to enter the water system.  In less common instances a BWA can be issued when there is a significant change in the turbidity reading. A BWA is issued after careful consideration among representatives from public health, regulatory agencies and municipal departments. 

When there is a BWA, it will be broadcast on the local news (radio, television, web) with instructions on what to do and how long it will last. 

The best way to make sure your water is safe for drinking, cooking or brushing your teeth is to boil your water.  To effectively kill the disease causing organisms, boil the water for at least one to five minutes.  Allow water to cool before use.  The water will taste “flat” but will be safe to use.  If you are unable to boil your water, you can use bleach or iodine.  Bleach will kill some, but not all, types of disease-causing organisms that may be in the water.  Add 1/8 teaspoon of regular, unscented, liquid household bleach for each gallon of water, stir it well and let it stand for 30 minutes before you use it. Store disinfected or boiled water in clean, air-tight containers with covers in the refrigerator. 

Hot (not boiled) soapy water will be sufficient for dishwashing and surface cleaning.  As a precaution, add one tablespoon of bleach per gallon. Unless specifically list in the BWA, laundry water and water for showering does not need to be treated.

Boil alerts are mostly for city and community water supplies.  If you have a well, you would want to boil your water after severe flooding or if your well pressure drops to almost non-existent (indicating a potential problem).  After correcting the problem or when the water recedes, it is recommended that you have your water tested by your local EPA certified laboratory to make sure it is safe to drink.

For a list of local certified laboratories or more information on safe drinking water, a very informative, reliable source is the EPA. 

Contact Cathy J.