Civil engineers participate in projects to provide clean, safe drinking water to communities in developing countries.

Water is fundamental to survival. But clean, safe drinking water is not available to more than 1.7 billion people (28 percent of the world’s population). And more than twice that number lack access to adequate sanitation, which is part of the problem. About 6,000 children—the equivalent of 18 fully loaded jumbo jets—die each day because of contaminated water. In less time than it takes to read this article, 20 children will die because of unsafe water.

According to the World Health Organization, 1.3 million children, most under the age of five, die every year of diarrheal disease caused by drinking contaminated water. Approximately 10 percent of those living in developing countries are infected with intestinal worms. Four billion cases of water-born diarrhea occur annually. Six million people are blind from trachoma. Large numbers of people are subjected to cholera and typhoid fever epidemics. And millions of people are adversely affected by the arsenic and other contaminates found in unsafe water. All told, water-related diseases, which are usually easy to prevent or to treat and are rarely seen in the affluent world, account for 80 percent of illnesses and deaths in the developing world.

Having clean, safe drinking water is the first step to break the cycle of poverty in which many people are trapped. Sick children cannot attend school and parents of sick children cannot work on a regular basis. Women have more children because of the anticipated deaths. This helps explain the response of a young boy in a developing country who was asked, "What do you want to be when you grow up?" His response: "Alive."

Working toward a solution
Pure Water for the World is a non-profit organization that works in remote regions of developing countries that lack sustainable, clean, safe drinking water. They work with local governments and community partners to analyze and select the appropriate technology for a community and to implement cost-effective projects. Pure Water for the World is expanding the technologies it uses to solve the water problems of the communities in which they work and have focused on developing educational programs for communities before implementing any solution to the drinking water problem.

After completing a project in a community, Pure Water for the World follows up with a parasitic treatment program. Finally, they have a comprehensive follow-up program to ensure that there is compliance with the proper water-handling techniques and that problems caused by contaminated water do not return.

Following are the most significant factors that determine the best approach to water purification in rural communities in countries such as Honduras:

• Cost—Villagers in rural third world countries cannot afford expensive techniques.
• Reliability—The purification system must operate for years with essentially no maintenance.
• Power—The ideal system will not be dependent on external power or sunlight to function.
• Location—Extensive field experience has determined that locating water purification in homes produces the most effective results.
• Simplicity—Education of the users and follow-up monitoring by trained personnel are essential to success. The simpler the system, the better the outcome.
• Availability—Equipment must be constructed from materials readily available in-country.

To satisfy all of these requirements, Pure Water for the World advocates slow sand filtration as the preferred methodology in most locations. Slow sand filtration has been in widespread use in large and small communities in Europe and America for centuries. On a small, individual household scale, this technique is ideally suited to the requirements of rural populations in developing countries.

The intermittent slow sand filter has proven economical and effective in thousands of field installations. A slow sand filter consists of a large basin, usually constructed of structural concrete or concrete block, that will contain a gravel under-drain system and support a specific particle size sand filter media. Filtration occurs both mechanically and biologically under extremely slow flows. Plant operation is such that operator diligence is reduced to approximately one to two hours per day during plant start up and one to two hours per week during regular operation, provided adequate water sampling occurs.

Removal of harmful contaminants and pathogens takes place on the top surface of the sand, 2 inches below the water surface. A natural biomass layer of microorganisms present in the contaminated water forms at this sand interface, actively degrading further organic material and removing it from the water, which then filters through the layers of sand. Water flowing from the outlet pipe is free of contaminants, clear in color, clean in taste and smell, and safe for human consumption.

Many published technical reports attest to the effectiveness of intermittent slow sand filtration. These reports confirm that under optimal operating conditions, the bio-sand filter is capable of removing 97 percent of fecal coliform, 100 percent of giardia cysts, 99.98 percent cyptosporidium oocysts, 100 percent of worms, 100 percent of parasites, and up to 90 percent of organic and inorganic toxicants from contaminated water.

Other benefits of a slow sand filter system are the lack of moving parts, no requirement for external power or sunlight, effectiveness in intermittent usage, centuries of proven results, low cost, and relatively simple construction from locally available materials. The slow sand filter can and will make a measurable difference in family health and peoples’ lives.

El Maguelar, Honduras project
As part of the solution, Rotary International has teamed with Pure Water For the World in a concerted effort to provide clean, safe potable water to developing countries. In Honduras, individual sand filters serve an important purpose for sparsely populated areas. An effort is underway to enlarge this service to provide potable water to entire villages.

The Bozeman, Mont., Rotary Club, along with Rotary Clubs from San Antonio, Texas, and Big Sky, Mont., decided to become involved in providing the necessary administration and oversight, as well as grant writing, for construction of a community slow sand filter in El Maguelar, Honduras, a community of approximately 1,200 people. The local contacts became the Rotary Club in Danli, Honduras.

Selection of a qualified design firm, project inspector, and contractor remain the responsibility of the Bozeman Rotary Club, in conjunction with the local Rotary Club in Danli, which is the main contact for the project. Several trips (at members’ expense) are required to ensure proper distribution of grant funds and adherence to budget items.

To familiarize themselves with a slow sand filter and how it functions, club members from Bozeman contacted the Montana Department of Environmental Quality to locate the nearest slow sand filter. The only fully functioning slow sand filter in Montana was located in White Sulphur Springs, a small community north of Bozeman. Gaston Engineering & Surveying, P.C., which was involved in design of that filter, consequently became involved in the grant proposal and specification for selection of a local (Honduran) design firm.

To encourage the recipient communities to take ownership of the treatment plant, project agencies providing grant money require that each family sign an agreement to contribute a monthly fee for plant operations, as well as donate sweat equity such as excavating for plant construction, installing concrete blocks, or obtaining sand filter material. Grant money is used to pay for engineering design and construction supervision by a regional engineering firm, for materials, and for specialized construction work, such as pipe fitting, liner installation, or plant control installation.

This project and other similar projects include a comprehensive education program to provide the community with the basic knowledge of water use, storage, and personal hygiene, and how all of these factors contribute to users’ health and well being. To reinforce the health benefits of having clean, safe drinking water, a parasitic treatment, follow-up, and monitoring is provided to ensure that the technologies are being used properly.

Water issues continue to be a major focus area for Pure Water for the World, which needs partners to implement additional projects throughout Central America and the Caribbean, and hopefully to expand to other countries.

Gerald Gaston, P.E., is with Gaston Engineering & Surveying, P.C., in Bozeman, Mont. (www.gastonengineering.com). Carolyn Crowley Meub is executive director of Pure Water for the World. She can be contacted at carolyn.meub@purewaterfortheworld.org.

SIDEBAR
Simple water solutions

Namawanga villagers must fetch their water on foot from distant sources that are often contaminated with animal and human waste or running dry during part of the year.

Members of the Engineers Without Borders (EWB) student chapter at the University of Massachusetts Amherst recently returned from a three-week trip to Kenya where they worked to improve drinking water for a rural farming village. It was the third visit of the group as part of its long-term Kenya Water Program, which is aimed at providing a self-sufficient water supply for several thousand people in the rural farming village of the Namawanga area in western Kenya.

Namawanga, a community that raises sugarcane, sweet potatoes, and corn, relies on water sometimes located more than 2 miles away. Villagers must fetch their water on foot from sources often contaminated with animal and human waste or running dry during part of the year. Each household spends as many as five hours per day gathering water.

The EWB project will impact Namawanga by creating reliable water sources that serve more than 3,000 people in the surrounding countryside and reduce their chances of contracting waterborne diseases such as dysentery, typhoid, and cholera. The improved water sources will also allow the residents more time to raise food, participate in income-generating activities, and attend school. The goal is to give Namawanga a water supply that is uncontaminated and sustainable by local technicians.

"The first thing we did on this trip was assess all the springboxes," said EWB Kenya Program team leader Christina Stauber, a graduate student in environmental engineering. A springbox is a structure made of a concrete retaining wall with steel piping that collects and stores water from a natural spring. Ideally, each springbox should function to protect the spring water from contamination by human and animal waste and provide a point of collection. But most of the springboxes in Namawanga are not operating effectively and the EWB has been improving them, chiefly by building fences around the boxes to keep out animals.

The EWB team also conducted water quality and flow measurements of water sources and checked the status of previously installed fencing. One fence had obviously been invaded by a cow and some posts had rotted in the 18 months since they were installed, so EWB worked with villagers to install steel fence posts set in concrete to keep out grazing animals.

The UMass Amherst EWB chapter has been raising the $20,000 required to drill a permanent deep borehole on the grounds of a technical school in Namawanga, where the surrounding community will have a clean, year-round water source. By contrast, it takes only about $100 to build a new springbox, but water availability is less reliable than a well and the water is more likely to be contaminated.

The UMass Amherst EWB chapter includes engineering and non-engineering students whose mission is to help disadvantaged communities improve their quality of life by developing environmentally friendly and economically sustainable projects.
—University of Massachusetts Amherst