October 31, 2010
Sanitation and bridge in La Granja and Nuevo Ferrocarril, El Salvador
contributor: Rob Goodier
Waste water from sinks, showers, and toilets once spilled into the streets of La Granja, a small town in El Salvador’s mountains near the Central American country’s capital, San Salvador. Pools of water bred pathogens near homes and throughways, posing a public health danger to people and pets.
Now, development experts are experimenting with tandem solutions to the problem, both in La Granja and in a neighboring village, Nuevo Ferrocarril: Infrastructure and education. The two communities and the local government are building a waste water collection system and launching a public health education campaign with the help of volunteers from the University of Wisconsin chapter of Engineers Without Borders and the Salvadoran Rotary Club.
Sanitation and malnutrition
Before the engineers began their work, the rate of diarrhea among children under the age of five spiked to 10% during the rainy season, when rain can wash waste water from the streets into drinking water supplies. Malnutrition for that group hovers at 30% year round, according to data from three local clinics. The two are facts are not coincidental, Jessica Lucido hypothesizes in a report (pdf) written for her graduate program at the University of Wisconsin.
After they finish, the volunteers and clinics plan to compare before-and-after statistics on intestinal microbe infections to rate their projects’ effectiveness. The results, and those of similar studies, could have life-saving implications.
Pride in infrastructure
Today, the 2500 residents of La Granja and Nuevo Ferrocarril can tap into a potable water line to turn on water in their homes. Until recently, though, their waste water has drained onto the streets and into a river, untreated.
Now, a grid of more than 4000 meters of PVC pipe underlies the streets of La Granja, and construction of a similar system should begin in Nuevo Ferrocarril in January 2011. Community leaders have organized volunteers into work teams to lend a hand. They have also gathered resident families together for health education workshops.
“We feel that for people to take pride in their system, they have to put in effort as well,” Missy Setz, of EWB-UW, told E4C in an email.
Costs and cost-cutting
Two of the project’s three phases are complete: The waste water collection system in La Granja, and a pedestrian bridge that spans a ravine between the two towns. The third phase, a similar collection system for Nuevo Ferrocarril, should begin in January 2011.
So far, the project has cost $94,000, and the last phase could cost another $44,000. The system is gravity driven – free of pumps – and maintains a 1 percent grade throughout. Wastewater flows to a treatment plant three kilometers from the towns, and treated water discharges into a stream.
The bridge between the towns supports a pipe that will tie their two collection systems together and transport waste to a treatment plant. As a footbridge and not just a pipe support, the bridge protects the safety of the two towns’ residents, too, Daniel Rivera, a Salvadoran engineer leading the projects in the two communities, told E4C in an email. Before it was built, people, including children, scrambled up and down the steep banks of the ravine to cross between the communities.
Nearly 40 manholes give access to the pipes at strategic points such as road intersections. If clogs develop, the city government can blast the lines clear with high-pressure water equipment.
Rivera maintains a photoblog with pictorial updates on their work and Spanish captions.