How sand, soda cans, and salt can help communities in Puerto Rico quench their thirst—safely—when disaster strikes.
As we drive our rented Jeep up the winding road towards Jayuya, between landscapes and landslides, we regularly pass pipes sticking out of the mountainsides, water flowing smoothly from them. People filling jugs and tanks from these pipes is now a typical sight in rural Puerto Rico. Residents across the island have also been relying on springs or streams for water because their regular, pump-dependent systems are down due to the power outages still plaguing many communities.
Since Hurricane Maria slammed into the island in late September, dead animals, structural damage in pipes, and treatment plant failures have compromised the quality of many local water sources, sparking concern about waterborne diseases like Leptospirosis, which is potentially fatal.
Imagine having worrisome questions about the quality of your water, and waiting weeks or even months for experts to conduct tests and report results before you know whether it’s safe to drink. Welcome to reality in Puerto Rico.
Now, imagine if you could find the answers yourself--right in your local hardware store or even in your own back yard.
That was the goal of a recent hands-on workshop for community leaders, university students, and relief workers in San Juan sponsored by Oxfam and the Puerto Rico Science, Technology & Research Trust. With help from professors and experts at the University of Puerto Rico (UPR) and the Massachusetts Institute of Technology’s D-Lab, participants learned a host of practical techniques for testing the quality of water and ensuring it’s drinkable.
“That was an amazing experience,” said Luis E. Rodriguez Reyes, an epidemiology student, after the workshop. “I learned how to make a sand water filter system to remove particulates. I learned how to make my own solar disinfection bag. I learned how to make a rocket stove--all with homemade materials.”
Next step? Participants already have plans to fan out across the island and share their new know-how with communities.
Here’s some of what we learned:
Sand in a bottle
Pedro Tarafa, a professor of civil and environmental engineering at the University of Puerto Rico, Mayagüez campus, showed us how to make water filters using sand, gravel, and an empty two-liter plastic soda bottle. Here, Luis E. Rodriguez Reyes and Alba R. Lacen Marte test out one of the models. The filtering process--one of the two most basic steps in water treatment--removes large particles and turbidity, and prepares water for the second step on its way to becoming drinkable: disinfection.
How to build a rocket stove
You’ve probably heard about disinfecting water by boiling it. But what happens when there is a power outage and you don’t own a gas stove? With direction from Christopher Papadopoulos, an engineering science and materials professor from UPR at Mayagüez, and Milton Olivera from Brigada Solidaria del Oeste, we built rocket stoves using several different sizes of metal cans, sand, and wood for fuel.
Fire up those soda cans
Mayra Nieves Rosa listened to Amy Smith, D-Lab co-founder, as she explained some of the fine points of making a stove from soda cans, thumbtacks, and isopropyl alcohol. The best part was they work: We boiled water and made instant coffee.
“I love it: It’s easy and very fast to make,” Lenulisy Rosado Estrada told us. “I think it’s very important to have knowledge. Any time we’re susceptible to natural phenomenon—hurricanes, droughts—anything can affect our systems. We should always be prepared. And one way is having knowledge of survival methods.”
Got salt? Presto! Now it’s chlorine
Together with Amy Smith, Harvard School of Public Health doctoral student Jessica Huang showed us how to mix salt with water, zap it with a current, and produce a chlorine solution to disinfect water.
“It’s really just salt water with a little energy running through it,” said Smith.
Here's an example:
Take your water for a suntan
One of the most fun sessions during the workshop involved designing our own solar water disinfection bags. Here, Ada Alvarez shows off an example made with plastic sheeting sealed with a heat-sealer. When stored in transparent containers, such as plastic bottles or bags like Alvarez's, water can be disinfected easily with a day's worth (or less) of ultraviolet radiation from the sun.
The power of body heat
With help from Susan Murcott, who is a drinking water and wastewater expert and a lecturer at the MIT D-Lab, we learned about water tests that can be performed easily without waiting weeks for results from the lab.
“Ewww!!” was the collective reaction when I revealed to fellow participants that I had pulled water samples from La Laguna del Caño, an urban lagoon well-known for its contamination, for overflowing, and even for being home to alligators. We learned how to run tests and analyze the myriad samples from the lagoon as well as those we collected from puddles and tap water.
Normally, to run these test samples, we would have had to incubate them with expensive laboratory incubators requiring electricity. We were very impressed to hear that we could use our own body heat instead. The waist-belt incubator, which Murcott is demonstrating above, can be locally made and worn for off-grid incubation.
At the end of the workshop, one participant summed it all up best with these words: “It was so important for us to go through this process and realize we can think outside the box and identify alternatives for our problems.”
Pamela C. Silva Díaz is Oxfam’s lead technician for public health in Puerto Rico. She was the principal coordinator of this workshop, participated in it, and is determined to spread the word: “The water treatment and testing workshop was not just insightful, but inspiring. I am very excited about the workshop itself, but I am even more excited about where we will take it. More than anything, I am excited about co-creating clever solutions to our new tropical challenges,” she said. The workshop was held at the Comprehensive Center for Cancer, UPR Medical Campus.