People in La Salitrera, Mexico, had access to water thanks to nearby rivers and groundwater wells, but it had become unsafe to drink. Water in this agricultural community was contaminated with twice the World Health Organization’s recommended limit for arsenic.

This meant that when brothers Miguel and Roberto needed to quench their thirst, the water they drank posed a serious health risk. 

Rusty Nails: An Unlikely But Effective Material

Arsenic, a naturally occurring toxin, can cause respiratory problems, cardiovascular disease and certain cancers. Children are especially susceptible to the effects of arsenic exposure.

This localized problem required a localized solution, which is where the Engineers Without BordersUSA Utah State University Chapter (EWB-USA USU) stepped in. They partnered with Miguel and Roberto’s community and found a long-term solution for the contaminated water supply.

The team determined that concrete biosand filters installed at individual homes were the best solution for La Salitera’s arsenic-laden water. Since standard biosand filters only remove bacteria contaminants, the team modified the design.

The new design utilized local materials such as concrete, washed sand and PVC pipes, along with an unexpected addition: rusty nails. These repurposed materials helped remove arsenic from the water.

La Salitrera community members gather supplies for the biosand filters

An Incredible Work Ethic

When EWB-USA USU students and mentors first traveled to La Salitera, they planned to construct three filters in 10 days. Anellise Reynolds, team lead on the project, reported that they constructed twice as many filters as planned thanks to the tremendous support and involvement of the community.

Miguel, Roberto, and others halted their typical daily work to labor alongside the students from first light until nightfall. The work was back-breaking – they had to gather large amounts of sand and gravel from the rivers to construct the filters.

Miguel’s home received the first biosand filter, but he continued to work so that other homes could receive filters as well.

“It was exhausting work, but totally worth it,” said Anellise.

Miguel’s home received the first completed biosand filter. But in the true community spirit, he continued to work tirelessly with the rest of the team until all the filters were complete. 

These six filters are life-changing for families. Clean, arsenic-free water is now readily available for them, creating a safer and healthier environment. 

EWB-USA USU team wanted the entire community to have access to a healthy, productive future. So they returned the following year to construct six more biosand filters. And of course, Miguel and Roberto worked alongside them every step of the way, ensuring their community can enjoy the health benefits of a clean glass of water. 

Photos courtesy of the EWB-USA Utah State University Chapter