He was horrified by the conditions in which children were living.
"It is not a place where people are supposed to live," he tells PEOPLE. "It's where the city throws its garbage."
So he decided to do something about it. Chavez, who had once run an orchestra in his nearby village Carapeguá, was inspired to create the Recycled Orchestra, where kids play instruments made from recycled garbage.
Cellos are made from oil cans and wood. Violins are made from whatever is around, including recycled forks.
"If the community wasn't next to a dumpster it would've never occurred to us to create instruments out of trash," says Chavez, 38. "This was just a natural solution based on our surroundings."
Chavez and the band are highlighted in Landfill Harmonic, a film that documents the harsh conditions of living on the landfill.
Courtesy Landfill Harmonic Film
"I know one shouldn't be naïve," Chavez says. "Music isn't going to change or fix all problems, but through the orchestra they can find stability they don't have in their family and communities."
Since its inception, Chavez has taught more than 100 kids. They say the band has done more for them than just bring music into their lives. It's brought hope.
"Before the orchestra, there was nothing to do," says Brandon Cabone, 16, who plays bass created from a can. "There are a lot of bad things to get into like drugs. It's been a big change in my life. My father is happy the orchestra is there."
Now, he says, he dreams of going to college.
"Favio has taught me many things about life and education," he says. "I would like to advance my education at a university, have a better life and integrate a formal orchestra."
In 2011, Chavez quit his job to devote all his time to the band.
"The orchestra is super important to me and I'm happy my wife is involved too," he says. "The kids are like our family now."
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