How Your Old CDs Can Turn Sewage Into Drinking Water
Good news, fans of terrible 90s bands—your unhealthy obsession with Hanson, Sugar Ray, or Creed could turn out to have a happy ending. No, their music will never be palatable, but the actual CDs on which their tunes were laser-printed, the very same audio discs currently collecting dust in your mom’s basement, could be used to make dirty water potable. At least this is the potential new use for old CDs recently proposed by a team of Taiwanese researchers.
“Optical disks are cheap and readily available,” said lead researcher Din Ping Tsai, a physicist at National Taiwan University, in a press release. “Close to 20 billion disks are already manufactured annually, so using old disks for water treatment might even be a way to cut down on waste.”
Each month, roughly 100,000 pounds of CDs become obsolete, with millions being sent to landfills around the world. When a CD decomposes, it releases Bisphenol-A, a toxic chemical that’s been linked to brain impairments, cancer and more.
Tsai’s process involves using a CD’s flat surface as a platform on which to grow zinc oxide. Later, when illuminated with UV light in a prototype water treatment device, the zinc oxide acts a photo-catalyst, breaking down organic pollutants in sewage water that’s filtered in by a hose.
In a test, the researchers found that “over 95 percent of the contaminants had broken down after just 60 minutes. That's about 150 ml of waste water per minute.” For comparison, a typical bottle of water contains 500 milliliters.
Tsai said the device could be used on a small scale to clean water that is polluted with domestic sewage, urban run-off and farm waste.
Globally, 884 million people don’t have access to safe drinking water. And the number one of cause of illness and death worldwide is diarrhea, 88 percent of which is caused by lack of access to sanitation facilities and unsafe drinking water.
So, despite the ick-problem—Drink recycled pee? Eww, gross!—there is a definitive need for turning wastewater into drinking water. And in certain parts of the world, including here in the United States, wastewater consumption is already a way of life. According to a 2012 New York Times op-ed by Jessica Yu, the director of Last Call at the Oasis (produced by Participant Media, TakePart’s parent company):
In Israel, more than 80 percent of household wastewater is recycled, providing nearly half the water for irrigation. A new pilot plant near San Diego and a national “NEWater” program in Singapore show it’s practical to turn wastewater into water that’s clean enough to drink. Yet, in most of the world, we are resistant to do so.
A 2011 study conducted by the University of California, Santa Cruz supports Yu’s assessment. More than 60 percent of respondents refused to drink water that had had any direct contact with sewage.
The loaded irony of this position was not lost on Carol Nemeroff, a psychologist associated with the study. “We are all downstream from someone else,” she said. “And even the nice, fresh, pure spring water? Birds and fish poop in it. So there is no water that has not been pooped or peed in somewhere.” In Orange County, California, recycled wastewater is pumped into underground cavities—a completely unnecessary step that the utility takes just so its customers feel like they’re getting water from the earth, not the toilet. Then there’s the fact that all water is recycled water: The amount of H2O in the earth’s atmosphere doesn't change; the only thing that changes is the form that it’s in (rain-, fresh- or seawater; liquid, gas or solid).
So while Tai and his team deserve credit for working to minimize the ecological damage of CDs, another obstacle awaits: Convincing the world to drink the purified water in the first place.