Artificial Wetland Uses Bacteria to Clean Pharmaceuticals From Sewage

From anxiety medication to birth control, pain killers, nutrient supplements and blood thinners, the remains of what we put into our bodies pass through the other end, off to the waste control centers that need to deal with our mess. Getting pharmaceutical leftovers out of the water so that it can be safely passed back into the environment is a costly and tricky task, and conventional waste water treatment techniques aren’t up to the task.

The introduction of drug remnants to the environment has even been found to affect the behavior of fish, says Smithsonian‘s Surprising Science blog:

Over the past decade, researchers have repeatedly discovered high levels of many drug molecules in lakes and streams near wastewater treatment plants, and found evidence that rainbow trout and other fish subjected to these levels could absorb dangerous amounts of the medications over time. Now, a study published today in Science finds a link between behavior-modifying drugs and the actual behavior of fish for the first time. A group of researchers from Umeå University in Sweden found that levels of the anti-anxiety drug oxazepam commonly found in Swedish streams cause wild perch to act differently, becoming more anti-social, eating faster and showing less fear of unknown parts of their environment.

The way to stamp down on any possible ecological effects of accidentally medicating the world’s waterways, they suggest, is to devise technologies to skim them out. Scientists are trying to do this, through reverse osmosis and ozone treatment, says science journalist Jill Adams for Ensia, but it’s really expensive.

An affordable and environmentally friendly alternate path to getting pharmaceutical waste out of the water, says Adams, can be found in a fifty-year-old approach—one that’s been on display for more than a decade at a small wastewater treatment plant in western New York. In the village of Minoa, she says, sits “a weedy lot measuring 100 by 200 feet.”

Beneath plants and rocks, an artificial wetland, brimming with bacteria, “hold the ability to do what few other water treatment systems can: remove pharmaceuticals, environmental pollutants of increasing concern in wastewater streams around the world. Fill this well with up to 130,000 gallons of drug-laced water and the next day it will come out clean enough to put into a nearby stream.”

The 18-year-old constructed wetland may seem simple, but there’s a lot of science and hard-earned experience behind the drug-removal process. Bacteria living in the wetland do the muscle work of breaking down organic compounds, and different species have different specialties, says Chris Nomura, a biochemist at SUNY-ESF.

The artificial wetland costs less than traditional wastewater treatment equipment, and “has almost no operational costs, Doelle says — no chemicals and no electricity.”

On the flip side, it takes a lot of land and can’t process waste nearly as quickly as a regular plant.

More from Smithsonian.com:

California’s Gender-Bending Fish Was Actually Just a Contamination Accident
Flushing Your Anti-Anxiety Pills Down the Toilet Could Affect the Behavior of Wild Fish

Colin Schultz | | READ MORE

Colin Schultz is a freelance science writer and editor based in Toronto, Canada. He blogs for Smart News and contributes to the American Geophysical Union. He has a B.Sc. in physical science and philosophy, and a M.A. in journalism.