Treating Waste Water Doesn’t Stop Chemicals from Contaminating Ground Water

Most wastewater treatment plants now use filters to separate “forever chemicals” out of drinking water, but don’t have the means to permanently eliminate them. This means they are still present when the sludge that has been filtered out of the water has been disposed of. The waste water that remains often flows into creeks and streams to groundwater.

USGS scientists conducted a study on pharmaceuticals and other contaminants in treated wastewater effluent at Fourmile Creek, a wastewater-dominated stream near Des Moines, Iowa. “Wastewater effluent contributed approximately 99 and 71 percent of the flow in Fourmile Creek during these sampling periods, respectively… Both stream and shallow groundwater samples were collected during October and December 2012 and analyzed for 110 pharmaceuticals… Analysis of stream-water samples collected downstream of wastewater effluent discharge revealed that 43 percent and 55 percent of pharmaceuticals analyzed were detected in October and December, respectively… 16 percent and 6 percent were detected [in shallow groundwater] during October and December, respectively, at a distance of 20 meters from the stream bank.”

Although the study was primarily to test for pharmaceuticals, it was stated that “Other mobile chemicals found in wastewater are expected to have similar fates”.

For the whole study, read here.