New Water Treatment Process Could Help Bring Dead Zones Back to Life

The number and extent of so-called marine “dead zones”--areas of coastal ocean waters where nearly all forms of marine life have been snuffed out due to lack of oxygen—has been on the rise for decades now, posing increasing threats to commercial and subsistence fisheries, recreational fishing and human health. Terrestrial runoff containing relatively high levels of phosphorous, primarily from agricultural fertilizers, has been identified as one of the main culprits.

Wastewater discharge from cities and urban centers is also to blame. In addition to phosphorous, there are growing concerns about a wide range of chemicals and substances being poured into coastal waters from urban sources—trace organics and hormones in pharmaceuticals and in personal care products (PPCPs) prominent among them.

Conducting an eight-week study as part of a multi-year partnership with the University of Wisconsin-Milwaukee, Veolia Water North America found that adding its Actiflo Carb technology to the traditional wastewater treatment process removed 75 percent of selected PPCPs and reduced phosphorous concentration to 0.05 milligrams per liter (mg/L) or less, a level well below the Environmental Protection Administration's (EPA) 1.0 mg/L threshold, according to a company press release.

Cleaning the U.S. water supply

As part of the multi-year partnership, the test study was conducted by a team of process engineers from Veolia Water and its Kruger, Inc. subsidiary working alongside scientists from UW-Milwaukee with the support of the Milwaukee Metropolitan Sewage District (MMSD) and the Water Environment Research Foundation. The results were released publicly at the annual WEFTEC conference to coincide with the 40th anniversary of the U.S. Clean Water Act.

"There is mounting concern across the U.S. about the impact of trace organics, such as hormones and pharmaceuticals, in our water systems and the potential threats they pose on human health, wildlife and the environment," said Dr. Rebecca Klaper, the lead scientist from University of Wisconsin-Milwaukee who worked on the study."This research showed that when Actiflo® Carb is added to a wastewater treatment process, it removes a significant portion of the pharmaceuticals tested.

Examining wastewater samples collected over the course of 2009-2010 during the first phase of the research project, the research project team found that trace organic compounds (TorCs) were still present in samples even after undergoing a secondary treatment process. As per the Clean Water Act, ”treated wastewater effluent discharged into the environment must be safe for all other water uses—including fishing, swimming, recreation and municipal drinking water supply,” Veolia Water notes.

New tertiary wastewater treatment process proves effective

The results prompted research partners to initiate a pilot study in which Veolia Water's Actiflo Carb was used to treat the secondary wastewater effluent. Actiflo Carb is a “high-rate clarification technology that relies on powdered activated carbon (PAC), which is known for its ability to remove pesticides, taste-and-odor-causing compounds, natural organic matter and many types of TorCs from water and wastewater,” Veolia Water explains.

Applying Actflo Carb to wastewater streams is more effective than conventional processes when it comes to removing phosphorous, pharmaceuticals and other trace organics, which are being found in ever-larger quantities in the U.S. water supply, Veolia Water North America chief technical officer Jim Hurst continued.

"We believe it will give wastewater facilities a way to stretch their treatment dollars while dramatically reducing pollution levels and achieving better water quality. The Clean Water Act initiated efforts to reduce water pollution in the U.S., and now this technology can take those efforts even further by addressing one of today's emerging water pollution issues."

Examining wastewater effluent after Acitflo Carb had been applied in the second phase of the researcy project revealed that the average TOrCs removal rate across all compounds reached 75 percent, demonstrating that it could serve “as an efficient barrier for tertiary wastewater treatment.” The results also exceeded expectations in terms of Actiflo Carb's ability to target and remove phosphorous at the same time.

*Photo credit: Milwaukee Metropolitan Sewage District