May 2008, Vol. 20, No.5

Research Notes

Team Studies Feasibility of New Reuse Technology

A self-sustainable wastewater treatment process to alleviate water scarcity has been awarded the £250,000 Brian Mercer Award for Innovation from the Royal Society (London). The process will be demonstrated on a large scale by a team comprised of Imperial College (London), Anglian Water (Huntingdon, U.K.), and Black & Veatch (Kansas City, Mo.).

According to a press release from Black & Veatch, Professor David Stuckey of Imperial College pioneered laboratory studies into wastewater treatment using submerged anaerobic membrane bioreactors (SAMBR). Black & Veatch sponsored an independent verification of the SAMBR process at Cranfield University (Cranfield, U.K.). The study confirmed that the small-footprint anaerobic process can achieve a high-quality effluent suitable for wastewater reuse, with a positive net energy yield and very low solids production.

Previously, anaerobic membrane bioreactors have been used only for industrial wastewater treatment with concentrated and warm effluents, according to the press release.

The award fosters a collaborative partnership comprising Imperial College, Anglian Water, and Black & Veatch, along with membrane suppliers GE Water & Process Technologies (Trevose, Pa.), Asahi (Malden, Mass.), Norit (Zenderen, The Netherlands) and Siemens Water Technologies (Warrendale, Pa.). Together, they will develop a field-scale, 50-m3 domestic SAMBR plant that will recycle wastewater, will produce enough energy to power itself and, with just a few hours of detention time, will be much smaller than traditional plants. Anglian Water will host the plant at its Water Innovation Center in Cambridge.

In parallel with the field work, ongoing laboratory research will further develop the SAMBR system, according to Black & Veatch.  

Study Finds Healthy River Ecosystems Vital to Removing Excess Nitrogen

Healthy streams with vibrant ecosystems play a critical role in removing excess nitrogen caused by human activities, according to a major national study recently published in Nature.

The research, by a team of 31 aquatic scientists across the United States, was the first to document just how much nitrogen that rivers and streams can filter through tiny organisms or release into the atmosphere through denitrification, according to an Oregon State University (OSU) press release. The study was funded by the National Science Foundation.

“The study clearly points out the importance of maintaining healthy river systems and native riparian areas,” said Stan Gregory, a stream ecologist in the Department of Fisheries and Wildlife at OSU, and a co-author of the study. “It also demonstrates the importance of retaining complex stream channels that give organisms the time to filter out nitrogen instead of releasing it downstream.”

The scientists conducted experiments in 72 streams across the United States and Puerto Rico that spanned a diversity of land uses, including urban, agricultural, and forested areas. They discovered that roughly 40% to 60% of nitrogen was taken up by the river system within 500 m of the source where it entered the river — if that ecosystem was healthy.

Tiny organisms such as algae, fungi, and bacteria that may live on rocks, pieces of wood, leaves or streambeds can absorb about half of the nitrogen that humans currently put into the sampled river sites, according to Sherri Johnson, a research ecologist with the U.S. Forest Service, and a courtesy professor of fisheries and wildlife at OSU.

“Streams are amazingly active places, though we don’t always see the activity,” Johnson said. “When you have a healthy riparian zone, with lots of native plants and a natural channel, the stream has more of an opportunity to absorb the nitrogen we put into the system instead of sending it downriver.”

The study is important, scientists say, because it provides some of the best evidence of the extent to which healthy rivers and streams can help prevent eutrophication.  

In Virginia, Universities Help Determine Nutrient Standards

A group of faculty and researchers from Virginia Polytechnic Institute and State University (Blacksburg, Va.) and three other universities are working with the Virginia Department of Environmental Quality to establish much-needed freshwater nutrient standards for the state.

This partnership is “quite a unique initiative for establishing water quality standards,” said Tamim Younos, who has served as the committee project leader since 2002. “It is one of the few such partnerships in the [United States] between research universities and a state agency.”

The multi-university Academic Advisory Committee, based at Virginia Tech’s Virginia Water Resources Research Center, has studied the safe levels of nitrogen and phosphorous in streams, rivers, lakes, and reservoirs since 2005.

According to the 2006 Virginia Water Quality Report released by the Department of Environmental Quality, the number of impaired areas of rivers, streams, lakes, and estuaries has increased during the past decade. In 1996, 4% of Virginia’s rivers and streams mileage, 15% of the lakes, and 22% of the estuary areas were reported as impaired. Ten years later, the reported impairments were 19% of rivers and streams, 94% of lakes, and 98% of estuaries.

The report notes that the increased number of impaired waters can be attributed in part to better water quality monitoring in Virginia over the past decade.

The good news is that a long-term analysis of Virginia’s surface waters shows improved levels of certain contaminants such as nitrogen, phosphorus, and bacteria. “[The Academic Advisory Committee] is trying to put this information in context by helping [the Department of Environmental Quality] establish safe benchmarks for these contaminants,” said Younos.

The committee members are using statistical methods and modeling techniques to establish nutrient criteria for the state's fresh waters. For example, based on committee recommendations, the Department of Environmental Quality has recently amended the Virginia Water Quality Standards regulation to protect Virginia’s reservoirs from nutrient harmful impacts.

Jean Gregory, environmental manager in the water quality standards program at the Department of Environmental Quality, said that the cooperation “has been invaluable” to the agency. Gregory also noted the positive feedback that the department had received from various stakeholders about the development of nutrients in lakes and reservoirs in particular.

The reports released by the Academic Advisory Committee to date are available at www.vwrrc.vt.edu/special_reports.html.

For more information, contact Ana Constantinescu at arconsta@vt.edu