June 2006, Vol. 18, No.6

Research Notes

Reactive Filtration Process Shows Dramatically Reduced Phosphorus Levels

A process designed to achieve significant reductions in phosphorus levels in sewage and industrial waste is being examined by two University of Idaho (UI; Coeur d’Alene) undergraduate students.

By evaluating the performance of UI environmental chemist Greg Moller’s patent-pending BluePRO™ process, the students are investigating whether a modification to the system might increase its effectiveness in removing phosphorus from wastewater. The research, which began in January, is being conducted at the Hayden, Idaho, municipal wastewater treatment plant’s Hayden Wastewater Research Facility, according to a UI press release.

The BluePRO process uses reactive filtration in which chemically modified wastewater percolates through a sand bed. Iron phosphate grows on the surface of the sand particles, removing the phosphorus from the water and diverting it into a filtered stream of iron phosphate solids.

Moller’s purification system reduces phosphorus levels in sewage and industrial waste, ultimately halting the growth of algae in rivers and streams, the press release states. The process results in cleaner water, lower operating costs, and more reliable operations for municipal waste processing facilities.

The original technology, the press release notes, is working better than predicted and is exceeding regulatory requirements. Initial pilot testing in 2004 at the Moscow, Idaho, wastewater treatment plant resulted in a greater than tenfold phosphorus reduction, from 800 ppb to 60 ppb. Data from the improved process, operating at a 950-m3/d (250,000-gal/d) facility in Hayden, has shown a thousandfold reduction in phosphorus, from 5 ppm to 5 ppb. The process also removes arsenic from drinking water. The Hayden facility is the first in the nation to test the system’s cost-effectiveness in full-scale, long-term operation. 

Pharmaceutical Metabolites Found in Wastewater

As the technology for detecting pharmaceuticals becomes more advanced, affordable, and readily available, more microcontaminants in wastewater are being detected. For the first time, metabolites of two antibiotics and a medical imaging agent were identified at wastewater treatment plants by chemists at the State University of New York’s University at Buffalo.

The data, according to a university news release, will allow wastewater treatment plants to begin monitoring for these byproducts.

The results, the news release notes, reinforce concerns about pharmaceutical compounds in wastewater effluent that may enter the water supply and their potential effects on humans, aquatic life, and the environment. Antibiotics and their metabolites can increase antibiotic resistance in the population, according to the press release. Synthetic hormones can act as endocrine disruptors by mimicking or blocking hormones and disrupting the body’s normal functions.

The researchers have identified the metabolites for sulfamethoxazole and trimethoprim, commonly prescribed antibiotics, and for a synthetic estrogen — a common ingredient in birth control pills and in hormone replacement therapy.

In research published in January in the journal Analytical Chemistry, the researchers also report that iopromide — a pharmaceutical imaging agent that patients consume before taking magnetic resonance imaging, or MRI, tests — is barely degraded in the conventional activated sludge process. However, the press release states, they found that when conditions in biological treatment systems are optimized for nitrogen removal, this imaging agent does degrade.

Diana Aga, assistant professor of chemistry at the university, said that these findings are important because it means wastewater treatment processes can be optimized to remove persistent pharmaceuticals in wastewater. Based on the team’s findings, she noted, a combination of biological, chemical, and physical processing techniques probably will be the most successful in completely removing pharmaceutical compounds and their metabolites from wastewater. 

Water Cycle Intensifies, No Increase in Storms or Floods

The U.S. Geological Survey (USGS) on March 15 announced the publication of a study showing that many aspects of the global water cycle, including precipitation and evaporation, have intensified. The report is quick to point out, however, that the data do not indicate that this trend has resulted in an increase in the frequency or intensity of tropical storms or floods during the past century, according to a USGS press release.

“A key question in the global climate debate is if the climate warms in the future, will the water cycle intensify and what will be the nature of that intensification,” said USGS scientist Thomas Huntington, who authored the study. “This is important because intensification of the water cycle could change water availability and increase the frequency of tropical storms, floods, and droughts, and increased water vapor in the atmosphere could amplify climate warming."

For the report, Huntington reviewed data presented in more than 100 peer-reviewed scientific studies. Although the data are incomplete and sometimes contradictory, the weight of evidence from past studies shows on a global scale that precipitation, runoff, atmospheric water vapor, soil moisture, evapotranspiration, growing season length, and wintertime mountain glacier mass are all increasing, the press release states.

“This intensification has been proposed and would logically seem to result in more flooding and more intense tropical storm seasons,” Huntington said. “But over the observational period, those effects are just not borne out by the data in a consistent way.”

Huntington notes that the long term and global scale of this study could accommodate significant variability, for example, the last two Atlantic hurricane seasons.

“We are talking about two possible overall responses to global climate warming: first an intensification of the water cycle being manifested by more moisture in the air, more precipitation, more runoff, more evapotranspiration, which we do see in this study; and second, the potential effects of the intensification that would include more flooding and more tropical storms which we don’t see in this study,” Huntington, said.

The research report was published in the March 16 issue of the Journal of Hydrology.