Invention to remove water contaminants earns Rittmann engineering award

Invention to remove water contaminants earns Rittmann engineering award

April 13, 2011

April 13, 2011

A new technology that removes dangerous contaminants from water has earned Arizona State University inventor Bruce Rittmann prestigious Environmental Engineering Excellence Award from the American Association of Environmental Engineers.  The organization will present the award to Rittmann on May 4 at the National Press Club in Washington, D.C.

Rittmann is the director of the Swette Center for Environmental Biotechnology in the Biodesign Institute at Arizona State University and a Regents’ Professor of environmental engineering in the School of Sustainable Engineering and the Built Environment, one of ASU’s Ira A. Fulton Schools of Engineering. His hydrogen-based membrane biofilm reactor (MBfR) removes contaminants, such as nitrate, perchlorate, selenate, chromate, and trichloroethene.  The presence of these contaminants in water supplies is a growing problem, but there is no cost-effective water treatment technology available to remove any of them, except for nitrate.

The MBfR has been extensively tested for its effect on many contaminants individually and in mixtures.  It is a versatile platform technology that can be used to treat drinking-water sources, ground or surface waters, industrial and agricultural wastewaters, and municipal wastewater. It is licensed and being commercialized by APTwater, Long Beach, Calif.

Perchlorate, for example, is a byproduct of rocket fuel that is found in the ground and river water throughout the southwestern United States.  According to the Centers for Disease Control, even low levels of it can affect the human thyroid.  So water treatment plants needed an efficient way to remove it from drinking water. That was what prompted Rittmann’s innovation.

“The hydrogen-based reactor relies on the natural processes of bacteria respiration to change contaminants to a harmless form,” explained Rittmann. “We combine our understanding of bacteria and create the environment they need to complete this cleaning process for us.”

The MBfR delivers hydrogen gas to bacteria that accumulate naturally on the outer surface of a gas-transfer membrane.  Through respiration, the bacteria oxidize and extract electrons from the hydrogen and transfer extra electrons to water contaminants, changing contaminants to harmless forms.

The key to the success of the MBfR is that it delivers hydrogen gas directly to the biofilm – the slime produced by bacteria colonies – by its diffusion through the wall of the gas-transfer membranes.  This makes hydrogen delivery nearly 100 percent efficient and virtually self-regulating.  In essence, the bacteria in the biofilm “pull” the hydrogen through the membrane wall when they consume it.

Rittmann was elected to the National Academy of Engineering in 2004 and is a Fellow of the American Association for the Advancement of Sciences. In 2009, he won the Research Excellence Award from the Arizona BioIndustry Association and the Simon Freese Environmental Engineering Award from the American Society of Civil Engineers.  He is listed as one of the world’s most highly cited researchers, with more than 440 publications, including more than 40 peer-reviewed publications on the MBfR.

For more information about the AAEE’s Awards Luncheon and Conference, visit http://www.aaee.net/.

About the competition
The Excellence in Environmental Engineering Competition rewards the best of today's environmental engineering. Its criteria define what it takes to be the best in environmental engineering practice: a holistic environmental perspective, innovation, proven performance and customer satisfaction, and contribution to an improved quality of life and economic efficiency.