Wastewater Treatment and Climate Change

Assistant Professor Kartik Chandran of the Department of Earth and Environmental Engineering is involved in research on engineered wastewater treatment technologies that are enabled by environmental microbiology and biotechnology.  He has recently received grants from the Water Environment Research Foundation (WERF), Technical University-Delft in the Netherlands, and utilities nationwide to further research his concerns that biological nitrogen removal (BNR) processes in wastewater treatment plants may, in fact, produce gases that are environmentally hazardous. His preliminary research has shown that nitric oxide (NO), nitrous oxide (N2O) and nitrogen dioxide (NO2) are often produced by standard BNR processes and that these nitrogen gases present an unacceptable environmental hazard.
 
“Biological Nitrogen Removal is currently only mandated and regulated in a few major metropolitan centers in the United States and is aimed at improving water quality in receiving water bodies.  Our studies show that BNR could be a significant contributor to atmospheric N2O and NO.  In the future, BNR is going to be a requirement around the nation and will lead to a significant flux of these gases into the atmosphere,” says Professor Chandran.
 
“Such increased releases would be a major public health hazard since the greenhouse impact of nitrous oxide is about three hundred times that of carbon dioxide,” he notes. “Nitric oxide is converted to nitrogen dioxide in the atmosphere, and that is one of the primary constituents of the orange smog present during peak air pollution events in urban areas.” 
 
“My research goal is to characterize nitrogenous emissions from wastewater treatment plants and to develop BNR technologies that will improve water quality, but not at the cost of deteriorating air-quality,” he says. “The entire wastewater industry is moving in the direction of sustainability and energy efficiency and this is one of the first projects relating to Global Climate Change that WERF has undertaken.  In fact, based on the results of our study at BNR plants nationwide, the Intergovernmental Panel on Climate Change (IPCC) and the U.S. Environmental Protection Agency are going to recommend continued inclusion or exclusion of the wastewater treatment industry on the list of significant contributors to global warming.” For more information on Professor Chandran’s research, go to:http://www.columbia.edu/~kc2288/.

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