2011 - Elucidation of the Rates and Extents of Pharmaceutical Biotransformation during Nitrification

Grant Award Year: 
Principal Investigator: 
Dr. Andrew Ramsburg
Research Description: 
Two important challenges facing the water quality community in the 21st century are management of nutrients and mitigation of microconstituents. To meet the challenge posed by nutrients, discharge standards across the northeastern United States are becoming more stringent. As a result, biological nutrient removal is becoming increasingly more common. Interestingly, recent research suggests that biological treatment aimed at controlling nutrient discharge may offer some utility in reducing concentrations of some microconstituents. The proposed study is motivated by the potential synergy between nutrient control and microconstituent attenuation, with specific emphasis placed on understanding pharmaceutical biotransformation by nitrifying organisms. Pharmaceuticals have been observed to be partially removed during wastewater treatment. However, the vast majority of studies examining the fate of pharmaceuticals through the wastewater treatment process focus on the disappearance of the parent compound. Few studies have elucidated biodegradation metabolites in wastewater treatment plant effluents, despite preliminary evidence that suggests ecotoxicity may increase along pharmaceutical transformation pathways, and mixture ecotoxicity may be appreciably higher than single component toxicity. Thus, there is a critical need for careful research to elucidate those biochemical processes that degrade pharmaceuticals during nutrient removal. The proposed project integrates laboratory experiments and mathematical modeling to quantitatively assess the fate of pharmaceuticals during nitrification. The research plan has three specific objectives: (i) elucidate the rates of pharmaceutical attenuation by nitrifying organisms, (ii) identify metabolites produced during the nitrification process, and (iii) develop modeling tools to predict pharmaceutical degradation within the context of enhanced nutrient removal. In contrast to most studies that group pharmaceutical fate and transport based upon pharmacology, we propose to link observed biodegradability to molecular descriptors of the pharmaceuticals examined. Research findings will be applicable to both natural and engineered systems where biological nitrification occurs in the presence of dilute pharmaceuticals. Results are anticipated to move the state-of-the-art toward development of predictive capabilities aimed at assessing pharmaceutical attenuation within treatment systems designed and operated for enhanced nutrient removal.