Biodegradation of imidacloprid and carbamazepine in municipal wastewater

Contaminants of emerging concern (CECs), such as pharmaceuticals, personal care products, endocrine-disrupting compounds, pesticides, herbicides and insecticides can be a major problem to the environment and human health. This study investigated the microbial degradation of imidacloprid and carbamazepine. The research focus on the challenge of degrading the neonicotinoid insecticide imidacloprid and the prescription drug carbamazepine in wastewater treatment and directly downstream systems. Discovering how to improve the poor removal of these compounds from wastewater is important to environmental health. Importantly, as wastewater becomes more reused either directly or indirectly, the increasing need for CEC biodegradation will be important to human health. A component of the first objective of this work is in collaboration with Dr. Nair at the University of Oklahoma (OU) who operated wetland mesocosm experiments for stormwater and wastewater effluent treatment. This first objective finds the extent that these constructed wetlands enrich for CEC-degrading bacteria. In the second objective, an outlet stream of treated wastewater is analyzed for the enrichment of CEC-degrading bacteria. The third objective is to determine the ability to enhance CEC degradation in wastewater treatment sludge through vitamin addition, redox cycling, and longer solid retention time (SRT). The three objectives together illustrate the extent and mechanisms of imidacloprid and carbamazepine biodegradation in wastewater systems. Historically, a significant amount of research has been performed on different conventional contaminants (nutrients and BOD), however, wastewater treatment must advance towards the degradation of CECs as water reuse increases in necessity and scale. The hope of this research is to help in the design of systems such that CECs may be better biodegraded.