Investigating the connection between nitrification and the removal of Pharmaceuticals using engineered bioreactors

摘要

Vast improvements in analytical techniques used to examine Pharmaceuticals and endocrine disrupting chemicals have helped to highlight the presence of xenobiotics at trace concentrations (ng/L) in wastewaters. This presentation will include initial findings regarding the fate of model pharmaceutical contaminants (carbamazepine, iopromide, and trimethoprim) by batch cultures of Nitrosomonas europaea and in bioreactors with nitrifying activated sludge from a municipal wastewater treatment plant. Laboratory-scale experiments showed that a significantly higher removal rate in nitrifying activated sludge relative to conventional activated sludge was observed for both iopromide and trimethoprim, while no significant removal was observed for carbamazepine up to 30 days. When the activity of the nitrifying bacteria was inhibited in activated sludge, the percent removal of iopromide decreased from 97 to 86% while trimethoprim removal decreased from 70 to 25%. However, the use of pure cultures of N. europaea in batch vessels showed no biodegradation of trimethoprim and carbamazepine. On the other hand, iopromide was continually transformed over 10 days of incubation. Chemical structures of metabolites of iopromide are proposed using the fragmentation patter obtained by ion-trap mass spectrometry.