(49a) Photodegradation of Pharmaceuticals in Partially Nitritated Wastewater

Certain pharmaceutically active compounds may not be readily removed in anaerobic wastewater treatment, and the effluents from anaerobic wastewater treatment processes often contain high levels of ammonia. A polishing step is therefore necessary to remove nitrogen and trace organic contaminants, in particular for reuse considerations. For nitrogen removal, an increasingly popular, sustainable biotechnology is the anammox process, which which involves a prepatory step for partial conversion of ammonia to nitrite. Given that nitrite is an efficient sensitizer for production of hydroxyl radical, a UV irradiation step after partial nitrification might also be used to create a de-facto advanced oxidation process during disinfection to remove pharmaceuticals. The direct and indirect photolysis of select pharmaceutical compounds was investigated in systems containing nitrite, ammonia, and effluent collected from a bench-scale reactor using a 450 W medium-pressure mercury vapor lamp. Results indicate that the presence of nitrite enhances the removal of pharmaceutical compounds.