| Pharmaceuticals are a growing concern because they are continually being introduced in the influent to municipal wastewater treatment plants (WWTPs). Understanding their removal mechanisms from available treatment processes is vital in preventing downstream contamination of our natural water resources. In this study, ibuprofen, a popular over-the-counter pain reliever, was monitored by taking wastewater samples throughout the City of Guelph municipal WWTP. The results showed greater than 99% of ibuprofen was removed in the aeration tank. Aerobic biodegradation was confirmed to be the dominant mechanism of ibuprofen removal. First-order kinetics were used to quantify ibuprofen biodegradation in a conventional WWTP aeration tank and in a membrane bioreactor (MBR) pilot plant. The rate constant, kbiol, for the conventional WWTP and the MBR were determined to be (-6.8 +/- 3.3) L/g SS*d and (-8.4 +/- 4.0) L/g SS*d, respectively. These two rate constants were found to be statistically similar. In addition, a biological nutrient removal (BNR) pilot system comprised of an anaerobic tank, an anoxic tank, and an aeration tank with a microfiltration membrane was sampled. Preliminary findings from the samplings suggest that ibuprofen can also be degraded anaerobically. |
