Ciprofloxacin removal during secondary domestic wastewater treatment in high rate algal ponds

This study investigated the removal of antibiotic ciprofloxacin during the treatment of real wastewater using high rate algal ponds (HRAP). When spiked at 2 mg/L into primary domestic wastewater, ciprofloxacin (CPX) was efficiently removed from laboratory scale photobioreactors continuously operated under various durations of artificial illumination and hydraulic residence times. Subsequent batch tests conducted with reactor microcosms showed CPX removal was mainly caused by photodegradation during daytime, and sorption to biomass during night time. These findings were confirmed during an experiment conducted in a 1000 L pilot HRAP operated outdoors, as well as during outdoor batch assays conducted using pilot HRAP microcosms. While these results highlight a potentially interesting treatment capacity in comparison to conventional biological treatment, further research must confirm these findings at relevant pollutant concentration (ng-mu g/L) and determine the fate and potential toxicity of degradation products. (C) 2017 Elsevier Ltd. All rights reserved.