Benzophenone and Diethyl Phthalate Removal from Real Wastewater by a Multi-stage Hybrid Reactor

Benzophenone (BP) and diethyl phthalate (DEP)—chemical substances of environmental concern due to potential toxicity—have been quantified in considerable concentrations in different environmental matrices worldwide. Wastewater treatment plants (WWTPs) with multi-stage hybrid biological systems have been considered a potential strategy to improve the removal of different micropollutants in wastewater from biological systems. On the other hand, investigations on the efficiency of these systems to treat real wastewater with focus on the removal of DEP are scarce, and there is no information on the removal of BP. The aim of this study was to evaluate the performance of a pilot-scale multi-stage hybrid bioreactor (MSHR) on the efficiency of BP and DEP removal from a real wastewater, whose composition varies over short periods of time, thus causing impacts on biological processes. The efficiency of the biological treatment was assessed in two different phases: (I) predominantly suspended biomass and (II) predominantly fixed biomass, both in the aerobic tank. Besides, this study presents and discusses the correlation between BP and DEP removal and different physical–chemical parameters and operating conditions. The highly variable composition of the influent illustrated by the variation in the organic load resulted in oscillation in the treatment performance. Despite this variation, the pilot-scale multi-stage hybrid bioreactor was able to remove up to 69.6% of BP and 74.5% of DEP, both in the phase of predominantly fixed biomass.