17 alpha-ethinylestradiol: An endocrine disrupter of great concern. Analytical methods and removal processes applied to water purification. A review

The xenobiotic 17 alpha-ethinylestradiol, an oral contraceptive component, is an endocrine disrupter (EDC) of great concern, with fish feminization induced for concentrations as low as ng L-1. EE2 occurrence in the aquatic environment can be linked to insufficient removal in wastewater treatment plants. The focus of this review is to consider optimum treatment Processes for removal of EE2. The main problem of EE2 is concentrations often below authors' limits of detection. Consequently, it is important to fully understand the advantages and disadvantages of different analytical techniques as this will determine confidence in comparison of the efficiency of different treatment processes. Solid-phase extraction followed by chromatography is widely used but alternative methods, such as solid-phase microextraction, stir bar sorptive extraction, or passive samplers, appear as promising tools. During the conventional activated sludge (AS) process, the incomplete sludge settlement results in lost of biomass, which means loss of EE2 adsorbed, and in low SRT, unsuited to nitrifying microorganisms that are responsible for EE2 biodegradation. Among bioprocesses, i.e., AS, membrane bioreactors (MBRs), biofilm, reactors, and sequencing batch reactors, MBR technology appears as a hopeful solution for the improvement of EDCs removal, and, more precisely, EE2. Alternative treatments such as photodegradation, granulated activated carbon, MnO2, and sand reactor or ozonation were tested in the laboratory and were shown to be inadequate. (C) 2008 American Institute of Chemical Engineers.