Membrane filtration in water recycling: removal of natural hormones
Recent detections of endocrine-disrupting chemicals (EDCs) in effluent are of great concern by sections of the community associated with the issue of reclaimed water recycling. In vitro and in vivo studies by many researchers have confirmed the impacts of EDCs on trout at the common concentration encountered in sewage effluent. Amongst many types of EDCs the impacts of steroid estrogens such as estrone, estradiol (natural hormones) and ethinylestradiol (a synthetic hormone) are prominent as they have far higher endocrine-disrupting potency than other synthetic EDCs (Johnson and Stumpter, 2001). Performance of conventional wastewater treatment of different plants on removal of these compounds varies greatly and, concentrations of some steroid estrogens in secondary effluent are still able enough to harm wildlife such as fish in particular (Johnson and Stumpter, 2001). In spite of the magnitude of this problem, research on the removal of EDCs in water and wastewater treatment remains to date very limited due to their relatively low concentration and the associated analytical difficulties.