Fate and removal of estrogens in municipal wastewater

Natural and synthetic estrogens are some of the most potent endocrine disrupting compounds found in municipal wastewater. Much research has been conducted on the source and fate of estrogens in wastewater treatment plants. Sorption and biodegradation are the primary removal mechanisms for estrogens in activated sludge systems, which are widely used biological treatment techniques for municipal wastewater treatment. However, when removal of estrogens in a wastewater treatment plant is incomplete, these compounds enter the environment through wastewater discharges or waste activated sludge at concentrations that can cause endocrine-reproductive system alterations in birds, reptiles and mammals. Therefore, studies have also focused on potential advanced treatment technologies with the aim of removing the compounds before discharging wastewater effluent or disposing waste sludge. This review discusses the physiological effects of these estrogens and the degree of problems estrogens pose as they enter the wastewater stream. Thereafter, this review also analyzes their fate in wastewater treatment systems and how they may reach drinking water sources. Furthermore, this review includes a discussion on various treatment technologies being investigated and future research trends for this pressing environmental issue.