Fate of estrogenic hormones in wastewater and sludge treatment: A review of properties and analytical detection techniques in sludge matrix

Estrogenic hormones (estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2)) are the major contributor to the total estrogenicity in waterways. Presence of these compounds in biosolids is also causing concern in terms of their use as soil amendment. In comparison with wastewater treatment, removal of estrogenic compounds in sewage sludge has received less attention. This paper presents a literature review regarding the source and occurrence of these pollutants in our environment. The removal pathways of estrogenic compounds in engineered systems, such as full-scale wastewater treatment plants (WWTPs), are also discussed. Review of the fate studies revealed that activated sludge system with nutrient removal shows very high (>90%) removal of estrogenic hormones in most of the cases. Although, aerobic digestion showed better attenuation of estrogenic compounds, anaerobic digestion increased the overall estrogenicity of biosolids. Finally, this paper highlights the challenges involved in analytical determination of these compounds in sewage sludge matrix.

► Activated sludge systems with nutrient removal high estrogenic hormone removal rates.
► Long HRT/SRT and high reactor estrogen loading increases removal efficiency.
► Anaerobic digestion results in a net increase in estrogenicity.