Removal of endocrine disrupting chemicals in a large scale membrane bioreactor plant combined with anaerobic-anoxic-oxic process for municipal wastewater reclamation Chunying Wu, Wenchao Xue, Haidong Zhou, Xia Huang and Xianghua Wen ABSTRACT The removal of eight typical endocrine disrupting compounds (EDCs) in a full scale membrane bioreactor combined with anaerobic-anoxic-oxic process (A 2 /O-MBR) for municipal wastewater reclamation located in Beijing was investigated. These EDCs, including 4-octylphenol (4-OP), 4-n- nonylphenol (4-n-NP), bisphenol A (BPA), estrone (E1), 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), estriol (E3) and 17α-ethinylestradiol (EE2), were simultaneously analyzed by gas chromatography/ mass spectrometry after derivatization. The concentrations of eight EDCs were also measured in sludge of anaerobic, anoxic, oxic and membrane tanks to measure sludge-water distribution coefficients (K d values) as the indicator of adsorption propensity of target compound to sludge. The removal efficiencies of EDCs reached above 97%, except for 4-n-NP removal efficiency of 72%, 4-OP removal efficiency of 75% and EE2 removal efficiency of 87% in the A 2 /O-MBR process. The high K d values indicated that the sludge had a large adsorption capacity for these EDCs, and significantly contributed to removal of EDCs. Yeast estrogen screen assay was performed on samples to assess the total estrogenic activity by measuring the 17β-E2 equivalent quantity (EEQ), expressed in ng-EEQ/L. The measured EEQ value was markedly reduced from 72.1 ng-EEQ/L in the influent to 4.9 ng-EEQ/L in the effluent. Anoxic tank and anaerobic tank contributed to 80% and 37% in total EEQ removal, respectively. Chunying Wu Wenchao Xue Haidong Zhou Xia Huang (corresponding author) Xianghua Wen State Key Joint Laboratory of Environmental Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China E-mail: xhuang@tsinghua.edu.cn Key words | endocrine disrupting chemicals, estrogenic activity, membrane bioreactor, municipal wastewater, sludge adsorption INTRODUCTION With advance in analytical instrumentations, more emer- ging micro-pollutants, such as endocrine disrupting compounds (EDCs), pharmaceuticals and personal care pro- ducts, etc., have been detected at low ng/L levels in sewage effluent (Westerhoff et al. ; Nakada et al. ). Further- more, the fate of their ubiquitous occurrence with a wide range has attracted considerable attentions from the public and regulators in recent years. Most of these con- cerns stem from their known aquatic and environmental impacts and potential human health effects at very low (part-per-trillion or part-per-quadrillion) concentrations. Especially the presence and the fate of EDCs are of growing concern since the discovery of the feminization of male fish and other aquatic organisms exposed to wastewater treat- ment plant effluents (Guillette et al. ; Sumpter & Jobling ). Recently it has also been discovered that some EDCs can have transgenerational effects due to abnor- mal DNA methylation patterns (Chang et al. ; Price et al. ). However, municipal wastewater treatment plants (MWTPs) are normally constructed for the efficient removal of biodegradable organic substances through bio- logical degradation. Namely, conventional biological 1511 © IWA Publishing 2011 Water Science & Technology | 64.7 | 2011 doi: 10.2166/wst.2011.140 Downloaded from https://iwaponline.com/wst/article-pdf/64/7/1511/444715/1511.pdf by guest on 26 May 2020