Occurrence and removal of bisphenol analogues in wastewater treatment plants and activated sludge bioreactor

Abstract

The occurrence and removal of ten bisphenol analogues (BPs) in municipal wastewater treatment plants (WWTPs) and laboratory scale activated sludge bioreactor (ASBR) were studied. All targeted BPs except for tetrachlorobisphenol A (TCBPA) were detected in the four WWTPs (W1, W2, W3 and W4) in the ng/L and ng/g dry weight range in wastewater and activated sludge, respectively, indicating that in addition to BPA, the BPA substitutes were widely used in our daily life and industrial production. Discrepant results regarding the removal efficiencies of BPs by different wastewater treatment processes were obtained. The removal rates were 55.6%, 24.4%, −10.1%, 71.4%, 38.9%, 58.0%, 39.1% and 6.4% in W1, 65.4%, 32.8%, 44.7, −13.5%, 20.1%, −29.6%, −25.1% and 99.4% in W2, 11.6%, 48.8%, 38.9%, 22.0%, 99.0%, −29.2%, −56.5% and 32.6% in W3, 33.9%, 30.5%, 17.4%, −47.6%, 62.9%, 83.0%, 4.4% and −4.3% in W4, for BPA, BPB, BPE, BPF, BPS, BPZ, BPAF and BPAP, respectively. The removal of ten targeted BPs in lab-scale continuous flow conventional ASBR and the key factors were investigated. The simulated laboratory-scale ASBR were highly effective in removing BPA, BPB, BPE, BPF, BPM and BPS with removal efficiencies of >94.3%, while BPZ, BPAP, BPAF and TCBPA were recalcitrant to elimination in the stimulated bioreactor with removal efficiencies of 71.3 ± 13.7%, 55.1 ± 21.2%, 47.4 ± 9.5% and 45.3 ± 16.6%, respectively. Protonation, hydrophobicity and molecular features of BPs were critical for their elimination in wastewater.