Biodegradation of Nonylphenol Ethoxylates in the Continuous Flow Activated Sludge Simulation Test

Biodegradation of representative nonylphenol ethoxylates, NP10EO, was investigated in the continuous flow activated sludge simulation test; the effect of hydraulic retention time(HRT) on its biodegradation was examined. The primary biodegradation degree of NP10EO was 96.5% at 3 hours hydraulic retention time and 96.2% at 6 hours hydraulic retention time; the ultimate biodegradation degree, which was 84.8% and 87.3%, respectively, indicated that the primary biodegradation of NP10EO was very easy and most NP10EO can be biodegraded ultimately, the prolonging of HRT had no influence on the primary biodegradation and little influence on the ultimate biodegradation. The possible biodegradation pathways of NPnEO, especially the biodegradation pathways of benzene ring in NPnEO, were proposed through Electrospray ionization-mass spectrometry analysis.