Analysis Of Perfluorinated Compounds And Evaluation Of Their Fate In Wasterwater Treatment Plant

Perfluorinated compounds (PFCs) is a new type of persistent organic pollutants (POPs), which could provide long-term and potential hazards for environment and human health. perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid(PFNA), perfluorodecanoic acid (PFDA), perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonate (PFOS) are selected as the target analytes in this research. An analytical method based on high-performance liquid chromatography (HPLC) with ion-trap mass spectrometry (MS) was developed for analysis of PFCs in wastewater. Wastewater was filtrated by 0.45μm glass fibre filters (GFF), Adjust pH to 3, and then extracted using WAX cartridges (Waters, U.S.A). Selected PFCs were detected using HPLC interfaced with a negative electrospray tandem ion-trap MS in MS2 full scan mode. Concentrations of PFCs in water were determinated by internal standard calibration curve quantification. In this way, ionization enhancement or suppression caused by matrix effect was eliminated and a sensitivity and selectivity result was achieved. With this method, the recoveries of surrogate standard in wastewater were 82±11% for mass-labelled perfluorononanoic acid (MPFOA) and 74±8% for mass-labelled perfluorooctane sulfonate (MPFOS). the recoveries of spike standard in blank samples were 106%-135% for selected PFCs and the relative standard deviations (RSD) were 7%-15%. Method quantitation limits (MQL) are 1-5 ng/L. which indicated that this method is suitable for the quantification of PFCs in wastewater.Grab samples of influent and effluent of primary clarifier, Anoxic-Oxic (A/O) activated sludge process and Biological Aerated Filter (BAF) process were collected by 6 sampling events over six months. In comparison, the PFCs concentrations of wastewater in Harbin were lower than most other countries and regions in the world. The total PFCs in different processes were 5.4-48.5 ng/L, PFOA and PFOS were the primary compounds of PFCs. The concentrations of other PFCs were low and many samples were not detected. The mass flow of total PFCs was 7g/d in influence and 4 g/d in effluent, which was also lower than other countries. It indicated the use of PFCs in Harbin was less. Wastewater treatment process play a certain role in the removal of PFCs. The primary clarifier can remove some PFCs. The PFCs removal efficiency in BAF process was better than A/O process. A/O process and the BAF process on the removal rate for PFOA were 29.4% and 33.7%, respectively, and both 11.8% for PFOS. However, the concentrations of PFOA and PFOS in oxidation tank of A/O and coagulation tank of BAF process increased obviously because of the biodegradation of precursors and the mixture of coagulant. PFCs had no significant difference between the dry season and the wet season. Correlation analysis showed that the source of PFOA and PFOS were different. PFOA may come from sewage discharge, while PFOS is mainly derived from industrial wastewater discharge.