Loading and removal of PAHs in a wastewater treatment plant in a separated sewer system. (1st September 2015) - Ozaki, Noriatsu
Abstract: The loading and removal of polycyclic aromatic hydrocarbons (PAHs) were measured and estimated in a wastewater treatment plant in a separated sewer system in a suburban area of Japan. The influent 16 PAHs concentration was 219 ± 210 ng L −1, whereas the effluent concentration was 43.5 ± 42.5 ng L −1 (mean ± sd). No clear diurnal or weekly fluctuation was observed. However, evaluation of long-term changes revealed PAH fluctuations continuing for more than 1 week. Half of the PAHs (63%) were biologically or chemically transformed, or vaporized in the treatment plant, while the remainder were discharged with effluent (28%) and excess sludge (9%). Measurement of the per capita loading of the treatment plant revealed values of 142 ± 53 and 28 ± 11 μg person −1 day −1 (mean ± 95% confidence interval) for influent and effluent, respectively. Isomer ratio analysis revealed that the PAHs originated from a mixture of petroleum, petroleum combustion, and burning of biomass residues. Graphical abstract: Highlights: PAHs concentration of a wastewater treatment plant in a separated sewer system was measured. Half of the PAHs were decomposed or vaporized and the remainder were discharged. The loading of PAHs from household and industrial emissions in aquatic systems was not negligible.