title: Profiles and removal efficiency of polycyclic aromatic hydrocarbons by two different types of sewage treatment plants in Hong Kong.
abstract: Sewage discharge could be a major source of polycyclic aromatic hydrocarbons (PAHs) in the coastal waters. Stonecutters Island and Shatin Sewage Treatment Works (SCISTW and STSTW) in Hong Kong, adopted chemically enhanced primary treatment and biological treatment, respectively. This study aimed at (1) determining the removal efficiencies of PAHs, (2) comparing the capabilities in removing PAHs, and (3) characterizing the profile of each individual PAHs, in the two sewage treatment plants (STPs). Quantification of 16 PAHs was conducted by a Gas Chromatography. The concentrations of total PAHs decreased gradually along the treatment processes (from 301±255 and 307±217ng/L to 14.9±12.1 and 63.3±54.1ng/L in STSTW and SCISTW, respectively). It was noted that STSTW was more capable in removing total PAHs than SCISTW with average total removal efficiency 94.4%±4.12% vs. 79.2%±7.48% (p<0.05). The removal of PAHs was probably due to sorption in particular matter, confirmed by the higher distribution coefficient of individual and total PAHs in solid samples (dewatered sludge contained 92.5% and 74.7% of total PAHs in SCISTW and STSTW, respectively) than liquid samples (final effluent-total contained 7.53% and 25.3% of total PAHs in STSTW and SCISTW, respectively). Despite the impressive capability of STSTW and SCISTW in removing PAHs, there was still a considerable amount of total PAHs (1.85 and 39.3kg/year, respectively for the two STPs) being discharged into Hong Kong coastal waters, which would be an environmental concern.
authors.affiliation: Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China; Department of Environmental Engineering, Jinan University, Guangzhou 510630, China; State Key Laboratory in Marine Pollution, Croucher Institute for Environmental Sciences, Hong Kong Baptist University and City University of Hong Kong, Kowloon Tong, Hong Kong, China.
authors.forename: Yu Bon
authors.initials: YB
authors.lastname: Man
authors.affiliation: Department of Geography, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
authors.forename: Ka Lai
authors.initials: KL
authors.lastname: Chow
authors.affiliation: College of Environment, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China.
authors.forename: Wing Yin
authors.initials: WY
authors.lastname: Mo
authors.affiliation: Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China.
authors.forename: Yung Hau
authors.initials: YH
authors.lastname: Chan
authors.affiliation: Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China; State Key Laboratory in Marine Pollution and Research Centre for the Oceans and Human Health, City University of Hong Kong, Kowloon Tong, Hong Kong, China.
authors.forename: James Chung Wah
authors.initials: JCW
authors.lastname: Lam
authors.affiliation: The Drainage Services Department, The Government of the Hong Kong Special Administrative Region, Hong Kong, China.
authors.forename: Frankie Tat Kwong
authors.initials: FTK
authors.lastname: Lau
authors.affiliation: The Drainage Services Department, The Government of the Hong Kong Special Administrative Region, Hong Kong, China.
authors.forename: Wing Cheong
authors.initials: WC
authors.lastname: Fung
authors.affiliation: Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China; Department of Environmental Engineering, Jinan University, Guangzhou 510630, China; State Key Laboratory in Marine Pollution, Croucher Institute for Environmental Sciences, Hong Kong Baptist University and City University of Hong Kong, Kowloon Tong, Hong Kong, China. Electronic address: minghwong@ied.edu.hk.
authors.forename: Ming Hung
authors.initials: MH
authors.lastname: Wong
mesh_terms: D006723:Hong Kong; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012722:Sewage / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: PAHs; Removal efficiency; Sewage; Sewage treatment plants; Sludge