Man Yu Bon, Chow Ka Lai, Cheng Zhang, Mo Wing Yin, Chan Yung Hau, Lam James Chung Wah, Lau Frankie Tat Kwong, Fung Wing Cheong, Wong Ming Hung
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.
Department of Geography, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
J Environ Sci (China). 2017 Mar;53:196-206. doi: 10.1016/j.jes.2016.04.020. Epub 2016 Jun 4.
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.
污水排放可能是沿海水域多环芳烃（PAHs）的主要来源。香港的昂船洲污水处理厂和沙田污水处理厂（SCISTW和STSTW）分别采用了化学强化一级处理和生物处理。本研究旨在：（1）确定两个污水处理厂（STPs）中多环芳烃的去除效率；（2）比较去除多环芳烃的能力；（3）表征各单一多环芳烃的特征。采用气相色谱法对16种多环芳烃进行定量分析。总多环芳烃浓度在处理过程中逐渐降低（STSTW和SCISTW中分别从301±255和307±217ng/L降至14.9±12.1和63.3±54.1ng/L）。值得注意的是，STSTW去除总多环芳烃的能力比SCISTW更强，平均总去除效率分别为94.4%±4.12%和79.2%±7.48%（p<0.05）。多环芳烃的去除可能是由于其在颗粒物上的吸附，这一点通过固体样品（SCISTW和STSTW的脱水污泥中分别含有总多环芳烃的92.5%和74.7%）中单一和总多环芳烃的分配系数高于液体样品（STSTW和SCISTW的最终出水总多环芳烃分别占25.3%和7.53%）得到证实。尽管STSTW和SCISTW在去除多环芳烃方面能力令人印象深刻，但仍有相当数量的总多环芳烃（两个污水处理厂分别为每年1.85和39.3千克）排放到香港沿海水域，这将是一个环境问题。
