State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Environ Sci Technol. 2013 Jan 15;47(2):732-40. doi: 10.1021/es304237m. Epub 2013 Jan 7.
Sewage treatment plants (STP) are an important source of short chain chlorinated paraffins (SCCPs) to the ambient environment through discharge of effluent and application of sludge. In this work, a field study was conducted to determine the behavior and possible removal of SCCPs during the sewage treatment process in an advanced municipal STP in Beijing, China. SCCPs were detected in all sewage water and sludge samples, and 97% of the initial mass loading in raw sewage was found to be associated with suspended matter. The total concentrations in raw influent, tertiary effluent, and dewatered sludge were 184 ± 19 ng/L, 27 ± 6 ng/L, and 15.6 ± 1.4 μg/g dry weight (d.w.), respectively. The dissolved concentrations of total SCCPs (∑SCCPs) significantly decreased during mechanical, biological, and chemical treatments. SCCP homologue profiles in aqueous phase were distinctly different from those in solid phase. Along the treatment process, the relative abundance of shorter chain and lower chlorinated congeners gradually increased in sewage water, but no obvious variations of homologue profiles were found in sludge. Mass flow analysis indicated, the removal efficiency in aqueous phase for ∑SCCPs was 82.2%, and the congener-specific removal efficiencies were positively related to their solid-water partition coefficients (K(d)). Mass balance results indicated that 0.8% and 72.6% of the initial SCCP mass loading were ultimately found in the effluents and dewatered sludge, respectively, while the remaining 26.6% was lost mainly due to biodegradation/biotransformation. It was suggested that the activated sludge system including basic anaerobic-anoxic-aerobic processes played an effective role in removing SCCPs from the wastewater, while the sorption to sludge by hydrophobic interactions was an important fate of SCCPs during the sewage treatment.
污水处理厂（STP）通过污水排放和污泥应用，是环境中短链氯化石蜡（SCCPs）的重要来源。本研究在中国北京的一个先进城市 STP 中进行了现场研究，以确定 SCCPs 在污水处理过程中的行为和可能的去除情况。所有污水和污泥样品中均检测到 SCCPs，并且发现初始质量负荷的 97%与悬浮物有关。原污水、三级出水和脱水污泥中的总浓度分别为 184±19ng/L、27±6ng/L 和 15.6±1.4μg/g 干重（d.w.）。在机械、生物和化学处理过程中，总 SCCPs（∑SCCPs）的溶解浓度显著降低。水相中的 SCCP 同系物谱明显不同于固相中的同系物谱。随着处理过程的进行，污水中较短链和较低氯化的同系物的相对丰度逐渐增加，但污泥中同系物谱没有明显变化。质量流分析表明，∑SCCPs 在水相中的去除效率为 82.2%，且同系物特异性去除效率与它们的固-水分配系数（K(d)）呈正相关。质量平衡结果表明，初始 SCCP 质量负荷的 0.8%和 72.6%最终分别出现在废水中和脱水污泥中，而其余 26.6%主要由于生物降解/生物转化而损失。研究结果表明，包括基本厌氧-缺氧-好氧工艺的活性污泥系统在从废水中去除 SCCPs 方面发挥了有效作用，而疏水性相互作用引起的 SCCPs 向污泥的吸附是 SCCPs 在污水处理过程中的一个重要归宿。
