Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA.
Water Quality Research and Development Division, Southern Nevada Water Authority, Henderson, NV 89015, USA.
Sci Total Environ. 2018 Nov 1;640-641:62-72. doi: 10.1016/j.scitotenv.2018.05.145. Epub 2018 May 29.
This study determined biotransformation rates (k) and sorption-distribution coefficients (K) for a select group of trace organic compounds (TOrCs) in anaerobic, anoxic, and aerobic activated sludge collected from two different biological nutrient removal (BNR) treatment systems located in Nevada (NV) and Ohio (OH) in the United States (US). The NV and OH facilities operated at solids retention times (SRTs) of 8 and 23 days, respectively. Using microwave-assisted extraction, the biotransformation rates of the chosen TOrCs were measured in the total mixed liquor. Sulfamethoxazole, trimethoprim, and atenolol biotransformed in all three redox regimes irrespective of the activated sludge source. The biotransformation of N, N-diethyl-3-methylbenzamide (DEET), triclosan, and benzotriazole was observed in aerobic activated sludge from both treatment plants; however, anoxic biotransformation of these three compounds was seen only in anoxic activated sludge from NV. Carbamazepine was recalcitrant in all three redox regimes and both sources of activated sludge. Atenolol and DEET had greater biotransformation rates in activated sludge with a higher SRT (23 days), while trimethoprim had a higher biotransformation rate in activated sludge with a lower SRT (8 days). The remaining compounds did not show any dependence on SRT. Lyophilized, heat inactivated sludge solids were used to determine the sorption-distribution coefficients. Triclosan was the most sorptive compound followed by carbamazepine, sulfamethoxazole, DEET, and benzotriazole. The sorption-distribution coefficients were similar across redox conditions and sludge sources. The biotransformation rates and sorption-distribution coefficients determined in this study can be used to improve fate prediction of the target TOrCs in BNR treatment systems.
本研究测定了从美国内华达州（NV）和俄亥俄州（OH）两个不同生物脱氮（BNR）处理系统采集的厌氧、缺氧和好氧活性污泥中一组选定的痕量有机化合物（TOrCs）的生物转化速率（k）和吸附-分配系数（K）。NV 和 OH 设施的固体停留时间（SRT）分别为 8 天和 23 天。通过微波辅助萃取，在总混合液中测量了所选 TOrCs 的生物转化速率。磺胺甲恶唑、甲氧苄啶和阿替洛尔在所有三种氧化还原区都发生了生物转化，而不管活性污泥的来源如何。在来自两个处理厂的好氧活性污泥中观察到 N，N-二乙基-3-甲基苯甲酰胺（DEET）、三氯生和苯并三唑的生物转化；然而，只有 NV 缺氧活性污泥中观察到这三种化合物的缺氧生物转化。卡马西平在所有三种氧化还原区和两种来源的活性污泥中均不易生物转化。阿替洛尔和 DEET 在 SRT 较高（23 天）的活性污泥中的生物转化速率较高，而甲氧苄啶在 SRT 较低（8 天）的活性污泥中的生物转化速率较高。其余化合物与 SRT 没有任何依赖关系。使用冻干、热失活的污泥固体来确定吸附-分配系数。三氯生是最具吸附性的化合物，其次是卡马西平、磺胺甲恶唑、DEET 和苯并三唑。在不同的氧化还原条件和污泥来源下，吸附-分配系数相似。本研究中确定的生物转化速率和吸附-分配系数可用于改善 BNR 处理系统中目标 TOrCs 的命运预测。
