Alidina Mazahirali, Shewchuk Justin, Drewes Jörg E
Water Reuse and Desalination Center (WDRC), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
Water Reuse and Desalination Center (WDRC), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia; Chair of Urban Water Systems Engineering, Technische Universität München, Garching, Germany.
Chemosphere. 2015 Mar;122:23-31. doi: 10.1016/j.chemosphere.2014.10.064. Epub 2014 Nov 20.
This study was undertaken to investigate whether changes in temperature experienced in MAR systems affect attenuation of trace organic chemicals (TOrCs). A set of laboratory-scale soil columns were placed in a temperature-controlled environmental chamber and operated at five different temperature set-points (30, 20, 10, 8 and 4°C) covering the range of typical groundwater temperatures in cold, moderate and arid climate regions. Removal of bulk organic carbon both in the infiltration zone as well as during deeper infiltration was independent of temperature. Of the 22 TOrCs investigated, only six chemicals exhibited changes in attenuation as a function of temperature. Attenuation of four of the compounds (diclofenac, gemfibrozil, ketoprofen and naproxen) decreased as the temperature was reduced from 30°C to 4°C, likely due to decreased microbial activity at lower temperatures. As the temperature was decreased, however, attenuation of oxybenzone and trimethoprim were noted to increase. This increased attenuation was likely due to more efficient sorption at lower temperatures, though possible changes in the microbial composition as the temperature decreased may also have contributed to this change. Changes in rate constants of attenuation (ka) for the biotransformed TOrCs with temperature suggested the existence of a critical temperature at 10°C for three of the four TOrCs, where significant changes to rates of attenuation occurred. Results from this study indicated that for most TOrCs, changes in temperature do not impact their attenuation. Thus, seasonal changes in temperature are not considered to be a major concern for attenuation of most TOrCs in MAR systems.
本研究旨在调查人工回灌（MAR）系统中经历的温度变化是否会影响痕量有机化学品（TOrCs）的衰减。一组实验室规模的土壤柱被放置在温度可控的环境舱中，并在五个不同的温度设定点（30、20、10、8和4°C）下运行，这些温度涵盖了寒冷、温和及干旱气候区域典型的地下水温度范围。在渗透区以及更深层渗透过程中，总有机碳的去除与温度无关。在所研究的22种TOrCs中，只有六种化学品的衰减随温度变化。当温度从30°C降至4°C时，四种化合物（双氯芬酸、吉非贝齐、酮洛芬和萘普生）的衰减降低，这可能是由于较低温度下微生物活性降低所致。然而，随着温度降低，观察到氧苯酮和甲氧苄啶的衰减增加。这种增加的衰减可能是由于较低温度下更有效的吸附，尽管随着温度降低微生物组成的可能变化也可能促成了这种变化。生物转化的TOrCs的衰减速率常数（ka）随温度的变化表明，四种TOrCs中的三种在10°C时存在一个临界温度，在该温度下衰减速率发生了显著变化。本研究结果表明，对于大多数TOrCs而言，温度变化不会影响其衰减。因此，温度的季节性变化不被认为是MAR系统中大多数TOrCs衰减的主要问题。
