BRGM, French Geological Survey, 3 Av. Claude Guillemin, B.P. 6009, F-45000 Orléans, France; Sorbonne Université, UMR 7619 Metis, CNRS, EPHE, Paris, France.
BRGM, French Geological Survey, 3 Av. Claude Guillemin, B.P. 6009, F-45000 Orléans, France.
Sci Total Environ. 2022 Aug 25;836:155643. doi: 10.1016/j.scitotenv.2022.155643. Epub 2022 May 2.
Soil Aquifer Treatment (SAT) can provide supplementary treatment of trace organic compounds (TrOCs) such as pharmaceutical and industrial compounds present in Secondary Treated Wastewater (STWW). Concern on presence of unregulated TrOCs in natural systems has raised recently as well as the interest in SAT systems for remediation. The present study quantifies, at the field scale over35 m of lateral groundwater flow, the effectiveness of the Agon-Coutainville SAT system (Manche, Normandy, France) for TrOCs removal by sorption and biodegradation through monitoring of seven TrOCs (oxazepam, carbamazepine, benzotriazole, tolyltriazole, caffein, paracetamol, ibuprofen) and major inorganic compounds as intrinsic tracers in STWW and groundwater during a 34-day STWW infiltration experiment during operational use of the SAT. Cationic exchanges and mixing between groundwater and STWW during the experiment were highlighted by major ions and geochemical simulations. Due to the low thickness of the unsaturated zone, a 1D analytical solution of the advection-dispersion equation (ADE) was applied on chloride data. Chloride was used as conservative intrinsic tracer to calibrate the horizontal flow and transport parameters such as the aquifer dispersion coefficient (D) and the average pore water velocity (ν) allowing estimation of the groundwater residence time. Transport and attenuation of the TrOCs were simulated assuming first-order degradation constant (μ) and linear retardation coefficient (R), calibrated to simulate the observed temporal changes in the breakthrough of TrOCs. Sorption was found to play a role in the transport of TrOCs, notably for oxazepam with a higher linear retardation coefficient value of 2.2, whereas no significant differences of retardation were observed for carbamazepine, tolyltriazole, benzotriazole (1.37, 1.35, 1.36 respectively). Estimated first order degradation rate constants, between 0.03d for carbamazepine and 0.09d for tolyltriazole, were generally high compared to the literature, possibly due to favourable redox conditions and important microbial activities within the system. This study provides evidence of the efficiency of the Agon-Coutainville SAT system for the removal of TrOCs.
土壤含水层处理（SAT）可以为二级处理废水（STWW）中的药物和工业化合物等痕量有机化合物（TrOCs）提供补充处理。最近，人们对天然系统中存在的未受管制的 TrOCs 以及对 SAT 系统修复的兴趣表示关注。本研究通过监测 STWW 和地下水中的七种 TrOC（奥沙西泮、卡马西平、苯并三唑、甲苯三唑、咖啡因、扑热息痛、布洛芬）和主要无机化合物作为内在示踪剂，在 SAT 运行期间进行的 34 天 STWW 渗透实验中，在 35 米的侧向地下水流动场尺度上量化了 Agon-Coutainville SAT 系统（法国诺曼底）对 TrOC 去除的有效性，这种去除是通过吸附和生物降解作用实现的。阳离子交换和实验过程中地下水和 STWW 之间的混合由主要离子和地球化学模拟突出显示。由于不饱和带的厚度较低，对流-弥散方程（ADE）的一维解析解应用于氯化物数据。氯化物被用作保守的内在示踪剂来校准水平流和传输参数，如含水层弥散系数（D）和平均孔隙水速度（ν），从而估计地下水停留时间。假设一阶降解常数（μ）和线性迟滞系数（R）来模拟 TrOCs 的观测到的时间变化，从而模拟 TrOCs 的传输和衰减。发现吸附在 TrOCs 的传输中起作用，奥沙西泮的线性迟滞系数值较高，为 2.2，而卡马西平、甲苯三唑、苯并三唑则没有观察到明显的迟滞差异（分别为 1.37、1.35、1.36）。估计的一阶降解速率常数在 0.03d（卡马西平）到 0.09d（甲苯三唑）之间，与文献相比通常较高，这可能是由于系统内有利的氧化还原条件和重要的微生物活性。本研究为 Agon-Coutainville SAT 系统去除 TrOCs 的效率提供了证据。
