Laboratory of Wastewater Treatment and Recycling, Research and Technology Center of Water, University of Carthage, BP 273, 8020, Soliman, Tunisia.
National School of Engineers of Sfax, University of Sfax, Soukra road, Km 4, 3038, Sfax, Tunisia.
Environ Sci Pollut Res Int. 2019 Sep;26(27):28071-28079. doi: 10.1007/s11356-019-06042-9. Epub 2019 Jul 29.
In arid Mediterranean countries, such as Tunisia, wastewater often has high salinity, being an obstacle to the elimination of microcontaminants for the reuse of water in agriculture. In this paper, the photo-Fenton process in raceway pond reactors (RPRs) has been successfully applied to a simulated secondary effluent from a Tunisian urban wastewater treatment plant (WWTP), with high chloride load. A mixture of three contaminants of emerging concern (CECs) was used as model pollutants at 50 μg/L each (one antibiotic, sulfamethoxazole and two pesticides, pyrimicarb and imidacloprid). All the assays were conducted at neutral pH with 0.1 mM Fe(III):EDDS at 1:1 molar ratio. The effect of hydrogen peroxide initial concentration (20, 30, and 90 mg/L) on microcontaminant removal was studied. Different liquid depths (5 and 15 cm) were selected to assess the relationship between the microcontaminant removal and the volumetric rate of photon absorption (VRPA). Although the reaction rate was initially photo-limited, after a short reaction time of 15 min, the final yield (≈ 80% of CEC removal) was limited by the photo-degradation of the Fe(III):EDDS complex and excess HO was found at all concentrations used. Therefore, treatment times below 15 min should be used. The treatment capacity was three times higher when the liquid depth was increased from 5 to 15 cm. For the first time, these results show that the operation of a 15 cm-deep RPR in continuous flow mode would be suitable for large-scale implementation of the solar photo-Fenton process.
在干旱的地中海国家，如突尼斯，废水通常具有高盐度，这是在农业中再利用水时消除微污染物的障碍。在本文中，光芬顿工艺在跑道池反应器（RPR）中已成功应用于突尼斯城市污水处理厂（WWTP）的模拟二级出水，该废水中含有高氯负荷。使用三种新兴关注污染物（CECs）的混合物作为模型污染物，每种污染物的浓度为 50μg/L（一种抗生素，磺胺甲恶唑和两种农药，吡虫啉和吡虫脒）。所有试验均在中性 pH 值下进行，Fe(III)：EDDS 的摩尔比为 1:1，浓度为 0.1mM。研究了初始过氧化氢浓度（20、30 和 90mg/L）对微污染物去除的影响。选择不同的液体深度（5 和 15cm）来评估微污染物去除与光子吸收体积速率（VRPA）之间的关系。尽管反应速率最初受到光限制，但在 15 分钟的短反应时间后，最终收率（≈80%的 CEC 去除）受到 Fe(III)：EDDS 配合物光降解的限制，并且在所有使用的浓度下都发现了过量的 HO。因此，应使用低于 15 分钟的处理时间。当液体深度从 5cm 增加到 15cm 时，处理能力提高了三倍。这些结果首次表明，在连续流模式下操作 15cm 深的 RPR 将适用于太阳能光芬顿工艺的大规模实施。
