Effluent Treatment and Valorization Laboratory (ETVL), Water Research and Technology Center (WATREC), Carthage University, Technopark Tourist Route of Soliman Nabeul, PO-box N°273-8020, Soliman, Tunisia; Faculty of Sciences of Tunis, University of Tunis El Manar, B.P. no. 94 - ROMMANA, Tunis 1068, Tunisia.
Effluent Treatment and Valorization Laboratory (ETVL), Water Research and Technology Center (WATREC), Carthage University, Technopark Tourist Route of Soliman Nabeul, PO-box N°273-8020, Soliman, Tunisia.
Sci Total Environ. 2019 Jun 20;670:644-653. doi: 10.1016/j.scitotenv.2019.03.220. Epub 2019 Mar 16.
The objective of this research was to evaluate the nitrogen removal in a single stage rural wastewater treatment system. It was a modified subsurface vertical flow (SSVF) constructed wetland. The so-called Anaerobic Ammonium Oxidation(ANAMMOX) process is favored by imposing a saturated zone at the bottom of the basin. The nitrogen removal performances of this modified SSVF were compared to those of a conventional hybrid system where the well-known nitrification-denitrification process is performed. This study was carried out using three lab-scale pilots of constructed wetlands during four months: (1) a hybrid constructed wetlands with a reed-Phragmites australis SSVF bed in serial with a cattail-Typha angustofolia SSHF bed (SSVF + SSHF). (2) A reed-Phragmites australis SSVF bed partially saturated at 40% of its depth (SSVF); (3) A cattail-Typha angustofolia SSVF bed partially saturated at 40% of its depth (SSVF). The results showed that the three configurations used in this study were efficient for most of the pollutants reduction. In fact, single-stage reactors have achieved similar chemical oxygen demand (COD) removal in comparison to the two-stage reactor independently of the macrophytes species. However, for Total Kjeldahl Nitrogen (TKN), a slightly higher nitrogen removal efficiency was recorded for (SSVF + SSHF) with an average removal rate of 53% versus 48% and 51% for SSVF and SSVF respectively. These findings were highlighted with fluorescent in situ hybridization (FISH) analysis, which demonstrated the presence of major differences in the community composition and abundance of the bacteria involved with denitrification and nitrification in the three systems. In fact, SSVF of the hybrid system was characterized by highest relative abundance of nitrifying bacteria (13% Nitrosomonas, 11% Nitrosospira, 14% Nitrospira and 10% Nitrobacter). While, the SSHF of hybrid system had larger number of denitrifying species than SSVF, with relative abundances of pseudomonas (3%), Paracoccus (9%), Zoogloea (6%), Thauera (4%), Thiobacillus (2%) and Aeromonas (1%). Interestingly, in the SSVF (planted with Thypha angustofolia) where the relative abundance of nitrifying bacteria was very low (4% Nitrosomonas, 4% Nitrosospira, 4% Nitrospira and 1% Nitrobacter), we have detected the presence of ANAMMOX bacteria (3%). Accordingly SSVF in the presence of Thypha angustofolia have favored the development of ANAMMOX activity in comparison to the other configurations.
本研究旨在评估单级农村废水处理系统中的氮去除效果。这是一种改良的地下垂直流（SSVF）构造湿地。所谓的厌氧氨氧化（ANAMMOX）过程有利于在盆地底部施加饱和区。将该改良的 SSVF 的氮去除性能与传统的混合系统进行了比较，该系统中进行了众所周知的硝化-反硝化过程。这项研究使用三个实验室规模的湿地进行了四个月：（1）芦苇-香蒲 SSVF 床与香蒲-菖蒲 SSHF 床串联的混合构造湿地（SSVF+SSHF）。（2）芦苇-香蒲 SSVF 床部分饱和至其深度的 40%（SSVF）。（3）香蒲-菖蒲 SSVF 床部分饱和至其深度的 40%（SSVF）。结果表明，本研究中使用的三种配置对于大多数污染物的减少都非常有效。实际上，与独立的两种植物物种相比，单级反应器对化学需氧量（COD）的去除率相似。然而，对于总凯氏氮（TKN），（SSVF+SSHF）的氮去除效率略高，平均去除率为 53%，而 SSVF 和 SSVF 分别为 48%和 51%。荧光原位杂交（FISH）分析突出了这些发现，该分析表明三种系统中反硝化和硝化细菌的群落组成和丰度存在重大差异。实际上，混合系统的 SSVF 具有硝化细菌的最高相对丰度（13%的亚硝化单胞菌，11%的硝化螺旋菌，14%的硝化螺旋菌和 10%的硝化杆菌）。而混合系统的 SSHF 比 SSVF 具有更多的反硝化种，相对丰度分别为假单胞菌（3%），副球菌（9%），动胶菌（6%），陶厄氏菌（4%），硫杆菌（2%）和气单胞菌（1%）。有趣的是，在 SSVF（种植有菖蒲）中，硝化细菌的相对丰度非常低（4%的亚硝化单胞菌，4%的硝化螺旋菌，4%的硝化螺旋菌和 1%的硝化杆菌），我们检测到存在 ANAMMOX 细菌（3%）。因此，与其他配置相比，在存在菖蒲的 SSVF 中有利于 ANAMMOX 活性的发展。
