Treatment of Organic Matter and Tetracycline in Water by Using Constructed Wetlands and Photocatalysis

Abstract

In this study, the ability of a bench-scale simulated constructed wetland (CW) to remove organic matter (OM) and tetracycline (TC) from water was examined. The performance of CW was evaluated by varying the initial concentrations of the target compounds and the hydraulic retention times (HRTs). Findings showed that OM removal efficiencies were 55.2–80.8%, 28.1–71.9% and 72.1–79.7% for ultraviolet absorbance at 254 nm (UV-254), dissolved organic carbon (DOC) and soluble chemical oxygen demand (sCOD) respectively, under 1 day-HRT, whereas higher initial DOC concentration achieved better removal efficiencies. Changing from 1 day-HRT to 2 day-HRT, the removal efficiency of OMs remained practically unchanged, while that of NH3-N increased considerably, from 61.7% to 73.0%, implying that the removal of ammonia in CW needs a longer time for complete treatment. CW also showed an excellent performance in removing TC, especially in the first two hours of operation through the absorption process. In addition, the findings from this research revealed an improvement in effluent water quality when photocatalysis (TiO2/α-Al2O3, with ultraviolet A (UVA) irradiation) was used as the post-treatment following CW, presented by the increase in removal efficiency of OMs of the combined system compared to that of CW alone. This study points to the possible and promising application of the low-cost water treatment system for dealing with OMs and TC in water.

Emerging pollutants—Part II: Treatment

“…The removal of EPs by CWs is mainly through the absorption and degradation (Li, Gao, et al, 2019; Li, Li, et al, 2019; Li, Zhang, Zeng, et al, 2019; Li, Liu, Zhang, Li, et al, 2019; Li, Zhang, Xia, Wang, et al, 2019; Li, Zhang, Hu, et al, 2019; Li, Sun, Zhang, Feng, et al, 2019; Li, Wang, et al, 2019; Li, Yuan, Gao, et al, 2019; Rabello et al, 2019). Adsorption is an important way to remove EPs, and the substrate, soil, and sediment of packed bed in CWs play major roles in adsorption (Nguyen, Chao, & Chen, 2019; Nguyen, Afzal, et al, 2019; Sardana, Cottrell, Soulsby, & Aziz, 2019; Zhao, Yan, et al, 2019; Zhao, Jian, et al, 2019). The degradation of EPs in CWs is mainly through microbial degradation, photolysis, and hydrolysis (Tara et al, 2019).…”

“…The degradation of EPs in CWs is mainly through microbial degradation, photolysis, and hydrolysis (Tara et al, 2019). In addition, EPs can be also absorbed by roots, stems, and leaves of plants in CWs (Nguyen, Chao, et al, 2019; Nguyen, Afzal, et al, 2019). The factors affecting the removal efficiency of CWs include treatment temperature, CW configuration, and plant species.…”

“…(Ilyas & Hullebusch, 2019; Paz, Salinas, & Matamoros, 2019). At present, many studies focus on the process parameter optimization and the development of combined processes of CWs and other technologies (Chen, Zhu, et al, 2019; Chen, Zhang, et al, 2019; Nguyen, Chao, et al, 2019; Nguyen, Afzal, et al, 2019).…”

Wetlands for environmental protection

“…Further, they also reported the first‐order removal rate coefficients for selected EOCs (Nivala, Kahl, et al, 2019). More than 80% of tetracycline was removed in a bench‐scale simulated CW in the first two hours of operation through the absorption process (Nguyen, Nguyen, et al, 2019).…”

Composition Characteristics of Organic Matter and Bacterial Communities under the Alternanthera philoxeroide Invasion in Wetlands

“…Plenty of studies showed that the exotic plant invasion might affect the accumulation of soil organic carbon (SOC) and organic nitrogen (ON) [8,9]. Soil organic matter (SOM) is the main form of OC and ON, the study on different SOM categories can further reveal the influence of alien plant invasion on the accumulation process of carbon and nitrogen [10]. The SOM can be divided into light fraction organic matter (LFOM) and heavy fraction organic matter (LFOM), through soil density difference [11].…”