Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Chinese Taiwan.
Water Sci Technol. 2010;62(10):2408-18. doi: 10.2166/wst.2010.492.
In Taiwan, more than 20% of the major rivers are mildly to heavily polluted by domestic, industrial, and agricultural wastewaters due to the low percentage of sewers connected to wastewater treatment plants. Thus, constructed or engineered wetlands have been adopted as the major alternatives to clean up polluted rivers. Constructed wetlands are also applied as the tertiary wastewater treatment systems for the wastewater polishment to meet water reuse standards with lower operational costs. The studied Kaoping River Rail Bridge Constructed Wetland (KRRBCW) is the largest constructed wetland in Taiwan. It is a multi-function wetland and is used for polluted creek water purification and secondary wastewater polishment before it is discharged into the Kaoping River. Although constructed wetlands are feasible for contaminated water treatment, wetland sediments are usually the sinks for organics and metals. In this study, water and sediment samples were collected from the major wetland basins in KRRBCW. The investigation results show that more than 97% of total coliforms (TC), 55% of biochemical oxygen demand (BOD), and 30% of nutrients [e.g. total nitrogen (TN), total phosphorus (TP)] were removed via the constructed wetland system. However, results from the sediment analyses show that wetland sediments contained high concentrations of metals (e.g. Cu, Fe, Zn, Cr, and Mn), organic contents (sediment oxygen demand = 1.7 to 7.6 g O(2)/m(2) d), and nutrients (up to 18.7 g/kg of TN and 1.22 g/kg of TN). Thus, sediments should be excavated periodically to prevent the release the pollutants into the wetland system and causing the deterioration of wetland water quality. Results of polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analysis reveal that a variation in microbial diversity in the wetland systems was observed. Results from the DGGE analysis indicate that all sediment samples contained significant amounts of microbial ribospecies, which might contribute to the carbon degradation and nitrogen removal. Gradual disappearance of E. coli was also observed along the flow courses through natural attenuation mechanisms.
在台湾，由于污水厂连接的污水管网比例较低，超过 20%的主要河流受到生活污水、工业污水和农业污水的轻度到重度污染。因此，人工湿地已被用作主要的河流污染治理替代方案。人工湿地也被应用于三级污水处理系统，以较低的运营成本对污水进行深度处理，达到回用水标准。研究中的高雄铁路桥人工湿地（KRRBCW）是台湾最大的人工湿地。它是一个多功能湿地，用于净化受污染的溪流河水，并在排入高屏溪之前进行二级污水深度处理。虽然人工湿地对受污染的水具有处理可行性，但湿地沉积物通常是有机物和金属的汇。在这项研究中，从 KRRBCW 的主要湿地盆地中采集了水样和沉积物样。调查结果表明，通过人工湿地系统去除了超过 97%的总大肠菌群（TC）、55%的生化需氧量（BOD）和 30%的营养物[例如总氮（TN）、总磷（TP）]。然而，沉积物分析结果表明，湿地沉积物中含有高浓度的金属（例如 Cu、Fe、Zn、Cr 和 Mn）、有机物质（沉积物需氧量 = 1.7 至 7.6 g O2/m2/d）和营养物（高达 18.7 g/kg 的 TN 和 1.22 g/kg 的 TN）。因此，应定期挖掘沉积物，以防止污染物释放到湿地系统中，并导致湿地水质恶化。聚合酶链反应（PCR）、变性梯度凝胶电泳（DGGE）和核苷酸序列分析的结果表明，湿地系统中的微生物多样性发生了变化。DGGE 分析结果表明，所有沉积物样品都含有大量的微生物核糖体，这些核糖体可能有助于碳降解和氮去除。大肠杆菌也沿着水流方向逐渐消失，这可能是由于自然衰减机制。
