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Membrane Water Treatment Volume 10, Number 1, January 2019 , pages 057-65 DOI: https://doi.org/10.12989/mwt.2019.10.1.057 |
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Contributions of emergent vegetation acting as a substrate for biofilms in a free water surface constructed wetland |
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Ruijun Zhao, Jing Cheng, Qingke Yuan, Yaoping Chen and Youngchul Kim
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| Abstract | ||
| This study assessed the contribution of emergent vegetation (Phragmites australis, Typha latifolia, and Nelumbo nucifera) to the submerged surface area, the amount of biofilms attached to the submerged portions of the plants, and the treatment performance of a free water surface (FWS) constructed wetland. Results showed that a 1% increase (31 m2) in the vegetative area resulted in an increase of 220 m2 of submerged surface area, and 0.48 kg Volatile Suspended Solids (VSS) of attached biofilm. As the vegetation coverage increased, effluent organic matter and total Kjeldahl nitrogen decreased. Conversely, a higher nitrate concentration was found in the effluent as a result of increased nitrification and incomplete denitrification, which was limited by the availability of a carbon source. In addition, a larger vegetation coverage resulted in a higher phosphorus in the effluent, most likely released from senescent biofilms and sediments, which resulted from the partial suppression of algal growth. Based on the results, it was recommended that constructed wetlands should be operated with a vegetation coverage of just under 50% to maximize pollutant removal. | ||
| Key Words | ||
| biofilm; emergent plant; free water surface wetland; submerged surface area; treatment performance; vegetation coverage | ||
| Address | ||
| Ruijun Zhao,Yaoping Chen: School of Earth and Environment, Anhui University of Science & Technology, Huainan City, 232001, China Qingke Yuan,Youngchul Kim: Department of Environmental Engineering, Hanseo University, Seosan City, Chungnam, 356-706, Korea Jing Cheng: Department of Resource and Environment, Anhui Science and Technology University, Chuzhou City, 233100, China | ||
