Effect of photosynthetically elevated pH on performance of surface flow-constructed wetland planted with Phragmites australis.
Combination of emergent and submerged plants has been proved to be able to enhance pollutant removal efficiency of surface flow-constructed wetland (SFCW) during winter. However, intensive photosynthesis of submerged plants during summer would cause pH increase, which may have adverse effects on emergent plants. In this study, nitrogen transformation of lab-scale SFCW under pH gradient of 7.5, 8.5, 9.5 and 10.5 was systematically investigated. The results showed that total nitrogen (TN) removal efficiency decreased from 76.3 ± 0.04 to 51.8 ± 0.04 % when pH increased from 7.5 to 10.5, which was mainly attributed to plant assimilation decay and inhibition of microbe activities (i.e., nitrite-oxidizing bacteria and denitrifiers). Besides, the highest sediment adsorption in SFCW was observed at pH of 8.5. In general, the combination of submerged and emergent plants is feasible for most of the year, but precaution should be taken to mitigate the negative effect of high alkaline conditions when pH rises to above 8.5 in midsummer.
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, People's Republic of China.
Xiaole
X
Yin
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, People's Republic of China. zhangjian00@sdu.edu.cn.
Jian
J
Zhang
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, People's Republic of China.
Zhen
Z
Hu
Environment Research Institute, Shandong University, Jinan, 250100, People's Republic of China.
Huijun
H
Xie
School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW, 2007, Australia.
Wenshan
W
Guo
School of Energy and Power Engineering, Shandong University, Jinan, 250100, People's Republic of China.
Qingsong
Q
Wang
School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW, 2007, Australia.
Huu Hao
HH
Ngo
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, People's Republic of China.
Shuang
S
Liang
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, People's Republic of China.
Shaoyong
S
Lu
College of Environmental Science and Engineering, Peking University, Beijing, 100871, People's Republic of China.
Weizhong
W
Wu
D001673:Biodegradation, Environmental; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000378:metabolism; D010788:Photosynthesis; D006109:Poaceae / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism*; D053833:Wetlands
D014874:Water Pollutants, Chemical; D009584:Nitrogen
Constructed wetland; Nitrification and denitrification; Nitrogen transformation; Photosynthetically elevated pH; Plant species combination