| Eutrophication of aquatic ecological destruction is the major problems that affecting people’s production and living,economic development.Nitrogen and phosphorus removal of eutrophication of water adopts the method of artificial wetland,that considered as low-cost and ecological alternatives to conventional methods of eutrophication treatment.Plants are considered to be the indispensable composition in constructed wetlands.It can not only take up the nitrate and phosphate as nutrition,but also provide energy to microbial.In this study,three wetland plant species(Scirpus triqueter,Phragmites australis,Zizania latifolia)were grown in monoculture and as a three-species mixture to compare the growth and the nitrate and phosphate removal efficiency in the same conditions;We also examined the effect of different aeration depth(water-aerated,sediment-water interface-aerated,sediment-aerated,non-aerated)on total nitrate(TN)and total phosphate(TP)removal efficiency by using the indoor experimental method;In order to explore the effect of the aeration to wetland plants,we combined the aeration and wetland plants;And we evaluated the TN and TP removal efficiency when the aeration and wetland plants worked together.The experiment was established from 2016.05 to 2016.07,the main research results as followed:(1)In our experiment,the relative growth rate(RGR)of the species were significantly different.The RGR of Scirpus triqueter,Phragmites australis,Zizania latifolia were grown in monoculture and as a three-species mixture were 0.0186、0.0145、0.027 and 0.0229,Phragmites australis grew weaker.Howere Phragmites australis grew better in sediment-aerated condition(p<0.05).(2)A comparison of total nitrate and phosphate by species treatment,and across sampling dates.The reduction rates of TN in water,Scirpus triqueter,Phragmites australis,Zizania latifolia,mix and unplanted were 74.09%,75.27%,76.28%,70.34%and 47.39%.The reduction rate of TP in water when in non-aerated,Scirpus triqueter,Phragmites australis,Zizania latifolia,mix and unplanted were 87.67%,88.22%,88.25%,85.44%and 63.58%.Planted in wetlands were more effective at reduction TN and TP in water than unplanted.And the three wetland plants to water purification ability were significantly different(p<0.05),Phragmites australis had the greatest purification ability to TN and TP in water.(3)Different aeration depth in reducing the TN and TP in water were significant higher than no aeration(p<0.05).The reduction rate of TN in water at the end of the experiment water-aerated,sediment-water interface-aerated,sediment-aerated,non-aerated were 76.24%,74.53%,80.80%and 47.38%.The reduction rate of TP in water at the end of the experiment water-aerated,sediment-water interface-aerated,sediment-aerated,non-aerated were 88.66%,79.50%,81.27%and 60.91%.Water-aerated had the greatest reduction rate of TP.Phragmites australis had the greatest purification ability to TN and TP in water.(4)This experiment by measuring the TN concentrations in the water when the reeds and sediment-aerated combination,the reduction rate of TN in water is 89.09%.The reduction rate of TP in water when in sediment-aerated,Scirpus triqueter,Phragmites australis,Zizania latifolia,mix and unplanted were 94.17%,95.87%,91.61%,94.17%and 81.27%,the rate of plants treatment were significantly higher than unplanted when in sediment-aerated treatment(p<0.05).In our experiment,we found that the reed has the best effect of removing TN and TP in the water;Sediment-aerated significantly promote the growth of reeds;Reeds and sediment-aerated worked together have the best removal effect of TN from water;Water-aerated can reduce effectively TP from water;Planted and sediment-aerated worked together have better removal effect of TP from water than sediment-aerated worked.The results can provide scientific basis for the management of eutrophication. |
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