A Study On The Application Of Phrynium In Wavy Subsurface Constructed Wetland

This paper describes a kind of wavy subsurface constructed wetland system constructed by cinders on the basis of subsurface constructed wetland. Phrynium, one of the Guangxi native plants was selected as wetland plants applied in the Wavy subsurface constructed wetland (W-SFCW) and subsurface constructed wetland (SFCW), in comparison with another wavy subsurface constructed wetland without any wetland plants, to observe its growth conditions, to compare its removal ability for COD,、NH4+-N and TP in the municipal sewage and to analyze the treatment effect of wavy subsurface constructed wetland with phryniums for municipal sewage and the feasibility of Phrynium as a wetland plant.Conclusions for this paper:Ⅰ) under the same experimental conditions, the W-SFCW with Phryniums has a better purification effects for municipal sewage. Its average removal rates for COD, NH4+-N and TP are66.06%,64.62%and84.03%respectively. In comparison with W-SFCW without any plant, they are6.77%,6.66%and5.36%respectively higher.Ⅱ) Under the same experimental conditions, both the W-SFCW with phryniums and the SFCW with phryniums have better purification effects. But comparing with SFCW with Phrynium, W-SFCW with Phrynium has higher rates for COD, NH4+-N and TP. They are5.63%,11.65%and6.08%respectively higher.III) After cultivating, phryniums adapt well to W-SFCW and SFCW. They grow lushly. Each plant can grow up to1meter without significantly withering in winter. Besides, their roots are vigorous. The amount of fibrous roots and root hairs becomes denser. The ends of the roots are tiny and multitudinous. In the south of35degrees north latitude, they are considered as constructed wetland plants.Ⅳ) The wavy subsurface constructed wetland with Phrynium illustrated in our study maintained a very good treatment effect under higher hydraulic loading (0.3m.d-1). The total removal rate for every pollutant from municipal sewage is over64%in our wetland system. After treated, the effluent quality can almost comply with the Class A Grade B of Urban Sewage Treatment Plant Pollutant Discharge Standards. If take it as a unit of constructed wetland systems, it would greatly improve the wetland treatment efficiency. The W-SFCW preferably optimizes the flow pattern of water flow under subsurface constructed wetland. The sewage flows wavy in the wetland, thus flows repeatedly through the upper, middle and lower layers under the wetland which makes the sewage experienced aerobic-facultative-anaerobic states repeatedly. This would fully activate the ability of purification of constructed wetlands; enhance the effect of the sewage treatment.Ⅴ) The result shows that the cheap cinders and gravels are feasible as adsorption filler for constructed wetland.The abovementioned results indicate that Phryniums can well adapt to the W-SFCW and SFCW and can be used as constructed wetland plants.