Preliminary Study On The Purification Of Waste Water By Wetland Plants And The Purification Mechanism

Because of the low cost and simple operation, the constructed wetland technology has been widely used in treating municipal wastewater,eutrophic water body,river ecological regulation,industrial and agricultural wastewater,etc[1]. Wetland plants as an important part in the wetland system play an important role on the effects of wetland wastewater treatment. However, the species of wetland plants is more; the distribution is limited geographically; and the purifying effect is different for different pollutants by different wetland plants, so selecting the wetland plants that has better purification for waste water and researching the mechanism of purification of sewage, is important for the construction of artificial wetlands and widespread application.The experiment selected 5 kinds of wetland plants in Shandong: Typha orientalis Presl.,Scindapsus aureun,S.trisetosus Tang et Wang,Rumex crispus Linn.,R.japonicus Thunb. to research their purification for waste water. Typha orientalis Presl. has the best purification in low, medium and high COD concentration waste water, 5-day degradation rate can reach 79.0%,74.6% and 62.7%,followed is S.trisetosus Tang et Wang and Scindapsus aureun, Rumex crispus Linn .and R.japonicus Thunb has poorer purification. Typha orientalis Presl. has the best purification in low, medium and high NH4+-N concentration waste water, 5-day degradation rate can reach 78.7%,60.8% and 73.7%,followed is Scindapsus aureun and S.trisetosus Tang et Wang, Rumex crispus Linn .and R.japonicus Thunb has poorer purification. The purification for COD and NH4+-N is better in medium concentration waste water than in high concentration waste water, the purification for COD and NH4+-N is better in medium concentration waste water than in the water out of the water sewage treatment plant.This research selected the three kinds wetland plants Typha orientalis Presl., Scindapsus aureun,S.trisetosus Tang et Wang who has better purification for waste water to rearch the relationship between the biological mechanism and the effect of purification of sewage of wetland plants. While the three kinds wetland plants purificating,absorpting and degradating waste water, the catalase and superoxide dismutase in their body become active, it shows that their has some relation between the biological mechanism and the effect of purification of sewage of wetland plants. While the purification is high, the two enzymes'activity maintains on a high level; while the purification has down, the enzyme activity will down at the same time.