Research On The Effect Of Constructed Wetland On The Removal Of Polycyclic Aromatic Hydrocarbons

With the development of petroleum industry,transport developed,ransportation industry,the environmental problems caused by natural disasters and man-made factors of oil spill and toxic and hazardous chemicals,water pollution is becoming more and more prominent,many of our rivers and lakes water actually by the oil pollution area of the infringement.According to the literature,the economic losses caused by ecological destruction and environmental pollution in China are as high as about 6000 one hundred million yuan each year.Not only so,because of ecological destruction and environmental pollution,human health has also been a threat,human of petroleum pollutants to the environment and human health caused more in-depth understanding of the harm to the depth,breadth and,emphasis on the harm is also growing.Wetland technology has received more and more attention since the 70 years of development in twentieth Century,but the research of wetland technology is mainly applied in the removal of nitrogen and phosphorus.This study through vertical flow constructed wetland in the greenhouse,research on wetland technology of PAHs contaminated the water purification effect,and through the regular harvest of wetland plants,to study the effect of plant harvest on PAHs removal effect.This study results show that the vertical flow constructed wetland for polluted by PAHs classes of all kinds of pollutants in the river all have certain removal effect.Different substrate wetland on conventional pollutants removal effect shows that zeolite substrate of organic and TN removal effect is good,the organic removal efficiency can reach 66.49%,highest of TP removal efficiency can reach 89.01%;Limestone substrate wetland of TP removal effect is good,the highest can reach 71.73%.Wetlands on PAHs removal effect of the results showed that the continuous water and intermittent water on the influence of different number of ring PAHs removal rate is different.For low ring PAHs naphthalene and phenanthrene,wetland removal effect of difference is not significant;for low ring PAHs naphthalene and phenanthrene,wetland removal effect of difference is not significant;of high ring PAHs(pyrene and benzo(a)pyrene,wetland removal effect difference is significant and intermittent inflow under the condition of wetland removal effect is good.The removal efficiency of PAHs was different in different substrate wetlands,and the removal efficiency was better for the limestone substrate wetlands.And with the increase in the number of benzene molecules inside the PAHs,the removal rate of PAHs was decreased.The best removal effect of naphthalene,the highest removal rate reached 72.86%-85.89%;benzo [a] pyrene removal effect is the worst,the highest removal rate reached 40.00%-46.00%.The effect of plant harvesting on the removal of PAHs from the wetland showed that wetland plant harvest could improve the removal rate of PAHs in wetland.After harvesting,the removal rates of naphthalene,phenanthrene,pyrene and benzene were increased by 0.89%-17.86%,1.56%-20.31%,11.36%-31.82% and [a],respectively.The removal rates of naphthalene,phenanthrene,pyrene and benzene were increased by,0.00%-26.67% and P.25 days after the harvest of wetland plants,the relative growth rate and harvest Arundo donax after wetland of PAHs removal rate recovered to the level before the harvest.