The Correlation Between The Activities Of Substrate Enzyme And The Purification Efficiency Of Wastewatwer In The Constructed Wetland Hybriding With TheHydroponic Ditch

Constructed wetland are more and used to treat domestic sewage ,industrial wastewater and agricultural runoff in recent decades. This constructed wetland treatment process has been international interested and applied due to its low operational and maintenance costs and high removal capacity for normal water pollution control. However, it has been still unclear that the effect of wetland depth on the mechanism of wastewater purification and enzyme activity distribution in constructed wetland. In this study, a pilot scale CW system was operated in a domestic sewage treatment plant in Xi'an. But,To constructed wetlands substrate enzyme activity still didn't do measure and study.The experimental system included three series with substrate depths of 0.1m, 0.3m and 0.6m. Each series was composed of a hydroponic ditch, a horizontal subsurface flow CW and a vertical flow CW. The effluent from the primary clarifier in the sewage treatment plant was intermittently conducted to the wetlands. Lolium perenne L. was planted both in the hydroponic ditches and the CW systems. In this study showed:(1) The spatial distribution and variation of activates of dehydrogenase, phosphatase and urease were studied at different hydraulic loading, different season and different substrate depth of CWs.(2) In hydroponic ditches and same type wetlands, the activity of three enzymes decreased with the increase of water depth or substrate depth. The high enzyme activity mainly distributed in the top and middle layers, and in the same depth of three CWs, the shallower substrate, the more activities of enzyme.(3)This variation tendency that caused by depth of substrate enzymes change trend, not by the seasons, hydraulic load, constructed wetland types of different (level flow and vertical flow) influence. The Correlation Between the Substrate Enzyme Activities and Purifieation of Wastewater in the Constructed Wetland were studied .Result showed(4)There was significant Positive correlation between activities of Phosphatase In the Substrate and removal rate of TP ,TN,SCOD ;there was positive correlation between activities of urease in the substrate and removal rate of TN and SCOD. there was positive correlation between activities of dehydrogenase in the substrate and removal rate of TN,NH4+-N,TP.And the removal rate of SCOD showed significant positive correlation .In general ,all these conclusion will give reference to future researches on utilizing substrate enzyme activities as evaluating purification efficiency and constructed wetland system operation well .