The Study On Relationship Of Substrates And Dephosphorization Mechanism In Subsurface Constructed Wetland

Currently researchers think that constructed wetland dephosphorization is because of substrates adsorption and settled,generally the dephosphorization effect of Constructed Wetland will descend after 1~2 years. This result makes applying and treating the substrates to be a new problem . at the same time, researchers found phosphorus sediment in constructed wetland.so it is important to further research phosphorus sediment in constructed wetland. If we choose the substrates that favors phosphorus sediment to make phosphorus sediment become the main function in dephosphorization in systems ,the substrates will possibility to be used for over a long time.The thesis emphasized a modified constructed subsurface wetland that called Wavy Subsurface Flow Constructed Wetland (W-SFCW), going on experiment to verify how important the phosphorus sediment in dephosphorization mechanism,and to find the capacity of different substrates by small experiment. The main results are:1,To mix 10% of limestone to Constructed Wetland substrates makes the dephosphorization effect high in 3 years. the W- SFCW had good dephosphorization rate ,it was 84.02%.2,Analyzed phosphorus'form and found that most of phosphorus in west water settled and existed in substrates and plant .experiments result indicated that organic phosphorus transforms to inorganic phosphorus, at least 43% of them transformed IP and existed in soil and block.3,Study outspreaded to reseach dephosphorization mechanism about W- SFCW ,found phosphorus sediment was the main function in dephosphorization in constructed wetland systems.In constructed wetland the substrates the sequence of total amount of phosphorus contained was: block> soil> plant, further experiment found it was mainly mineral phosphorus in block and soil.4,The small experiment of W- SFCW used the opposite high metal content substrates limestone and cinder to compare, the quality of phosphorus sediment of the three kinds of substrates was in order : cinder > limestone> soil. The author finally get that constructed wetland systems with cinder substrates will have even stably and long haul dephosphorization qality effect . We can research more substrates to raise Constructed Wetland technique.