Deep Removal Of Contaminants In Water By Myriophyllum Spicatum In An Artificial Waterway

In recent years,with the accelerated urbanization process,a large number of industrial and domestic wastewater was produced,which has brought great problems to the entire water environment.Moreover,despite the higher and higher acceptance rates of sewage to the waste water treatment plant(WWTP),the effluent quality was still far below the national V class surface water standard.The effluent of the WWTP has made lots damage to the environment and the water purification capacity due to the high concentration of COD,ammonia and total phosphorus.Therefore,it is very important to find effective ways dealing with the effluent of sewage plant and improve the downstream surface water quality.The existing methods of surface water treatment and remediation are usually due to physical,chemical and biological principles,all of them catch different advantages and disadvantages.For now,given to the low cost and no secondary pollution of biological methods,more and more research has focused on it.In this experiment,two kinds of aquatic plants Myriophyllum spicatum and Eichhornia crassipes with high efficiency of nitrogen removal were selected,and the biological floating bed with enhanced ability of biological nitrogen removal were selected as the experiment groups,to investigate the feasibility of using these methods to remove ammonia in the river.The details of the experiment are as follows:1)A river was simulated in the lab,and 10 cm soil was filled in the bottom of the simulated river.The input water quality of the river was dependent on the standard of level A.2)The average removal rates of ammonia nitrogen,total phosphorus,and COD in treatment of biological floating bed were 42%,10%,and 74% respectively.The average removal rates of ammonia nitrogen,total phosphorus,and COD in treatment of Myriophyllum spicatum were 86%,30%,and 87% respectively.The average removal rates of ammonia nitrogen,total phosphorus,and COD in treatment of Eichhornia crassipes were 88%,40%,and 81% respectively.The results suggested that the aquatic plants were more effective in removing ammonia in the water than the biological floating bed,and Myriophyllum spicatum was better than Eichhornia crassipes.3)In another experiments around the Hydraulic Retention Time(HRT)and temperature,the results showed that a longer HRT of 7 days was better in removing ammonia in the river than 4 days,the average removal rates of ammonia nitrogen,total phosphorus were 86% and 32%.Myriophyllum spicatum showed a better ammonia removal efficiency in 26 degrees than 32,the average removal rates of ammonia nitrogen,total phosphorus were 18% and 13%.4)In all the experiments above,water samples were collected for further molecular analysis.There were 2 kinds of nitrifying bacteria,4 kinds of ammonifying bacteria,4 kinds of simultaneous nitrifying-denitrifying bacteria.