Treatment of Sewage Containing Nitrogen and Phosphorus by Using Substrates in Constructed Wetland

NH+4-N、NO-2-N、NO-3-N、PO3-4、COD removal effect of Sampling point 1～5 was investigated and studied.When the hydraulic load was 0.65 m3/m2·d by the peristaltic pump continuously,the causes and mechanism were analyzed,which provided the basis for the construction of constructed wetlands substrate.Constructed wetland system formed biofilm and substrates system tended to be mature during two weeks.The results showed that the removal rate of nitrogen and COD by the above system could reach 90%.The removal efficiency of phosphorus fluctuated strongly from 90% to 0,even desorption would appear.It could be concluded that the system contribute effectively to remove the nitrogen and organic material and especially microbe contributed less to the removal of phosphorus.Zeolite could be used as substrates to remove nitrogen in constructed wetland.Coal ash had some effect on adsorption of phosphorus but lack lasting effect.