Study on Removal of Nitrogen and Phosphorus in Wastewater by Constructed Wetland

To study the effects of constructed wetland system on the treatment of wastewater of different nutrient concentrations,an experiment was conducted by employing a hybrid planar flow,cultivating plant types in different seasons,and configuring the size and porosity of the substrate in different layers under outdoor natural conditions.The process consisted of two phases.In the first phase,where Xichi pool eutrophic water was used as the inflow,the water quality experienced two periods of instability and stability,and was stable after the 25th day.The average removal rates of total phosphorus(TP),and total nitrogen(TN) were 60%,80.46%,respectively.In the second phase,the system maintained relatively high impact resistance and stability,with average removal rates of TP,TN reaching 86.8%,90.08%,respectively.As a result,the effluent water quality met the Surface Water Environment Quality Standard Class and Urban Sewage Treatment Plant Emission Standards(an A class standard).The results demonstrated that this wetland treatment system can effectively remove N,P from the wastewater with different qualities,and still have treatment capability for sewage in a one-year cycle.