Sewage Cleaning Abilities of Five Wetland Plants

The sewage cleaning ability of 5wetland plants,including Phragmites australis,Scirpus validus,Lythrum salicaria,Scirpus planiculmis and Typha angustata,were compared in constructed wetland simulated for domestic sewage treatment.The results demonstrated that:(1)The treatment system with wetland plants has higher removal efficiency to CODcr,ammonia nitrogen(NH4+-N),total nitrogen(TN)and total phosphorus(TP)than that without wetland plants(P0.05).The removal efficiency of 5wetland plants were determined that ranged 80.2%~88.5%,98.4%~99.3%,68.8%~83.8%,89.7%~97.2%for CODcr,NH4+-N,TN and TP,respectively.(2)The five wetland plants absorbed most of the phosphorus in sewage(89.7%~97.9%),and the surplus in sewage were very little(2.1%~10.3%).There was no retention in soil.The distribution of total nitrogen in sewage,plants and soils have very big difference.The total nitrogen absorption of P.australis,S.validus,T.angustata were higher(76.1%~83.4%)than that of L.salicaria,S.planiculmis(45.0%,46.8%).(3)For these 5wetland plants,the ability of nitrogen accumulation is higher than that of phosphorus accumulation.The 5wetland plants showed a distinct phosphorus and ammonium-nitrogen removal.The results of principal component analysis shows that P.australis,T.angustataand S.validus are the better ones among the five wetland plants in experiment of domestic sewage clean,followed by L.salicariaand S.planiculmis.