The Design And Application Of Soil - Plant Ecosystem Research

In recently years, soil plant ecological system is developed to treat sewage, for the use of the triple coordination function plants, matrix and microorganisms. It has the advantage of stable discharging water, low infrastructure costs, low operate costs and both aesthetic.However, the pollutants removal promance were influenced by many factors, such as plant species, hydraulic retention time (HRT). microbial, the composition of the matrix and so on. These factors limit results of its decontamination, and some hinder to be widely used of soil and plant ecological system.This paper constructed four different ecological plant beds:PI Calamus plant bed, P2Phragmites plant bed, P3polyculture plant bed and control plant bed.The influence of HRT, plant species to wastewater strainaway rate and the space distribution of N,P etc will be researched in this paper.First, through test experiments, the best HRT will be determined.The removal effencies of plant species to N, P etc will be got in the middle system. So as make the contribution to soil and plant ecological system. Test results were list as follows:(1) The removal efficiencies of NH4+-N.TN.CODcr were the best when HRT was7d, the highest removal efficiencies were99.58%,99.65%,78.56%.For TP. the highest was96.7%when HRT was6d. The lowest removal efficiencies of NH4+-N and TN were81.73%、43.02%when HRT was5d.Fpr TP.1.2%with HRT=4d. for CODcr.36.41%with HRT=3d.(2) Through fitting analysis of the polynomial and index function to remove pollutants. fitting equation was obtained. Fitting results showed P2system was better. NH4+-N polynomial and index function fitting analysis results found that the correlation of dependent and independent variables (R2) are0.973and0.964, respectively.But index function fitting analysis F refers to (562.6)> F (72.4).To TN R2=0.925and0.906, and Fin(149.35)>FPo(50.659).To TP, R2=0.946and0.909, Fin(132.19)>FPo(70.59).Result of the case study showed(1) The study of plant species indicated that vegetation systems were better than non-vegetation systems for the pollutants removal. Phragmites is better than calamus.The average removal performance of NH4+-N in plant systems were up to87.85%、97.55%、86.98%.To TN were up to81.44%、92.58%、79.15%.To TP were up to86.78%、89.99%、 86.55%. To CODcr were up to55.96%、65.75%、56.74%. P2system of ultimate effluent was qualified to Standard A of "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002)"(NH4+-N<5mg/1, TN<15mg/l, TP<0.5mg/l, CODcr<50mg/l). P1and P3systems of ultimate effluent were qualified to Standard B of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002),(NH4+-N<8mg/I, TN<20mg/l,TP<1mg/l, CODcr<60mg/l), we can say plants systems are very effective to the removal of N, P etc pollutant.(2) Due to the microbial activity of root higher removal performance of NH4+-N and TN were mainly in the upper and the lowest layers. The pH value of the water also proved the results. The P remval was mainly in the upper and middle two layers. This may because of the P adsorption processes by the matrix in the systems. In this treatment processes, plant absorbtion of P was little.