Study On The Anaerobic Underflow Multistage Composite Constructed Wetland System Of The Application And The Mechanism Of Biological Phosphorus Removal

Anaerobic underflow multistage composite constructed wetland system is a economic and efficient new multi-functional combined process,constructed wetland system which has a unique structure,novel materials,which is conducive to decentralized management and maintenance and also very suitable to deal with the dispersed rural domestic sewage and the river restoration project.To study the treatment of rural sewage effect and phosphorus removal effect on the anaerobic underflow multistage composite constructed wetland system,and artificial wetland biological phosphorus removal mechanism,this paper through on-the-spot investigation,selected constructed wetland as the study of subjects in junction of Town,Kunshan City,Kam dispersed rural.The research results is benefit for mining the function of artificial wetland ecology and sustainability,developing the process which is suitable for treating rural waste water containing phosphorus.The main content and important conclusions of this work are summarized as follows:?1?Comparing the import and export of water quality the single surface flow constructed wetland,two stage subsurface constructed wetland and anaerobic underflow multistage composite artificial wetland showed that the concentration of COD,NH₄⁺-N,SS,TP were 4.4⁶.9mg/L,39⁵2mg/L,41⁶9mg/L,1.2¹.9mg/L;53⁷1mg/L,4.2⁴.7mg/L,25.0⁴2.0 mg/L,1.0¹.6mg/L;11²0mg/L,2.0⁴.1mg/L,4⁸mg/L,0.09⁰.21mg/L respectively,and the water removel rates of COD,NH₄⁺-N,SS,TP were accounted for30%-60%,14%-58%,approximately 75%,14%⁵7%;30%⁴5%,20%⁵5%,approximately80%,40%⁵3%;75%⁹0%,62%⁷5%,approximately 92%,91%⁹5%,and three of the diff-erent multi-function combination of anaerobic underflow multistage composite constructed wetland of the removal rate of COD,NH₄⁺-N,SS,TP were 40.9%,20.7%,64.1%,54.8% in the combination process system,which the effluent water quality fully meet A standard level of the?GB18918-2002?,which is the best of the removal and very stabilizing effect;?2?The study of the space structure and effect of phosphorus removel and the rules of each cell internal phosphorus distribution,migration and transformation of the Anaerobic underflow multistage composite artificial wetland showed that the system is a detachable multilevel cell by the FRP module composition,which the quantity can be adjusted according to the quantity of sewage,and the different flow pattern formed the different micro-environment of the anaerobic/aerobic/anaerobic,aerobic/anaerobic/aerobic,aerobic/anaerobic,anaerobic/aerobic and so on,which is conducive to the removal of nitrogen and phosphorus,and the different flow pattern formed played different roles on the phosphorus removel,the system which the rate of TP highest reach 95.5% and the minimum effluent concentration only reach 0.075mg/L;the import and export water average concentration of TP,DTP,DIP,DOP,PP were 0.097⁵.44mg/L,0.033⁵.25mg/L,0.048⁵.027mg/L,0.005⁰.769mg/L,0.064¹.152mg/L in the system cell,and concentra-tion of different phosphorus forms was basic little difference,TP greater than DTP,DTP greater than DIP,DIP greater than PP,PP greater than DOP,and the concentration of TP,DTP,DIP reached the maximum in the anaerobic subsurface flow constructed wetland system,reacher the minimum in the rear system,also which had the same change trend,the change trend of the DOP and PP concentration was influenced by the cell internal nature;?3?Studying on each cell of different forms of phosphorus removal rate of anaerobic subsurface flow multistage combined constructed wetland showed that the multi-functional space structure and continuous anaerobic environment is an important factor which affecting the effect of the biological phosphorus removal in and the artificial wetland,anaerobic subsurface flow constructed wetland and the first stage combined flow artificial wetland play a major role for the TP,DTP,DIP,DOP PP removal in the whole system,which the removal rates were-63.01%,-94.28%,-121.01%,-6.23%,57.1%;70.22%,99.52%,123.31%,-40.26%,18.68%,and all other cells play a supporting role,according to the above research results,with the coupling relationship between microorganism and plant,substrate,and other theory,preliminary studying on artificial wetland biological phosphorus removal mechanism.