Study On Characteristics Of Fold-flow And Lateral-flow Constructed Wetlands For Municipal Wastewater Treatment

The constructed wetlands wastewater treatment has the characteristic of " one high three low one not", namely the high efficiency, the low investment, the low operating cost, the low maintenance technology and basic does not use electricity, But at the same time it was the question of easily blocked up, high landuse, load slightly, and in the wetland bed the dissolved oxygen is low,which made denitrogenation effect is not very good and so on. This experiment in view of the present constructed wetlands existence question, in the foundation of the existing of subsurface constructed wetlands, designed a set of new constructed wetlands—Folds flow constructed wetlands + Lateral flow constructed wetlands, attempted to enhance the sewage treatment efficiency of the constructed wetlands, to increase the efficiency of wetland bed useness to reduce landuse and HRT, at the same time reduced the possibility of blocked up. and the experimental had conducted to study the characteristics of it.A kind of enzyme-enhanced bio-filling ,which is a patent product developed by Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment ,Ministry of Education, P.R.China is used in the constructed wetlands. The bio-filling has a surface accumulates in a big way, large number of micro-holes and high strength, which is advantageous to reproduces in microorganism's adhering to stick cohere with the growth, maintenance many biomasses, moreover is advantageous to the microorganism metabolism process which needs the oxygen and the nutrients mass in transfer process. This experimental use the local grows plant—Cyperus alternifelies, Arundo donaxl, canna glauca L and Acorus calamus L. In the experiment, the constructed wetlands hang the membrane in nature, the water successive enters and water level monitor continuously. When the influent is about 2~2.3m3/d,Namely HRT is about 72h and the water quality relatively stable, after the experiment starts 30 days, through the examination discovery, plant growth well and the microorganism are extremely rich, the COD value of effluent stabilizes between 50 ~ 60mg/L, removal rate achieved 80% above, Now it is considered that start-up is over successfully.In the loading operation period, the experiment is divided into R = 0.5 and R = 1, five groups of experiment are designed by controlling HRT in each kind of situation, test data in each operational group are analysed separately. The test result indicated, with the increase of HRT, the removal rate of COD obviously decreases in the...