Research On Influence Factors Of Controllable Multiple Sources Aeration Constructed Wetlands

The constructed wetland is a kind of wetland by artificial construction and regulation, through optimizing the ecological system of physical, chemical and biological effects to realize wastewater treatment. Compared the constructed wetland with the traditional sewage biochemical treatment technology, you will find that constructed wetland have many features, such as low construction cost and operation cost, good treatment effect, ecological restoration function and create ecological landscape. In recent years, with the deeper realization about the constructed wetland, it is widely used in the treatment of city rainstorm runoff, sewage and industrial wastewater.Aiming at the complicated operation mechanism and influence factors of constructed wetland treatment system, this study used two series of vertical flow constructed wetland system to research on BOD5/COD, air-water ratio, hydraulic load and aeration depth with orthogonal test method. Each influence factor is set with four different levels: the BOD5/COD is 0.20, 0.25, 0.30 and 0.35, respectively;the air-water ratio is 4:1,6:1,8:1 and 12:1, respectively; the hydraulic load is 0.08m/d, 0.10m/d, 0.14m/d and 0.20m/d, respectively;the aeration depth is 5cm,15 cm,25cm and 35 cm, respectively.Using the orthogonal test table to analyze the experimental results, we can get the following conclusions:In the constructed wetland treatment system: the main influence factor of pH is the BOD5/COD; the main influence factors of the dissolved oxygen are aeration depth(in the first stage constructed wetland) and BOD5/COD(in the second stage constructed wetland); the main influence factors of the C/N are BOD5/COD(in the first stage constructed wetland) and hydraulic load(in the second stage constructed wetland); the main influence factor of COD removal rate is the aeration depth; the main influence factor of nitrogen removal rate is the hydraulic load; the main influence factor of total phosphorus concentration is the BOD5/COD; the main influence factor of ammonia concentration is the hydraulic load; the main influence factors of the nitrite concentration are aeration depth(in the first stage constructed wetland) and hydraulic load(in the second stage constructed wetland); the main influence factor of the nitrate concentration is hydraulic load.Effects of different levels of BOD5/COD, air-water ratio, hydraulic load and aeration depth of constructed wetland are significant different.