Efficiency Analysis Of Treating Polluted River By Three Constructed Wetlands

To solve some questions, such as uneven water distribution, low dissolved oxygen within the system, etc. We put forward a new concept—pulse vertical flow constructed wetland in the experiment. The experiment analyzed the efficiency difference between subsurface flow constructed wetland, ordinary vertical flow constructed wetland and pulse vertical flow constructed wetland on treating Daqing river.The research is mainly on: a)The mode of startup, plant growth and influence of different water distribution were studied at the startup period. b) Analyzed the efficiency difference on removal of COD, NH₄⁺-N, TN and TP, etc between three constructed wetlands at the stabilization period. c) Analyzed the efficiency difference on removal of algae and microcystins between three constructed wetlands.The main results were summarized as following: a) River water directly to start three constructed wetland systems had been successful. Plants and microbial had shown a strong ability to adapt to the sewage. The pulse water distribution was propitious to speed up the startup period of constructed wetland and improve the efficiency removal of system. b) The difference between three constructed wetlands at the removal efficiency of TP and SS was not obviously. Pulse vertical constructed wetland was better than ordinary vertical constructed wetland and subsurface flow constructed wetland at the removal efficiency of NH₄⁺/-N and TN. Pulse vertical constructed wetland and ordinary vertical constructed wetland were better than subsurface flow constructed wetland at the removal efficiency of COD. Extended Range degradation of the main pollutants remained in the first-class constructed wetland. The degradation speed was slow up at the second and third class. Three was some space for removal loading for three constructed wetlands. The best HLR was 0.6m³ /m²Â·d under experimental conditions for three constructed wetlands. c) These constructed wetlands all had good removal efficiency for algae. The removal ration of algae of pulse vertical constructed wetland, ordinary vertical constructed wetland, subsurface flow constructed wetland was 85%,84% and 86%, respectively. At the removal efficiency of microcystins, subsurface flow constructed wetland was the best, the removal ration was 89%, ordinary vertical constructed wetland was 82%, pulse vertical constructed wetland was only 73%.