Reaearch On Shallow Surface Flow Constructed Wetland Of Reaction Kinetics In Dephosphorization And Decarburization

Although the sewage discharge rates are now beyond80%in our country, the developments of the sewage treatment regionally are still imbalanced. Due to arbitrarily discharged rural domestic sewage, the domestic sewage is still one of the main sources of the water pollution. For the multiple characteristics of the vertical-flow constructed wetland, it is the best resolution to deal with the bottleneck of the domestic sewage treatment in our country. The study on the vertical-flow constructed wetland is significant to the current situation of wastewater treatment in ChinaIn this paper, analog vertical flow model was used. The influence factors of the pollutant degradation in the constructed wetland were investigated, thereby exploring the influence factors of the pollutant removal rates in the vertical-flow constructed wetland, developing the decarbonization and dephosphorization first-order kinetic model. The main research results are as following:1).The interval from the startup to the steady operation was found to be24days, via the results of the water quality measured during the startup period of the vertical flow constructed wetland system. In the steady operation, the optimal hydraulic loading condition of the system was determined as0.12m3/m2.d through the regular patters of the removal rates of COD and TP under different hydraulic loading conditions. Under the optimal hydraulic load conditions, the removal rates of COD and TP were91.0%and42.9%respectively.2).To study the influence of different water depths on the effectiveness of the decarbonization and dephosphorization. Under the same hydraulic load condition, the corresponding removal rates of the COD and TP were increasing with increase of the water depth. Moreover, the water depth had greater effect on the removal rate of the COD than that of the TP.3). To investigate the influence of the DO on the removal rates of COD and TP under the optimal hydraulic load conditions. The parts with higher DO values exhibited relatively higher removal rate of the COD. The change of the DO value was mostly negatively correlated with the removal rate of the COD, while it had little influence on the removal rate of the TP.4).According to the measured experiment datum, first order kinetic model was used to develop the first order kinetic model equations for the organic matter and total phosphorus degradation in the vertical-flow constructed wetland.