Investigation On Biological In-situ Remediation Technology Of Urban Typical Polluted River

The rapid development of industry and economy inevitably causes the destruction of ecological environment.The black and odorous water has been basically eliminated after the regulation of short river courses in Beijing,but the water quality of it still has the risk of eutrophication.The long-term maintenance and purification of polluted river water quality is still the focus of attention.Slope wetland technology is a deformation process of constructed wetland.Different substrate materials will lead to different purification effect.Gravelk,ceramsite and zeolite（1:1）were selected as matrix materials to simulate the fluctuation of water level in urban river by changing hydraulic conditions.The purification effect of pollutants in slope wetland under different hydrodynamic conditionswas studied.The results showed that the apparent removal rates of COD,NH₃-N,TN and TP at the water depth=0.4 m and the HRT=1 day were 3491.38mg/h·m³,70.88mg/h·m³,665.15mg/h·m³,81.13mg/h·m³,respectively and the effect of the matrix material（ceramsite mixed with zeolite=1:1）is better than that of gravel,and the purification capacity of each index is increased by about 10%.As a new ecological restoration method,submerged plant combination was often considered to have water quality maintenance effect.Four combinations of Potamogeton wrightii Morong+Potamogeton pectinatus,Myriophyllum spicatum+Elodea canadensis Michx,Hydrilla verticillata+Ceratophyllum demersumand Cabomba caroliniana A.Gray+Vallisneria natans（Lour.）were selected to explore the purification effect of different plant combinations on slightly polluted river water.It was found that the removal efficiency of four submerged plant combinations for polluted river water remained 21.28%～38.93%,and the difference was not significant.Through the weight calculation and comparison of the results,it showed that Myriophyllum spicatum+Elodea canadensis Michx was the best for the polluted river water.The coupling optimization of slope wetland technology and submerged plant combination technology was carried out to explore the in situ repair capability of the coupled ecosystem,and the degradation effect of pollutants and Volatile Organic Compounds（VOCs）in the coupling ecosystem was confirmed to be efficiency.It was found that the water purification capacity of the reactor could be improved by appropriately lowering the water level and prolonging the HRT.Under the conditions of water level=0.4 m,HRT=5 days and flow rate=3m/s,the removal rates of conventional pollutants and VOCs were 38.65%～46.45%and 67.74%～100%,respectively.This study provides a reference model for water quality restoration of urban polluted river,and it is a beneficial attempt in the process of urban polluted river water purification.Figure 25;Table 24;Reference 113...