Landscape Water-Sediment Restoration Based On Ecological Floating Bed And Chemical-Biological Method

The eutrophication of landscape water has become a common water environment problem at home and abroad in recent years.If there is eutrophication in the landscape water,the self-purification capacity of the water will be seriously reduced,and the pollutant content will increase significantly,which will have a great impact on the natural and residential environment.River sediment pollution is one of the main causes of eutrophication of landscape water.A large amount of nitrogen,phosphorus and other pollutants are stored in the sediment.When the external pollution source of water is cut off,the sediment will become internal pollution source and release contaminants into the water.Therefore,it is necessary to study the restoration methods of landscape eutrophication and river sediment pollution through experiments.In the experiment,devices with enhanced ecological floating bed-sediment was built.Aerobic denitrifying bacteria,bioprobiotics and calcium nitrate were added to the sediment respectively to explore the repair effect of eutrophic water and sediment by bacteria combination and ecological floating bed.The main conclusions are as follows:?1?Five devices were equipped with sediment,and the other two devices were not.The device which had both ecological floating bed and bacteria could remove pollutant in water and sediment most significantly.And the removal rate of COD_Crr was above 80%,the removal rate of ammonia nitrogen could reach 90%.In the sediment-free devices,the device with floating bed could effectively remove pollutant.The ecological floating bed showed remarkable effect on the restoration of eutrophic water.The devices had the highest pollutant removal rate during May and June.The rainfall was frequent and large from July to September,so the removal rate was affected.The weather was cold from October to November.The microbial metabolic activity was slow,and the pollutant removal rate was decreased.?2?By analyzing microbial diversity of surface water,bottom water and sediment of seven devices,it is revealed that the microbial diversity of sediment was higher than that of water.The ecological floating bed could improve microbial diversity of the water and the sediment.The microbial diversity of water and sediment during the mid-term?September?experiment was generally higher than that in the early experiment?June?,and the results indicated that the microbial diversity increased as the devices operated.In the final sequencing,the microbial diversity of water and sediment was lower than that of the initial stage,because the final operation was in winter,and the cold weather reduced the number and variety of microorganisms.?3?The Monod kinetic model was carried out on the removal of COD_Crr and TN from three floating bed-sediment devices.The correlation coefficients of curve fitting were all above 0.8.The fitting effect was good,which indicating that the Monod dynamic equation was suitable for describing the degradation process of COD_Crr and TN.