Simulation And Experimental Study On Water Quality Of Urban River Course By Integrating Sediment Aeration Measures

Endogenous pollution is an important reason for the black odor of water bodies.Various nutrients in the river channel gradually settle to the surface of the sediment through various physical,chemical and biological effects.Under certain physical and chemical and environmental conditions,nutrients from the sediment Re-release and enter the water body,thereby forming a pollution load on the water body,causing source pollution in the water body.Relying on the national science and technology major project "Research and Demonstration Project of Integrated Control Technology for Water Cycle Purification of Haihe Main Tributary River Network",this paper takes static water as the research object,and aims to alleviate the black odor phenomenon of water body as the ultimate goal.Purification effect,the specific content is as follows:(1)The monthly monitoring of the water quality of Hucanghe for 19 months,analysis of the single water quality identification index of four indicators of dissolved oxygen,ammonia nitrogen,total phosphorus,and chemical oxygen demand,clarifying that the main pollutants of Hucanghe are organic substances and Total phosphorus;obtained from the comprehensive identification index analysis of the monthly monitoring data,30% of the months in which the water quality rating of Hucanghe River is rated as Ⅴ or worse than Ⅴ,the overall water environment quality is poor,and it is more prominent in July to September.(2)Collecting river sediment and river water for laboratory tests.Through comprehensive analysis of various pollutant concentrations,first-order kinetic analysis,and comparison of removal rates,it was clear that sediment aeration can significantly improve the oxidation-reduction environment of the mud-water system and promote the mud-water system.The degradation of ammonia nitrogen and the conversion of soluble phosphorus to insoluble phosphorus are divided into three stages: rapid release,degradation reaction,and dynamic equilibrium.(3)Make a complete set of aeration device,and carry out in-situ tests on the sediment aeration at the local size of the river in Hucang River.The indicators such as ammonia nitrogen,nitrate nitrogen and total nitrogen in the overlying water are detected.The data obtained from the analysis: Mud aeration can effectively improve the redox environment of the mud-water system and promote the degradation of ammonia nitrogen in the mud-water system.The reaction process can also be regarded as three phases: rapid release,degradation reaction,and dynamic equilibrium.Based on the comparison of the pollutant removal effect of the detection points at different distances from the aeration center,three sets of aeration devices are proposed as a set,each with an interval of 2 ～ 3m and each set with an interval of 10 m.(4)A numerical simulation model of the local size of the river channel was established.Water temperature was calibrated through self-tested meteorological data,and water quality parameters were confirmed through calibration of ammonia nitrogen.Based on the data from April 2018 to October 2019,the concentration of ammonia nitrogen exceeded 1mg / L,four working conditions were developed,and the time required to purify to class III water was simulated.