Research On Water Environment Pollution Prevention And Control Methods In The Beijing-Tianjin-Hebei Basin Based On SWAT Mode

Water pollution is the main cause of global ecological degradation and seriously affects the water supply of the people.Along with the rapid economic and social development and urbanization process,water quality shortage caused by water pollution has become an increasingly serious threat to people’s survival and development.Beijing,Tianjin and Hebei region as China’s "capital economic circle",is the political,economic and cultural center,is also an important national food production area.In recent years,the rapid economic development of the Beijing-Tianjin-Hebei region has led to the pollution of surface waters in the region’s watersheds by industrial wastewater,rural sewage,agricultural fertilization and livestock breeding.Some stream sections in the Beijing-Tianjin-Hebei region have serious water pollution,and water pollution prevention and control has become an important strategic task.At present,most of China’s point source pollution source discharge requirements to meet the local water pollution comprehensive discharge standards that can be discharged into the water bodies.However,the number of existing industrial enterprises in Beijing,Tianjin and Hebei region is large,and the distribution of a wide range of pollutant discharge standards in the waters of each region is different,the lack of integrated consideration.The simultaneous discharge of multiple point sources has caused the pollution load to seriously exceed the standard and pollute the waters of the basin.In addition,Hebei Province is also one of the important grain producing areas,unreasonable application of pesticides and fertilizers will also bring a certain degree of water decent source pollution.The prevention and control of water environment pollution in the Beijing-Tianjin-Hebei region is imminent.This paper uses the international more mature water environment SWAT(Soil &Water Assessment Tool)model to simulate the surface water environmental quality in the study area,according to the spatial distribution characteristics of ammonia nitrogen pollution load,total phosphorus pollution load,pollution reduction and upgrading of industrial enterprises,sewage plants and fertilizer reduction and efficiency of pollution prevention methods,comprehensive research and analysis,with the aim of predicting the response of different Pollution prevention and control measures under the response of pollutant loads and pollution reduction effect,and targeted pollution prevention and control strategies.The main research results are as follows:(1)The surface water environment model of Beijing-Tianjin-Hebei region was established,and the water environment and water quality characteristics of the region were simulated more comprehensively,and a pollution source database was constructed with local industrial enterprises and wastewater treatment plants as point sources and agricultural fertilization,rural living and livestock and poultry breeding as non-point sources.(2)Completed the screening of 121 state-controlled water quality monitoring cross-sections in the Beijing-Tianjin-Hebei region,and screened a total of 41 simulated cross-sections(16 V and poor V water cross-sections)that can better represent the water environmental quality conditions in the Beijing-Tianjin-Hebei region.Based on the modeled water quantity,the sediment,ammonia nitrogen and total phosphorus parameters of the sections to be simulated were determined,and the simulation results of the monitoring sections were fitted to validate the simulation results and account for the ammonia nitrogen fluxes in each basin in 2015.(3)A pollution abatement treatment plan for the study area is proposed,focusing on pollution abatement for all sewage plants and industrial enterprises in accordance with surface water environmental quality standards,which can reduce the ammonia nitrogen pollution load by 48.66% and total phosphorus load by 3.69% in the Beijing-Tianjin-Hebei basin in this case.The contribution of surface source pollution prevention and control is not significant,taking Ziya River as an example,when the amount of fertilizer applied in the basin is reduced by 20%,the ammonia nitrogen pollution load in the river can only be reduced by 0.29% and total phosphorus can be reduced by 1.41% in the flat water period.(4)Due to the increased rate of urbanization in the Beijing-Tianjin-Hebei region,point source pollution loads such as the concentration of effluent from industrial enterprises and sewage plants dominate.The discharge of all sewage plants and industrial enterprises to meet the standards of surface water environmental quality standards can make all sections reach Class III and above with the greatest reduction in pollution load.Therefore,it is necessary for all sewage plants and industrial enterprises in the Beijing-Tianjin-Hebei region to strictly control the discharge of their pollution loads to surface water environmental quality standards for compliance.The upgrading of industrial enterprises and sewage plants should be used as an important measure to control the pollution of the water environment in Beijing,Tianjin and Hebei,and to improve the quality of river water bodies in Beijing,Tianjin and Hebei in general.