Study On Integrated Mode Of Water Ecological Restoration Technology In Coastal Industrial Belt

Differrent from general case,coastal industrial belt has many unique features,such as mixed industrial and residential resources,complex and diverse pollution sources,high proportion of construction land,more constructed wetlands and high impact load on the sea.Therefore,its water ecological environment is characterized by fragile eco-environment,eutrophication,high salt contentration and so on.In this paper,a technical integration system for water ecological environment governance and restoration is constructed to deal with the water environment deterioration in coastal industry.The system mainly includes three parts,namely,water ecological environment health assessment,water ecological environment governance and restoration technology library,and its integration module for coastal industrial belt.The first part is mainly used to evaluate the water ecological environment health status of the research area,and figure out the problems lies.The second part divides the technologies selected into three categories:pollution source control,water pollution treatment,and water ecological restoration,then compares and analysis these technologies in 9 aspects,such as principle of action,applicable conditions,advantages and disadvantages,etc.Based on the former two,combining the problems of the research area with the technical information offered in the technical library,the last part is established to deal with the problems lied.First,establish a preliminary plan through qualitative analysis,and optimize the plan by quantitative analysis.The evaluation results of Tianjin Binhai New Area show that the ecological integrity of the Duliujianhe River and Qilihai Wetlands are the two areas need to focus on.Taking the Duliujianhe River as a typical case for water ecological environment governance and restoration research.It was divided into four regions and 21 sub-watersheds,according to the administrative division and the distribution of pollution sources.Through quantitative calculation,NH3-N was identified as a key pollutant affecting the water quality of the Duliujianhe River basin.Based on the qualitative analysis,a technology integration plan for the reduction of key pollutants has been established,which mainly includes four technologies:sewage interception management,agricultural non-point source pollution control,artificial wetland and coastal ecological restoration.Under the constraint of multi-objective conditions,the cost-benefit model was used to optimize the space of ammonia nitrogen reduction in 21 sub-watersheds.Through quantitative calculation,ammonia nitrogen was identified as a key pollutant affecting the water quality of the Duliujian River Basin.Based on the qualitative analysis,a technology integration plan for the reduction of key pollutants has been established,which mainly includes four technologies:sewage interception management,agricultural non-point source pollution control,artificial wetland and coastal ecological restoration.The cost-benefit model was used to optimize the allocation of ammonia nitrogen reduction in 21 sub-watersheds,and the reduction of different technologies was optimized on the basis of meeting the constraints.In conclusion,the total project cost is 12.666 billion yuan,and the total reduction of NH3-N is 665.8 t·a^-1.In the 21 sub-basin,57.3%of the total removal is allocated to the South Canal,Ziyahe River,Yundong Drainage,and Qingjinghuang Drainage.The highest cost of the four technologies is the sewage interception pipe（10.475 billion yuan）,followed by artificial wetland technology（1.397 billion yuan）,agricultural non-point source pollution control technology（422 million yuan）,and riparian ecological restoration technology（3.72）.Billion).