Practical Exploration Of Key Techniques For Identification And Assessment Of Ecological Environmental Damage To Surface Water And Sediments

As a derivative of industrial civilization,how to solve the problems of sustainable economic development and ecological environment protection has become an important problem in the environmental field.The Opinions on Accelerating the Construction of Ecological Civilization issued by the State Council in 2015 put forward the idea of"establishing an independent and fair assessment system for ecological environmental damage".Therefore,the assessment of ecological environmental damage has become an important measure to relieve environmental damage in China,as well as an important link in the compensation and repair of ecological environmental damage.However,in the process of gradually establishing the standard system and technical route for identification and assessment of ecological environmental damage,there are many technical difficulties,such as determination of environmental baseline,determination of causality,quantification of environmental damage value,etc.,which affect the efficiency and quality of identification and assessment to a certain extent.Therefore,the practical exploration of key technologies for identification and assessment of ecological environmental damage is the law,regulation an important step in the construction of the standards and norms system is conducive to the overall formation of the technical standard system framework for the identification and assessment of ecological environmental damage,and is also an important part of the construction of ecological civilization.In this study,two typical water damage cases were taken as examples to discuss the practical application of key links in the identification and assessment of ecological damage of surface water and sediments.1)Two models,matlab-based two-dimensional steady-state mixed attenuation model and MIKE 21 water quality model,are used to simulate and reduce the damage range of river pollution caused by sewage discharge,so as to solve the problem that it is difficult to quantify the damage objects in identification and evaluation due to the untimely monitoring of damage behavior;2)Determine the possible pollution situation of the source and the receptor river by identifying the characteristic pollutants,and judge the causality from every link in the causality chain of the damage caused by the source reaching the receptor through the diffusion migration path;3)Based on the substitution equivalence method,quantify the damage during the water ecosystem service period,formulate the corresponding ecological restoration scheme and calculate the ecological restoration project cost;When quantifying the damage value of resources,the virtual governance cost method is used to quantify the value of service function when it is difficult to calculate the service loss due to the lack of certain data of the damage value of service function Finally,based on the above two kinds of pollution damage,the damage value is quantified The main results of this paper are as follows:(1)The damage to surface water in Case 1 has ceased,and the situation that the surface water quality exceeded the discharge label caused by the illegal discharge of mud-water mixture no longer exists.Matlab two-dimensional steady-state mixed attenuation mathematical model and MIKE 21 water quality model restore the physical quantification of pollutant damage at the time of the incident,and simulate and calculate the diffusion trend and impact range of non-persistent pollutants such as COD in the river pollution case caused by illegal sewage discharge.The results show that there is a certain difference between the simulation results of the mathematical model and the MIKE 21 water quality model.The lengths of pollutant influence are 4000 m and 5100m,and the total pollution influence ranges are 112000 m~2 and 358700 m~2.The prediction results of the mathematical model are smaller than those simulated by the MIKE 21 water quality model result.The diffusion trend of pollutants is also different.In the simulation of the mathematical model,the pollutants gradually decay in a"terraced field"centered on the sewage outlet.The concentration of pollutants near the sewage outlet exceeds the baseline level.As the distance from the sewage outlet increases,the concentration Constantly;while in the MIKE 21 water quality model simulation,the pollutant concentration first increases to the maximum value,and then tends to remain constant when it reaches a certain concentration.(2)Determine the correlation between pollution sources and damage based on the pathways of pollutant migration and transformation,ultimately serving the causal relationship between pollution behavior and environmental damage.Based on the analysis method of multivariate statistics,by identifying and analyzing the characteristic pollutants such as heavy metals and volatile organic pollutants in the second case of ink wastewater discharge causing river pollution,and comparing them with the pollutants in the polluted river,it is determined that the pollutants have homology;At the same time,there is a reasonable exposure path between ink wastewater and damaged sediment,namely wastewater water sediment;There is a temporal and spatial correlation between water pollution behavior and environmental damage,therefore,there is a causal relationship between the environmental pollution behavior of discharged ink containing wastewater and sediment environmental damage.(3)When the damage value is quantified,when the ecosystem services or resources can be restored or the damage value can not be calculated,the actual application of the substitution equivalence method and the virtual treatment cost method in the ecological damage assessment is analyzed.The quantitative results are as follows:1)The substitution equivalence method based on the establishment of restoration scheme is used to measure the degree of water ecological damage,the selection of habitat area is quantified according to the key parameters such as damage degree time and restoration degree time,and the loss of water services is calculated as follows:the restoration area is 2.42 hm~2,and the compensation restoration area is 1.91hm~2.Therefore,the compensation value of substitution equivalence method is 573,000yuan by using ecological floating bed plant restoration technology for planting reeds;2)Based on the virtual treatment cost method,the damage amount is quantified under the condition that it is difficult to calculate the service loss due to the lack of certain data.By determining the unit treatment cost coefficient of pollutants,the damage value is calculated to be 411,000 yuan,that is,the total cost of the damage value of a sewage treatment plant in case one is 984,000 yuan.