| The key factor in solving frequent water pollution accidents is how to identify the source information(discharge location,discharge time,discharge amount or discharge rate)that caused the accident as soon as possible,and then simulate and predict the development process of pollution accident.However,most of the researches on the identification of pollutants use statistics and other uncertain methods,which need a large amount of preliminary work and have many uncertain factors.The existing early warning system has the problem of long simulation time.Therefore,this paper aims at the rapid simulation and prediction of the water quality change process after a pollution accident,established a two-dimensional river instantaneous pollution early-warning model based on the two-dimensional advection-diffusion equation.In order to quickly and accurately grasp the information of pollution sources,proposed identification methods for instantaneous and continuous pollution sources based on the emergency monitoring network.The paper analyzed the feasibility and accuracy of the identification methods and it was proved that the identification methods were fast and efficient,simple deployment and good feasibility.The main research content of this paper are as follows(1)On account of the analytical model of two-dimensional advectiondiffusion-reaction equation,designed and developed an early warning system.Given the information of the pollution source,the early warning system can predict the changes in the concentration of pollutants in the polluted downstream rivers for a period of time,and give an alarm on the situation in which the key water quality management sections exceed the standard.The government departments concerned can also simulate the extent to which pollutants are treated on the system,and formulate economical and feasible treatment measures as much as possible.(2)By reversely solving the two-dimensional advection-diffusion analytical equation and continuous integration equation,proposed identification methods for two-dimensional river instantaneous and continuous pollution sources.Based on the identification methods,the two-point and four-point symmetrical river emergency monitoring network are proposed.By calculating the difference value of the target pollutant concentrations in the spatial and temporal domains,the location,the discharge duration and the discharge intensity were obtained.(3)The paper analyzed the impacts of the emergency monitoring network layout on the identification accuracy.By designing the pollution scenario,calculated the relative errors between the pollution source design values and the identification values under different emergency monitoring network layouts,and verified the feasibility and accuracy of the identification method.(4)Based on the warning model and identification method,after collecting the geographic scope of the rivers and the national and provincial monitoring sections in Jinhua City,the paper used C++ to write the early warning and identification calculation program,then designed and developed a early warning and identification system for river chemical spill incidences in Jinhua City.By setting water pollution accidents,the system was used to simulate and predict the water quality changes process after the pollution accidents,identify the unknown water pollution information that occurred in the rivers of Jinhua City.Then the calculated values of the pollution source information were compared with the designed values.It proved that the early warning and identification system has been better applied in the rivers of Jinhua City and has higher reliability,which can provide an intuitive and scientific basis for relevant departments to respond to water pollution accidents and help them to handle pollution accidents quickly,reasonably and economically. |
