Study On Modeling Method Of The PCDD/Fs Dispersion And Deposition Emitted From A Hazardous Waste Incineration Plant

Estimating the environmental impact by using air dispersion model is an economic method.However,the parameters required by modeling work might be unavailable due to poor management.Instead,choosing the parameters subjectively might lead to good results,but not objective.This paper studied the subjective factor in modeling work,like the selection of input data and parameters and the method of modeling upset process.By studing these parts,this paper found some measures to avoid the influence of subjective factor in modeling work.First,this paper study the impact of model input data,mainly like meteorological condition terrain and landuse on maximum ground concentration and the corresponding distance.Wind speed seriously affects the modeling results.When wind speed reaches 3 m/s and 5 m/s,the distance of maximum ground concentration and the corresponding concentration reach their maximum among all study scenarios.The influence of wind direction on result mainly due to the different terrain and land use in different directions.When there are multiple meteorological data available,choosing the one agree better with actual states is reasonable.For the source emitting large amount of pollutions,onsite data is recommended to be used in modeling work.This paper found a method to modeling the upset period,and the results are compared with the ambient sampling data.The predicted ground concentration is 0.226 pg I-TEQ/Nm~3,while the observed concentration is 0.292 pg I-TEQ/Nm~3.Therefore,this method could be used to modeling the upset period,thus avoid the problem of choosing upset factor subjectively.Furthermore,this paper proposes a method to estimate some of parameters which would vary with time and site.Then subjective decision of these parameters would not be essential.The predicted TEQ of soil concentration calculated by using estimated parameters is 5.374 I-TEQ pg/g while the observation is 3.934 I-TEQ pg/g.The prediction and observation are in the same order of magnitude,which shows the method could estimate the parameters properly.At last,this paper deviate a new function based on the function recommended by EPA to estimate the soil concentration without historical emission and concentration data.The TEQs of soil in 2012are predicted.The ratio of prediction and observation of soil TEQs vary from 1.01 to 1.93.