The Simulation Of Emission Limits For Paper Making,Slaughter And Beer Industries Based On Petri Net And BAT

With the rapid development of economy,quantities of industrial wastewater discharged into rivers nearby which seriously affects peoples living environment.And paper making,slaughter and beer industries have produced obvious infulences to the water quality of rivers nearby.So we make the three typical polluting industries as research samples and according to the characteristics of sewage from three typical industries,we use the best available technology as the mean to make emission threshold of three typical industries,so as to control the influence of sewage from typical industries to the water quality of qinghe and improve it.According to the process of production and pollution discharging,OPMSE which is based on Petri Net is used to simulate the pollution reduction ability of BAT process.The simulation results can provide a basis for the emission threshold and can also provide guiding significance for the improvement of wastewater treatment technics.The method of interval computation is used in the process of simulating.And the simulations were executed for several times and all the results were collected as the statistical samples.When all data follows or approximately follows a normal distribution,the simulation result samples were used for interval estimation of meaning value of overall normal distribution and obtaining the confidence intervals.Through the literature review and the field research,the concentration index(BOD,COD,NH3-N)of sewage is concluded so that we can get the range of pollution concentration in the sewage from three typical industries.Then,through the simulation of OPMSE and the BAT treating of sewage,we can get the 90%,95%and 99%confidence intervals of normal distribution mean of pollution concentration.In the paper industry,the 99%confidence interval of COD is(34.09,41.84),the 99%confidence interval of BOD is(6.65,8.40),the 99%confidence interval of NH3-N is(6.28,7.34).In the slaughtering industry,the 99%confidence interval of COD is(43.31,52.86),the 99%confidence interval of BOD is(20.83,23.78),the 99%confidence interval of NH3-N is(6.83,8.13).In the beer industry,the 99%confidence interval of COD is(75.83,95.95),the 99%confidence interval of BOD is(19.30,25.88),the 99%confidence interval of NH3-N is(5.68,6.85).Then making a comparison between the emission standards and simulation results and we can get new emission threshold of three typical pollutant industries.The direct emission threshold of paper industry is COD=45mg/L,BOD=9mg/L,NH3-N =8mg/L.For the slaughtering industry,the direct emission threshold of the slaughtering industry is COD=65mg/L,BOD=25mg/L,NH3-N =10mg/L.The direct emission threshold of beer industry is COD=125mg/L,BOD=30mg/L,NH3-N =8mg/L.It is proved that the Petri net technology is feasible for the prevention and control of water pollution in the typical polluting industries.