Study On The Leakage Source Strength Of Typical Hazardous Waste Landfill And Its Assessmenton The Environmental Risk

Landfill is the final disposal method for hazardous waste (HW) treatment.The environment risk of which is different from that of municipal solid waste(MSW) landfill because the hazardous substance such as heavy metals will notattenuate over many years. The impermeable layer leakage is the mainenvironmental risk of hazardous waste landfill. Studying on leakage sourcestrength of hazardous waste landfill is significant and important to calculateenvironment risk of HW landfill.Hundreds of samples of HW and leachate are collected from more than tenHW landfills, Experimental analysis shows the main type of landfilled HW aresolidified fly ash, slag and sludge, and leachate concentration exceeds thecorresponding Integrated Wastewater Discharge Standard. The main hazardousconstituents are Hg、Pb、Zn and Cr. The initial landfill leachate concentration(CL0) is one of the most important parameter to calculate source intensit y oflandfill leakage pollution. Experimental simulated column study is carried onabout the total Cr dissolution in different height of columns and pH conditionsof leaching agent using solidified fly ash. We just define the CL0corresponding with collecting leaching liquid volume by comparing differenttotal Cr concentrations. The research shows that the CL0changes with differentheight of column and pH. The CL0value ascends as h increases, but it has noobvious regularity with scope of pH from3to6.5. We also preliminarilyestablish the simple mathematical model relationship about the CL0, h and pH.A case study of environmental risk is introduced about a HW landfill locatedin Southwest China on the basis of previous leachate concentration and leakagescene analysis. The classical Monte Carlo model and EPACMTP model are usedto calculate the environmental risk assessment. The results show that theprobability of leakage of this HW landfill is85%more than the acceptable risk.This landfill site needs to do the groundwater pollution risk assessment due to alarger leakage risk. The leakage leachate will pollute the groundwater graduallyin the28year later. The pollution probability will get maximum value (equal toone) in the40th years and the main pollutants are Ni and Pb. In the normalcircumstances the non-carcinogenic hazard quotient is1.05, and in the adversesituation(such as heavy rainfall, more leaksand hydrogeological conditions conducive to pollutant diffusion) the non-carcinogenic hazards is1.34.