The Evaluation For Environmental Impact Of Coal Fly Ash Disposing Land-fill In Huainan

Coal fly ash is the residue of the combustion of coal, it contains some poisonous and harmful trace elements such as B,Cu,Mn,Mo,Zn,As,Cd,Pb,Ni,Se and so on. These trace elements' cumulation in soil can directly or indirectly harm the vegetable and animal, and they can also hurt human through the food chain. This thesis takes Huainan as the background, research the main two ash landfill ponds Shangyao and Gaohuang's around environment, aim at the coal fly ahs which discharge to landfill ponds in great deal every year, analysis the trace elements' different configuration, evaluate the mobility in different conditions, establish the foundation for further researching harmful trace elements and the risk of ecological health, sample the soil,water,sediment in ambience of the ash landfill ponds, combine the integration of the trace elements in coal fly ash to evaluate the pollution situation of ambience of ash landfill ponds.First we choose different types of coal fly ash from power station including first grade ash, second grade ash,mixed ash and ash residue, research the different forms of trace elements in coal fly ash using BCR. Use acetum to distill dissoluble form; use hydrochloric acid hydroxylamine to distill the Fe/Mn oxidation form; use acetate ammonia digested with peroxide hydrogen to distill the organic form; use aqua fortis to distill residues form. The distilled liquor was analysis by ICP—AES. Sample the soil,water,sediment in ambience of the ash landfill ponds according to the standard of《Environment inspection techno-criterion》. The total content is analyzed through (HClO₄+HNO₃+HF) acid digestion, and then is determined by ICP—AES. As,Se,Hg were digested by HNO₃+HCl, and then were determined by HG—AFS.The result shows that trace elements in coal fly ash were mainly in residue form, other forms' proportion is lower than 10%. The quantity of trace elements in coal fly ash is hard to mobile to environment, so its harm to environment is also low. The trace elements in soil, water, sediment surrounding environment did not overrun the criterion, there is no ecological risk for the moment. But as the time goes, the forms' proportion will change, trace elements' dissolvable form's proportion will increase, so mass of coal fly ash still has the possibility to transfer trace elements to environments, we should insist on detecting the trace elements in environment for a long time.