生物质电厂灰渣理化特性及土地利用潜在生态环境风险评价

Physicochemical Properties of Biomass Power Plant Ash Residue and Potential Ecological Environmental Risks Evaluation of Land Use

通过对某生物质电厂的底渣、混渣的采样分析,调查灰渣的无机元素、重金属、pH、电导率、浸出毒性等理化特性,在此基础上对灰渣土地利用潜在生态环境风险进行评价。结果表明:与底渣相比,混渣中S、Cl、Cd含量明显较高,这可能是混渣中混入的飞灰所导致的;重金属浸出毒性试验显示,底渣和混渣浸出液中的重金属含量均远低于GB 3838、GB/T 14848或GB 5749标准限值;潜在生态风险指数法评价结果显示,底渣潜在污染风险很低,而混渣中的Cd对生态环境的潜在污染风险相对较高;人群健康风险评价显示,底渣、混渣的非致癌风险很低,对于致癌风险,底渣和混渣通过呼吸途径方式为无致癌风险,通过皮肤接触的致癌风险为可接受,Ni、Cr是较大的贡献因子。

By sampling and analyzing bottom ash(BA)and mixed ash(MA)of biomass power plant,the physicochemical properties of the ash,including inorganic elements,heavy metals,pH,conductivity and leaching toxicity,were investigated.The potential ecological environmental risk of ash land use were analyzed;results showed that compared with the BA,the contents of S,Cl and Cd in the MA were obviously higher,which may be caused by the fly ash mixed in the MA;the toxicity experiment of heavy metal leaching showed that the heavy metal content in the BA and MA leaching solution was far below the limit values of GB 3838,GB/T 14848 GB5749.The risk evaluation results showed that the potential pollution risk of BA was very low,while Cd in MA had relatively high risk of pollution to the environment.The results of USEPA model evaluation showed that the non-carcinogenic risk of heavy metals in BA and MA is low.The carcinogenic risk is in the acceptable range,among which Ni and Cr is the major contributing factor.