某垃圾焚烧发电厂溶质迁移模拟及健康风险评价

SOLUTE MIGRATION SIMULATION AND HEALTH RISK ASSESSMENT FOR A WASTE INCINERATION POWER PLANT

垃圾焚烧发电厂的运营会带来一系列诸如地下水污染、土壤污染和温室气体排放等生态环境问题。以某市生活垃圾焚烧发电厂厂区为研究对象,在事故工况条件下厂内垃圾仓、渗滤液处理站和生活污水处理站3个区域存在发生渗漏的风险性,通过Modflow和MT3D模拟分析事故工况下渗滤液中COD在地下水中的运移过程;并利用美国环保局(USEPA)推荐的健康风险评价模型对污水处理厂周围水体中重金属进行健康风险评价。结果表明:该厂区内渗滤液在事故工况下,缓慢向下扩散,COD的最大扩散范围逐渐扩大,浓度逐渐升高,到25年时最大扩散范围可达到27 924.62 m^2,迁移距离为192.53 m,浓度达到205.45 mg/L左右。在事故工况下,垃圾焚烧发电厂3个污染源随时间延长污染范围和距离会不断扩大,对地下水会产生一定污染。健康风险大小依次为Cr>As>Cu>Pb>Zn,通过饮水途径所致健康风险中,Cr对厂区所引起的致癌风险最大(4.1×10^(-7)a^(-1)),Cu的非致癌风险最大(1.4×10^(-10)a^(-1)),但均低于国际辐射防护委员会(ICRP)推荐的通过饮水途径导致的最大可接受风险水平(5.0×10^(-5)a^(-1))。

The operation of waste incineration power plants brought a series of ecological and environmental problems,such as groundwater pollution,soil pollution and greenhouse gas emission. A waste incineration power plant was selected as the object of this study. The leakage risk might happen under the accident condition in three areas of the study region,including the warehouse,the leachate treatment station and the domestic sewage treatment station. The migration process of COD in leachate under the accident working condition was simulated by Modflow and MT3D. And then the health risk assessment model recommended by US Environmental Protection Agency（ USEPA） was adopted to evaluate the health isks of heavy metals in water bodies around sewage treatment plants. The results showed that the leachate in the plant would slowly spread down,and the maximum COD diffusion range and the concentration would gradually increase under the accident condition. In 25 years,The maximum diffusion range will reach 27 924. 62 m^2,the migration distance would be 192. 53 m,and the concentration of COD would be about 205. 45 mg/L. Under the accident condition,the three pollution sources of the waste incineration power plant would extend the pollution range and distance continuously,which could cause certain pollution to the groundwater. The intensity order of the health risk was Cr As Cu Pb Zn. In the health risks associated with drinking water,Cr（ 4. 1 ×10^-7 a^-1） had the highest carcinogenic risk,while Cu（ 1. 4 × 10^-10 a^-1） had the highest non-carcinogenic risk. However,all risks were lower than the maximum acceptable risk level associated with drinking water（ 5. 0 × 10^-5 a^-1） recommended by the International Commission on Radiation Protection（ ICRP）.