基于病毒防护的填埋场隔离距离研究

Landfill isolation distance based on virus protection

为研究渗滤液中致病性病毒对填埋场隔离距离的影响,提出一种基于系统健康风险目标的建模方法,用于确定地下水梯度、水力传导系数和包气带厚度对隔离距离的影响,基于线性剂量-效应模型和可接受的感染风险[<10^-4/(人a)]推导确定了饮用水肠道病毒浓度限值,通过耦合渗漏源强模型-以及水流和病毒在包气带中的纵向迁移转化和含水层中的水平迁移转化模型,构建了污染物泄露-迁移-降解的解析模型,并基于Monte-Carlo模拟表征解析模型中参数的不确定性.选择某典型生活垃圾填埋场开展案例研究,结果表明,在砂含水层中为44~564m,在砾石含水层中为91m^2.39km,在粗砾石含水层中为1.74~27.29km;地下水梯度从0.001变化到0.05,导致最高梯度处的隔离距离比最低梯度大10~20倍;当包气带厚度从1m增加到10m时,隔离距离可缩短到10m以内.隔离距离的确定需根据具体的安全防护要求和水文地质条件确定.

For researching the isolation distance of landfill with virus as isolation target,a modeling method based on system health risk objective was proposed to determine the influence of groundwater gradient,hydraulic conductivity and aeration zone thickness on isolation distance.Based on linear dose-effect model and acceptable infection risk[<10^-4/(person a)],the concentration limit of enterovirus in drinking water was deduced.An analytical model of pollutant leakage-migration-degradation was constructed by coupling the leakage source strength model with the vertical migration and transformation model of water flow and virus in the aeration zone and the horizontal migration and transformation model in the aquifer.The uncertainty of parameters in the analytical model was characterized by Monte-Carlo simulation,and then a typical domestic waste landfill site was selected for case study.The result indicated that the isolation distance in sand aquifer is 44~564m,in gravel aquifer was 91m^2.39km and in coarse gravel aquifer was 1.74~27.29km.Groundwater gradient changed from 0.001 to 0.05,resulting in the isolation distance at the highest gradient was 10~20 times larger than that at the lowest gradient.When the thickness of aeration zone increases from 1 to 10m,the isolation distance could be shortened to less than 10m.The research indicated that the determination of isolation distance should be based on specific safety requirements and hydrogeological conditions.