垃圾渗滤液重金属镉的地下水污染源强定量评价

Quantitative evaluation of cadmium pollution source intensity in groundwater from landfill leachate

以某垃圾填埋场为研究区,建立了基于过程模拟法的地下水污染源强定量评价模型,对垃圾渗滤液中重金属镉的地下水污染源强进行定量评价。以研究区的包气带介质及评价模型为基础,对镉在包气带中的折减提出了几种假设,得出折减函数;提出了基于折减函数法的地下水污染源强定量评价方法,并建立了相应的折减函数模型。结果表明:该模型应用于研究区,在渗滤液中镉的初始浓度为0.05 mg/L;有效包气带介质为13 m,经过15.4 a镉的折减系数为0.013,进入地下水中的镉浓度为5.13×10^(-4)mg/L,与过程模拟的评价结果接近,经过15.4 a连续入渗后,地下水中镉浓度的模拟结果与监测结果较相符,评价模型的可靠性得到验证。

A landfill site was selected as research area to build a quantitative evaluation model for the pollution source intensity of the groundwater based on process simulation. This model was applied for landfill leachate to evaluate the pollution source intensity of cadmium in groundwater. Based on the study on the medium in unsaturated zone located in the research area and using the quantitative evaluation model of process simulation,several assumptions were proposed in relation to the reduction of cadmium in the unsaturated zone. The reduction function was then produced, based on which the quantitative evaluation method was developed for pollution source intensity in groundwater, and the reduction model correspondingly established. This model was applied to the research area, and the results showed that when the initial concentration of Cd in the leachate was 0. 05 mg/L, the effective vadose zone was 13 m, the cadmium reduction was calculated at 0. 013 and the entrance groundwater concentration was 5. 13 × 10^（-4） mg/L, after continuous penetration via 15. 4 years. The simulated cadmium concentrations were consistent with the survey concentrations of this landfill groundwater. As the simulation result is comparatively fit with the monitoring result, the reliability of this evaluation model is verified.