Kildsgaard J, Engesgaard P
Environment and Resources DTU Groundwater Research Centre, Technical University of Denmark, Building 115, 2800 Lyngby, Denmark.
J Contam Hydrol. 2001 Aug;50(3-4):261-85. doi: 10.1016/s0169-7722(01)00109-7.
Two-dimensional models for biological clogging and sorptive trace transport were used to study the progress of clogging in a sand box experiment. The sand box had been inoculated with a strip of bacteria and exposed to a continuous injection of nitrate and acetate. Brilliant Blue was regularly injected during the clogging experiment and digital images of the tracer movement had been converted to concentration maps using an image analysis. The calibration of the models to the Brilliant Blue observations shows that Brilliant Blue has a solid biomass dependent sorption that is not compliant with the assumed linear constant Kd behaviour. It is demonstrated that the dimensionality of sand box experiments in comparison to column experiments results in a much lower reduction in hydraulic conductivity (factor of 100) and that the bulk hydraulic conductivity of the sand box decreased only slightly. However, in the central parts of the clogged area, the observations and simulations clearly show a complex picture of flow diverting the injected nutrients around the clogged area as fingers. The calibration of the model demonstrates that the physical and microbiological processes (advection, dispersion, attachment-detachment, growth-decay) are all needed to capture the progress of clogging.
利用生物堵塞和吸附性微量传输的二维模型，研究了砂箱实验中的堵塞过程。该砂箱已接种一条细菌带，并持续注入硝酸盐和醋酸盐。在堵塞实验期间定期注入亮蓝，利用图像分析将示踪剂移动的数字图像转换为浓度图。模型针对亮蓝观测数据的校准表明，亮蓝具有与固体生物量相关的吸附作用，不符合假设的线性常数Kd行为。结果表明，与柱实验相比，砂箱实验的尺度导致水力传导率的降低幅度要低得多（100倍），且砂箱的总体水力传导率仅略有下降。然而，在堵塞区域的中心部分，观测和模拟结果清楚地显示出一幅复杂的图景：注入的养分以指状流绕过堵塞区域。模型校准表明，需要物理和微生物过程（平流、弥散、附着-分离、生长-衰减）来描述堵塞过程。
