通过在垂直方向和水平方向上操作填充有筛分含水层材料的流通柱，研究了柱方向对微小隐孢子虫大小微球运输的影响。微球在垂直柱中的突破发生在约1.7个孔体积之后，在此之后，微球浓度在182到556个微球/L之间（去除约4.6到5.1个对数）。在水平方向操作的色谱柱中，约2.9个孔体积后的微球浓度范围为1100-1200微米/升（去除约4.3至4.4个对数）。不幸的是，在实验过程中，微球可能没有完全突破。本研究的初步结果表明，在垂直位置操作的柱中，微小隐球菌大小的微球的去除率可能略高。这一结果与以下假设相一致，即地下胶体过滤和运输的实验室研究应采用水平方向的色谱柱，因为垂直色谱柱可能会加强沉降对微生物的去除。 此外，水平柱中沿土壤顶部形成优先流路（由介质沉降引起）和分析等因素也可能会使这些结果复杂化。包括16个参考文献、图表。

The impact of column orientation on the transport of C. parvum-sized microspheres was investigated by operating flow-through columns packed with sieved aquifer material in vertical and horizontal orientations. Breakthrough of microspheres in the vertical columns occurred after ~1.7 pore volumes, after which microsphere concentrations ranged from 182 to 556 microspheres/L (~4.6 to 5.1 log removal). In columns operated in the horizontal orientation, microsphere concentrations after ~2.9 pore volumes ranged from 1100 - 1200 micropheres/L (~4.3 to 4.4 log removal). Unfortunately, complete breakthrough of microspheres may not have occurred during the experiments. The preliminary results of this study suggest that slightly higher removals of C. parvum-sized microspheres may be possible in columns operated in a vertical position. This result is consistent with the hypothesis that laboratory investigations of colloidal filtration and transport in the subsurface should be conducted with columns in a more horizontal orientation because vertical columns may enchance the removal of microorganisms by sedimentation. It is also possible that factros such as the formation of preferential flow paths along the top of the soil in the horizontal columns (resulting from media settling) and analytical may complicate these results. Includes 16 references, figures.