Laboratory Column Technique for the Measurement of Colloid Transport in Variably-saturated Porous Media
Author: Kelly Dean Cherrey
Publisher:
Published: 2002
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKUniformly desaturated porous media. A coarse sand matrix which reached residual water content near 20 cm of water suction was used to verify the utility of the technique. Colloid suspensions were uniformly applied using a sprinkler with low dead volume, trivial concentration attenuation, and minimal nuisance dispersion. Unsaturated outflow suction was applied with a hanging water column through a 65 micron porous glass frit. Matric potential was measured along the column (internal diameter and length of 5 and 20 cm, respectively) at five locations. Transport breakthroughs were measured with a NaNO3 conservative tracer and two types of colloids: those removed from the matrix (native colloids) and those modified by a simulated Hanford tank-waste solution (Zhao et al., 2001). NaNO3 and colloid outflow concentrations were measured in real-time using absorbance spectroscopy. Average water content was determined from column weight and matric potential was measured using porous ceramic cups coupled with electronic strain-gage transducers. An effective saturation () design error of = 0.01 was easily verified during operation.
