Wenjing Sang's research (see poster) began studying the effects of hydraulic fracturing flowback water and natural gas brine on colloid transport. Her study uses the sophisticated HIROX microscope to visualize colloid transport and water movement in soils. This early work comprised of simple metal leaching experiments were conducted using glass columns filled with sand, to study how metals in flowback water and brine leach out from the sandy column by DI water flush. Metal concentrations measured at the bottom of the column. As expected, most applied metals leached through the sand and therefore did not bind to the sand particles.
Current work focuses on the deposition and release of colloids, which is tested by adding polystyrene latex colloids to sandy columns. On the bright field microscope, these polystyrene colloids show up intense-red in between light-grey sand particles, which makes colloid movement easy to track. By visualizing colloid movement with the bright field microscope, and by monitoring colloid concentrations at the bottom of the sand column, effects of flowback water and brine on colloid transport are evaluated. While we currently use simplifications of soils (clean sand) and colloids (polystyrene particles) to improve our understanding of the processes, we will ultimately perform similar experiments with real soils. With this work we contribute to improve understanding of the environmental effects of spills of hydrofracking fluids.
Wenjing Sang, BEE Soil & Water
Tammo S. Steenhuis, BEE Soil & Water
Cathelijne Stoof, BEE Soil & Water