Delivery of Vegetable Oil Suspensions in a Shear Thinning Fluid for Enhanced Bioremediation

Journal Article · Wed Apr 01 00:00:00 EDT 2015 · Journal of Contaminant Hydrology, 175-176:17-25

DOI:https://doi.org/10.1016/j.jconhyd.2015.02.001· OSTI ID:1184982

Zhong, Lirong; Truex, Michael J.; Kananizadeh, Negin; Li, Yusong; Lea, Alan S.; Yan, Xiulan

In situ anaerobic biological processes are widely applied for dechlorination of chlorinated solvents in groundwater. A wide range of organic substrates have been tested and applied to support the dechlorination processes. Vegetable oils are a promising substrate and have been shown to induce effective dechlorination, have limited geochemical impacts, and good longevity. Distribution of vegetable oil in the subsurface, because it is a non-aqueous phase material, has typically been addressed by creating emulsified oil solutions. In this study, inexpensive waste vegetable oils were suspended in a xanthan gum solution, a shear-thinning fluid, as an alternative oil delivery mechanism. The stability, oil droplet size and distribution, and rheological behavior of the oil suspensions that are created in the xanthan solutions were studied in batch experiments. The injectability of the suspensions and oil distribution in porous medium were evaluated in column tests. Numerical modeling of the oil droplet transport and distribution in porous media was conducted to help interpret the column-test data. Batch studies showed that simple mixing of vegetable oil and xanthan solution produced stable suspensions of the oil as micron-size droplets. The mixture rheology retains shear-thinning properties that facilitate improved uniformity of substrate distribution in heterogeneous aquifers. Column tests demonstrated successful injection of the vegetable oil suspension into porous medium. This study provided evidence that vegetable oil suspensions in xanthan are a potential substrate to support in situ anaerobic bioremediation with favorable injection properties.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1184982
• Report Number(s): PNNL-SA-106469; 400403209
• Journal Information: Journal of Contaminant Hydrology, 175-176:17-25, Journal Name: Journal of Contaminant Hydrology, 175-176:17-25
• Country of Publication: United States
• Language: English