(68b) Effect of Near-Electrode Additives on Electrokinetic Remediation of Brine Spills

Brine, or produced water, is a byproduct of extracting oil and natural gas from the earth. This salty water comes out of the same reservoir rock that contains the oil and gas and can contain salt concentration upwards of 10% by weight. If the brine is not correctly handled and spills onto the ground, it can kill vegetation in the short-term and prevent plants from growing in the affected area for decades. Additionally, brine spills can swell clays present in the soil which, when combined with the loss of vegetation, cause catastrophic erosion of the area. A promising method of treating brine spills without large-scale excavation of the spill site is electrokinetic remediation (EKR). EKR does not require and pumps or major equipment after the initial installation of the hardware. EKR can also be implemented in remote, isolated areas because the technique can be powered by on-site solar panels with no need for access to the electrical grid. EKR involves using a network of buried electrodes to attract the dissolved salt species to the anode or cathode respectively, where they can be concentrated and removed without requiring large-scale excavation of the spill site and loss of vital top soil. However, EKR can suffer from pH and conductivity limitations due to a build-up of certain chemical species near the electrodes used for the technique, limiting its performance and requiring controlled cycling or modulation of the electric field. This research investigates the effect of various near-electrode additives for use as buffers and absorptives to enhance the effectiveness of EKR. The additives were assessed using a bench-scale testing device with model soils along with test soil from a historical brine spill on the Tall Grass Prairie Preserve located in Osage County, OK.

References:

1. Meko, T. & Karklis, L. The United States of oil and gas. Washington Post (2017).
2. Produced Water Society. Produced Water 101 - The Produced Water Society. Available at: http://www.producedwatersociety.com/produced-water-101/. (Accessed: 29th August 2019)
3. Meehan, M., Sedivec, K., DeSutter, T., Augustin, C. & Daigh, A. Environmental Impacts of Brine (Produced Water). (2017).
4. Flesher, J. Drilling boom means more harmful waste spills. Associated Press (2015).
5. Virkutyte, J., Sillanpää, M. & Latostenmaa, P. Electrokinetic soil remediation — critical overview. Sci. Total Environ. 289, 97–121 (2002).