Optimization and comparison of radioanalytical methods for the determination of radium and other alpha-emitting radionuclides in process water samples from the oil & gas industry
Date
2022
Authors
Coupannec, Maelle, author
Sudowe, Ralf, advisor
Brandl, Alexender, committee member
Johnson, Thomas, committee member
Borch, Thomas, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
A major concern arising from hydraulic fracturing is the generation of a large volume of flowback water potentially containing various amounts of dissolved Naturally Occurring Radioactive Material (NORM). Up to four million gallons of water-based fluid is injected per well, of which 10–70% is subsequently recovered as flowback. Improving the separation and measurement of "Technologically Enhanced Naturally-Occurring Radioactive Material" (TENORM) is a priority in efficiently determining the amount of radionuclides present. An accurate assessment of radium concentration in flowback water is needed to understand potential environmental contamination from hydraulic fracturing sites and bodies of water affected by the mining industry. A significant scientific challenge in radium determination in flowback water is the presence of chemical analogues, calcium, barium, and strontium, in the flowback and produce water. Thus, the development of an accurate radium measurement and separation process is an essential step for appropriate disposal of the flowback water as regulated or non-regulated NORM-containing wastes. Non-destructive analysis of radium using direct gamma spectrometry measurements was performed on flowback water and provided accurate quantities. However, the long counting time necessary to achieve the detection limits renders the analysis impractical. Several approaches to improving radium separation and measurement methods are explored in this work. Pre-conconcentration of radium with barium sulfates was investigated to provide a more rapid gamma screening. The use of Actinide resin instead of TRU resin for column separations was studied as a means to preconcentrate Th, U, and Po in flowback and produced water from the oil and gas industry. The use of an actinide resin is expected to improve the recently developed EPA method for alpha and beta dual analysis for a complete Ra, Th, U, and Po screening or flowback water. Complete separation of radium from the wastewater matrix is ideal and will provide faster radium analysis, reducing the costs associated with handling, treatment, and disposal of wastewater. Multiple proprietary extraction chromatographic resins developed by TrisKem Int. (Bruz, France) were investigated as a function of nitric acid concentration to quantify and enhance the separation of radium from its chemical analogues. Separation of strontium from the resin matrix could easily be achieved using TKI, Sr, or Pb resin as large separation factors were obtained. The TK101 resin is promising for achieving the more difficult separation of barium from radium as the separation factor was found to be 4.3 at 0.04 M HNO3.
Description
Rights Access
Subject
hydraulic fracturing
radium
fracking
TENORM
NORM