Produced water's impact on soil properties: Remediation challenges and opportunities

Authors: GREEN, AARON - North Dakota State University; DESUTTER, THOMAS - North Dakota State University; MEEHAN, MIRANDA - North Dakota State University; DAIGH, AARON - North Dakota State University; O'BRIEN, PETER - US Department Of Agriculture (USDA)

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2020
Publication Date: 7/27/2020
Citation: Green, A., DeSutter, T.M., Meehan, M.A., Daigh, A.L.M., O'Brien, P.L. 2020. Produced water's impact on soil properties: Remediation challenges and opportunities. Agrosystems, Geosciences & Environment. 3(1):e20042. https://doi.org/10.1002/agg2.20042.
DOI: https://doi.org/10.1002/agg2.20042

Interpretive Summary: Development of alternative methods for oil and natural gas production, such as hydraulic fracturing (aka fracking), have dramatically increased production in the upper Great Plains, USA. However, these methods also produce large volumes of wastewater, known as brine, that contains salts, oil, and drilling solutions. Accidental releases of brine into agricultural land, natural grasslands, or wetlands can occur during the extraction, storage, and transportation of brine. Brine can be directly toxic to vegetation and organisms in soil and wetlands, and it can alter the soil structure and chemistry, making it difficult to reestablish vegetation. This manuscript reviews numerous strategies that have been developed to remediate brine contamination and identifies pros and cons associated with each. Notably, some of the most commonly implemented techniques are often costly, slow, and may provide inconsistent results. Thus, this review also identifies novel techniques that are currently being developed to improve the success of brine-contaminated soil remediation. These techniques need to be refined with additional research, but their implementation may be necessary as continued oil and natural gas production will likely be accompanied by more accidental releases of brine in the future. This review is useful in guiding land managers to choose appropriate remediation techniques to reduce environmental impact and maximize soil reclamation success, which will become increasingly more important as continued oil and natural gas production will likely be accompanied by more accidental releases of brine on agricultural land in the future.

Technical Abstract: The choice of remediation technique when brine (i.e., wastewater that is produced during oil and gas production) is released into the environment depends on the severity of contamination, environmental factors, cost-effectiveness, and relative efficiency of salt removal. The objective of this review is to summarize the current practices that are used to remediate brine spills or abandoned evaporation pits within the Bakken and Three Forks regions of the Williston Basin within the upper Great Plains (USA). The most common current methods are ‘dig and haul’ and the use of chemical amendments such as gypsum (CaSO4) or organic amendments (manure, straw, etc.) to promote soil flocculation and the downward leaching of salts out of the topsoil. These methods, however, can fail to achieve sustained remediation success in a cost-effective and timely manner, making continued research into alternative methods necessary. The use of electrokinetics, crystallization inhibitors, wicking materials, and plant-growth promoting rhizobacteria hold promise for in-situ cleanup of contaminated sites.