Advances in EVO Deployment to Enhance Subsurface Distribution for Anaerobic Bioremediation
Emulsified vegetable oil (EVO) slowly ferments and can act in the subsurface as an organic carbon and hydrogen source that stimulates organohalide-respiring bacteria that in turn mineralize chlorinated solvents. Although emulsifying vegetable oil allowed overcoming limitations of pure vegetable oil injection and minimize field interventions by using a long-lasting electron donor, hundreds of EVO injection events over the past years has demonstrated that EVO effects are limited to the area in the immediate vicinity of the injection point. This is evident through low TOC values measured even tens of meters downgradient to injection points where only acetic acid predominates. A favorable fatty acid diversity seems to be limited to the injection points immediate vicinity (< 5 meters).
This presentation will review the history of EVO injections and provide an overview of advances in EVO formulations to overcome the challenges associated with poor fatty acid subsurface distribution and biofouling. The development of water-miscible, slowly-fermenting and aquifer buffering formulations are capable of in-situ generation of both soluble and slowly fermenting electron donors required for the anaerobic remediation of organohalide compounds contaminating soils and groundwater. These nee formulations are advancing the state of the practice for subsurface EVO distribution.
|Cut off date||12-03-2020|