First Year Progress Report: In Situ CO2 Sparging into a Caustic Brine Plume
Presented on Wednesday, May 7, 2014
Robert Mutch Jr., P.Hg., P.E.1 and Richard Carbonaro, Ph. D., P.E.2, (1)Mutch Associates, LLC, (2)Mutch Associates, LLC, Ramsey, NJ
In situ sparging of gaseous CO
2 is being conducted on a nine-acre, caustic brine plume in southeastern Georgia to neutralize the plume and to reduce levels of mercury and other heavy metals. The plume exhibits high pH levels ranging from 10.5 to 12, densities as high as 1.08 g/mL, high dissolved silica concentrations, and mercury ranging from 50 to 1000 μg/L. The plume lies at the base of the moderate to low permeability Satilla Aquifer in the Georgia coastal plain at depths ranging from 30 to 50 feet below ground surface.
Planned as a three year implementation, this paper presents the findings of the preliminary laboratory testing, a major pilot-scale test, and the results of the first year of implementation of the full-scale system. The pilot test involved a single sparge well and 13 monitoring wells at varying depths and radial distances up to 100 feet. Monitoring wells were equipped with Hach field electrodes to monitor pH continuously and in real time and Solinst automatic data loggers to monitor water level mounding and collapse during intermittent sparging operations. The pilot test demonstrated that pH within a radial distance of up to 60 feet table and encompassing a total aquifer volume of approximately 6500 cubic feet could be reduced to near neutral pH. Mercury levels declined by 80% to 90% and significant declines in silica, arsenic, and chromium were also observed. The first year of operations involves CO2 sparging into 64 sparge wells and pH monitoring in more than 30 observation wells. Pressure transducers will also be deployed to monitor transient mounding caused by the sparging activities.
Robert Mutch Jr., P.Hg., P.E.
Mutch Associates, LLC
Robert Mutch Jr. is President and Principal Groundwater Hydrologist of Mutch Associates in Ramsey, New Jersey. He has more than 35 years of experience in hydrogeology, groundwater modeling, environmental forensics, and remediation engineering. His areas of specialization include numerical modeling of groundwater flow and solute transport, environmental forensics, DNAPL behavior, and fractured rock hydrogeology. Mutch has also been an Adjunct Professor at Manhattan College for 20 years and at Columbia University for seven years, where he teaches graduate level courses in applied hydrogeology, contaminant transport in the environment, and groundwater and contaminant transport modeling.
Richard Carbonaro, Ph. D., P.E.
Mutch Associates, LLC, Ramsey, NJ
Richard Carbonaro has extensive experience in the field of fate and transport of metals and other contaminants in soils and sediments. He has managed research projects related to water quality monitoring of urban pollutants, transport modeling of metals in sediments, unit-world modeling of metals in lakes for toxicity assessment, and partitioning of metals onto organic carbon. His doctoral work focused on the environmental fate and transformations of chromium in the environment. Carbonaro is also experienced in developing, modifying, and using mathematical solute transport models for both steady state and time-variable conditions.
