Research Projects

Bedrock Bioremediation Center
Bioventing of No. 2 Fuel Oil Contaminated Soils
Enhanced Bioremediation of Oil-Contaminated Salt Marshes

PIs: N.E. Kinner, T. Ballestero, J. Benoit, F. Birch, W. Bothner,
L. Brannaka, M. Davis, S. Jones, L. Tisa
Research Scientist: K. Newman
Post Doctoral Student: S. Gonzalez
Graduate Students: W. Nasser, P. Foster, G. Pulido

Dr. Kinner is the Director of the Bedrock Bioremediation Center (BBC) at the University of New Hampshire, which specializes in multidisciplinary research on bioremediation of organically contaminated bedrock aquifers. The Center is comprised of a consortium of faculty from the University's Environmental Research Group (ERG), and the UNH Departments of Microbiology, Earth Sciences, and Natural Resources. The BBC, in conjunction with the U.S. Air Force's environmental engineering program at the Pease International Tradeport (Portsmouth, NH), is developing and evaluating technologies for enhanced bioremediation of the bedrock aquifer at Pease Site 32.

Water flowing through fractures in bedrock aquifers is used for drinking water in much of the United States. Remediation of these aquifers, once contaminated, is often deferred because of difficulties in characterizing the extent of the problem and the lack of appropriate cleanup technologies. One possible inexpensive and efficient method for remediating these sites in situ may be bioremediation using the naturally-occurring microorganisms that live along the fractures in the bedrock. However, very limited data are available on the success/implementation of bioremediation in bedrock aquifers. The overall goal of the BBC is to improve our understanding of this new technology, develop methods to apply and enhance its use, and to monitor its effectiveness in situ. For more information on the BBC, access the Center's website at www.bbc.unh.edu.

Project:  
Bioventing of No. 2 Fuel Oil Contaminated Soils: Effects of Acclimation, Temperature, Air Flowrate and Nutrients

PI: N.E. Kinner
Graduate Student: D. Deming

The New Hampshire Department of Environmental Services (NHDES) anticipates that there will be an increasing number of sites discovered throughout the State that are contaminated with No. 2 fuel oil, particularly associated with leaking storage tanks at private homes. A significant portion of the contamination at these sites will be located in the vadose zone. While several techniques exist for remediating No. 2 fuel contamination in the vadose zone, bioventing is potentially the best suited for use at sites associated with private homes. Bioventing is low cost and does not require removal of the basement floor and excavation of the soil below it.

Dr. Kinner and Julie Simonton (M.S., UNH, 1998) completed an 18 month laboratory study of bioventing for NHDES in 1998. This study evaluated the extent to which biodegradation of No. 2 fuel occurs during bioventing as a function of oxygen, nutrient, and bacterial addition. Only a few locations within the bioventing test columns exhibited a decrease in soil TPH concentration. A mass balance on CO2 production indicated that >10% of the TPH may have been degraded. However, because of the natural variability of the TPH concentrations associated with the soil, a decrease of <30% would have been difficult to detect. A mass balance also showed that nutrient availability, particularly for phosphorus and possibly nitrogen or potassium, may have limited biodegradation. Multivariate analysis indicated that temperature, air flowrate, nutrient and bacterial addition, soil moisture, and time affected the TPH concentration associated with the soil. However, temperature and time were dependent variables because experimental temperature increased over time.

During the course of the bioventing study, many issues arose that are being addressed in the next phase of the research conducted by Dr. Kinner and Diana Deming. The following specific objectives of the current research are designed to address these issues.

· Determine the effect of acclimation time prior to the start of bioventing on biodegradation rates during bioventing.
· Determine the effect of temperature variation after the onset of biodegradation.
· Determine the effects of nutrient amendments and air flowrate on bioventing.

The following experimental conditions are being evaluated at 20-22°C and 10°C for acclimated and non-acclimated soils: two air flowrates (a typical bioventing flowrate and a reduced flowrate); and the effects of nutrients, in conjunction with the normal (typical) air flowrate. Controls are also being run simultaneously for each condition. A factorial experiment design is being used.

Project:  Enhanced Bioremediation of Oil-Contaminated Salt Marshes

PIs: N.E. Kinner, T.P. Ballestero, S.H. Jones
Graduate Students: J. Gilbert, D. Hildebrand, M. Bubier

Of all the estuarine and coastal environments, salt marshes are the most ecologically sensitive areas impacted by oil spills. Remediation of oil-contaminated marshes is difficult with cutting and burning of marsh grass, sediment removal and replanting, or natural attenuation being common current practices. Enhanced bioremediation, such as adding nutrients using a variety of surface application methods, has been tried for several kinds of shoreline environments, but has been hampered because much of the nitrogen/phosphate is lost during tidal flushing. In 1997, we received grants from the Cooperative Institute for Coastal and Estuarine Environmental Technologies (CICEET) and the New Hampshire Department of Environmental Services (NHDES) to evaluate three types of enhanced bioremediation systems (nutrient, air, and nitrate amendments) in an oil-contaminated salt marsh in Portland, ME.

The innovation in this research was to inject the amendments directly into the subsurface using horizontal wells placed in the marsh sediments. Based on multivariate regression analysis of two field seasons of data, the nutrient amendment is showing significant removal of both short chain aliphatic and aromatic petroleum hydrocarbons (only 2% and 19% probability of false positives, respectively). The air and nitrate amendments are showing significant removal of long chain aliphatics (<1% probability of false positives). However, air amendments are problematic because they are difficult to add and can cause subsidence in the marsh. We have received funding from CICEET and NHDES to continue the current project from August 2000 to July 2002.

The goals of this phase of the research are to: (i) collect two more complete field seasons of data to validate our preliminary conclusions, and (ii) to optimize, design, and test two prototype nutrient and/or nitrate amendment injection systems. Prior to doing the prototype design, we will conduct field experiments to better understand dispersion of the amendments in the sediments and to examine/optimize application rates. The expected outcome of this research will be a cost-effective method to enhance the natural rates of in situ biodegradation of petroleum-contaminated salt marshes including development of a low-impact prototype device to optimize addition of the liquid amendments to the sediments where they are needed by the microorganisms and plants. Upon favorable development of the prototype(s), full-scale development by companies in the private sector will be pursued.