The Environmental Research Group has a significant amount of research on-going in the area of contaminant fate, transport, and in-situ remediation methods. Areas of interest of the faculty involved in this type of research include:

• Movement, monitoring, and biodegradation of petroleum hydrocarbon contamination in soils, groundwater, and salt marshes.
   
  
• Colloidal-facilitated contaminant transport and development of colloid-based remediation methods
   
  
• Innovative well construction methods for assessment of contaminated sites.
   
  
• Transport and fate of groundwater contaminants in the vadose zone,
   
  
• Hydrologic and contaminant attenuation processes in cold regions,
   
  
• Groundwater-surface water interactions,
   
  
• Natural contaminant attenuation processes
   
  
• Bioremediation of contaminated subsurface environments

Below a few current projects are highlighted.

Project
In-Situ Reactive Wall Formation with Colloidal Materials.

Contact: Dr. Kevin Gardner

These projects are focused on putting reactive barrier walls in place by colloid deposition. The advantages are that much less material is required and deep contamination or inaccessible areas are not a problem as they are with trench and backfill approaches. In addition, sites with heterogeneous stratigraphy, which may cause significant variations in groundwater flow fields, may be more effectively treated with a reactive wall formed by colloid deposition rather than a single-thickness wall typical of reactive barrier walls. To date two types of walls have been developed: zero-valent iron walls and catalyst walls, in which a chemical oxidant would be required to react with the contaminant and catalyst.

Project
Enhanced Bioremediation of Oil-Contaminated Salt Marshes

Contact: Dr. Nancy Kinner

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.

Project
Investigation of Mechanisms of Surfactant-Induced Hydraulic Conductivity Changes in Soil Flushing Operations

Contact: Dr. Kevin Gardner

A major concern with the use of surfactant flushing to mobilize non-aqueous phase liquids in aquifers is specific mineral-surfactant interactions which may effect significant permeability changes in the soil formation. Soils are being investigated for loss of permeability upon flushing with solution containing a number of nonionic and anionic surfactants. Surfactant / clay interactions are being further investigated as the cause of the permeability reductions, both from transport/rearrangement and swelling.

Project
Bedrock Bioremediation Center

Contact: Dr. Nancy Kinner

The Bedrock Bioremediation Center (BBC) at the University of New Hampshire 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

Contact: Dr. Nancy Kinner

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.

Project
Development of a Risk Analysis Framework for Beneficial Use of Secondary Materials

Contact: Dr. Kevin Gardner

This project is being conducted to answer the following questions:
How should States decide whether a secondary material is safe for use in different types of applications? What are the risks associated with using a byproduct that may have some elevated levels of contaminants, and how can this risk be quantified?
The purpose of this project is to develop a risk analysis framework for beneficial use of secondary materials. The first stage of the project involves understanding of water movement in the roadway environment. HYDRUS2D, a variably saturated two-dimensional model for water flow and solute transport, is being used to simulate water movement in the roadways. The model is being calibrated and verified with data from MnROAD, a field facility project of MnDOT. Ultimately, a rigorous fate, transport, and risk assessment model will be developed with the focus of realistically estimating leachate concentrations and risk from a number of typical, high-volume roadway applications. Based on this model and results for various highway environments, a simplified risk assessment approach will be developed for use by State environmental agencies in support of beneficial use determinations.