TURNING BROWNFIELDS

• Definition US EPA 1997

abandoned, idled or under-used industrial and commercial facilities where expansion or redevelopment is complicated by real or perceived environmental contamination

• Definition US Brownfield Rehabilitation Act 2002real property, the expansion, redevelopment or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant or contaminant

• potential Resource Conservation and Recovery Act Brownfield (RCRA)is a facility that is not in full use, where there is redevelopment potential and where reuse or redevelopment is slowed due to real or perceived concerns about actual or potential contamination, liability, and RCRA requirements.

Defining the overall long-term goals of the brownfields project is a crucial element iidentifying appropriate technologies for site investigation and cleanup

Bioremediation allows natural processes to clean up harmful chemicals in the environment. Microscopic “bugs” or microbes that live in soil and groundwater like to eat certain harmful chemicals, such as those found in gasoline and oil spills. When microbes completely digest these chemicals, they change them into water and harmless gases such as carbon dioxide.

• In order for microbes to clean up harmful chemicals, the right temperature, nutrients (fertilizers), and amount of oxygen must be present in the soil and groundwater. These conditions allow the microbes to grow and multiply—and eat more chemicals.

• One way they improve conditions is to pump air, nutrients, or other substances (such as molasses) underground.

• The right conditions for bioremediation cannot always be achieved underground. At some sites, the weather is too cold or the soil is too dense. At such sites the soil is dug up to clean it above ground where heaters and soil mixing help improve conditions. After the soil is dug up, the proper nutrients are added. Oxygen also may be added by stirring the mixtureor by forcing air through it. However, some microbes work better without oxygen. With the right temperature and amount of oxygen and nutrients, microbes can do their work to“bioremediate” the harmful chemicals.

• Phytoremediation represents a group of innovative technologies

that use plants and natural processes to remediate or stabilize

hazardous wastes in soil, sediments, surface water, or groundwater.

• Phytoremediation does not require the excavation of soil, and its application may require only minimal material handling.

• Phytoremediation is the direct use of living green plants for in situ (in-place or on-site) risk reduction for contaminated soil, sludges, sediments, and groundwater, through removal, degradation, or containment of the contaminant

• Phytoremediation can have a positive effect on the aesthetic character of a site, may be an attractive alternative for use at large sites at which other methods of remediation are not cost-effective or practical, and can be used in conjunction with other technologies

Phytoremediation biological processes

• Hydraulic Control, also known as phytohydraulics uses plants that have a high transpiration rate to take up large quantities of water to contain contaminants and prevent their further migration.

• Phytodegradation, also known as phytotransformation, is the uptake of organic contaminants from soil and groundwater, followed by their degradation in plant tissue. After uptake, the plant either stores the contaminants or volatizes or metabolizes the contaminants completely to carbon dioxide and water.

• Phytoextraction uses plants to transport metals from the soil and concentrate them into roots and aboveground shoots that can be harvested. Some grasses accumulate surprisingly high levels of metals in their shoots without exhibiting toxic effects.

• Phytostabilization uses plants to limit the mobility and bioavailability of metals in soil. The process helps to stabilize the soil matrix to minimize erosion and migration of sediment. In addition, the process minimizes the

generation of airbornecontaminants caused by wind erosion.

Bowers Landfill, Pickaway County, Ohio • BEFORE

Hazardous waste landfill filled with municipal, chemical, and industrial waste

• PROBLEM  Soil, groundwater, and surface water contaminated with volatile organic compounds and PCBs

Hazardous and non-hazardous surface debris

SOLUTION  

Surface Debris removed to a licensed facility Sediments removed and dewatered Clay cap constructed Groundwater monitoring system installed

AFTER • Wetlands home for plants,

wildlife and migratory birds

IMPACT• Productive use of land

as an ecological sanctuary

Fort Devens Site, Massachusetts

AFTER

Large-scale public and private reuse and redevelopment

IMPACT

Revitalization of local economy with jobs and income, spending, and public revenues, and enhanced social and ecological benefits

BEFORE

Contaminated soil and groundwater from almost 80 years of military operation

PROBLEM 

80 areas with soil or groundwater contamination, including waste oil from leaking underground tanks, arsenic from a municipal landfill, and polychloroethlyene at an airfield.

SOLUTION  

Over 40 short-term actions to remove immediate threats  

Installation of protective soil and asphalt covers over areas of contamination

Removal of contaminated soils and installation of groundwater treatment system  

Other cleanups planned