Greenfields, on the other hand, are undeveloped parcels of land, while the term “greyfield” is sometimes used to refer to dilapidated or abandoned properties that are not contaminated. “Brownfield” also excludes the most severely contaminated hazardous waste sites such as Superfund sites.

“Brownfields are real property – the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant.”

US Environmental Protection Agency

History

Pittsburgh is a well-established leader in brownfield redevelopment. As a city with a history entrenched in the steel industry, it has no shortage of brownfield sites. A 1998 report by graduate students in Public and International Affairs at the University of Pittsburgh stated:

“The immense brownfield sites of the Mon Valley allow for a wide range of reuses in which economic development, for both the region and the individual communities, can be linked with community development. Redevelopment of these sites, as well as the hundreds of smaller brownfields within the city of Pittsburgh, can be used to bring people and jobs back to areas that already have infrastructure in place. Finding new uses for the vacant, sometimes polluted industrial sites that do not generate much tax revenue and are neighborhood-blighting influences will benefit neighborhoods, cities, and the entire Pittsburgh region. ”

– Graduate School of Public and International Affairs, University of Pittsburgh

Developers are pursuing projects in the Pittsburgh region. Along the Monongahela River, former steel plants and other contaminated sites have been converted into impressive commercial, residential, and mixed-use projects.

• Station Square, completed in 2002, included historic building reuse as well as the cleanup of a coal freight site.
• A 120-foot-tall slag pile in Squirrel Hill South was covered with topsoil and the nearby Nine Mile Run stream was restored in order to build Summerset at Frick Park, a $250 million residential development.
• A site previously owned by LTV Steel Co. was converted into SouthSide Works, improving property values and providing public riverfront access.
• Another steel mill site became the Pittsburgh Technology Center (PDF), an office park and research hub.
• In Hazelwood, Hazelwood Green sits on the former site of two successive steel manufacturing companies. Asbestos, petroleum, and polychlorinated biphenyl (PCB) on the grounds were mitigated through phytoremediation (the use of plants that can contain, degrade, or eliminate pollutants) in order to prepare it for a new mixed-use development.

Numerous other brownfields in Duquesne, McKeesport, Homestead, and Johnstown, as well as Pittsburgh, have been remediated after contamination with heavy metals, petroleum, asbestos, and other substances. Many of the projects have detailed case studies by the Western Pennsylvania Brownfields Center.

Remediation Process

Land remediation starts with looking at a property’s past uses and identifying possible contaminants. Visible indicators such as soil staining may also be present. This initial study of the site is part of what is called a Phase I Environmental Site Assessment. Brownfield remediation grants available from the Environmental Protection Agency are contingent on conducting “All Appropriate Inquiries” into site conditions according to rules laid out by ASTM International. (The EPA assists with site assessments at eligible sites.)

If Phase I does not produce definitive results, a Phase II assessment may be needed for further investigation.

The process for remediation depends largely on zoning and the intended use of the property. A parking lot, for instance, will require a different level of cleanup than a lot being converted to a community garden. Future residential sites have higher standards than commercial sites and thus will likely take longer and be more expensive to treat.

Remediation techniques are divided into those for groundwater and those for soil. Common approaches to treating soil include:

• Point-source contamination removal: removal of polluting pipes, tanks, or other objects.
• Excavation and disposal: a common practice if an area is already going to be excavated; difficulties can include site accessibility, depth of contamination, and area safety issues; soil can be treated off-site and returned to the project site, or it may be used on a landfill site.
• Containment: for complex pollution problems or large areas; sites that are surface-sealed must be maintained similar to a landfill with consideration to groundwater; containment may be used for parking lots or industrial buildings without basements, but this can restrict future changes to site use.
• Immobilization: for sites with heavy metal contamination of groundwater; metals may include lead, chromium, arsenic, zinc, and mercury, among others, and immobilization uses chemical processes to fix these metals to soil particles so that they cannot leach out.
• Soil vapor extraction: used for contamination above the water table; involves drilling of extraction wells and creation of a vacuum to pull out underground VOCs in vapor form.
• Phytoremediation: planting species that produce chemicals that react with or immobilize contaminants, species that can degrade contaminants around their roots, or species that draw up contaminants from the soil into shoots and leaves, which must then be disposed of.
• Microbial remediation: speed the degradation of hydrocarbon contaminants with the use of microbes.
• Mycoremediation: use of fungal species to degrade contaminants.
• Thermal desorption: heating of soil to make contaminants more volatile; when contaminants off-gas from the soil, they can be collected and destroyed.

Groundwater remediation takes longer and is harder to measure, but strategies include the following:

• Pump and treat: most common groundwater cleanup method, which involves pumping out groundwater and purifying it; this method varies in complexity based on how many types of contaminants are in question.
• Air sparging: used together with soil vapor extraction; air is injected into the ground below the water table to push contaminant vapors up toward the surface.
• Chemical oxidation: introduction of an oxidant to react with contaminants and break them down into less harmful compounds; a variation of this can be used to treat soil.
• Groundwater circulation wells: Water injected with compressed air flows upward in underground wells, and contaminants are removed in vapor form along the way.
• Permeable reactive barrier: A trench up to 50 feet deep is filled with material that can react with contaminants or filter them out as groundwater flows through the barrier; in some cases, impermeable side walls are built to funnel water through the reactive barrier.

The American Planning Association has a guide of common contaminants and remediation techniques. 

Soil or water testing may be necessary after remediation to determine its effectiveness.

Additional Considerations

In many instances, cost determines whether development of a brownfield is feasible, as well as which technologies are employed. The U.S. Department of Housing and Urban Development (HUD) administers Brownfield Economic Development Initiative (BEDI) grants to promote economic development on brownfields and other underused properties.

Time constraints also play a big part in remediation decisions, discouraging long-term strategies and treatments and compelling more teams to opt for quick fixes such as excavation and containment. Another consideration is the technical reliability of the chosen remediation method, as any remaining pollutants will need to be managed over time.

Finally, liability presents a concern in some cases. Following the passage of the Comprehensive Environmental Regulation, Compensation, and Liability Act (CERCLA) in 1980, the past, present, and future owners and users of a site could be held liable for cleanup. In 2002, the Small Business Liability Relief and Brownfields Revitalization Act, among other things, added liability protections to CERCLA for bona fide prospective purchasers, innocent landowners, and contiguous property owners.

The Pennsylvania Land Recycling Program (also called Act 2) sets standards for brownfield cleanups within PA and provides liability protection for sites that meet those standards.

Advantages of Brownfield Remediation and Redevelopment

• Removal or treatment of harmful substances
• Increased area property values
• Existing infrastructure maintained for location and community linkage
• Less land use than comparable greenfield developments
• Avoidance of urban sprawl
• Economic benefits from reinvestment in blighted properties
• Community pride and vitality

Related Links

Brownfields Assistance Program
Soil Contamination and Urban Agriculture (PDF)
GTECH: ReClaim