Brownfield Remediation: Why It’s Needed and How It’s Done
The EPA defines a brownfield as a “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”. Brownfields are usually closed or unused industrial facilities such as abandoned factories or old warehouses in a suburban area. However, they can also be found on smaller pieces of land where commercial buildings like dry cleaners or gas stations previously were. These are all locations where brownfield remediation is necessary.
Identifying a Brownfield
An Environmental Site Assessment (ESA) investigation determines the presence of hazardous materials in these locations. The law requires an ESE since the passage of the Comprehensive Environmental Response, Compensation, and Liability Act in 1980 holding the purchaser of said properties liable for contaminants or pollutants found on the land. The EPA estimates that there are over 450,000 brownfield sites in the United States. However, this estimate only includes properties in which an ESA investigation has been performed. The actual number of brownfields in the US may be much higher. When a site has been identified as a brownfield, remediation is needed.
Why Brownfield Remediation is Important
Brownfield remediation is an important issue for both environmental and economic reasons. The cost of brownfield cleanup often exceeds the value of the land after cleanup. Therefore, developers have been extremely hesitant to take on such an endeavor. As a result, abandoned and unsightly brownfields often stay idle, lowering local real estate values and hindering economic development in the area.
These sites are often in prime real estate locations near a populated workforce and public transportation which gives them immense potential for economic growth. Since brownfield remediation is crucial for job creation and aiding the economic expansion of local communities, government programs now make it easier for developers to take action. The main goal is to transform these brownfields into “green spaces” which benefit human health, the environment, and the surrounding communities.
Brownfield Remediation Options
The type of brownfield remediation option will depend on the contaminants present and the level of those contaminants. While excavation is a more traditional method, it can be quite costly. There are other methods that allow for the treatment of pollutants onsite without hauling them away.
Engineered caps can seem like a band-aid covering up the contaminants in a brownfield without actually protecting the environment. However, using engineered caps encloses all the contaminants, preventing them from spreading vertically or horizontally throughout the site. There are three main types of engineered caps:
- Impermeable Caps prevent water from flowing down and carrying contaminants into the groundwater. They are made by using a multilayer system of geosynthetics including a geomembrane liner, a geotextile cushion or separation layer, and a geocomposite drainage layer.
- Low Permeable Caps help to create and maintain asphalt or concrete areas. This includes parking lots, roadways and building foundations that act as surface barriers. These caps prevent the infiltration of surface water and the movement of pollutants.
- Permeable Soil Caps involve a partial excavation of the soil on site. A portion of the contaminated soil is removed and an orange demarcation fabric is installed, acting as a barrier and a filter. The orange demarcation geotextile fabric allows water to pass through while helping to prevent contaminants from spreading upwards. Filling the area with clean soil completes the process. Residential areas require 2-3 feet of soil while non-residential areas require 10 feet of soil. The orange demarcation fabric is also available with the words “Do Not Dig” to prevent future excavation damage.
Leachate Collection Systems
Using drainage geocomposites or geotextile filter fabrics, leachate collection systems direct and collect water that has percolated through a solid and leached out some of the elements. After collection, it is ready to transport offsite for disposal.
Groundwater Migration Barriers
The use of geomembrane liners creates an effective underground containment barrier. The barrier cuts off the route of the problem and prevents contaminated groundwater from spreading beyond the property.
When toxic gases are present in a brownfield, the use of multi-layer geomembrane liners creates an effective vapor barrier. This prevents poisonous gases from breaking through the surface and infiltrating the environment or indoor air quality of buildings onsite.
Brownfield Remediation Can Revitalize a Community
Brownfield remediation is important for protecting our environment as well as helping communities to grow and prosper. IWT Cargo-Guard offers various geosynthetics, geomembrane liners, and geotextile fabrics to assist developers with soil remediation and brownfield redevelopment. Our experts will determine the best remediation method for your project and help you select the right products. Contact us today to get started!