Brownfield Remediation: Why It’s Needed and How It’s Done
A brownfield is defined by the EPA 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 un-used industrial facilities such as an abandoned factory or an old warehouse 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
The presence of hazardous materials in these locations is determined by an Environmental Site Assessment (ESA) investigation. This has been required by law ever since the Comprehensive Environmental Response, Compensation, and Liability Act passed in 1980 making the purchaser of said properties liable for any contaminants or pollutants found on the land. The EPA estimates that there are over 450,000 brownfield sites in the United States. However, that 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 not only for environmental reasons but for economic reasons as well. Because the cost of cleaning brownfields often surpasses what the land would be worth after, developers have been extremely hesitant to take on such an endeavor. This means that abandoned and unsightly brownfields just sit 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 in the economic expansion of local communities, government programs are now making 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 communities surrounding them.
Brownfield Remediation Options
The type of remediation option that is used on a brownfield will depend on the contaminants present and the level of those contaminants. While excavation is a more traditional method, it can be quite costly and there are other methods that allow for the pollutants to be treated on site without hauling them away.
Engineered caps can seem like they are just a band-aid covering up the contaminants in a brownfield without actually doing anything to protect the environment. However, using engineered caps actually encloses all the contaminants, preventing them from spreading vertically or horizontally throughout the site. There are three main types of engineered caps:
- Impermeable Caps are used to 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 at the same time. The area is then filled with clean soil. For residential areas, 2-3 feet of soil is used while 10 feet of soil is used for non-residential areas. To prevent future excavations from causing unnecessary damage, the words “Do Not Dig” can be printed on the orange demarcation fabric.
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. Once it is collected it is transported offsite and disposed.
Groundwater Migration Barriers
Geomembrane liners are used to create an underground containment barrier with are used to cut off the route of the problem and prevent contaminated groundwater from spreading beyond the property.
When toxic gases are present in a brownfield, multi-layer geomembrane liners are used to create a vapor barrier which prevents poisonous gases from breaking through the surface and infiltrating the environment or the indoor air quality of any buildings that are on the site.
Brownfield Remediation Can Revitalize a Community
Brownfield remediation is not only important for protecting our environment but it also goes a long way in helping communities to grow and prosper. IWT Cargo-Guard offers many types of geosynthetics, geomembrane liners, and geotextile fabrics in order to assist developers with soil remediation and brownfield redevelopment. Our experts will know exactly what remediation method is best for your project and can help you select the products you need to get the jobs done right. Contact us today to get started!