Remediation Technologies Applicable to Brownfields
Cleanup technologies may be required to remove or destroy onsite contamination if regulators are unwilling to accept the levels of contamination present or if the types of contamination are not conducive to the use of institutional controls or containment technologies. Cleanup technologies fall broadly into two categories--ex situ and in situ.
An ex situ technology treats contaminated materials after they have been removed and transported to another location. After treatment, if the remaining materials, or residuals, meet cleanup goals, they can be returned to the site. If the residuals do not yet meet cleanup goals, they can be subjected to further treatment, contained on site, or moved to another location for storage or further treatment. A cost-effective approach to cleaning up a Brownfield site may be the partial treatment of contaminated soils or groundwater, followed by containment, storage, or further treatment off site.
In situ technologies treat contamination in place and are often innovative technologies. Examples of in situ technologies include phytoremediation, bioremediation, soil flushing, oxygen-releasing compounds, air sparging, and treatment walls. In some cases, in situ technologies are feasible, cost-effective choices for the types of contamination that are likely on Brownfield sites. Planners, however, do need to be aware that cleanup with in situ technologies is likely to take longer than with ex situ technologies. Several innovative technologies are available to address soils and groundwater contaminated with organics, such as solvents and some PAHs, which are common problems at Brownfield sites. Maintenance requirements associated with in situ technologies depend on the technology used and vary widely in both effort and cost. Groundwater treatment systems will require varying levels of post-cleanup care and verification testing. If an in situ system is in use at the site, it will require regular operations support and periodic maintenance to ensure that the system is operating as designed.
Additional information regarding remediation technologies applicable to Brownfields can be found at the EPA website.
Green remediation is the practice of considering all environmental effects of cleanup actions and incorporating strategies to maximize the net environmental effects of those actions. The sustainable practices emphasize the need to more closely evaluate core elements of a cleanup project such as energy requirements and air emissions.
Strategies for green remediation rely on sustainable development whereby environmental protection does not preclude economic development, and economic development is ecologically viable today and in the long run. The ultimate goals of developing and employing such strategies are:
- Support use and reuse of remediated parcels
- Increase operational efficiencies
- Reduce pollutant and waste burdens
- Minimize degradation or enhance ecology
- Reduce air emissions and greenhouse gas production
- Minimize impacts to water quality and water cycles
- Conserve natural resources
- Achieve greater long-term financial return from investments
- Increase sustainability of site cleanups
Additional information regarding Green Remediation as it applies to Brownfield redevelopment can be found at EPA's website and in Green Remediation: An EPA Perspective (pdf).