Innovative remediation techniques used at distressed brownfields in recent years include in situ thermal remediation, bioremediation and in situ oxidation. Often, these strategies are used in conjunction with each other or with other remedial strategies such as soil vapor extraction. In this process, vapor from the soil phase is extracted from soils and treated, which has the effect of removing contaminants from the soils and groundwater beneath a site. Binders can be added to contaminated soil to prevent chemical leaching. Some brownfields with heavy metal contamination have even been cleaned up through an innovative approach called phytoremediation, which uses deep-rooted plants to soak up metals in soils into the plant structure as the plant grows. After they reach maturity, the plants &ndash; which now contain the heavy metal contaminants in their tissues &ndash; are removed and disposed of as hazardous waste.
Research is under way to see if some brownfields can be used to grow crops, specifically for the production of biofuels. Michigan State University, in collaboration with DaimlerChrysler and NextEnergy, has small plots of soybean, corn, canola, and switchgrass growing in a former industrial dump site in Oakland County, Michigan. The intent is to see if the plants can serve two purposes simultaneously: assist with phytoremediation, and contribute to the economical production of biodiesel and/or ethanol fuel.
The regeneration of brownfields in the United Kingdom and in other European countries has gained prominence due to greenfield land restrictions as well as their potential to promote the urban renaissance. Development of brownfield sites also presents an opportunity to reduce the environmental impact on communities, and considerable assessments need to take place in order to evaluate the size of this opportunity.