Brownfield Land Site
From Swikipedia
Introduction
Brownfields are abandoned or underused industrial and commercial facilities available for re-use. Expansion or redevelopment of such a facility may be complicated by real or perceived environmental contaminations.
Brief Description
Remediation
Remediation of a brownfield site is the removal of all known contaminants to levels considered safe for human health. Redevelopment can only take place after all environmental health risks have been assessed and removed. Remediation can be expensive and complex, and this needs to be seriously considered before purchasing brownfield land. Not all sites are deemed suitable for remediation, particularly if the costs exceed the value of the land after development.
In the last few years several new and exciting remediation technologies have started to emerge. These are proving to be relatively low-cost compared to traditional processes, with the benefit of protecting and preserving the environment:
• Bioremediation uses the natural processes of indigenous bacteria, microorganisms, plants, enzymes and fungi to destroy or neutralise toxins and contaminants.
• Phytoremediation uses plants to store contaminants in their leaves and stems (bioaccumulation). Some contaminants such as heavy metals can be harvested and mined for reuse (phytomining). With phytoremediation, it is critical that contaminants do not enter the food chain. With this in mind, scientists are currently exploring the value of biofuel and energy crops as phytoremediators.
• In-Situ Chemical Oxidation injects oxygen or chemical oxidants into the contaminated soil or water to destroy harmful compounds.
These new remediation technologies are providing important information about the abilities of natural processes to transform poisonous materials back into a harmless state. This information has widespread application in many situations, but is particularly relevant for restoration of the damaged environment and rehabilitation of brownfield land.
Barriers to redevelopment
Many contaminated brownfield sites sit unused for decades because the cost of cleaning them to safe standards is more than the land would be worth after redevelopment. However, redevelopment has become more common in the first decade of the 21st century, as developable land grows less available in highly populated areas. Also, the methods of studying contaminated land have become more sophisticated and established.
In the process of cleaning contaminated brownfield sites, surprises are sometimes encountered, such as previously unknown underground storage tanks, buried drums or buried railroad tank cars containing wastes. When unexpected circumstances arise, the cost for clean-up increases, and as a result, the cleanup work may be delayed or stopped entirely. To avoid unexpected contamination and increased costs, many developers insist that a site be thoroughly investigated prior to commencing remedial cleanup activities.
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