Brownfield sites are derelict industrial or commercial sites. They are areas ripe for redevelopment but can often be polluted or contaminated by the prior industrial works carried out on the land. With the premium on space in the UK, it is prudent to make full use of these spaces and as a result land remediation practices have been developed to remove noxious substances, revitalise the soil and make the land fit for development.
Remediated land can be used for a number of different things from social housing, commercial properties and to provide communities with usable green spaces. The land can also be used to grow crops for biofuels whilst also sustaining their own ecosystems. Red Industries have the most experienced land remediation team in the UK and employ a variety of land remediation and soil stabilisation techniques to make land fit for use again. There are many techniques which may be used, including:
In Site & Ex Situ Bioremediation
Bioremediation is the use of micro-organism metabolism to remove pollutants. Either naturally occurring or specially bred bacteria are used to consume contaminants from extracted groundwater. This can occur in situ, where the bacteria are added to the natural environment or ex situ, where the contaminated substances are removed from the site and treated elsewhere. There are also sub-types of bioremediation including mycoremediation which involves adding specific fungi to contaminated soil to reduce the number of pollutants therein. The results can be staggering: in one experiment, soil contaminated by diesel oil was inoculated with mycelia of oyster mushrooms and after four weeks over 95% of the polycyclic aromatic hydrocarbons had been reduced to non-toxic components. You can find out more about bioremediation at Wikipedia. This talk here is also really informative:
Phytoremediation is the process of dealing with environmental contamination problems with the use of plants. Some plants are able to contain, degrade or eliminate various metals, pesticides, solvents, explosives, crude oil and its derivates. Many plants such as mustard plants, alpine pine-cress and hemp have proven to be successful at hyper-accumulating contaminants at toxic waste sites. This method can be very effective in dealing with extreme products such as lead, uranium and arsenic but it does require a long-term commitment, making it unsuitable when a faster turn-around is required.
These techniques are often used in conjunction with one another. They rely on the interaction between a binder and the soil to prevent or reduce the spread of contaminants. The former aims to contain the contaminants in a solid product to that they are not affected by air or rainfall whilst the latter seeks to add reagents with the effect of changing the chemical constituents into a more chemically stable state. It is a successful land remediation technique employed in many countries however there are several disadvantages such as the fact that there is some residual liability associated with the practice as the contaminants are not actually removed from the site. A lot of cement is also used so many environmentally conscientious analysts prefer other methods due to the high levels of CO2 used to make cement.
Before commencing a construction or redevelopment project, it is important to plan adequately. The Environment Agency has a lot of information regarding this including soil guidelines and contamination procedures. Soil remediation is an essential first step to any brownfield site or other land of questionable background. Remaining hazardous waste could be detrimental not only to natural ecosystems but also to residents and potentially new buildings themselves. When building a new property, it is important to consider the environmental consequences of the project. Environmental consultants like Pick Everard consider the sustainability of building and redevelopments projects and can advise developers as to the viability of a project from the soil to the building materials used and the environmental costs of the construction process.
The UK construction industry needs the economic boost of new projects and with technologies such as these, the potential is there for new spaces to harness the power of biological organisms to make a future fit to last.