The advantage of using bioremediation rather than digging up the contaminated soil and placing it elsewhere is that only moderate capital investment is required as the process is low in energy input. In addition, the processes are environmentally safe, do not generate waste and are self-sustaining. In many cases, bioremediation not only offers a permanent solution to the problem, but is also cost effective. Cleaning up existing terrestrial environmental contamination in the United States alone can cost as much as USD 1 trillion. Bioremediation can help reduce the costs of treatment as follows (Ball and Kadali, 2012):
- • Treating contamination in place: most of the cost associated with traditional cleanup technologies is associated with physically removing and disposing of contaminated soils. Because engineered bioremediation can be carried out in place by delivering nutrients to contaminated soils, it does not incur removal-disposal costs.
- • Harnessing natural processes: at some sites, natural microbial processes can remove or contain contaminants without human intervention. In these cases where intrinsic bioremediation (natural attenuation) is appropriate, substantial cost savings can be realised.
- • Reducing environmental stress: because bioremediation methods minimise site disturbance compared with conventional cleanup technologies, post-cleanup costs can be substantially reduced.
As a technology, bioremediation has a global application. In the United Kingdom alone it has been estimated that there are some 100 000 sites, which will take between GBP 10 000 million and GBP 20 000 million to clean up. In terms of the nature of the bioremediation process used, this depends greatly on the nature and quantity of the pollution. Nevertheless, bioremediation is an applicable technology for a range of pollutants. Figure 8.3 shows the range of industries that use bioremediation as a technology (Ball, 2007).