PEP Review 97-14
Published: May 2000
The remediation of contaminated sites remains a significant cost and liability risk for many chemical and energy companies. Phytoremediation is an innovative, potentially cost-saving set of methods for bioremediating contaminated soils using plants.
The effectiveness of traditional soil bioremediation, which uses microorganisms, is limited to certain easily degradable compounds. By contrast, phytoremediation can be applied to soils contaminated with recalcitrant organics, metals, and radionuclides. Phytoremediation can also be used to remediate shallow aquifers. Phytoremediation is typically used in situ.
Phytoremediation has been the subject of extensive research interest in recent years, because of the potential of remediating a site at a relatively low cost compared to conventional remediation methods. Phytoremediation is not a solution to all contaminated sites; however, given certain specific conditions, it can offer significant cost savings over other remedial methods.
This Process Economics Program (PEP) review discusses the different kinds of phytoremediation, and the mechanisms by which they work. It also presents cost estimates for use of phytoremediation for controlling a shallow aquifer contaminated with organics, and for remediating soils contaminated with metals. These will be compared to the costs of using conventional remediation technologies.
SRI Consulting has found that phytoremediation is significantly cheaper than conventional remediation technologies if conditions are favorable. These are: shallow contamination, and (ín the case of phytoextraction) target concentrations close to the concentrations at the site. in certain cases, such as using phytoremediation rather than pump-and-treat, initial capital expenditures may be higher for phytoremediation than for the conventional alternative, but the savings in operating costs lead to significant net savings.
Large energy and chemical companies, environmental engineering firms, and small specialist phytoremediation firms have all contributed to the development of phytoremediation technologies.
Growth predictions for the phytoremediation market have been optimistic, ranging between $200 and $370 million by 2005 (R980103). However, because of the difficulty in patenting phytoremediation methods , it is not certain that the market will remain distinct from the rest of the remediation market, as there are relatively few technological barriers to entry into the phytoremediation market.