Phytoremediation of Radionuclides
Disposal of Radioactive Materials
Disposal
Disposal of radioactive material will always be difficult and highly scrutinized, since for the most part radionuclides cannot be destroyed or rendered harmless in a time frame acceptable to humanity. The best options are based upon minimizing the waste followed by long-term storage in an appropriate facility. Traditional options entomb the radioactive materials in concrete or vitrified soils, usually after minimizing the waste by particle detection and segregation, or incineration. Phytoremediation is a unique option because the waste minimization occurs at the front end, whereas traditional methods rely upon excavation and transport of massive volumes of material before the minimization occurs. If phytoextraction of pollutants is used, only the plant biomass needs to be treated as hazardous waste, assuming the phytoremediation of the soil was successful. In a rhizofiltration system, both the plant biomass and water must be treated as hazardous. Plant biomass concentrates the radionuclides and therefore a limited amount of hazardous waste is created. Usually, the contaminated plant biomass is incinerated (Negri and Hinchman 2000) by a licensed facility. The ash created by incineration is the only radioactive waste remaining and the appropriate disposal method will depend upon the concentrations of radionuclides. The following diagrams illustrates a typical hazardous waste incinerator:
