Glossary Biomineralization A process by which living organisms produce minerals. - Chernobyl Ukrainian city site of the largest nuclear power plant accident in history. - Cut-off-wall Underground structure designed to prevent the flow of water. - DART Deep aquifer remediation tool. - Diffusion Movement of ions and molecules from places of higher concentration to places of lower concentration. - Electrochemical remediation Remediation technologies comprising electrochemical transport and transformation methods. - Electrokinetic screens Structures used to prevent radionuclides from diffusing from the polluted area into the environment. - Electromigration Transport of charged ions or ion complexes in solution. - Electroosmosis Movement of liquid relative to a charged stationary surface, - Electrophoresis Movement of charged particles relative to a stationary fluid. - Enhanced electrochemical remediation Use of pH control and additives to improve removal efficiency. - EURT East Urals Radioactive Trail area contaminated due to a nuclear accident. - Natural attenuation (NA) Remediation relying entirely on natural processes. - Permeable reactive barriers Passive in situ treatment zones of reactive material that degrades or immobilizes contaminants as groundwater flows through it. - Phytoremediation Soil remediation using living plants and their associated microorganisms. - Radionuclide or radioisotope An atom with an unstable nucleus whose excess energy is available to be imparted to a newly-created radiation particle within the nucleus or to an atomic electron. - Total material requirement (TMR) Sum of domestic and imported primary natural resources and their hidden flows.
The present work shows that U can be effectively removed from groundwater using permeable reactive barriers with hydroxyapatite (HAP) as reactive material. The main factor influencing the removal processes is the composition of the groundwater, namely the concentration of Ca and carbonate. Sorption of U onto the HAP surface seems to be the dominant removal process with the possibility of remobilisation. Newly formed U-phosphate minerals were detected by ESEM/EDX and XRD in samples with high U content indicating either a dissolution-precipitation mechanism or sorption onto the apatite surface followed by alteration of the structure. The formed U-phosphate minerals are stable under common groundwater conditions and can be remobilised only at high pH-values and high carbonate concentrations.
Permeable reactive barriers
(2005)