| Summary: | This thesis consists of the following papers: PAPER I: Pedersen, K. B., Lejon, T., Jensen, P. E. & Ottosen, L. M. «Chemometric analysis for pollution source assessment of harbour sediments in Arctic locations”. (Manuscript). Published version available in Water, Air, & Soil Pollution 2015, 226:150. PAPER II: Pedersen, K. B., Kirkelund, G. M., Ottosen, L. M., Jensen, P. E. & Lejon, T. (2015). Multivariate methods for evaluating the efficiency of electrodialytic removal of heavy metals from polluted harbour sediments. Available in Journal of Hazardous Materials. 283. 712-720. PAPER III: Pedersen, K. B., Lejon, T., Jensen, P. E. & Ottosen, L. M. Screening of Variable Importance for Optimsing Electrodialytic Remediation of Heavy Metals from Polluted Harbour Sediments. (Manuscript). Accepted manuscript version available in Munin at https://munin.uit.no/handle/10037/8974 . Published version available in Environmental Technology 2015, 36(18). . PAPER IV: Pedersen, K. B., Ottosen, L. M., Jensen, P. E. & Lejon, T. : Comparison of 2-compartment, 3-compartment and stack designs for electrodialytic removal of heavy metals from harbour sediments. Manuscript). Accepted manuscript version available in Munin at http://hdl.handle.net/10037/8705 . Published version available in Electrochimica Acta 2015. 181: 48-57. PAPER V: Pedersen, K. B., Jensen, P. E., Ottosen, L. M. & Lejon, T.: Optimisation of 2-compartment cell for electrodialytic removal of heavy metals. (Manuscript). Published version with title “An optimised method for electrodialytic removal of heavy metals from harbour sediments” available in Electrochimica Acta 2015, 173: 432-439. PAPER VI: Pedersen, K. B., Lejon, T., Jensen, P. E. &, Ottosen, L. M.: Applying multivariate analysis as decision tool for evaluating sediment-specific remediation strategies. (Manuscript). Published version available in Chemosphere 2016, 151: 59-67. PAPER VII: Pedersen, K. B., Lejon, T., Jensen, P. E. &, Ottosen, L. M.: Influence of temperature on the simultaneous electrodialytic remediation of PAH, PCB, TBT and heavy metals. (Manuscript). Published version with title "Simultaneous electrodialytic removal of PAH, PCB, TBT and heavy metals from sediments” available in Journal of Environmental Management 2017, 198(1):192-202. PAPER VIII: Pedersen, K. B., Lejon, T., Jensen, P. E. &, Ottosen, L. M.: Multivariate analysis for assessing influence of sediment properties and experimental variables on the electrodialytic removal of Cu, Pb and Zn from harbour sediments (Manuscript). Published version with title “The influence of sediment properties and experimental variables on the efficiency of electrodialytic removal of metals from sediment” available in Journal of Environmental Chemical Engineering 2017, 5(6):5312-5321. PAPER IX: Pedersen, K. B., Lejon, T., Jensen, P. E. &, Ottosen, L. M.: Degradation of oil products including polyaromatic hydrocarbons during electrodialytic remediation. (Manuscript). Published version with title “Degradation of oil products in a soil from a Russian Barents hot-spot during electrodialytic remediation” available in SpringerPlus 2016 ;Volum 5(168):1-10. Electrodialytic remediation (EDR) is a method for removing pollutants from different materials achieved by acidification and transport processes induced by application of an electric field of low intensity. In the thesis, EDR was shown to be a reliable technology for removal of heavy metals, PAH, PCB and TBT from harbour sediments. The final concentrations of heavy metals met the background criteria (non-polluted) as defined by OSPAR, while further optimisation of EDR is necessary for achieving similar levels of PAH, PCB and TBT. Multivariate analysis was used to evaluate the efficiency of EDR of the harbour sediments, sampled in the Arctic region (Norway and Greenland). One of the most important factors affecting the outcome was the type of sediment, emphasizing the need for developing site- and sediment specific remediation strategies. Some of the more important sediment properties were cation exchange capacity, content of carbonate, content of organic matter, grain size distribution and how the pollutants were bound in the sediment. The efficiency of EDR, with regards to metal removal, was tested in two cell designs and a stack, the 2-compartment cell being found to be most efficient with regards to faster acidification of the sediment, faster removal of heavy metals and lower energy consumption. The removal of naturally occurring metals was however also highest and if limiting the removal of these is desirable, future EDR designs may rely on both the 2- and 3-compartment cell designs. The stack was found to be the poorest design with low EDR efficiency and was not recommended in future scaling-up efforts. The experimental variables found to have the highest influence on the efficiency of EDR depended on the pollutant as well as the EDR design. In general, current density, remediation time and temperature had the greatest influence on the removal of heavy metals, while stirring rate, light and temperature were more important for removal of PAH, PCB and TBT. Optimal settings varied depending on the specific pollutant and in some cases opposite settings were optimal for the different pollutants. High temperatures (20 oC) were for instance found to improve the removal of heavy metals and TBT due to higher desorption of metals, while low temperatures (4 oC) increased the removal of PAH and PCB, probably due to microbial communities in the sediments not adapted to higher temperatures. This obviously has implications for future optimisation efforts. However, optimal settings for simultaneous removal of heavy metals, PCB and TBT to satisfactory levels were found by a multivariate model and EDR is hence a promising method for future remediation of harbour sediments.
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