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Vorträge und Posterpräsentationen (ohne Tagungsband-Eintrag):

A. Vesely, H. Trombitas:
"Construction and Operation of a Microfiltration Plant for the Treatment of Radioactive Wastewater";
Vortrag: ICEM┤09, The 12th International Conference on Environmental Remediation and Radioactive Waste Management, Liverpool; 11.10.2009 - 15.10.2009.



Kurzfassung:
By contract with the Austrian government, Nuclear Engineering Seibersdorf is treating all radioactive waste occurring in Austria. In addition, decommissioning works of former nuclear research installations are performed. Waste water is generated during these operations (decontamination, incineration with flue gas scrubbing, evaporation, drying), as well as in nearby research laboratories and has to be treated before emission to the receiving water.

At present this waste water is treated by nuclide specific co-precipitation (e. g. iron hydroxide, barium sulphate, copper cyanoferrate etc.) followed by filtration with a pressurised disk-filter, working with a pre-coat (diatomaceous earth). The filter cake is dried in a vacuum drier and supercompacted before long-time interim storage. With this process good results are obtained regarding the purification, but a rather high amount of radioactive waste is generated: the filter cake contains only approx. 10% of solids from the waste water and the precipitation step, the rest being filter aid.
Therefore, research was carried out to find a process working without filter aid. Inquiries on a laboratory scale showed that this goal could be attained by a microfiltration process. With a 600 nm membrane, the radionuclides could be separated, requiring co-precipitation only in some cases. In the next step, trials with a semi-technical scale microfiltration plant were carried out over several months. This plant operated in a cross-flow mode, with a ceramic filter candle (alumina), area 1 m▓. All the basic filtration parameters could be studied (flux, transmembrane pressure, linear velocity etc.), enabling the design of a large scale plant. These trials showed also that it is absolutely necessary to provide a pre-filtration step. In order to define the appropriate machinery, trials in 1:1 scale were carried out. The process chosen was filtration with an inclined filter (polyester filter tissue, nominal pore diameter 20 Ám).
Based on these findings, a large scale plant was designed and constructed, with a total filtration area of 30 m▓. Details of the plant layout are presented, as well as first operational experiences.

Schlagworte:
Microfiltration Wastewater

Erstellt aus der Publikationsdatenbank des AIT Austrian Institute of Technology.