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Biological removal of selenate and ammonium by activated sludge in a sequencing batch reactor

Research output: Contribution to journalArticleScientificpeer-review


Original languageEnglish
Pages (from-to)11-19
Number of pages9
JournalBioresource Technology
Publication statusPublished - 2017
Publication typeA1 Journal article-refereed


Wastewaters contaminated by both selenium and ammonium need to be treated prior to discharge into natural water bodies, but there are no studies on the simultaneous removal of selenium and ammonium. A sequencing batch reactor (SBR) was inoculated with activated sludge and operated for 90 days. The highest ammonium removal efficiency achieved was 98%, while the total nitrogen removal was 75%. Nearly a complete chemical oxygen demand removal efficiency was attained after 16 days of operation, whereas complete selenate removal was achieved only after 66 days. The highest total Se removal efficiency was 97%. Batch experiments showed that the total Se in the aqueous phase decreased by 21% with increasing initial ammonium concentration from 50 to 100 mg L−1. This study showed that SBR can remove both selenate and ammonium via, respectively, bioreduction and partial nitrification-denitrification and thus offer possibilities for treating selenium and ammonium contaminated effluents.


  • Activated sludge, Elemental selenium, Selenate bioreduction, Sequencing batch reactor, Simultaneous nitrification and denitrification

Publication forum classification

Field of science, Statistics Finland