Keywords
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Continuous bioreactor, Denitrification, Granule, Inhibitory effect,
Nitrate, Nitrite
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Abstract
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The denitrification potential of a continuous denitrifying granular-sludge bioreactor
for concentrated nitrate/nitrite wastes was investigated. Granules were
cultivated using nitrite as sole electron acceptor. Complete denitrification could
be achieved at nitrite, nitrate, and nitrate-nitrite mixture (50:50) loading rates
up to 2.7, 3 and 3 g NL–1d–1, respectively. The maximum nitrite and nitrate
reduction capacities were limited by the biomass concentration. Removal of nitrate
and nitrite was studied with constant biomass concentration at different pH
values. A lower pH value resulted in a considerable increase of inhibitory effects
of both nitrite and nitrate whereby nitrate exhibited the more significant impact.
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