Response
of Different <i>Nitrospira</i> Species
To Anoxic Periods Depends on Operational DO
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Abstract
The
exploitation of a lag phase in nitrate production after anoxic
periods is a promising approach to suppress nitrite oxidizing bacteria,
which is crucial for implementation of the combined partial nitritation-anammox
process. An in-depth study of the actual lag phase in nitrate production
after short anoxic periods was performed with varied temperatures
and air flow rates. In monitored batch experiments, biomass from four
different full-scale partial nitritation-anammox plants was subjected
to anoxic periods of 5β60 min. Ammonium and the nitrite that
was produced were present to reproduce reactor conditions and enable
ammonium and nitrite oxidation at the same time. The lag phase observed
in nitrite oxidation exceeded the lag phase in ammonium oxidation
after anoxic periods of more than 15β20 min. Lower temperatures
slowed down the conversion rates but did not affect the lag phases.
The operational oxygen concentration in the originating full scale
plants strongly affected the length of the lag phase, which could
be attributed to different species of <i>Nitrospira</i> spp.
detected by DGGE and sequencing analysis