Abstract: Shortcut nitrification for ammonium-rich wastewater is energy-saving
and cost-effective procedure that has become one of the hotspots in the field
of biological denitrogenation. An orthogonal experiment was performed to study
the combined effects of operational parameters on the performance of
internal-loop airlift bioreactor for shortcut nitrification. The optimum
operational parameters for the shortcut nitrification were found as temperature
35°C, pH 8.0, dissolved oxygen concentration 1.0 mg/L, ammonium
concentration 4 mmol/L and HRT 16 h, which have different influence on the
performance of shortcut nitrification reactor. The pH, temperature and
dissolved oxygen concentration have significant bearing on the process. The
results showed that the shortcut nitrification reactor could be successfully
started up within 42 d, and the reactor performance is steady with minimum
NO_2^-/NO_x^- of 85.2%, maximum 93.4% and
average value of 91.4% in effluent. Based on the analysis of experimental data,
a new control strategy named "priority + combination" for shortcut
nitrification was suggested. Through this strategy, the startup and operation
of shortcut nitrification for ammonium-rich sludge digester liquids were
optimized. The control strategy works well to keep the reactor operation in
steady state and in achieving high-efficiency for shortcut nitrification.
