Abstract: A Laboratory-scale packed bed reactor with microbial
cellulose as the biofilm carrier was used to investigate the
denitrification of high-strength nitrate wastewater with specific
emphasis on the effect the nitrogen loading rate and hydraulic
retention time. Ethanol was added as a carbon source for
denitrification. As a result of this investigation, it was found that up
to 500 mg/l feed nitrate concentration the present system is able to
produce an effluent with nitrate content below 10 ppm at 3 h
hydraulic retention time. The highest observed denitrification rate
was 4.57 kg NO3-N/ (m3 .d) at a nitrate load of 5.64 kg NO3-
N/(m3 .d), and removal efficiencies higher than 90% were obtained
for loads up to 4.2 kg NO3-N/(m3 .d). A mass relation between COD
consumed and NO3-N removed around 2.82 was observed. This
continuous-flow bioreactor proved an efficient denitrification system
with a relatively low retention time.