2006 Volume 42 Issue 4 Pages 159-168
This study focuses on anaerobic ammonium oxidation (anammox) treatment performance for nitrogen removal using malt ceramics (MC) as a biomass carrier. A fixed-bed reactor using MC material with 3 to 5 mm diameter pieces (Reactor 1) was operated for 368 days and another using MC material with 10 to 15 mm diameter pieces (Reactor 2) was operated for 280 days. For Reactor 1, with an HRT of 3 h, the influent concentrations of NH4－N and NO2－N were both increased stepwise from 150 mg N/l to 225 mg N/l with NH4－N removal efficiency of about 81% and NO2－N removal efficiency of 90%. Then, the influent concentrations of NH4－N and NO2－N were increased to 250~275 mg N/l, each, and removal efficiencies of NH4－N and NO2－N decreased to 75% and 85%, respectively. The T－N removal rates of Reactor 1 increased stepwise from 0.6 to 3.1 kg N/m3/day from day 187 to day 315. Ratios of T－N removal, NO2－N removal, and NO3－N production to NH4－N removal for Reactor 1 were 1.98:1.15:0.17, respectively. For Reactor 2, with an HRT of 3 h, the influent concentrations of NH4－N and NO2－N were both increased stepwise from 100 mg N/l to 225 mg N/l and removal efficiencies of NH4－N and NO2－N were high at 80% and 93%, respectively. However, when the influent concentrations of NH4－N and NO2－N were increased to 250~275 mg N/l, each, removal efficiencies of NH4－N and NO2－N decreased to 72% and 84%, respectively. The T－N removal rates of Reactor 2 were similar to those of Reactor 1 with 0.7 to 3.1 kg N/m3/day from the day 146 to day 230. Ratios of T－N removal, NO2－N removal, and NO3－N production to NH4－N removal for Reactor 2 were 2.03:1.2:0.17, respectively. In addition, distinctive red granular anammox biomass grew at the bottom parts of the reactors during both runs. By DNA analyses, both KSU－1 and KU－2 strains were detected in anammox sludge of Reactor 2, with the KSU－1 strain being dominant.
