Document Type : Original Research Paper
Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, SC, Brazil
Department of Sanitary and Environmental Engineering, Federal University of Santa Maria, RS, Brazil
Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, SC, Brazil & Campus Universitário, Florianópolis, SC Brazil
A biofilm sequencing batch reactor with a volume of 1.42 m3, nylon nets providing a 4,140 m2/
m3 support area for biofilms and an automated operation with 8 hour cycles was studied. The duration of the experiment was 135 days. Removal efficiencies e≥ 80% were obtained for carbonaceous matter, producing an effluent with 31±26.8 mg/L of filtered COD, 7±3.6 mg/L of BOD5 and 12±3.2 mg/L of TOC. The average removal efficiency of ammonium was 77 ± 16.6%, with a mean concentration in the effluent of 14 ± 10.2 mg NH4-N/L. The denitrification efficiency was 80±14.7%. The effluent characteristics met the requirements of Brazilian environmental standard for discharge to receiving water bodies. A kinetic study of nitrification and denitrification showed that during the aerobic phase the specific rate of ammonium consumption was 0.057 g NH4-N/g VSS.d and the production of NOx-N was 0.074 g NOx-N/g VSS.d, while the specific rate of NOx-N consumption was 0.05 g NOx-N/g VSS.d during the anoxic phase. The suspended and fixed biomass was composed of 50% ammonium-oxidizing bacteria (AOB).