title: Removal of nitrogen from industrial wastewaters by three-step nitrification and denitrification.
abstract: The removal of nitrogen from industrial wastewaters carrying about 1,000 mg NH4-N and urea-N/l was investigated on a laboratory scale. The use of a three-step nitryfying activated sludge with adjustment of pH from step to step resulted in 99% oxidation of both forms of nitrogen to nitrites. The efficiency of nitrification was 18 mg N/l/h. Total time of wastewater aeration depended  on nitrogen concentration and was 33-54 hours. Complete dentrification of NO2-N was obtained in packed-bed reactor with the use of acetic acid as a carbon source. Efficiency of denitrification was 361 mg N/l/h.
mesh_terms: D000085:Acetates / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D009573:Nitrites / Q000138:chemical synthesis; D009584:Nitrogen / Q000302:isolation & purification*; D010100:Oxygen / Q000494:pharmacology; D012722:Sewage; D014865:Waste Disposal, Fluid; D014877:Water Pollution, Chemical / Q000517:prevention & control*
chemical_list: D000085:Acetates; D007220:Industrial Waste; D009573:Nitrites; D012722:Sewage; D009584:Nitrogen; D010100:Oxygen