Single-sludge nitrogen removal: Modeling and experimental results Academic Article uri icon


  • Laboratory-scale, single-sludge units were used to evaluate different kinetic, stoichiometric, and materials balance equations. Feed consisted of domestic wastewater spiked with carbonaceous organics and ammonium chloride. For approximately 2 mg/L of effluent ammonia or more, the nitrification reaction was zero-order. The specific nitrification rate was $2.3\ {\rm g}\ {\rm NH}_{4}{}^{+}-{\rm N}/{\rm g}\ {\rm N}\ {\rm VSS}\bullet {\rm d}$ . The minimum aerobic sludge age for nitrification at 20°C was 2.5 days. Denitrification was controlled by the COD removal reaction, which was best described by a first-order rate equation with a coefficient of 0.026 mg/L • d and 14 mg/L non-degradable COD. Nitrate utilization and endogenous respiration coefficients were $0.144\ {\rm mg}\ {\rm NO}_{3}{}^{-}-{\rm N}/{\rm mg}\ {\rm COD}\bullet {\rm d}$ and $0.007\ {\rm g}\ {\rm NO}_{3}{}^{-}-{\rm N}/{\rm g}\ {\rm VSS}\bullet {\rm d}$ . Effluent nitrate increased with increasing recycle because of low COD in the anoxic basin. The microbial composition of the biomass agreed qualitatively with predicted values.

publication date

  • January 1, 1986