Experimental evaluation of modelling alternatives and process parameters for the single-sludge nitrogen removal system

Experiments were carried out on bench-scale activated sludge units operated continuously in the single-sludge mode. A synthetic feed consisting of glucose, acetate, ammonium chloride and essential elements was used. The results served to examine the validity of various expressions for process modeling, and to derive several process parameters. For effluent ammonia of approximately 0. 5 mg l** minus **1 a specific nitrification rate of 0. 75 multiplied by (times) gNH//4** plus -N multiplied by (times) gVSS** minus **1 day** minus **1 was selected. The maximum nitrification rate was above 1. 9 gNH//4** plus -N multiplied by (times) gVSS** minus **1 day** minus **1 and the maximum denitrification rate was 1. 7 gNO//3** minus N multiplied by (times) gVSS** minus **1 multiplied by (times) day** minus **1. The yield and decay coefficients were determined as 0. 31 gVSS multiplied by (times) gCOD** minus **1 and 0. 018 day** minus **1 respectively, for the heterotrophs, and 0. 246 gVSS multiplied by (times) gNH//4** plus -N** minus **1 and 0. 007 day** minus **1, respectively, for the autotrophs. Microbial counts were in qualitative agreement with predicted values.