The kinetics of microbial nitrification☆

The conversion of organic nitrogen to nitrate was examined to determine the type of reaction of each stage and the effect of operating variables (microbial concentration, pH, temperature) on these reaction rates. The information was correlated into a system of equation which mathematically defined the reaction sequence. The results showed ammonification to be a first order reaction and both nitrification reactions were zero order. Substrate levels ranged from 100 to 1200 mg Nl−1, pH conditions examined ranged from 6.0 to 8.5 and temperature range from 9 to 35°C. The paper also discussed the use of the kinetic data in design of nitrification systems.