Uso da respirometria para avaliar a influência de fatores operacionais e ambientais sobre a cinética de nitrificação.

Abstract

Several investigations have been carried out in systems with nitrogen removal, seeking to establish among other things the best environment for the bacteria Nitrosomonas and Nitrobacter, responsible for the nitrification process. With the aim to make a contribution to the evolution of systems with nitrogen removal, an experimental investigation was carried out with the main objective to evaluate the influence of operational and environmental factors on the kinetics of nitrifying bacteria, using methodology based on respirometry. During the experimental investigation two activated sludge systems were operated, treating sewage from the city of Campina Grande. Both systems were conventional Bardenpho systems, but one had an anaerobic UASB reactor as a pre treatment unit. The influence of pH, temperature, DO concentration and nature of the pre treatment on the metabolism of nitrifying bacteria were also investigated. The obtained results show that both nitritation and nitratation are suitably described by Monod kinetics. It was established that the anaerobic pre treatment influences the constant of the maximum specific growth rate of Nitrosomonas and Nitrobacter. This constant is also influenced significantly by pH. It was shown that an inversion occurred maximum metabolic rate of Nitrosomonas and Nitrobacter in the range of 25 a 30°C (transition range), Nitrosomonas being limiting below the transition range and Nitrobacter above it.