Determinação das constantes cinéticas de nitritação e nitratação em função da temperatura.

Abstract

The Anammox process is essentially autotrophic denitrification in which ammoniacal nitrogen is oxidized by nitrite to molecular nitrogen. Nitrite can be produced in wastewater by the oxidation of ammonia by Nitrosomonas. However, it has to be avoided that bacteria of the genus Nitrobacter develop to avoid the oxidation of nitrite to nitrate. The Anammox process is applied particularly in ammonium rich waters and poor in organic material, such as effluent from anaerobic digesters. In practice it has been successfully applied to effluent from sludge digesters heated to 37 ° C, but application at room temperature in Europe (5 to 15 ° C) has not been efficient due to the difficulty of eliminating the nitration step. In the present research, it was tried to establish if the partial nitrification is feasible for the range of sewage temperature in Brazil, for a possible application of the Anammox process aiming at the removal of nitrogen from UASB reactor effluents. For this, the kinetic constants of nitriding and nitration were determined in an activated sludge system between the temperature range of 12.7 ° C to 31 ° C and the half-saturation constants of the dissolved oxygen. The respirometry was the tool used to determine nitration and nitration rates and to estimate the other relevant kinetic constants, and it is shown by the results that this is a useful tool in the determination of kinetic constants. The values of the kinetic constants of the nitriding and nitrating agents as a function of temperature showed a tendency of nitriding over nitration over the entire range. By determining the age minimum sludge for nitriding and nitration it can be estimated that operating a sludge activated system at room temperature adopting a sludge age of 4 days can promote partial nitrification.