Treatment of urban or industrial wastewater, comprises performing an aerated nitrification phase and a non-phase denitrification phase, where the nitrification phase comprises estimating the concentration of nitrogen oxide

摘要

The process for treatment of urban or industrial wastewater, comprises performing an aerated nitrification phase and a non-phase denitrification phase, where the nitrification phase comprises estimating the concentration of nitrogen oxide, and regulating the flow of air for reducing the concentration of nitrogen oxide. The airflow is increased when the formation of nitrogen oxide is detected. The concentration of nitrogen oxide is estimated by a direct measure of liquid phase detector and from the evolution of concentration of nitrogen nitrite. The process for treatment of urban or industrial wastewater, comprises performing an aerated nitrification phase and a non-phase denitrification phase, where the nitrification phase comprises estimating the concentration of nitrogen oxide, and regulating the flow of air for reducing the concentration of nitrogen oxide. The airflow is increased when the formation of nitrogen oxide is detected. The concentration of nitrogen oxide is estimated by a direct measure of liquid phase detector and from the evolution of concentration of nitrogen nitrite. In denitrification phase, soluble biochemical oxygen demand is regulated for which a ratio of biochemical oxygen demand and nitrogen nitrate is greater than 2.5. The air flow for ventilation is further increased by one step after appearance of nitrite. After a period of time, a new measure of the concentration of nitrite-nitrogen is performed and if it is greater than the previous measure, the airflow is further increased by one step and if it is less than the previous measure, the airflow remains on the same setting, and the operation is repeated at each time interval until the concentration of ammonium-nitrogen reaches a minimum threshold. The nitrogen oxide formed from denitrification is detected using nitrogen oxide analyzer and/or estimated from kinetic denitrification of nitrate. The denitrification phase is stopped after the concentration of nitrogen-nitrate attains predetermined threshold. The age of the sludge is maintained sufficient for the amount of nitrate to be denitrified in the denitrification step. The biological oxygen demand is supplied with coarse water. The configuration of biological tank with pre- or post-denitrification is such that the recirculation is varied so that the ratio of soluble biological oxygen demand on the nitrate is greater than 2.5.