Treating effluents containing nitrogen in the form of ammonium in biological reactor, by introducing volume of effluent in complete cycle in reactor thus allowing to exert pressure favorable to the development and activity of bacteria

摘要

The process for treating effluents containing nitrogen in the form of ammonium in a biological reactor (1), comprises introducing a volume of effluent to be treated in complete cycle in the reactor thus allowing to exert a pressure favorable to the development and activity of bacteria. Each volume fraction is treated during a sub-cycle that comprises a supplying phase by volume fraction, a first aerated step in which total or partial oxidation of ammonium nitrite takes place, and a second anoxic non-aerated step in which nitrites and ammonium are converted into nitrogen gas. The process for treating effluents containing nitrogen in the form of ammonium in a biological reactor (1), comprises introducing a volume of effluent to be treated in complete cycle in the reactor thus allowing to exert a pressure favorable to the development and activity of bacteria. Each volume fraction is treated during a sub-cycle that comprises a supplying phase by volume fraction, a first aerated step in which total or partial oxidation of ammonium nitrite takes place, and a second anoxic non-aerated step in which nitrites and ammonium are converted into nitrogen gas. During the first aerated step the concentration of oxygen dissolved in the biological reactor is maintained at 0.1-0.6 mgO 2/L by stopping or starting of the air supply in the reactor. A ratio of nitrogen-nitric oxide:ammonium-nitrogen is adjusted to 0.9-1.5 at the starting of non-aerated step. The non-aerated step is performed by deammonification without supply of carbon substrate. The first aerated step is controlled according to conductivity and the concentration of dissolved oxygen measured in the biological reactor. The air supply is stopped if a threshold value of the conductivity is reached before a fixed duration. A part (40-60%) of the ammonium flow supplied by a volume of effluent is transformed into nitrites, and the remainder part of the ammonium flow is sufficient to ensure that the produced nitrites and non oxidized ammonium during the first step are converted into gaseous nitrogen. An additional supply (50-110%) of effluent is introduced at the starting of the second non-aerated step. The supply time of effluent to be treated is 7-10% of the total duration of the treatment cycle. The concentration of oxygen is measured on line in the sequential biological reactor using a probe, and is managed by a computer or controller, which integrates real-time measurements and allows to stop or start the supply of air in the reactor. The ammonium-nitrogen concentration in the reactor is measured indirectly by the conductivity and directly by a specific ammonia probe. An independent claim is included for an installation for treating effluents containing nitrogen in the form of ammonium in a biological reactor.