Prodn of potable water from river water - by biological elimination of ammoniacal nitrogen by nitrifying bacteria

摘要

River water is treated for the prodn. of potable water by process involving the biological elimination of the ammoniacal nitrogen. The oxidn. of these impurities is effected by the intervention of bacteria contained in the water and accumulated in a certain vol. of the sludge in a coalescence tank. This is situated in the downstream zone of the flocculation compartments preceding a settling tank. The sludge is recycled from the base of the coalescence tank to the inlet of the raw water and serves to support the nitrifying bacteria and so assures the biological nitrification of the impurities contg. ammoniacal nitrogen. Apart from the action of the nitrifying bacteria, biological oxidn. results from the presence of oxygen in the water to be treated; if this is not sufficient an addition can be made downstream of the flocculation compartments. Because of the recirculation of the sludge without interruption, an appreciable improvement results in the efficiency of the elimination of the ammoniacal nitrogen.