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1991
Journal Article
Titel
Untersuchungen zur Verbesserung der Nitrifikation in eine zweistraßige Kläranlage
Abstract
Within the framework of a research project sponsored by the Federal Ministry of Research and Technology, comparative tests were carried out in a municipal sewege treatment plant with two seperate aeration systems - nitrification alone, and nitrification with an upstream denitrification stage. The results show that the nitrification level is higher in that part of the plant which an upstream denitrification stage, although in the latter, compared to the single-stage nitrification plant, the space available for nitrification was reduced by the volume of the denitrification stage. On the other hand, the activity of the ammonia-oxiding bacteria, as measured in the return sludge, was lower in the system with the denitrification stage. Nitrogen profile measurements along the aeriation tank showed a very different nitrification behaviour in the two biologies. In the part without a denitrification stage, NHher part of the plant the reduction was grea behind the denitrification zone than at the end. These observations suggest different levels of activity of the aeriation line (and hence also in the return sludge). In both aeriation tanks it was necessary to even out the nitrogen load at the intake in order th achieve even and low NH4-N concentration at the outlet end. Particular importance must be attached to the return flows from the sewage treatment stage which on normal workdays account for a large portion of the total nitrogen load ( over 30 % in the present case).