STOAT and the oxygen requirements of an activated sludge plant

The various activated sludge models within STOAT, a whole works package, we re used to predict the oxygen requirements of a hypothetical activated slud ge plant. The predictions which were obtained were then compared with the v alues calculated from standard equations. The results showed that there wer e very definite differences both between the predictions made by the models and between the model predictions and those produced using standard equati ons. The results also showed that, for carbonaceous oxidation, the GOD-base d model in STOAT (IAWQ model) was applicable to a wider range of process co nditions than the BOD-based model (ASAL model). The IAWQ model was also fou nd to be a more useful tool in optimising a nitrogen removal system.