Improvements to a stoat model of a full scale wastewater treatment works through the use of detailed mechanistic studies

The performance of a wastewater treatment works has been simulated using a dynamic modelling package from WRc, STOAT. The estimation of appropriate parameter values has been performed both prior to and after detailed investigations of the mechanisms of oxygen transfer and mixing within the aeration lanes of the activated sludge plant. Interpretation of reactor mixing characteristics in the light of dissolved oxygen data is considered. The need for accurate information concerning solids retention times is exemplified by the model's sensitivity to sludge wastage rates.