CLARIFIER SLUDGE-BLANKET BEHAVIOR AT INDUSTRIAL ACTIVATED-SLUDGE PLANT

The solids flux theory has traditionally been used for clarifier design. However, it's use for analysis of clarifier behavior in operating plants has been largely overlooked due to the intensive data requirements and complex graphic analysis. It was previously demonstrated that the theory can be presented as simple operating curves which can be used to predetermine blanket failure. Elsewhere, new control boundaries were used in the derivation of the theory, making possible the prediction of the rate of rise or fall of blankets in laboratory-scale clarifiers. In the present paper, the newly configured model is used to predict blanket performance in full-scale clarifiers. The predicted rates correlate well with the observed rates (r2 = 0.93). The effects of measurement error, such as flow rates and settling rates, on the ability to predict the performance of the sludge blanket are studied. Errors associated with predicting the blanket performance outweigh errors in observing the movement of the blanket and are in agreement with the magnitude of scatter in the actual data.