ABSTRACT
Influence of hydraulic properties on baffled stabilization ponds performance was studied. The hydraulic model was studied by tracer t e s t . From this t e s t , the Dispersion Number Index, d was evaluated for each of the five ponds at four different hydraulic loadings. The results of this f i r s t part of the study formed basis for the second part which is the performance of facultative ponds. The performance of laboratory baffled facultative ponds was investigated by the measurement of Biochemical Oxygen Demand (BOD); Chemical Oxygen Demand (COD) and Suspended Solids (SS) of synthetic milk waste. Also the changes in Alkalinity, the Dissolved Oxygen (DO) and pH of the ponds were measured. The results show that for good efficiency, the actual (mean) detention time must be greater or at least equal to the nominal detention time. Also the ratio of the effective volumes of two different ponds of the same dimension and shape is equal to the r a t i o of their actual (mean) detention times. Generally, excessive short-circuiting are reduced by some baffle arrangements in the ponds. The results indicate that baffled ponds have low values of Dispersion Index, d and exhibit flow patterns nearer to a plug flow. The overall performance is improved by increasing the number of baffles. Baffled ponds are analogous to ponds in series or a stream. A significant oxygen demand and SS are imposed on the ponds contents by algae. In terms of organic removal and bacterial die-off, the results indicate that baffled pond performs better than a plain pond of the same size operating at approximately the same hydraulic and organic loadings.