AWWA ACE91095

This article presents the results of tracer and ozonation tests performed as part of a more comprehensive pilot-scale investigation conducted at the F.E. Weymouth Filtration Plant, Metropolitan Water District of Southern California, La Verne, California. The ozonation tests were designed to study the effect of dispersion on ozone concentration profiles in the water column. A computer model was developed and calibrated with the results from the tracer and ozonation tests. The model was then used to predict observed ozone concentration profiles inside the contactor, and residuals in the contactor effluent for several other experiments performed during the Metropolitan pilot investigation. Experimental results and model predictions for tracer tests indicated that mixing conditions inside the ozone bubbler-diffuser contactors could change from high-mixing to close to plug-flow within the range of typical operating conditions. In general, dispersion was independent of the height of the water column in the contactor for constant gas and water flow rates.