Prediction and Measurement of Bubble Formation in Water Treatment

Abstract

Water utilities can experience problems from bubble formation during conventional treatment, including impaired particle settling, filter air binding, and measurement as false turbidity in filter effluent. Coagulation processes can cause supersaturation and bubble formation by converting bicarbonate alkalinity to carbon dioxide by acidification. A model was developed to predict potential bubble formation during coagulation, and its accuracy was confirmed using an apparatus designed to physically measure the actual volume of bubbles formed. Alum acted similar to hydrochloric acid for initializing bubble formation, and higher initial alkalinity, lower final solution pH, and increased mixing rate tended to increase bubble formation.