K.J.Ives Professor of Public Health Engineering University College London Industrial application of the use of bubbles to float fine particles in water began before the beginning of this century, in the field of mineral processing. Such bubble flotation was applied very little outside mineral processing, until about 1960 when the dissolved air process, which has already had some success in the pulp and paper industry, was applied to water and wastewater treatment. The subsequent two decades saw not only a growth development for water and wastewater treatment, but also a growing cognisance of...