Abstract
The separation of dispersed oil from water requires that the dispersed oil drops move to and coalesce at the oil-water interface. Normally the coalescence step of this separational process as applied to waste water treatment is neglected because the time for coalescence to occur is short relative to the migration time. Indeed, in the API design of oil skimmers (API 1963) the coalescence time and the thickness of the oil layer are both neglected. Nevertheless, some conditions when coalescence is important for waste treatment are: 1.in the design and operation of decanters upstream of the waste treatment process. The effectiveness of these dictate the complexity of the waste water treatment.2.in solvent extraction methods for treating stable dispersions of oily waste water. Such a method has been successfully developed to treat the oily waste from rolling mills in steel companies (Woods and Zirimenya (1968 ff) ).3.when concentrated, stable emulsions are the waste.4.when space is at a premium (Woods (1968), Shackleton et al (1960) and Douglas and Elliott (1961)).
Our knowledge of coalescence in liquid-liquid systems is limited and often contradictory. Consider first some background on what we know about coalescence. Then, we describe an experimental technique and recent results on the coalescence of single drops at a planar interface.
Study on Filtration Characteristics of Crude Lecithin/Water Emulsion for Food Oily Waste Water Treatment.
