Coalescence in wastewater treatment technology: specifics and methods

Summary

Characteristics of water-immiscible organic liquids in wastewater from the perspective of the treatment process using coalescence are considered. With the presented material attempts are made to summarize and systematize the information on the natural phenomenon of coalescence that is determined by the physicochemical properties of water-immiscible liquids; to structure the information on the processes occurring during coalescence and the factors influencing them. The main types of emulsified organic liquids in water, including macroemulsions, microemulsions, and nanoemulsions, and their properties are discussed. The key stages of interaction between organic liquid droplets and water resulting in natural demulsification are identified, including droplet transport, droplet collisions, film drainage, film rupture, and droplet coalescence. A classification of coalescence intensification methods and materials used is proposed based on the additional energy required. Demulsification methods are presented for the main types of emulsions in wastewater.

Key words

wastewater , coalescence , macroemulsions , nanoemulsions , microemulsions , natural demulsification , demulsification