Scaling

Abstract

Scaling is one of the most vexing problems affecting the use of membranes for pressure‐driven desalination. The scaling problems most commonly encountered are caused by calcium carbonate, calcium sulfate, and silica in brackish water RO; calcium carbonate and calcium sulfate in seawater RO; and calcium carbonate and calcium phosphate in desalination of municipal wastewater. This article surveys the conditions leading to scaling, mechanisms by which scaling can cause flux decline, thermodynamics and kinetics of scaling, present state of the art in preventing scaling, new processes proposed for mitigating the problem, and new techniques for detecting the onset of scaling.