One of the limitations of the RO membrane desalination is to treat
effluentswith a very lowconcentration of suspended solids tominimize
the problems associated with membrane fouling [38]. As a result, the
efficiency of the desalination process is reduced as increasing the
osmotic pressure may increase the overall energy consumption. Therefore,
the need for an appropriate pretreatment method becomes inevitable
to ensure the feasibility and efficiency of RO systems. Several
research investigations revealed that pretreatment technologies ahead
of the RO membrane desalination could have positive effects on the
overall operational performance such asminimizingmembrane fouling,
increasing the removal of suspended solids and dissolved organic matters
from sea waters. These pretreatment technologies may be conventional
such as coagulation, flocculation and scale inhibition or nonconventional
such as ultrafiltration (UF), microfiltration (MF) and
nanofiltration (NF).
The selection of the pretreatment technology is of a great importancewhile
treating various types of salinewaters by using diverse pretreatment
strategies. In this article, an overview of the performance of
different ROmembrane desalination systems coupled with various pretreatment
technologies is summarized in the subsequent sections