1. Desalination Process: Pretreatment,
Treatment, and Post-Treatment
As a generic umbrella term, desalination refers to the process of removing salts and
minerals from water or from soil. The use of the process for producing safe-drinking
water is a more crucial objective and hence the most common. The primary intention of
which is to remove ionic contaminants which originate from natural or artificial sources.
The sophisticated water desalinating process begins with pretreatment, followed by the
actual treatment, and finally the post-treatment.
The pretreatment phase is designed to remove relatively large contaminants that could
interfere with the actual treatment process. Scale formation and membrane fouling
are commonly removed during this phase. In this phase, coagulation and membrane
filtration remove particulate matter as well as organic particles. To minimize fouling,
a disinfecting substance such as chlorine is applied which also helps the reduction of
pathogens.
In the treatment phase, microbial contaminants are either removed or inactivated. When
inactivated, the potential for microorganisms to survive must be carefully monitored
since this problem could arise during the handling of the water system. Hence, a vital
part of the treatment process is to monitor the system for efficiency and effectiveness.
In membrane systems, for instance, the integrity of the membrane must be checked
consistently since the barrier function heavily relies on this component. Pathogens can
easily pass through compromised membranes and contamination becomes even more
pronounced as treated water undergoes thermal distillation. Water systems, therefore,
consists of several repetitive cycles and tests to ensure high-quality desalinated drinking
water.
Final disinfection and conditioning processes are carried out in the post-treatment
phase. This phase involves blending and re-mineralization so that the aggressive nature
of the treated water is suppressed. When properly implemented, the post-treatment
processes ensure that the treated water can be kept for long in storage. When the entire
desalinating process is done, efficient distribution systems must be implemented for the
drinking water to reach the target population.