To ensure potable water of drinking quality, chemical treatment is required for reverse- osmosis freshwater generators. What is the purpose of chemical pre-treatment?

Correct Answer: Option C — Chemical pre-treatment sterilizes the sea water entering the unit to prevent bacteria from becoming resident in the reverse-osmosis unit filters and membrane modules.

Chemical pre-treatment is essential to prevent biofouling and scaling within the membrane modules. By sterilizing the incoming seawater, the system prevents bacteria and microorganisms from colonizing the membrane surface, which would otherwise degrade performance, reduce flux, and necessitate frequent, costly chemical cleanings or premature membrane replacement.