Question 89General Subjects - Assistant Engineer

The correct answer is C. Chemical pre-treatment sterilizes the sea water entering the reverse osmosis unit to prevent bacteria from becoming resident in the reverse osmosis filters and membrane modules. The purpose of chemical pre-treatment is to disinfect the inlet seawater and prevent the growth of bacteria within the reverse osmosis system. This is necessary to ensure the quality of the potable water produced by the reverse osmosis unit. Without proper pre-treatment, bacteria could colonize the filters and membranes, potentially contaminating the freshwater output. The other options are incorrect because they do not address the primary purpose of chemical pre-treatment, which is disinfection of the inlet seawater rather than removal of particulates or post-treatment sterilization.