Dear Ali,Common practices ...

Dear Ali, Common practices depends upon the concentration or load of Colloidal and NOM in the Seawater. Anyway following are some economical and available options to be considered step wise as the extent and complexity of the pre-treatment systems for removing or reducing colloidal and organic fouling depends on site conditions. In case of open seawater intake, reverse osmosis membranes should be protected against a variety of foulants, necessitating an extensive pre-treatment process otherwise in case of Seawater coming from Bore Well will definitely have less exetensive pre-treatment process; Low Level NOM Concentration Pre-Chlorination (This can either be done prior to Multimedia or Post Multimedia-------->Single Stage/Double Stage Multimedia Filters --------->Activated Carbon Filters (In some cases if required).......... High Level NOM Concentration Coagulation/Flocculation--------->Sedimentation or Floatation------->Single Stage/Double Stage Multimedia Filters --------->Pre-Chlorination (This can either be done prior to Multimedia or Post Multimedia------->Activated Carbon Filters (In some cases if required).......... When the above is completed, then it goes to UF or NF and then RO. Hope this addressed your query properly.