Pre-treatment involves the sequence of (i) open seawater intake, (ii) fine screen filtration, (iii) water chlorination at the intake point, and filtration through (iv) spruce multi-media filters (SMF to remove particulate and colloidal matter). The water is chlorinated once a week for a period of 1 h to prevent microbial growth on the inside of the water intake pipe and the SMF. Thereafter, a portion of the water flow is directed to fill the SMF backwash water tank (an SMF is backwashed every 12 h for a period of ≈30 min) while the remaining water flow is directed towards the RO treatment trains