Reverse Osmosis Plants

Seawater is extracted from deep shore wells sunk in Coralline Limestone. This configuration has produced very good quality water, free from silt and organic material. The feed water boost pumps serve the dual purpose of providing the pressure required to filter seawater through 5 micron cartridge filters and also provide adequate suction pressure for the high-pressure pumps’ inlet. The former ensure silt free water to the membranes at all times, and the latter provide the pressure required to drive the desalination process. At a pressure of 83 bar (69 bar at Ghar Lapsi Reverse Osmosis), acidified seawater (or brackish water) is fed into semi-permeable membranes that separate the feed stream into potable water and brine. The residual brine stream, still at high pressure, is piped into an energy recovery device, which retrieves the energy available in this stream. The low pressure brine is returned to sea. The potable water produced is disinfected by chlorine addition and remineralised by the addition of lime. The final stage in the process is the pumping of the product into the distribution network.   

Ċirkewwa Reverse Osmosis Plant
Cirkewwa - Reverse Osmosis Plant
 
Nominal Capacity: 18,600m3/day
Number of Trains : 2 × 3,000m3/day - 3 × 4,200m3/day
Configuration : Single Pass
Recovery : 42 per cent
Operating Pressure : 83 Bar (1200 PSI)
Feed Intake : Beach Wells
Feed TDS : 39,000 mg/I
Feed Temperature : 19°C
 
Pembroke Reverse Osmosis Plant
Pembroke - Reverse Osmosis Plant
 
Nominal Capacity : 54,000m3/day
Number of Trains : 6 × 4,400m3/day - 6 × 4,600m3/day
Configuration : Single Pass
Recovery : 45 per cent
Operating Pressure : 83 Bar (1200 PSI)
Feed Intake : Beach Wells
Feed TDS : 39,000 mg/I
Feed Temperature : 19°C
 
Għar Lapsi Reverse Osmosis Plant
Ghar Lapsi - Reverse Osmosis Plant
 
Nominal Capacity : 24,000m3/day   
Number of Trains : 12 × 2,000m3/day
Configuration : Single Pass
Recovery : 33 per cent
Operating Pressure : 69 Bar (1000 PSI)
Feed Intake : Beach Wells
Feed TDS : 39,000  mg/I
Feed Temperature : 19 - 25 °C