Jersey Waterworks

Client: The Jersey New Waterworks Company Limited

Process: Reverse Osmosis

Country: Jersey

Contract Description: Decommission existing M.S.F. Plant/Construct S.W.R.O. Plant.

Contract Value: US$ 7.5 million

Contract Date: December 1997

Contract Completed Date: April 1999

Capacity: 6,000 m³/per day

Sea Water Conversion: 45%

Sea Water Feed Quality: 39,000mg/l (tds)

Fresh Water Output Quality: < 400 mg/l (tds)

Specific Energy Usage: 6.8kWh per m³ water produced

Max. Electrical Power Demand: 1,750 kW


Process Description:

Seawater is pumped through downward flow type pressure vessels filled with a dual filter media of sand and anthracite. (The filters are automatically back-washed at pre-set periods to provide optimum water quality.) Final filtration upstream of the R.O. trains is provided by an array of cartridge filter vessels.

The R.O. plant comprises of four independent trains, each fitted with 156 spiral wound type membrane elements. Filtered water is supplied to the R.O. membranes by high-pressure multi-stage centrifugal pumps. The membranes convert 45% of the sea water into fresh water, the remaining water is rejected as brine. This sea water reject (brine) is used to operate turbine driven pumps that are positioned in series with the high pressure pumps, thus allowing the recovery of energy which would otherwise be lost.