Perth Seawater Desalination Plant - Intake

General description

The Perth seawater intake is an 8 m diameter cylindrical structure positioned on the seabed 11 m below sea level, 200 m offshore in Cockbun Sound. The structure is 5.5 m tall with the upper 2 m consisting of a coarse screen. The seawater intake is connected to the onshore facility through a 2300 mm diameter GRP pipeline.

Pump

The onshore facility is predominantly below sea level to enable gravity flow into the wet well. Pumps help the screened seawater through to the pretreatment filtration system, passing first through a chemical dosing system.

Any chemical treatment

The seawater is shock-dosed at the intake with sodium hypochlorite at intervals of one to two weeks to eliminate biological growth in the system. Sodium bisulphite is injected into the filtered seawater to neutralise residual chlorine in the seawater and prevent membrane damage from the sodium hypochlorite.