How does a watermaker work?

In a conventional watermaker, a high pressure pump similar to a pressure washer, boosts the incoming raw water pressure up to 800-1000 PSI (55 - 69 Bar). Large pumps use brute force to hammer seawater against a back-pressure valve in order to generate this pressure. Only a small percentage of the water pumped through a watermaker passes through the membranes and comes out as fresh drinking water. The result is that a significant amount of energy is wasted pumping the entire quantity of raw water to such a high pressure.

When seawater exits the membranes in a watermaker, that water is still under pressure, up to 1000 PSI (69 Bar). Spectra’s unique energy recovery device transfers the energy normally wasted in conventional systems at the membrane exit, and passes it to the incoming raw water, dramatically lowering the power required to operate the system. All of Spectra’s watermakers use a similar energy recovery technology; the high pressure waste stream from the membranes is channeled to the underside of the pump piston, allowing them to recover 90% of the available energy. All Spectra Watermakers adjust automatically to changes in water temperature and salinity as part of the hydraulic design, so there is no need to rely on complex electronics or make manual adjustments in different climates, bays, rivers, or oceans.