Energy Recovery Device

Mit Water integrates energy recovery devices (ERDs) into seawater reverse osmosis systems to significantly reduce energy consumption by recovering hydraulic pressure energy from the high-pressure brine reject stream. ERD technology is essential for making seawater desalination economically viable at scale.

Working Principle

In an SWRO system, the concentrated brine reject stream leaves the membrane at a pressure only slightly below the feed pressure (typically 60-65 bar). An ERD captures this pressure energy and transfers it directly to a portion of the incoming seawater feed, reducing the net work required by the high-pressure pump. Isobaric (pressure exchanger) devices achieve over 95% energy transfer efficiency.

System Integration

Our SWRO systems are designed with integrated ERDs, typically isobaric pressure exchanger devices. The system includes the ERD unit, booster pump, high-pressure pump, associated piping and instrumentation, and PLC control for flow balancing. With ERDs, SWRO energy consumption can be reduced from 6-8 kWh/m3 to 2.5-4.0 kWh/m3.

Energy recovery devices are standard in modern SWRO desalination plants:

  • Large-scale municipal seawater desalination plants
  • Industrial SWRO systems for process water
  • Brackish water RO with high recovery (brine energy recovery)
  • Containerised and mobile desalination units
  • Offshore platform and marine desalination
  • Island resort and remote community water supply

Technical Parameters

ERD TypeIsobaric pressure exchanger or turbocharger
Energy Transfer Efficiency94% to 97% (isobaric type)
Pressure RatingUp to 83 bar
Flow Range5 to 60 m3/h per ERD unit
MaterialSuper duplex stainless steel or ceramic rotor
Energy Saving40% to 60% versus no ERD
System Energy2.5 to 4.0 kWh/m3 (with ERD)
ControlPLC with flow balancing and pressure monitoring