Operation of the RO Kinetic® energy recovery system: Description and real experiences Original Research Article

Along with the older style centrifugal energy recovery devices (ERDs), there has been a recent proliferation of ERDs that employ positive displacement mechanisms. These “pressure-equalising” or isobaric ERDs transfer the energy from the membrane reject stream directly to the membrane feed stream. This direct, positive displacement approach results in a net transfer efficiency up to 97% [R.L. Stover, Seawater reverse osmosis with isobaric energy recovery devices. Desalination, 203 (2007) 168–175]. A number of devices have been developed to recover pressure energy from the brine reject stream. These ERDs fall into two general categories: centrifugal and isobaric devices.