DIFFERENTIAL REVERSE OSMOSIS METHOD AND APPARATUS

摘要

A system for treating water has a plurality of concatenated reverse osmosis (RO) units, each having a membrane. Water to be treated is fed to one side of the membrane at a pressure to overcome osmotic pressure across the membrane and to force permeate to the other side of the membrane. The water on the one side of the membrane retains dissolved solids to become concentrate. Concentrate from a downstream RO unit is directed to the other side of the membrane of the upstream RO unit to mix the directed concentrate from the downstream RO unit with the permeate of the upstream RO unit. The mixed concentrate and permeate from the upstream unit is then treated at the downstream RO unit.