Schematic representation of indirect (A, left side) and direct (B, right side) feed water distribution systems. In both examples, reverse osmosis is the last process in a purification cascade. With an indirect feed distribution system (A), product water from the reverse osmosis unit passes into a storage tank. A separate pump circulates water from the storage tank to the point of use (ie, dialysis stations). Water not used for dialysis is returned to the storage tank so that purified water flows in a continuously recirculating loop. With a direct feed distribution system (B), product water from the reverse osmosis unit passes directly to the point of use (ie, dialysis stations). Water not used for dialysis is returned to the feed side of the reverse osmosis system so that purified water flows in a continuously recirculating loop.
