Patent ID: 7077962

Claim:
Apparatus for membrane softening of potable water, said apparatus comprising: a reverse osmosis (RO) membrane for softening and demineralizing potable water, said reverse osmosis (RO) membrane producing an (RO) permeate and an (RO) concentrate; a microfiltration (MF) membrane for receiving the (RO) concentrate and producing an (MF) permeate and (MF) concentrate; hydraulic pathways for recycling the (MF) permeate to the potable water for return to said reverse osmosis (RO) membrane at a pH level suitable for suppressing deposition of solids on the reverse osmosis (RO) membrane; a pressurized concentrate storage tank including seed crystals, the storage tank being in fluid communication between the reverse osmosis (RO) membrane and the microfiltration (MF) membrane for receiving (RO) concentrate at a pH that is conducive to metastable precipitation of calcium carbonate on the seed crystals; and lines for delivery of (RO) permeate for use.