Patent ID: 6863822

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 initially disposed 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.