US006537456B2  (12)  United States Patent  Mukhopadhyay  (10)  Patent No.:  US 6,537,456 B2  *Mar.25,2003  (45)  Date of Patent:  (54)  METHOD AND APPARATUS FOR HIGH  EFFICIENCY REVERSE OSMOSIS  OPERATION  (76)  Inventor:  Debasish Mukhopadhyay,  4211  Pomona Ave., Palo Alto, CA (US)  94306  ( *)  Notice:  This patent issued on a continued pros› ecution application filed under 37 CFR  1.53( d), and is subject to the twenty year  patent term provisions of 35 U.S.C.  154(a)(2).  Subject to any disclaimer, the term of this  patent is extended or adjusted under 35  U.S.C. 154(b) by  O  days.  This patent is subject to a terminal dis› claimer.  (21)  Appl. No.:  09/242,249  (22)  PCT Filed:  Aug. 12, 1997  (86)  PCT No.:  PCT/US97/14239  §  371 (c)(l),  (2), ( 4) Date:  Sep. 28, 1999  (87)  PCT Pub. No.:  WO98/06483  PCT Pub. Date:  Feb. 19, 1998  (51)  Int. Cl.7  ................................................  BOID 61/00  (52)  U.S. Cl.  .......................  210/652;  210/638; 210/639;  210/650; 210/651; 210/661; 210/900  (65)  Prior Publication Data  Related U.S. Application Data  (60)  Provisional application No. 60/036,682, filed on Mar. 1,  1997, and provisional application No. 60/077,189, filed on  Aug. 12, 1996.  US 2002/0125191 Al Sep. 12, 2002  (58)  Field of Search  ................................. 210/639, 652,  210/638, 661, 651, 195.2, 257.2, 263, 663,  650, 900; 204/450  (56)  References Cited  U.S. PATENT DOCUMENTS  3,715,287 A  *  2/1973 Johnson  (List continued on next page.)  FOREIGN PATENT DOCUMENTS  DE  1792304 A2  3/1972  (List continued on next page.)  JP-50-75987-A2  (Jun.  1975)-Derwent Abstract  of  KOKAI.  Primary Examiner-Ana  Fortuna  (74)  Attorney, Agent, or Firm-R.  Reams Goodloe, Jr.  OTHER PUBLICATIONS  (List continued on next page.)  (57)  ABSTRACT  A  process for treatment of water via membrane separation to  remove hardness and non-hydroxide alkalinity by simulta› neous removal in a weak acid cation exchange resin. The  process includes ionization of sparingly ionizable  components, such as silica, by adjusting the pH up to about  10.5 or higher. Their separation by the membrane is signifi› cantly increased. The passage of boron, silica and TOC is  reduced by a factor of ten or more. Recovery of 90% or  higher is achievable with most brackish feedwaters, while  substantial reduction in cleaning frequency is simulta› neously achieved. The apparatus used for the water treat› ment process includes reverse osmosis membrane(s)  (30),  mixed bed ion exchange unit (  44, 46),  micron filter (  48),  ultraviolet sterilization unit (  49),  decarbonation unit  (20),  and electrodeionization unit  (150).  36 Claims, 11 Drawing Sheets  10  RAW  WATER  ~-~:  I  I  A~  13y  14  11  11  1  ANION  1-X  16  31  32  REJECT  49  u  V 