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# (12) United States Patent 

# Mukhopadhyay 

# (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). 

(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 

## (65) Prior Publication Data 

US 2002/0125191 Al Sep. 12, 2002 

(60) Provisional application No. 60/036,682, filed on Mar. 1, 1997, and provisional application No. 60/077,189, filed on Aug. 12, 1996. 

(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 

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. 

## Related U.S. Application Data 

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# (10) Patent No.: US 6,537,456 B2 

# *Mar.25,2003 (45) Date of Patent: 

(58) Field of Search ................................. 210/639, 652, 210/638, 661, 651, 195.2, 257.2, 263, 663, 650, 900; 204/450 

## (56) References Cited 

DE 1792304 A2 3/1972 

JP-50-75987-A2 (Jun. 1975)-Derwent Abstract of KOKAI. 

Primary Examiner-Ana Fortuna (74) Attorney, Agent, or Firm-R. Reams Goodloe, Jr. 

## (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). 

3,715,287 A * 2/1973 Johnson 

US006537456B2 

## U.S. PATENT DOCUMENTS 

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## FOREIGN PATENT DOCUMENTS 

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## OTHER PUBLICATIONS 

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## 36 Claims, 11 Drawing Sheets 

