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# c12) United States Patent 

# Mukhopadhyay 

# (54) METHOD FOR HIGH EFFICIENCY REVERSE OSMOSIS OPERATION 

(71) Applicant: Debasish Mukhopadhyay, Palo Alto, CA (US) 

(72) Inventor: Debasish Mukhopadhyay, Palo Alto, CA (US) 

( *) Notice: Subject to any disclaimer, the term ofthis patent is extended or adjusted under 35 U.S.C. 154(b) by 94 days. 

(21) Appl. No.: 13/666,750 

(22) Filed: Nov. 1, 2012 

## (65) Prior Publication Data 

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(60) Continuation of application No. 11/342,135, filed on Jan. 26, 2006, which is a continuation of application No. 09/243,237, filed on Feb. 2, 1999, now abandoned, which 1s a division of application No. 

(51) Int. Cl. 

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(52) U.S. Cl. CPC ................ C02F 9/00 (2013.01); BOID 611022 (2013.01); BOID 61/025 (2013.01); BOID 61/04 (2013.01); 

This patent is subject to a terminal dis› claimer. 

## Related U.S. Application Data 

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# (IO) Patent No.: US 9,073,763 B2 

# (45) Date of Patent: *Jul. 7, 2015 

(58) Field of Classification Search CPC .............. C02F 9/00; C02F 1/42; C02F 1/441; C02F 1/20; C02F 1/52; C02F 1/66 USPC .................. 210/652, 651, 639, 653, 663, 661 See application file for complete search history. 

## (56) References Cited 

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JP-50-075987-A2 ( Jun. 1975)-Derwent Abstract of Kokai (2 pages). 

Primary Examiner -Ana Fortuna 

(74) Attorney, Agent, or Firm - R. Reams Goodloe, Jr. 

## (57) ABSTRACT 

A process for treatment of water. Hardness and non-hydrox› ide alkalinity are removed from feedwaters to an extent suf› ficient to avoid scaling when concentrated. Sparingly ioniz› able components in the feedwater are urged toward increased ionization by increasing the pH of the feedwater. In this manner, species such as silica become highly ionized, and (a) their rejection by membranes used in the process is signifi› cantly increased, and (b) their solubility in the reject stream from the membrane process is significantly increased. Spar› ingly ionized species such as boron, silica, and TOC are highly rejected. Recovery ratios of ninety percent (90%) or higher are achievable with many feedwaters, while simulta› neously achieving a substantial reduction in cleaning fre› quency of membranes used in the process. 

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US009073763B2 

## U.S. PATENT DOCUMENTS 

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## FOREIGN PATENT DOCUMENTS 

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## OTHER PUBLICATIONS 

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## 68 Claims, 11 Drawing Sheets 

