System and Method for the Treating of Water by Reverse Osmosis or Nanofiltration
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention relates to a system and process for treating a feedwater wherein the system includes at least one or nanofiltration unit that receives a feed under high pressure and produces a concentrate that is directed to and held at low pressure in a concentrate accumulator. Generally the permeate or the inlet feedwater is maintained at a constant flow rate. Periodically the system is switched from a mode 1 or normal operating process to a mode 2 where the concentrate is drained from the concentrate accumulator. However, in mode 2, the feedwater is still directed into the system and through the RO or nanofiltration unit which produces the permeate and the concentrate.
1 Citation
42 Claims
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1-23. -23. (canceled)
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24. A process for treating a feedwater in a system including a reverse osmosis (RO) or nanofiltration unit and a concentrate accumulator, the process comprising:
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a. in a first mode of operation; i. wherein the RO or nanofiltration unit produces a permeate and a concentrate; ii. directing the concentrate to the concentrate accumulator and accumulating the concentrate therein; iii. splitting the permeate into first and second permeate streams; v. mixing the feedwater with the second permeate stream to form a feedwater-permeate mixture; vi. after mixing the feedwater with the second permeate stream, directing the concentrate from the concentrate accumulator and mixing the feedwater-permeate mixture with the concentrate to form a second mixture; vii. pressurizing and pumping the second mixture through the RO or nanofiltration unit and producing the first and second permeate streams and the concentrate and continuing to direct the concentrate to the concentrate accumulator; viii. wherein during the first mode of operation, neither the feedwater nor the first or second permeate streams are directed into the concentrate accumulator; b. in a second mode of operation; i. draining a portion of the concentrate from the concentrate accumulator; ii. while draining a portion of the concentrate from the concentrate accumulator, pressurizing and directing the feedwater-permeate mixture through the RO or nanofiltration unit and continuing to produce the concentrate; iii. while draining a portion of the concentrate from the concentrate accumulator, continuing to direct concentrate from the RO or nanofiltration unit into the concentrate accumulator; iv. wherein during the second mode of operation, neither the feedwater nor the first or second permeate streams are directed into the concentrate accumulator; and c. wherein the process is a continuous process that continues to direct concentrate from the RO or nanofiltration unit into the concentrate accumulator in both the first and second modes. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
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33. A process of recovering dissolved solids from a feedwater by employing a reverse osmosis (RO) or nanofiltration unit operated in two different modes wherein the RO or nanofiltration unit produces a permeate and concentrate, the process comprising:
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a. in a first mode of operation; i. directing the concentrate from the RO or nanofiltration unit into a concentrate accumulator and accumulating the concentrate therein; ii. maintaining the concentrate in the concentrate accumulator under a low pressure; iii. bypassing the concentrate accumulator with the feedwater and mixing the feedwater with a portion of the permeate to form a feedwater-permeate mixture; iv. mixing the feedwater-permeate mixture with a portion of a concentrate from the concentrate accumulator to form a second mixture; v. directing the second mixture into and through the RO or nanofiltration unit to produce the permeate and the concentrate; b. in a second mode of operation; i. draining a portion of the concentrate from the concentrate accumulator; ii. while draining a portion of the concentrate from the concentrate accumulator, continuing to bypass the concentrate accumulator with the feedwater and directing the feedwater-permeate mixture through the RO or nanofiltration unit; and iii. while draining the portion of the concentrate from the concentrate accumulator, continuing to direct the concentrate from the RO or nanofiltration unit into the concentrate accumulator. - View Dependent Claims (34, 35, 36, 37, 38, 39)
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40. A membrane system for treating a feedwater and configured to operate in a first mode and a second mode, the membrane system comprising:
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an RO or nanofiltration unit configured to produce a permeate and a concentrate; a permeate delivery line for directing a portion of the permeate to a delivery point; a permeate recycle line configured to recycle a portion of the permeate produced by the RO or nanofiltration unit; a pressurized concentrate accumulator configured to accumulate concentrate produced by the RO or nanofiltration unit; a concentrate line operatively connected between the RO or nanofiltration unit and the concentrate accumulator for directing concentrate from the RO or nanofiltration unit to the concentrate accumulator; a pump having a low pressure side and a high pressure side disposed between the concentrate accumulator and the RO or nanofiltration unit; a first feedwater line which during the first mode of operation is configured to direct the feedwater to a point where the feedwater is mixed with the permeate from the permeate recycle line to form a feedwater-permeate mixture; a feedwater-permeate mixture line for conveying the feedwater-permeate mixture to a point between the pump and the RO or nanofiltration unit; a concentrate feed line connected between the concentrate accumulator and the pump for directing concentrate from the concentrate accumulator to the pump; wherein said concentrate accumulator, during the first mode of operation, is configured to induce the concentrate to flow under pressure from the concentrate accumulator to the pump; a second feedwater line that during the second mode of operation is configured to direct the feedwater to a low pressure side of the pump; a concentrate drain line wherein in the second mode of operation is configured to drain concentrate directly from the concentrate accumulator and wherein the pressurized concentrate accumulator is operative to induce the flow of concentrate from the concentrate accumulator into the drain line; and wherein the first and second feedwater lines and the permeate recycle line are isolated from the concentrate accumulator such that neither feedwater or permeate is directed into the concentrate accumulator. - View Dependent Claims (41, 42, 33)
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Specification