System and method for the treating of water by reverse osmosis or nanofiltration
AssigneeVeolia Water Solutions & Technologies Support
InventorsBernard Roy Mack, Dale L. Wynkoop
Life of this patent
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Abstract
The present invention relates to a system and process for treating a feedwater wherein the system includes at least one RO 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.
Claims9
A process for treating a feedwater in a system including a reverse osmosis (RO) or nanofiltration unit and a concentrate accumulator, the process comprising:
- 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.
Dependencies are inferred from the claim text.