Water treatment system and method

• US 8,864,971 B2
• Filed: 02/15/2013
• Issued: 10/21/2014
• Est. Priority Date: 11/13/2003
• Status: Expired due to Term

• Current Assignee: Evoqua Water Technologies LLC (Xylem, Inc.)
• Original Assignee: Evoqua Water Technologies LLC (Xylem, Inc.)
• Inventors: Jha, Anil D., Wilkins, Frederick C., Freydina, Evgeniya, Sezgi, Aytac, Madhusudan, Reshma
• Primary Examiner(s): Phasge, Arun S
• Application Number:
  US13/768,362
• Publication Number:
  US 20130256135A1
• Time in Patent Office: 613 Days
• Field of Search: 204/523, 204/524, 204/525, 204/529
• US Class Current: 204/523
• CPC Class Codes: C02F 1/42 by ion-exchange ion-exchange in general B01J
• CPC Class Codes: C02F 1/4602 for prevention or elimination of deposits
• CPC Class Codes: C02F 1/469 by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
• CPC Class Codes: C02F 1/4695 electrodeionisation
• CPC Class Codes: C02F 2201/46115 Electrolytic cell with membranes or diaphragms
• CPC Class Codes: C02F 2201/4612 Controlling or monitoring
• CPC Class Codes: C02F 2201/4613 Inversing polarity
• CPC Class Codes: C02F 2209/005 Processes using a programmable logic controller [PLC]
• CPC Class Codes: C02F 2303/16 Regeneration of sorbents, filters
• CPC Class Codes: C02F 5/00 Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents softening using ion-exchange C02F1/42

Abstract

A treatment system provides treated or softened water to a point of use by removing at least a portion of any undesirable species contained in water from a water source. The treatment system can be operated to reduce the likelihood of formation of any scale that can be generated during normal operation of an electrochemical device. The formation of scale in the treatment system, including its wetted components, may be inhibited by reversing or substituting the flowing liquid having hardness-causing species with another liquid having a low tendency to produce scale, such as a low LSI water. Various arrangements of components in the treatment system can be flushed by directing the valves and the pumps of the system to displace liquid having hardness-causing species with a liquid that has little or no tendency to form scale.

Claims

1. A method of treating a liquid, comprising:

establishing a first liquid circuit having liquid to be treated flowing therein from a reservoir to a first compartment inlet of an electrochemical device;

establishing a second liquid circuit having a concentrating liquid flowing therein from a second compartment outlet of the electrochemical device to a second compartment inlet;

establishing a third liquid circuit having liquid to be treated flowing therein from the reservoir to the second compartment inlet; and

flushing at least one of the first liquid circuit and the third liquid circuit periodically with treated water having an LSI of less than about 2 from the reservoir in response to a rate of demand or a time of demand to inhibit scale formation.

2. The method of claim 1, further comprising establishing a fourth liquid circuit having the concentrating liquid flowing therein from the first compartment outlet to the first compartment inlet.

3. The method of claim 1, further comprising applying an electric field across the electrochemical device.

4. The method of claim 3, further comprising reversing a polarity of the applied electric field after establishing the third liquid circuit.

5. The method of claim 1, wherein establishing the third liquid circuit comprises actuating a first valve to direct the liquid to be treated to flow through a first pump.

6. The method of claim 5, further comprising actuating a second valve to direct the concentrating liquid to flow through a second pump.

7. The method of claim 1, further comprising measuring at least one of a pressure, temperature, flow rate, pH, conductivity and composition of the liquid.

8. The method of claim 1, wherein the first liquid circuit and the third liquid circuit are flushed simultaneously, and wherein the first and second compartments are flushed in parallel with the treated liquid.

9. The method of claim 1, further comprising flushing the second liquid circuit by actuating a first valve to direct treated water from the first liquid circuit to the second liquid circuit, and actuating a second valve to direct treated water from the second liquid circuit to the first liquid circuit, wherein the first and second compartments are flushed sequentially with the treated water.

10. The method of claim 1, further comprising establishing a fourth liquid circuit having liquid from the reservoir flowing therein from the reservoir to the first and second compartments.

11. The method of claim 10, wherein the liquid from the reservoir has a negative LSI.

12. The method of claim 1, further comprising delivering at least a portion of the treated liquid to a point of use.

13. The method of claim 12, further comprising post treating the treated liquid prior to delivering the treated liquid to the point of use.

14. The method of claim 1, further comprising disinfecting at least a portion of any component of any of the first liquid circuit, the second liquid circuit and the third liquid circuit.

15. A method of treating water from a reservoir, comprising:

passing at least a portion of water to be treated through a depleting compartment of an electrochemical device to produce treated water having an LSI of less than about 2;

circulating a concentrating stream through a concentrating compartment of the electrochemical device;

circulating at least a portion of the concentrating stream through the depleting compartment; and

flushing at least one of the depleting compartment and the concentrating compartment periodically with the treated water in response to a rate of demand or a time of demand to inhibit scale formation.

16. The method of claim 15, further comprising passing at least a portion of the water to be treated through a pump.

17. The method of claim 15, further comprising flushing the depleting compartment while flushing the concentrating compartment.

18. The method of claim 15, further comprising flushing the depleting and concentrating compartments with treated water sequentially.

19. The method of claim 15, further comprising passing the water from the reservoir through the depleting compartment after passing the water through the concentrating compartment.

20. The method of claim 15, further comprising:

applying an electric field through the electrochemical device; and

reversing a polarity of the applied electric field.