PROCESS FOR PRODUCING RECLAIMED WATER AND SYSTEM FOR PRODUCING RECLAIMED WATER

• US 20120031838A1
• Filed: 09/22/2011
• Published: 02/09/2012
• Est. Priority Date: 03/27/2009
• Status: Active Grant

• Current Assignee: Metawater Company Limited
• Original Assignee: Metawater Company Limited
• Inventors: NOGUCHI, Motoharu, KOZONO, Hideki, AOKI, Michiko
• Granted Patent: US 9,028,695 B2
• Time in Patent Office: Days
• US Class Current: 210/636
• CPC Class Codes: B01D 2321/168 Use of other chemical agents
• CPC Class Codes: B01D 65/02 Membrane cleaning or sterilisation ; Membrane regeneration
• CPC Class Codes: C02F 1/281 using inorganic sorbents
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration
• CPC Class Codes: C02F 1/5236 using inorganic agents
• CPC Class Codes: C02F 1/56 Macromolecular compounds
• CPC Class Codes: C02F 1/78 with ozone C02F1/4672 takes precedence
• CPC Class Codes: C02F 2103/20 from animal husbandry
• CPC Class Codes: C02F 2209/03 Pressure
• CPC Class Codes: C02F 2209/11 Turbidity
• CPC Class Codes: C02F 2303/16 Regeneration of sorbents, filters
• CPC Class Codes: C02F 9/00 Multistage treatment of water, waste water or sewage

Abstract

The process includes operation as follows: putting ozone generated by an ozone generator into raw water, in a normal mode, to subject the raw water to ozone treatment; injecting a flocculant into the raw water before or after the ozone treatment; filtering the raw water by a separation membrane after the ozone treatment and the injection of the flocculant; and intermittently setting cleaning mode to put a larger quantity of cleaning ozone than that in the normal mode into the raw water so as to intermittently increase the concentration of dissolved ozone, thereby cleaning the filtration membrane.

Claims

1. A process for producing reclaimed water, comprising the operations of:

in a normal mode, putting ozone generated by an ozone generator into raw water to subject the raw water to ozone treatment;

injecting a flocculant into the raw water before or after the ozone treatment;

filtering the raw water by a separation membrane after the ozone treatment and the injection of the flocculant; and

intermittently setting a cleaning mode to put a larger quantity of cleaning ozone than in the normal mode into the raw water so as to intermittently increase the concentration of a dissolved ozone, thereby cleaning the filtration membrane.

2. The process for producing reclaimed water according to claim 1, wherein a transmembrane pressure of a pressure difference between an upstream side and a downstream side of the separation membrane is measured, and in the case where an increasing speed of the transmembrane pressure exceeds a predetermined value, the cleaning ozone is put into the raw water thereby to intermittently increase the concentration of the dissolved ozone.

3. The process for producing reclaimed water according to claim 2, wherein the turbidity of the raw water is measured, and in the case where the turbidity exceeds a predetermined value, the cleaning mode is not set.

4. The process for producing reclaimed water according to claim 2, wherein the quantity of input ozone or ozone consumption in the normal mode is measured, and in the case where the quantity of the input ozone or the ozone consumption exceeds a predetermined value, the cleaning mode is not set.

9. The process for producing reclaimed water according to claim 3, wherein the quantity of input ozone or ozone consumption in the normal mode is measured, and in the case where the quantity of the input ozone or the ozone consumption exceeds a predetermined value, the cleaning mode is not set.

5. A system for producing reclaimed water, comprising:

an ozone processor with an ozone generator that generates ozone, and for to putting the ozone into raw water, in a normal mode, to carry out ozone treatment of the raw water, and for intermittently setting a cleaning mode to put a larger quantity of cleaning ozone than in the normal mode into the raw water so as to intermittently increase the concentration of dissolved ozone;

a flocculant injection unit for injecting a flocculant into the raw water before or after the ozone treatment; and

a membrane filtration unit located at the downstream of the ozone processor and the flocculant injection unit, and for carrying out membrane filtration of the raw water by a separation membrane.

6. The system for producing reclaimed water according to claim 5, further comprising a transmembrane pressure measuring unit for measuring a transmembrane pressure of a pressure difference between an upstream side and a downstream side of the separation membrane, wherein the cleaning mode is set in the case where an increasing speed of the transmembrane pressure measured by the transmembrane pressure measuring unit exceeds a predetermined value, and the cleaning ozone is put into the raw water to intermittently increase the concentration of dissolved ozone.

7. The system for producing reclaimed water according to claim 6, further comprising a turbidity measuring unit for measuring the turbidity of the raw water, wherein the cleaning mode is not set in the case where the turbidity measured by the turbidity measuring unit exceeds a predetermined value.

8. The system for producing reclaimed water according to claim 6, wherein the cleaning mode is not set in the case where the quantity of the input ozone or the ozone consumption in the normal mode exceeds a predetermined value.

10. The system for producing reclaimed water according to claim 7, wherein the cleaning mode is not set in the case where the quantity of the input ozone or the ozone consumption in the normal mode exceeds a predetermined value.